Logo link to homepage

Bulletin of the Global Volcanism Network

All reports of volcanic activity published by the Smithsonian since 1968 are available through a monthly table of contents or by searching for a specific volcano. Until 1975, reports were issued for individual volcanoes as information became available; these have been organized by month for convenience. Later publications were done in a monthly newsletter format. Links go to the profile page for each volcano with the Bulletin tab open.

Information is preliminary at time of publication and subject to change.

Recently Published Bulletin Reports

Ibu (Indonesia) Daily ash explosions continue, along with thermal anomalies in the crater, October 2022-May 2023

Dukono (Indonesia) Continuing ash emissions, SO2 plumes, and thermal signals during October 2022-May 2023

Sabancaya (Peru) Explosions, gas-and-ash plumes, and thermal activity persist during November 2022-April 2023

Sheveluch (Russia) Significant explosions destroyed part of the lava-dome complex during April 2023

Bezymianny (Russia) Explosions, ash plumes, lava flows, and avalanches during November 2022-April 2023

Chikurachki (Russia) New explosive eruption during late January-early February 2023

Marapi (Indonesia) New explosive eruption with ash emissions during January-March 2023

Kikai (Japan) Intermittent white gas-and-steam plumes, discolored water, and seismicity during May 2021-April 2023

Lewotolok (Indonesia) Strombolian eruption continues through April 2023 with intermittent ash plumes

Barren Island (India) Thermal activity during December 2022-March 2023

Villarrica (Chile) Nighttime crater incandescence, ash emissions, and seismicity during October 2022-March 2023

Fuego (Guatemala) Daily explosions, gas-and-ash plumes, avalanches, and ashfall during December 2022-March 2023



Ibu (Indonesia) — June 2023 Citation iconCite this Report

Ibu

Indonesia

1.488°N, 127.63°E; summit elev. 1325 m

All times are local (unless otherwise noted)


Daily ash explosions continue, along with thermal anomalies in the crater, October 2022-May 2023

Persistent eruptive activity since April 2008 at Ibu, a stratovolcano on Indonesian’s Halmahera Island, has consisted of daily explosive ash emissions and plumes, along with observations of thermal anomalies (BGVN 47:04). The current eruption continued during October 2022-May 2023, described below, based on advisories issued by the Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as Indonesian Center for Volcanology and Geological Hazard Mitigation, CVGHM), daily reports by MAGMA Indonesia (a PVMBG platform), and the Darwin Volcanic Ash Advisory Centre (VAAC), and various satellite data. The Alert Level during the reporting period remained at 2 (on a scale of 1-4), except raised briefly to 3 on 27 May, and the public was warned to stay at least 2 km away from the active crater and 3.5 km away on the N side of the volcano.

According to MAGMA Indonesia, during October 2022-May 2023, daily gray-and-white ash plumes of variable densities rose 200-1,000 m above the summit and drifted in multiple directions. On 30 October and 11 November, plumes rose a maximum of 2 km and 1.5 km above the summit, respectively (figures 42 and 43). According to the Darwin VAAC, discrete ash emissions on 13 November rose to 2.1 km altitude, or 800 m above the summit, and drifted W, and multiple ash emissions on 15 November rose 1.4 km above the summit and drifted NE. Occasional larger ash explosions through May 2023 prompted PVMBG to issue Volcano Observatory Notice for Aviation (VONA) alerts (table 6); the Aviation Color Code remained at Orange throughout this period.

Figure (see Caption) Figure 42. Larger explosion from Ibu’s summit crater on 30 October 2022 that generated a plume that rose 2 km above the summit. Photo has been color corrected. Courtesy of MAGMA Indonesia.
Figure (see Caption) Figure 43. Larger explosion from Ibu’s summit crater on 11 November 2022 that generated a plume that rose 1.5 km above the summit. Courtesy of MAGMA Indonesia.

Table 6. Volcano Observatory Notice for Aviation (VONA) ash plume alerts for Ibu issued by PVMBG during October 2022-May 2023. Maximum height above the summit was estimated by a ground observer. VONAs in January-May 2023 all described the ash plumes as dense.

Date Time (local) Max height above summit Direction
17 Oct 2022 0858 800 m SW
18 Oct 2022 1425 800 m S
19 Oct 2022 2017 600 m SW
21 Oct 2022 0916 800 m NW
16 Jan 2023 1959 600 m NE
22 Jan 2023 0942 1,000 m E
29 Jan 2023 2138 1,000 m E
10 May 2023 0940 800 m NW
10 May 2023 2035 600 m E
21 May 2023 2021 600 m W
21 May 2023 2140 1,000 m W
29 May 2023 1342 800 m N
31 May 2023 1011 1,000 m SW

Sentinel-2 L1C satellite images throughout the reporting period show two, sometimes three persistent thermal anomalies in the summit crater, with the most prominent hotspot from the top of a cone within the crater. Clear views were more common during March-April 2023, when a vent and lava flows on the NE flank of the intra-crater cone could be distinguished (figure 44). White-to-grayish emissions were also observed during brief periods when weather clouds allowed clear views.

Figure (see Caption) Figure 44. Sentinel-2 L2A satellite images of Ibu on 10 April 2023. The central cone within the summit crater (1.3 km diameter) and lava flows (gray) can be seen in the true color image (left, bands 4, 3, 2). Thermal anomalies from the small crater of the intra-crater cone, a NE-flank vent, and the end of the lava flow are apparent in the infrared image (right, bands 12, 11, 8A). Courtesy of Copernicus Browser.

The MIROVA space-based volcano hotspot detection system recorded almost daily thermal anomalies throughout the reporting period, though cloud cover often interfered with detections. Data from imaging spectroradiometers aboard NASA’s Aqua and Terra satellites and processed using the MODVOLC algorithm (MODIS-MODVOLC) recorded hotspots on one day during October 2022 and December 2022, two days in April 2023, three days in November 2022 and May 2023, and four days in March 2023.

Geologic Background. The truncated summit of Gunung Ibu stratovolcano along the NW coast of Halmahera Island has large nested summit craters. The inner crater, 1 km wide and 400 m deep, has contained several small crater lakes. The 1.2-km-wide outer crater is breached on the N, creating a steep-walled valley. A large cone grew ENE of the summit, and a smaller one to the WSW has fed a lava flow down the W flank. A group of maars is located below the N and W flanks. The first observed and recorded eruption was a small explosion from the summit crater in 1911. Eruptive activity began again in December 1998, producing a lava dome that eventually covered much of the floor of the inner summit crater along with ongoing explosive ash emissions.

Information Contacts: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as Indonesian Center for Volcanology and Geological Hazard Mitigation, CVGHM), Jalan Diponegoro 57, Bandung 40122, Indonesia (URL: http://www.vsi.esdm.go.id/); MAGMA Indonesia (Multiplatform Application for Geohazard Mitigation and Assessment in Indonesia), Kementerian Energi dan Sumber Daya Mineral (URL: https://magma.esdm.go.id/v1); Copernicus Browser, Copernicus Data Space Ecosystem, European Space Agency (URL: https://dataspace.copernicus.eu/browser/); MIROVA (Middle InfraRed Observation of Volcanic Activity), a collaborative project between the Universities of Turin and Florence (Italy) supported by the Centre for Volcanic Risk of the Italian Civil Protection Department (URL: http://www.mirovaweb.it/); Hawai'i Institute of Geophysics and Planetology (HIGP) - MODVOLC Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/).


Dukono (Indonesia) — June 2023 Citation iconCite this Report

Dukono

Indonesia

1.6992°N, 127.8783°E; summit elev. 1273 m

All times are local (unless otherwise noted)


Continuing ash emissions, SO2 plumes, and thermal signals during October 2022-May 2023

Dukono, a remote volcano on Indonesia’s Halmahera Island, has been erupting continuously since 1933, with frequent ash explosions and sulfur dioxide plumes (BGVN 46:11, 47:10). This activity continued during October 2022 through May 2023, based on reports from the Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG; also known as Indonesian Center for Volcanology and Geological Hazard Mitigation, CVGHM), the Darwin Volcanic Ash Advisory Centre (VAAC), and satellite data. During this period, the Alert Level remained at 2 (on a scale of 1-4) and the public was warned to remain outside of the 2-km exclusion zone. The highest reported plume of the period reached 9.4 km above the summit on 14 November 2022.

According to MAGMA Indonesia (a platform developed by PVMBG), white, gray, or dark plumes of variable densities were observed almost every day during the reporting period, except when fog obscured the volcano (figure 33). Plumes generally rose 25-450 m above the summit, but rose as high as 700-800 m on several days, somewhat lower than the maximum heights reached earlier in 2022 when plumes reached as high as 1 km. However, the Darwin VAAC reported that on 14 November 2022, a discrete ash plume rose 9.4 km above the summit (10.7 km altitude), accompanied by a strong hotspot and a sulfur dioxide signal observed in satellite imagery; a continuous ash plume that day and through the 15th rose to 2.1-2.4 km altitude and drifted NE.

Figure (see Caption) Figure 33. Webcam photo of a gas-and-steam plume rising from Dukono on the morning of 28 January 2023. Courtesy of MAGMA Indonesia.

Sentinel-2 images were obscured by weather clouds almost every viewing day during the reporting period. However, the few reasonably clear images showed a hotspot and white or gray emissions and plumes. Strong SO2 plumes from Dukono were present on many days during October 2022-May 2023, as detected using the TROPOMI instrument on the Sentinel-5P satellite (figure 34).

Figure (see Caption) Figure 34. A strong SO2 signal from Dukono on 23 April 2023 was the most extensive plume detected during the reporting period. Courtesy of the NASA Global Sulfur Dioxide Monitoring Page.

Geologic Background. Reports from this remote volcano in northernmost Halmahera are rare, but Dukono has been one of Indonesia's most active volcanoes. More-or-less continuous explosive eruptions, sometimes accompanied by lava flows, have occurred since 1933. During a major eruption in 1550 CE, a lava flow filled in the strait between Halmahera and the N-flank Gunung Mamuya cone. This complex volcano presents a broad, low profile with multiple summit peaks and overlapping craters. Malupang Wariang, 1 km SW of the summit crater complex, contains a 700 x 570 m crater that has also been active during historical time.

Information Contacts: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as Indonesian Center for Volcanology and Geological Hazard Mitigation, CVGHM), Jalan Diponegoro 57, Bandung 40122, Indonesia (URL: http://www.vsi.esdm.go.id/); MAGMA Indonesia (Multiplatform Application for Geohazard Mitigation and Assessment in Indonesia), Kementerian Energi dan Sumber Daya Mineral (URL: https://magma.esdm.go.id/v1); Darwin Volcanic Ash Advisory Centre (VAAC), Bureau of Meteorology, Northern Territory Regional Office, PO Box 40050, Casuarina, NT 0811, Australia (URL: http://www.bom.gov.au/info/vaac/); NASA Global Sulfur Dioxide Monitoring Page, Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center (NASA/GSFC), 8800 Greenbelt Road, Goddard, Maryland, USA (URL: https://so2.gsfc.nasa.gov/); Sentinel Hub Playground (URL: https://www.sentinel-hub.com/explore/sentinel-playground).


Sabancaya (Peru) — May 2023 Citation iconCite this Report

Sabancaya

Peru

15.787°S, 71.857°W; summit elev. 5960 m

All times are local (unless otherwise noted)


Explosions, gas-and-ash plumes, and thermal activity persist during November 2022-April 2023

Sabancaya is located in Peru, NE of Ampato and SE of Hualca Hualca. Eruptions date back to 1750 and have been characterized by explosions, phreatic activity, ash plumes, and ashfall. The current eruption period began in November 2016 and has more recently consisted of daily explosions, gas-and-ash plumes, and thermal activity (BGVN 47:11). This report updates activity during November 2022 through April 2023 using information from Instituto Geophysico del Peru (IGP) that use weekly activity reports and various satellite data.

Intermittent low-to-moderate power thermal anomalies were reported by the MIROVA project during November 2022 through April 2023 (figure 119). There were few short gaps in thermal activity during mid-December 2022, late December-to-early January 2023, late January to mid-February, and late February. According to data recorded by the MODVOLC thermal algorithm, there were a total of eight thermal hotspots: three in November 2022, three in February 2023, one in March, and one in April. On clear weather days, some of this thermal anomaly was visible in infrared satellite imagery showing the active lava dome in the summit crater (figure 120). Almost daily moderate-to-strong sulfur dioxide plumes were recorded during the reporting period by the TROPOMI instrument on the Sentinel-5P satellite (figure 121). Many of these plumes exceeded 2 Dobson Units (DU) and drifted in multiple directions.

Figure (see Caption) Figure 119. Intermittent low-to-moderate thermal anomalies were detected during November 2022 through April 2023 at Sabancaya, as shown in this MIROVA graph (Log Radiative Power). There were brief gaps in thermal activity during mid-December 2022, late December-to-early January 2023, late January to mid-February, and late February. Courtesy of MIROVA.
Figure (see Caption) Figure 120. Infrared (bands 12, 11, 8A) satellite images showed a constant thermal anomaly in the summit crater of Sabancaya on 14 January 2023 (top left), 28 February 2023 (top right), 5 March 2023 (bottom left), and 19 April 2023 (bottom right), represented by the active lava dome. Sometimes gas-and-steam and ash emissions also accompanied this activity. Courtesy of Copernicus Browser.
Figure (see Caption) Figure 121. Moderate-to-strong sulfur dioxide plumes were detected almost every day, rising from Sabancaya by the TROPOMI instrument on the Sentinel-5P satellite throughout the reporting period; the DU (Dobson Unit) density values were often greater than 2. Plumes from 23 November 2022 (top left), 26 December 2022 (top middle), 10 January 2023 (top right), 15 February 2023 (bottom left), 13 March 2023 (bottom middle), and 21 April 2023 (bottom right) that drifted SW, SW, W, SE, W, and SW, respectively. Courtesy of NASA Global Sulfur Dioxide Monitoring Page.

IGP reported that moderate activity during November and December 2022 continued; during November, an average number of explosions were reported each week: 30, 33, 36, and 35, and during December, it was 32, 40, 47, 52, and 67. Gas-and-ash plumes in November rose 3-3.5 km above the summit and drifted E, NE, SE, S, N, W, and SW. During December the gas-and-ash plumes rose 2-4 km above the summit and drifted in different directions. There were 1,259 volcanic earthquakes recorded during November and 1,693 during December. Seismicity also included volcano-tectonic-type events that indicate rock fracturing events. Slight inflation was observed in the N part of the volcano near Hualca Hualca (4 km N). Thermal activity was frequently reported in the crater at the active lava dome (figure 120).

Explosive activity continued during January and February 2023. The average number of explosions were reported each week during January (51, 50, 60, and 59) and February (43, 54, 51, and 50). Gas-and-ash plumes rose 1.6-2.9 km above the summit and drifted NW, SW, and W during January and rose 1.4-2.8 above the summit and drifted W, SW, E, SE, N, S, NW, and NE during February. IGP also detected 1,881 volcanic earthquakes during January and 1,661 during February. VT-type earthquakes were also reported. Minor inflation persisted near Hualca Hualca. Satellite imagery showed continuous thermal activity in the crater at the lava dome (figure 120).

During March, the average number of explosions each week was 46, 48, 31, 35, and 22 and during April, it was 29, 41, 31, and 27. Accompanying gas-and-ash plumes rose 1.7-2.6 km above the summit crater and drifted W, SW, NW, S, and SE during March. According to a Buenos Aires Volcano Ash Advisory Center (VAAC) notice, on 22 March at 1800 through 23 March an ash plume rose to 7 km altitude and drifted NW. By 0430 an ash plume rose to 7.6 km altitude and drifted W. On 24 and 26 March continuous ash emissions rose to 7.3 km altitude and drifted SW and on 28 March ash emissions rose to 7.6 km altitude. During April, gas-and-ash plumes rose 1.6-2.5 km above the summit and drifted W, SW, S, NW, NE, and E. Frequent volcanic earthquakes were recorded, with 1,828 in March and 1,077 in April, in addition to VT-type events. Thermal activity continued to be reported in the summit crater at the lava dome (figure 120).

Geologic Background. Sabancaya, located in the saddle NE of Ampato and SE of Hualca Hualca volcanoes, is the youngest of these volcanic centers and the only one to have erupted in historical time. The oldest of the three, Nevado Hualca Hualca, is of probable late-Pliocene to early Pleistocene age. The name Sabancaya (meaning "tongue of fire" in the Quechua language) first appeared in records in 1595 CE, suggesting activity prior to that date. Holocene activity has consisted of Plinian eruptions followed by emission of voluminous andesitic and dacitic lava flows, which form an extensive apron around the volcano on all sides but the south. Records of historical eruptions date back to 1750.

Information Contacts: Instituto Geofisico del Peru (IGP), Centro Vulcanológico Nacional (CENVUL), Calle Badajoz N° 169 Urb. Mayorazgo IV Etapa, Ate, Lima 15012, Perú (URL: https://www.igp.gob.pe/servicios/centro-vulcanologico-nacional/inicio); Buenos Aires Volcanic Ash Advisory Center (VAAC), Servicio Meteorológico Nacional-Fuerza Aérea Argentina, 25 de mayo 658, Buenos Aires, Argentina (URL: http://www.smn.gov.ar/vaac/buenosaires/inicio.php); MIROVA (Middle InfraRed Observation of Volcanic Activity), a collaborative project between the Universities of Turin and Florence (Italy) supported by the Centre for Volcanic Risk of the Italian Civil Protection Department (URL: http://www.mirovaweb.it/); Hawai'i Institute of Geophysics and Planetology (HIGP) - MODVOLC Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/); NASA Global Sulfur Dioxide Monitoring Page, Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center (NASA/GSFC), 8800 Greenbelt Road, Goddard MD 20771, USA (URL: https://so2.gsfc.nasa.gov/); Copernicus Browser, Copernicus Data Space Ecosystem, European Space Agency (URL: https://dataspace.copernicus.eu/browser/).


Sheveluch (Russia) — May 2023 Citation iconCite this Report

Sheveluch

Russia

56.653°N, 161.36°E; summit elev. 3283 m

All times are local (unless otherwise noted)


Significant explosions destroyed part of the lava-dome complex during April 2023

Sheveluch (also spelled Shiveluch) in Kamchatka, has had at least 60 large eruptions during the last 10,000 years. The summit is truncated by a broad 9-km-wide caldera that is breached to the S, and many lava domes occur on the outer flanks. The lava dome complex was constructed within the large open caldera. Frequent collapses of the dome complex have produced debris avalanches; the resulting deposits cover much of the caldera floor. A major south-flank collapse during a 1964 Plinian explosion produced a scarp in which a “Young Sheveluch” dome began to form in 1980. Repeated episodes of dome formation and destruction since then have produced major and minor ash plumes, pyroclastic flows, block-and-ash flows, and “whaleback domes” of spine-like extrusions in 1993 and 2020 (BGVN 45:11). The current eruption period began in August 1999 and has more recently consisted of lava dome growth, explosions, ash plumes, and avalanches (BGVN 48:01). This report covers a significant explosive eruption during early-to-mid-April 2023 that generated a 20 km altitude ash plume, produced a strong sulfur dioxide plume, and destroyed part of the lava-dome complex; activity described during January through April 2023 use information primarily from the Kamchatka Volcanic Eruptions Response Team (KVERT) and various satellite data.

Satellite data. Activity during the majority of this reporting period was characterized by continued lava dome growth, strong fumarole activity, explosions, and hot avalanches. According to the MODVOLC Thermal Alerts System, 140 hotspots were detected through the reporting period, with 33 recorded in January 2023, 29 in February, 44 in March, and 34 in April. Frequent strong thermal activity was recorded during January 2023 through April, according to the MIROVA (Middle InfraRed Observation of Volcanic Activity) graph and resulted from the continuously growing lava dome (figure 94). A slightly stronger pulse in thermal activity was detected in early-to-mid-April, which represented the significant eruption that destroyed part of the lava-dome complex. Thermal anomalies were also visible in infrared satellite imagery at the summit crater (figure 95).

Figure (see Caption) Figure 94. Strong and frequent thermal activity was detected at Sheveluch during January through April 2023, according to this MIROVA graph (Log Radiative Power). These thermal anomalies represented the continuously growing lava dome and frequent hot avalanches that affected the flanks. During early-to-mid-April a slightly stronger pulse represented the notable explosive eruption. Courtesy of MIROVA.
Figure (see Caption) Figure 95. Infrared (bands B12, B11, B4) satellite imagery showed persistent thermal anomalies at the lava dome of Sheveluch on 14 January 2023 (top left), 26 February 2023 (top right), and 15 March 2023 (bottom left). The true color image on 12 April 2023 (bottom right) showed a strong ash plume that drifted SW; this activity was a result of the strong explosive eruption during 11-12 April 2023. Courtesy of Copernicus Browser.

During January 2023 KVERT reported continued growth of the lava dome, accompanied by strong fumarolic activity, incandescence from the lava dome, explosions, ash plumes, and avalanches. Satellite data showed a daily thermal anomaly over the volcano. Video data showed ash plumes associated with collapses at the dome that generated avalanches that in turn produced ash plumes rising to 3.5 km altitude and drifting 40 km W on 4 January and rising to 7-7.5 km altitude and drifting 15 km SW on 5 January. A gas-and-steam plume containing some ash that was associated with avalanches rose to 5-6 km altitude and extended 52-92 km W on 7 January. Explosions that same day produced ash plumes that rose to 7-7.5 km altitude and drifted 10 km W. According to a Volcano Observatory Notice for Aviation (VONA) issued at 1344 on 19 January, explosions produced an ash cloud that was 15 x 25 km in size and rose to 9.6-10 km altitude, drifting 21-25 km W; as a result, the Aviation Color Code (ACC) was raised to Red (the highest level on a four-color scale). Another VONA issued at 1635 reported that no more ash plumes were observed, and the ACC was lowered to Orange (the second highest level on a four-color scale). On 22 January an ash plume from collapses and avalanches rose to 5 km altitude and drifted 25 km NE and SW; ash plumes associated with collapses extended 70 km NE on 27 and 31 January.

Lava dome growth, fumarolic activity, dome incandescence, and occasional explosions and avalanches continued during February and March. A daily thermal anomaly was visible in satellite data. Explosions on 1 February generated ash plumes that rose to 6.3-6.5 km altitude and extended 15 km NE. Video data showed an ash cloud from avalanches rising to 5.5 km altitude and drifting 5 km SE on 2 February. Satellite data showed gas-and-steam plumes containing some ash rose to 5-5.5 km altitude and drifted 68-110 km ENE and NE on 6 February, to 4.5-5 km altitude and drifted 35 km WNW on 22 February, and to 3.7-4 km altitude and drifted 47 km NE on 28 February. Scientists from the Kamchatka Volcanological Station (KVS) went on a field excursion on 25 February to document the growing lava dome, and although it was cloudy most of the day, nighttime incandescence was visible. Satellite data showed an ash plume extending up to 118 km E during 4-5 March. Video data from 1150 showed an ash cloud from avalanches rose to 3.7-5.5 km altitude and drifted 5-10 km ENE and E on 5 March. On 11 March an ash plume drifted 62 km E. On 27 March ash plumes rose to 3.5 km altitude and drifted 100 km E. Avalanches and constant incandescence at the lava dome was focused on the E and NE slopes on 28 March. A gas-and-steam plume containing some ash rose to 3.5 km altitude and moved 40 km E on 29 March. Ash plumes on 30 March rose to 3.5-3.7 km altitude and drifted 70 km NE.

Similar activity continued during April, with lava dome growth, strong fumarolic activity, incandescence in the dome, occasional explosions, and avalanches. A thermal anomaly persisted throughout the month. During 1-4 April weak ash plumes rose to 2.5-3 km altitude and extended 13-65 km SE and E.

Activity during 11 April 2023. The Institute of Volcanology and Seismology, Far Eastern Branch, Russian Academy of Sciences (IVS FEB RAS) reported a significant increase in seismicity around 0054 on 11 April, as reported by strong explosions detected on 11 April beginning at 0110 that sent ash plumes up to 7-10 km altitude and extended 100-435 km W, WNW, NNW, WSW, and SW. According to a Tokyo VAAC report the ash plume rose to 15.8 km altitude. By 0158 the plume extended over a 75 x 100 km area. According to an IVS FEB RAS report, the eruptive column was not vertical: the initial plume at 0120 on 11 April deviated to the NNE, at 0000 on 12 April, it drifted NW, and by 1900 it drifted SW. KVS reported that significant pulses of activity occurred at around 0200, 0320, and then a stronger phase around 0600. Levin Dmitry took a video from near Békés (3 km away) at around 0600 showing a rising plume; he also reported that a pyroclastic flow traveled across the road behind him as he left the area. According to IVS FEB RAS, the pyroclastic flow traveled several kilometers SSE, stopping a few hundred meters from a bridge on the road between Klyuchi and Petropavlovsk-Kamchatsky.

Ashfall was first observed in Klyuchi (45 km SW) at 0630, and a large, black ash plume blocked light by 0700. At 0729 KVERT issued a Volcano Observatory Notice for Aviation (VONA) raising the Aviation Color Code to Red (the highest level on a four-color scale). It also stated that a large ash plume had risen to 10 km altitude and drifted 100 km W. Near-constant lightning strikes were reported in the plume and sounds like thunderclaps were heard until about 1000. According to IVS FEB RAS the cloud was 200 km long and 76 km wide by 0830, and was spreading W at altitudes of 6-12 km. In the Klyuchi Village, the layer of both ash and snow reached 8.5 cm (figure 96); ashfall was also reported in Kozyrevsk (112 km SW) at 0930, Mayskoye, Anavgay, Atlasovo, Lazo, and Esso. Residents in Klyuchi reported continued darkness and ashfall at 1100. In some areas, ashfall was 6 cm deep and some residents reported dirty water coming from their plumbing. According to IVS FEB RAS, an ash cloud at 1150 rose to 5-20 km altitude and was 400 km long and 250 km wide, extending W. A VONA issued at 1155 reported that ash had risen to 10 km and drifted 340 km NNW and 240 km WSW. According to Simon Carn (Michigan Technological University), about 0.2 Tg of sulfur dioxide in the plume was measured in a satellite image from the TROPOMI instrument on the Sentinel-5P satellite acquired at 1343 that covered an area of about 189,000 km2 (figure 97). Satellite data at 1748 showed an ash plume that rose to 8 km altitude and drifted 430 km WSW and S, according to a VONA.

Figure (see Caption) Figure 96. Photo of ash deposited in Klyuchi village on 11 April 2023 by the eruption of Sheveluch. About 8.5 cm of ash was measured. Courtesy of Kam 24 News Agency.
Figure (see Caption) Figure 97. A strong sulfur dioxide plume from the 11 April 2023 eruption at Sheveluch was visible in satellite data from the TROPOMI instrument on the Sentinel-5P satellite. Courtesy of Simon Carn, MTU.

Activity during 12-15 April 2023. On 12 April at 0730 satellite images showed ash plumes rose to 7-8 km altitude and extended 600 km SW, 1,050 km ESE, and 1,300-3,000 km E. By 1710 that day, the explosions weakened. According to news sources, the ash-and-gas plumes drifted E toward the Aleutian Islands and reached the Gulf of Alaska by 13 April, causing flight disruptions. More than 100 flights involving Alaska airspace were cancelled due to the plume. Satellite data showed ash plumes rising to 4-5.5 km altitude and drifted 400-415 km SE and ESE on 13 April. KVS volcanologists observed the pyroclastic flow deposits and noted that steam rose from downed, smoldering trees. They also noted that the deposits were thin with very few large fragments, which differed from previous flows. The ash clouds traveled across the Pacific Ocean. Flight cancellations were also reported in NW Canada (British Columbia) during 13-14 April. During 14-15 April ash plumes rose to 6 km altitude and drifted 700 km NW.

Alaskan flight schedules were mostly back to normal by 15 April, with only minor delays and far less cancellations; a few cancellations continued to be reported in Canada. Clear weather on 15 April showed that most of the previous lava-dome complex was gone and a new crater roughly 1 km in diameter was observed (figure 98); gas-and-steam emissions were rising from this crater. Evidence suggested that there had been a directed blast to the SE, and pyroclastic flows traveled more than 20 km. An ash plume rose to 4.5-5.2 km altitude and drifted 93-870 km NW on 15 April.

Figure (see Caption) Figure 98. A comparison of the crater at Sheveluch showing the previous lava dome (top) taken on 29 November 2022 and a large crater in place of the dome (bottom) due to strong explosions during 10-13 April 2023, accompanied by gas-and-ash plumes. The bottom photo was taken on 15 April 2023. Photos has been color corrected. Both photos are courtesy of Yu. Demyanchuk, IVS FEB RAS, KVERT.

Activity during 16-30 April 2023. Resuspended ash was lifted by the wind from the slopes and rose to 4 km altitude and drifted 224 km NW on 17 April. KVERT reported a plume of resuspended ash from the activity during 10-13 April on 19 April that rose to 3.5-4 km altitude and drifted 146-204 km WNW. During 21-22 April a plume stretched over the Scandinavian Peninsula. A gas-and-steam plume containing some ash rose to 3-3.5 km altitude and drifted 60 km SE on 30 April. A possible new lava dome was visible on the W slope of the volcano on 29-30 April (figure 99); satellite data showed two thermal anomalies, a bright one over the existing lava dome and a weaker one over the possible new one.

Figure (see Caption) Figure 99. Photo showing new lava dome growth at Sheveluch after a previous explosion destroyed much of the complex, accompanied by a white gas-and-steam plume. Photo has been color corrected. Courtesy of Yu. Demyanchuk, IVS FEB RAS, KVERT.

References. Girina, O., Loupian, E., Horvath, A., Melnikov, D., Manevich, A., Nuzhdaev, A., Bril, A., Ozerov, A., Kramareva, L., Sorokin, A., 2023, Analysis of the development of the paroxysmal eruption of Sheveluch volcano on April 10–13, 2023, based on data from various satellite systems, ??????????? ???????? ??? ?? ???????, 20(2).

Geologic Background. The high, isolated massif of Sheveluch volcano (also spelled Shiveluch) rises above the lowlands NNE of the Kliuchevskaya volcano group. The 1,300 km3 andesitic volcano is one of Kamchatka's largest and most active volcanic structures, with at least 60 large eruptions during the Holocene. The summit of roughly 65,000-year-old Stary Shiveluch is truncated by a broad 9-km-wide late-Pleistocene caldera breached to the south. Many lava domes occur on its outer flanks. The Molodoy Shiveluch lava dome complex was constructed during the Holocene within the large open caldera; Holocene lava dome extrusion also took place on the flanks of Stary Shiveluch. Widespread tephra layers from these eruptions have provided valuable time markers for dating volcanic events in Kamchatka. Frequent collapses of dome complexes, most recently in 1964, have produced debris avalanches whose deposits cover much of the floor of the breached caldera.

Information Contacts: Kamchatka Volcanic Eruptions Response Team (KVERT), Far Eastern Branch, Russian Academy of Sciences, 9 Piip Blvd., Petropavlovsk-Kamchatsky, 683006, Russia (URL: http://www.kscnet.ru/ivs/kvert/); Institute of Volcanology and Seismology, Far Eastern Branch, Russian Academy of Sciences (IVS FEB RAS), 9 Piip Blvd., Petropavlovsk-Kamchatsky 683006, Russia (URL: http://www.kscnet.ru/ivs/eng/); Kamchatka Volcanological Station, Kamchatka Branch of Geophysical Survey, (KB GS RAS), Klyuchi, Kamchatka Krai, Russia (URL: http://volkstat.ru/); Hawai'i Institute of Geophysics and Planetology (HIGP) - MODVOLC Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/); MIROVA (Middle InfraRed Observation of Volcanic Activity), a collaborative project between the Universities of Turin and Florence (Italy) supported by the Centre for Volcanic Risk of the Italian Civil Protection Department (URL: http://www.mirovaweb.it/); Copernicus Browser, Copernicus Data Space Ecosystem, European Space Agency (URL: https://dataspace.copernicus.eu/browser/); Kam 24 News Agency, 683032, Kamchatka Territory, Petropavlovsk-Kamchatsky, Vysotnaya St., 2A (URL: https://kam24.ru/news/main/20230411/96657.html#.Cj5Jrky6.dpuf); Simon Carn, Geological and Mining Engineering and Sciences, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931, USA (URL: http://www.volcarno.com/, Twitter: @simoncarn).


Bezymianny (Russia) — May 2023 Citation iconCite this Report

Bezymianny

Russia

55.972°N, 160.595°E; summit elev. 2882 m

All times are local (unless otherwise noted)


Explosions, ash plumes, lava flows, and avalanches during November 2022-April 2023

Bezymianny is located on the Kamchatka Peninsula of Russia as part of the Klyuchevskoy volcano group. Historic eruptions began in 1955 and have been characterized by dome growth, explosions, pyroclastic flows, ash plumes, and ashfall. During the 1955-56 eruption a large open crater was formed by collapse of the summit and an associated lateral blast. Subsequent episodic but ongoing lava-dome growth, accompanied by intermittent explosive activity and pyroclastic flows, has largely filled the 1956 crater. The current eruption period began in December 2016 and more recent activity has consisted of strong explosions, ash plumes, and thermal activity (BGVN 47:11). This report covers activity during November 2022 through April 2023, based on weekly and daily reports from the Kamchatka Volcano Eruptions Response Team (KVERT) and satellite data.

Activity during November and March 2023 was relatively low and mostly consisted of gas-and-steam emissions, occasional small collapses that generated avalanches along the lava dome slopes, and a persistent thermal anomaly over the volcano that was observed in satellite data on clear weather days. According to the Tokyo VAAC and KVERT, an explosion produced an ash plume that rose to 6 km altitude and drifted 25 km NE at 1825 on 29 March.

Gas-and-steam emissions, collapses generating avalanches, and thermal activity continued during April. According to two Volcano Observatory Notice for Aviation (VONA) issued on 2 and 6 April (local time) ash plumes rose to 3 km and 3.5-3.8 km altitude and drifted 35 km E and 140 km E, respectively. Satellite data from KVERT showed weak ash plumes extending up to 550 km E on 2 and 5-6 April.

A VONA issued at 0843 on 7 April described an ash plume that rose to 4.5-5 km altitude and drifted 250 km ESE. Later that day at 1326 satellite data showed an ash plume that rose to 5.5-6 km altitude and drifted 150 km ESE. A satellite image from 1600 showed an ash plume extending as far as 230 km ESE; KVERT noted that ash emissions were intensifying, likely due to avalanches from the growing lava dome. The Aviation Color Code (ACC) was raised to Red (the highest level on a four-color scale). At 1520 satellite data showed an ash plume rising to 5-5.5 km altitude and drifting 230 km ESE. That same day, Kamchatka Volcanological Station (KVS) volcanologists traveled to Ambon to collect ash; they reported that a notable eruption began at 1730, and within 20 minutes a large ash plume rose to 10 km altitude and drifted NW. KVERT reported that the strong explosive phase began at 1738. Video and satellite data taken at 1738 showed an ash plume that rose to 10-12 km altitude and drifted up to 2,800 km SE and E. Explosions were clearly audible 20 km away for 90 minutes, according to KVS. Significant amounts of ash fell at the Apakhonchich station, which turned the snow gray; ash continued to fall until the morning of 8 April. In a VONA issued at 0906 on 8 April, KVERT stated that the explosive eruption had ended; ash plumes had drifted 2,000 km E. The ACC was lowered to Orange (the third highest level on a four-color scale). The KVS team saw a lava flow on the active dome once the conditions were clear that same day (figure 53). On 20 April lava dome extrusion was reported; lava flows were noted on the flanks of the dome, and according to KVERT satellite data, a thermal anomaly was observed in the area. The ACC was lowered to Yellow (the second lowest on a four-color scale).

Figure (see Caption) Figure 53. Photo showing an active lava flow descending the SE flank of Bezymianny from the lava dome on 8 April 2023. Courtesy of Yu. Demyanchuk, IVS FEB RAS, KVERT.

Satellite data showed an increase in thermal activity beginning in early April 2023. A total of 31 thermal hotspots were detected by the MODVOLC thermal algorithm on 4, 5, 7, and 12 April 2023. The elevated thermal activity resulted from an increase in explosive activity and the start of an active lava flow. The MIROVA (Middle InfraRed Observation of Volcanic Activity) volcano hotspot detection system based on the analysis of MODIS data also showed a pulse in thermal activity during the same time (figure 54). Infrared satellite imagery captured a continuous thermal anomaly at the summit crater, often accompanied by white gas-and-steam emissions (figure 55). On 4 April 2023 an active lava flow was observed descending the SE flank.

Figure (see Caption) Figure 54. Intermittent and low-power thermal anomalies were detected at Bezymianny during December 2022 through mid-March 2023, according to this MIROVA graph (Log Radiative Power). In early April 2023, an increase in explosive activity and eruption of a lava flow resulted in a marked increase in thermal activity. Courtesy of MIROVA.
Figure (see Caption) Figure 55. Infrared satellite images of Bezymianny showed a persistent thermal anomaly over the lava dome on 18 November 2022 (top left), 28 December 2022 (top right), 15 March 2023 (bottom left), and 4 April 2023 (bottom right), often accompanied by white gas-and-steam plumes. On 4 April a lava flow was active and descending the SE flank. Images using infrared (bands 12, 11, 8a). Courtesy of Copernicus Browser.

Geologic Background. The modern Bezymianny, much smaller than its massive neighbors Kamen and Kliuchevskoi on the Kamchatka Peninsula, was formed about 4,700 years ago over a late-Pleistocene lava-dome complex and an edifice built about 11,000-7,000 years ago. Three periods of intensified activity have occurred during the past 3,000 years. The latest period, which was preceded by a 1,000-year quiescence, began with the dramatic 1955-56 eruption. This eruption, similar to that of St. Helens in 1980, produced a large open crater that was formed by collapse of the summit and an associated lateral blast. Subsequent episodic but ongoing lava-dome growth, accompanied by intermittent explosive activity and pyroclastic flows, has largely filled the 1956 crater.

Information Contacts: Kamchatka Volcanic Eruptions Response Team (KVERT), Far Eastern Branch, Russian Academy of Sciences, 9 Piip Blvd., Petropavlovsk-Kamchatsky, 683006, Russia (URL: http://www.kscnet.ru/ivs/kvert/); Kamchatka Volcanological Station, Kamchatka Branch of Geophysical Survey, (KB GS RAS), Klyuchi, Kamchatka Krai, Russia (URL: http://volkstat.ru/); Hawai'i Institute of Geophysics and Planetology (HIGP) - MODVOLC Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/); MIROVA (Middle InfraRed Observation of Volcanic Activity), a collaborative project between the Universities of Turin and Florence (Italy) supported by the Centre for Volcanic Risk of the Italian Civil Protection Department (URL: http://www.mirovaweb.it/); Copernicus Browser, Copernicus Data Space Ecosystem, European Space Agency (URL: https://dataspace.copernicus.eu/browser/).


Chikurachki (Russia) — May 2023 Citation iconCite this Report

Chikurachki

Russia

50.324°N, 155.461°E; summit elev. 1781 m

All times are local (unless otherwise noted)


New explosive eruption during late January-early February 2023

Chikurachki, located on Paramushir Island in the northern Kuriles, has had Plinian eruptions during the Holocene. Lava flows have reached the sea and formed capes on the NW coast; several young lava flows are also present on the E flank beneath a scoria deposit. Reported eruptions date back to 1690, with the most recent eruption period occurring during January through October 2022, characterized by occasional explosions, ash plumes, and thermal activity (BGVN 47:11). This report covers a new eruptive period during January through February 2023 that consisted of ash explosions and ash plumes, based on information from the Kamchatka Volcanic Eruptions Response Team (KVERT) and satellite data.

According to reports from KVERT, an explosive eruption began around 0630 on 29 January. Explosions generated ash plumes that rose to 3-3.5 km altitude and drifted 6-75 km SE and E, based on satellite data. As a result, the Aviation Color Code (ACC) was raised to Orange (the second highest level on a four-color scale). At 1406 and 1720 ash plumes were identified in satellite images that rose to 4.3 km altitude and extended 70 km E. By 2320 the ash plume had dissipated. A thermal anomaly was visible at the volcano on 31 January, according to a satellite image, and an ash plume was observed drifting 66 km NE.

Occasional explosions and ash plumes continued during early February. At 0850 on 1 February an ash plume rose to 3.5 km altitude and drifted 35 km NE. Satellite data showed an ash plume that rose to 3.2-3.5 km altitude and drifted 50 km NE at 1222 later that day (figure 22). A thermal anomaly was detected over the volcano during 5-6 February and ash plumes drifted as far as 125 km SE, E, and NE. Explosive events were reported at 0330 on 6 February that produced ash plumes rising to 4-4.5 km altitude and drifting 72-90 km N, NE, and ENE. KVERT noted that the last gas-and steam plume that contained some ash was observed on 8 February and drifted 55 km NE before the explosive eruption ended. The ACC was lowered to Yellow and then Green (the lowest level on a four-color scale) on 18 February.

Figure (see Caption) Figure 22. Satellite image showing a true color view of a strong ash plume rising above Chikurachki on 1 February 2023. The plume drifted NE and ash deposits (dark brown-to-gray) are visible on the NE flank due to explosive activity. Courtesy of Copernicus Browser.

Geologic Background. Chikurachki, the highest volcano on Paramushir Island in the northern Kuriles, is a relatively small cone constructed on a high Pleistocene edifice. Oxidized basaltic-to-andesitic scoria deposits covering the upper part of the young cone give it a distinctive red color. Frequent basaltic Plinian eruptions have occurred during the Holocene. Lava flows have reached the sea and formed capes on the NW coast; several young lava flows are also present on the E flank beneath a scoria deposit. The Tatarinov group of six volcanic centers is located immediately to the south, and the Lomonosov cinder cone group, the source of an early Holocene lava flow that reached the saddle between it and Fuss Peak to the west, lies at the southern end of the N-S-trending Chikurachki-Tatarinov complex. In contrast to the frequently active Chikurachki, the Tatarinov centers are extensively modified by erosion and have a more complex structure. Tephrochronology gives evidence of an eruption around 1690 CE from Tatarinov, although its southern cone contains a sulfur-encrusted crater with fumaroles that were active along the margin of a crater lake until 1959.

Information Contacts: Kamchatka Volcanic Eruptions Response Team (KVERT), Far East Division, Russian Academy of Sciences, 9 Piip Blvd., Petropavlovsk-Kamchatsky, 683006, Russia (URL: http://www.kscnet.ru/ivs/); Copernicus Browser, Copernicus Data Space Ecosystem, European Space Agency (URL: https://dataspace.copernicus.eu/browser/).


Marapi (Indonesia) — May 2023 Citation iconCite this Report

Marapi

Indonesia

0.38°S, 100.474°E; summit elev. 2885 m

All times are local (unless otherwise noted)


New explosive eruption with ash emissions during January-March 2023

Marapi in Sumatra, Indonesia, is a massive stratovolcano that rises 2 km above the Bukittinggi Plain in the Padang Highlands. A broad summit contains multiple partially overlapping summit craters constructed within the small 1.4-km-wide Bancah caldera and trending ENE-WSW, with volcanism migrating to the west. Since the end of the 18th century, more than 50 eruptions, typically characterized by small-to-moderate explosive activity, have been recorded. The previous eruption consisted of two explosions during April-May 2018, which caused ashfall to the SE (BGVN 43:06). This report covers a new eruption during January-March 2023, which included explosive events and ash emissions, as reported by Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as Indonesian Center for Volcanology and Geological Hazard Mitigation, CVGHM) and MAGMA Indonesia.

According to a press release issued by PVMBG and MAGMA Indonesia on 26 December, primary volcanic activity at Marapi consisted of white gas-and-steam puffs that rose 500-100 m above the summit during April-December 2022. On 25 December 2022 there was an increase in the number of deep volcanic earthquakes and summit inflation. White gas-and-steam emissions rose 80-158 m above the summit on 5 January. An explosive eruption began at 0611 on 7 January 2023, which generated white gas-and-steam emissions and gray ash emissions mixed with ejecta that rose 300 m above the summit and drifted SE (figure 10). According to ground observations, white-to-gray ash clouds during 0944-1034 rose 200-250 m above the summit and drifted SE and around 1451 emissions rose 200 m above the summit. Seismic signals indicated that eruptive events also occurred at 1135, 1144, 1230, 1715, and 1821, but no ash emissions were visually observed. On 8 January white-and-gray emissions rose 150-250 m above the summit that drifted E and SE. Seismic signals indicated eruptive events at 0447, 1038, and 1145, but again no ash emissions were visually observed on 8 January. White-to-gray ash plumes continued to be observed on clear weather days during 9-15, 18-21, 25, and 29-30 January, rising 100-1,000 m above the summit and drifted generally NE, SE, N, and E, based on ground observations (figure 11).

Figure (see Caption) Figure 10. Webcam image of the start of the explosive eruption at Marapi at 0651 on 7 January 2023. White gas-and-steam emissions are visible to the left and gray ash emissions are visible on the right, drifting SE. Distinct ejecta was also visible mixed within the ash cloud. Courtesy of PVMBG and MAGMA Indonesia.
Figure (see Caption) Figure 11. Webcam image showing thick, gray ash emissions rising 500 m above the summit of Marapi and drifting N and NE at 0953 on 11 January 2023. Courtesy of PVMBG and MAGMA Indonesia.

White-and-gray and brown emissions persisted in February, rising 50-500 m above the summit and drifting E, S, SW, N, NE, and W, though weather sometimes prevented clear views of the summit. An eruption at 1827 on 10 February produced a black ash plume that rose 400 m above the summit and drifted NE and E (figure 12). Similar activity was reported on clear weather days, with white gas-and-steam emissions rising 50 m above the summit on 9, 11-12, 20, and 27 March and drifted E, SE, SW, NE, E, and N. On 17 March white-and-gray emissions rose 400 m above the summit and drifted N and E.

Figure (see Caption) Figure 12. Webcam image showing an eruptive event at 1829 on 10 February 2023 with an ash plume rising 400 m above the summit and drifting NE and E. Courtesy of PVMBG and MAGMA Indonesia.

Geologic Background. Gunung Marapi, not to be confused with the better-known Merapi volcano on Java, is Sumatra's most active volcano. This massive complex stratovolcano rises 2,000 m above the Bukittinggi Plain in the Padang Highlands. A broad summit contains multiple partially overlapping summit craters constructed within the small 1.4-km-wide Bancah caldera. The summit craters are located along an ENE-WSW line, with volcanism migrating to the west. More than 50 eruptions, typically consisting of small-to-moderate explosive activity, have been recorded since the end of the 18th century; no lava flows outside the summit craters have been reported in historical time.

Information Contacts: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as Indonesian Center for Volcanology and Geological Hazard Mitigation, CVGHM), Jalan Diponegoro 57, Bandung 40122, Indonesia (URL: http://www.vsi.esdm.go.id/); MAGMA Indonesia, Kementerian Energi dan Sumber Daya Mineral (URL: https://magma.esdm.go.id/v1).


Kikai (Japan) — May 2023 Citation iconCite this Report

Kikai

Japan

30.793°N, 130.305°E; summit elev. 704 m

All times are local (unless otherwise noted)


Intermittent white gas-and-steam plumes, discolored water, and seismicity during May 2021-April 2023

Kikai, located just S of the Ryukyu islands of Japan, contains a 19-km-wide mostly submarine caldera. The island of Satsuma Iwo Jima (also known as Satsuma-Iwo Jima and Tokara Iojima) is located at the NW caldera rim, as well as the island’s highest peak, Iodake. Its previous eruption period occurred on 6 October 2020 and was characterized by an explosion and thermal anomalies in the crater (BGVN 45:11). More recent activity has consisted of intermittent thermal activity and gas-and-steam plumes (BGVN 46:06). This report covers similar low-level activity including white gas-and-steam plumes, nighttime incandescence, seismicity, and discolored water during May 2021 through April 2023, using information from the Japan Meteorological Agency (JMA) and various satellite data. During this time, the Alert Level remained at a 2 (on a 5-level scale), according to JMA.

Activity was relatively low throughout the reporting period and has consisted of intermittent white gas-and-steam emissions that rose 200-1,400 m above the Iodake crater and nighttime incandescence was observed at the Iodake crater using a high-sensitivity surveillance camera. Each month, frequent volcanic earthquakes were detected, and sulfur dioxide masses were measured by the University of Tokyo Graduate School of Science, Kyoto University Disaster Prevention Research Institute, Mishima Village, and JMA (table 6).

Table 6. Summary of gas-and-steam plume heights, number of volcanic earthquakes detected, and amount of sulfur dioxide emissions in tons per day (t/d). Courtesy of JMA monthly reports.

Month Max plume height (m) Volcanic earthquakes Sulfur dioxide emissions (t/d)
May 2021 400 162 900-1,300
Jun 2021 800 117 500
Jul 2021 1,400 324 800-1,500
Aug 2021 1,000 235 700-1,000
Sep 2021 800 194 500-1,100
Oct 2021 800 223 600-800
Nov 2021 900 200 400-900
Dec 2021 1,000 161 500-1,800
Jan 2022 1,000 164 600-1,100
Feb 2022 1,000 146 500-1,600
Mar 2022 1,200 171 500-1,200
Apr 2022 1,000 144 600-1,000
May 2022 1,200 126 300-500
Jun 2022 1,000 154 400
Jul 2022 1,300 153 600-1,100
Aug 2022 1,100 109 600-1,500
Sep 2022 1,000 170 900
Oct 2022 800 249 700-1,200
Nov 2022 800 198 800-1,200
Dec 2022 700 116 600-1,500
Jan 2023 800 146 500-1,400
Feb 2023 800 135 600-800
Mar 2023 1,100 94 500-600
Apr 2023 800 82 500-700

Sentinel-2 satellite images show weak thermal anomalies at the Iodake crater on clear weather days, accompanied by white gas-and-steam emissions and occasional discolored water (figure 24). On 17 January 2022 JMA conducted an aerial overflight in cooperation with the Japan Maritime Self-Defense Force’s 1st Air Group, which confirmed a white gas-and-steam plume rising from the Iodake crater (figure 25). They also observed plumes from fumaroles rising from around the crater and on the E, SW, and N slopes. In addition, discolored water was reported near the coast around Iodake, which JMA stated was likely related to volcanic activity (figure 25). Similarly, an overflight taken on 11 January 2023 showed white gas-and-steam emissions rising from the Iodake crater, as well as discolored water that spread E from the coast around the island. On 14 February 2023 white fumaroles and discolored water were also captured during an overflight (figure 26).

Figure (see Caption) Figure 24. Sentinel-2 satellite images of Satsuma Iwo Jima (Kikai) showing sets of visual (true color) and infrared (bands 12, 11, 8a) views on 7 December 2021 (top), 23 October 2022 (middle), and 11 January 2023 (bottom). Courtesy of Copernicus Browser.
Figure (see Caption) Figure 25. Aerial image of Satsuma Iwo Jima (Kikai) showing a white gas-and-steam plume rising above the Iodake crater at 1119 on 17 January 2022. There was also green-yellow discolored water surrounding the coast of Mt. Iodake. Courtesy of JMSDF via JMA.
Figure (see Caption) Figure 26. Aerial image of Satsuma Iwo Jima (Kikai) showing white gas-and-steam plumes rising above the Iodake crater on 14 February 2023. Green-yellow discolored water surrounded Mt. Iodake. Courtesy of JCG.

Geologic Background. Multiple eruption centers have exhibited recent activity at Kikai, a mostly submerged, 19-km-wide caldera near the northern end of the Ryukyu Islands south of Kyushu. It was the source of one of the world's largest Holocene eruptions about 6,300 years ago when rhyolitic pyroclastic flows traveled across the sea for a total distance of 100 km to southern Kyushu, and ashfall reached the northern Japanese island of Hokkaido. The eruption devastated southern and central Kyushu, which remained uninhabited for several centuries. Post-caldera eruptions formed Iodake (or Iwo-dake) lava dome and Inamuradake scoria cone, as well as submarine lava domes. Recorded eruptions have occurred at or near Satsuma-Iojima (also known as Tokara-Iojima), a small 3 x 6 km island forming part of the NW caldera rim. Showa-Iojima lava dome (also known as Iojima-Shinto), a small island 2 km E of Satsuma-Iojima, was formed during submarine eruptions in 1934 and 1935. Mild-to-moderate explosive eruptions have occurred during the past few decades from Iodake, a rhyolitic lava dome at the eastern end of Satsuma-Iojima.

Information Contacts: Japan Meteorological Agency (JMA), Otemachi, 1-3-4, Chiyoda-ku Tokyo 100-8122, Japan (URL: http://www.jma.go.jp/jma/indexe.html); Japan Coast Guard (JCG) Volcano Database, Hydrographic and Oceanographic Department, 3-1-1, Kasumigaseki, Chiyoda-ku, Tokyo 100-8932, Japan (URL: https://www1.kaiho.mlit.go.jp/kaiikiDB/kaiyo30-2.htm); Copernicus Browser, Copernicus Data Space Ecosystem, European Space Agency (URL: https://dataspace.copernicus.eu/browser/).


Lewotolok (Indonesia) — May 2023 Citation iconCite this Report

Lewotolok

Indonesia

8.274°S, 123.508°E; summit elev. 1431 m

All times are local (unless otherwise noted)


Strombolian eruption continues through April 2023 with intermittent ash plumes

The current eruption at Lewotolok, in Indonesian’s Lesser Sunda Islands, began in late November 2020 and has included Strombolian explosions, occasional ash plumes, incandescent ejecta, intermittent thermal anomalies, and persistent white and white-and-gray emissions (BGVN 47:10). Similar activity continued during October 2022-April 2023, as described in this report based on information provided by Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM, or the Center of Volcanology and Geological Hazard Mitigation), MAGMA Indonesia, the Darwin Volcanic Ash Advisory Centre (VAAC), and satellite data.

During most days in October 2022 white and white-gray emissions rose as high as 200-600 m above the summit. Webcam images often showed incandescence above the crater rim. At 0351 on 14 October, an explosion produced a dense ash plume that rose about 1.2 km above the summit and drifted SW (figure 43). After this event, activity subsided and remained low through the rest of the year, but with almost daily white emissions.

Figure (see Caption) Figure 43. Webcam image of Lewotolok on 14 October 2022 showing a dense ash plume and incandescence above the crater. Courtesy of MAGMA Indonesia.

After more than two months of relative quiet, PVMBG reported that explosions at 0747 on 14 January 2023 and at 2055 on 16 January produced white-and-gray ash plumes that rose around 400 m above the summit and drifted E and SE (figure 44). During the latter half of January through April, almost daily white or white-and-gray emissions were observed rising 25-800 m above the summit, and nighttime webcam images often showed incandescent material being ejected above the summit crater. Strombolian activity was visible in webcam images at 2140 on 11 February, 0210 on 18 February, and during 22-28 March. Frequent hotspots were recorded by the MIROVA detection system starting in approximately the second week of March 2023 that progressively increased into April (figure 45).

Figure (see Caption) Figure 44. Webcam image of an explosion at Lewotolok on 14 January 2023 ejecting a small ash plume along with white emissions. Courtesy of MAGMA Indonesia.
Figure (see Caption) Figure 45. MIROVA Log Radiative Power graph of thermal anomalies detected by the VIIRS satellite instrument at Lewotolok’s summit crater for the year beginning 24 July 2022. Clusters of mostly low-power hotspots occurred during August-October 2022, followed by a gap of more than four months before persistent and progressively stronger anomalies began in early March 2023. Courtesy of MIROVA.

Explosions that produced dense ash plumes as high as 750 m above the summit were described in Volcano Observatory Notices for Aviation (VONA) at 0517, 1623, and 2016 on 22 March, at 1744 on 24 March, at 0103 on 26 March, at 0845 and 1604 on 27 March (figure 46), and at 0538 on 28 March. According to the Darwin VAAC, on 6 April another ash plume rose to 1.8 km altitude (about 370 m above the summit) and drifted N.

Figure (see Caption) Figure 46. Webcam image of Lewotolok at 0847 on 27 March 2023 showing a dense ash plume from an explosion along with clouds and white emissions. Courtesy of MAGMA-Indonesia.

Sentinel-2 images over the previous year recorded thermal anomalies as well as the development of a lava flow that descended the NE flank beginning in June 2022 (figure 47). The volcano was often obscured by weather clouds, which also often hampered ground observations. Ash emissions were reported in March 2022 (BGVN 47:10), and clear imagery from 4 March 2022 showed recent lava flows confined to the crater, two thermal anomaly spots in the eastern part of the crater, and mainly white emissions from the SE. Thermal anomalies became stronger and more frequent in mid-May 2022, followed by strong Strombolian activity through June and July (BGVN 47:10); Sentinel-2 images on 2 June 2022 showed active lava flows within the crater and overflowing onto the NE flank. Clear images from 23 April 2023 (figure 47) show the extent of the cooled NE-flank lava flow, more extensive intra-crater flows, and two hotspots in slightly different locations compared to the previous March.

Figure (see Caption) Figure 47. Sentinel-2 satellite images of Lewotolok showing sets of visual (true color) and infrared (bands 12, 11, 8a) views on 4 March 2022, 2 June 2022, and 23 April 2023. Courtesy of Copernicus Browser.

Geologic Background. The Lewotolok (or Lewotolo) stratovolcano occupies the eastern end of an elongated peninsula extending north into the Flores Sea, connected to Lembata (formerly Lomblen) Island by a narrow isthmus. It is symmetrical when viewed from the north and east. A small cone with a 130-m-wide crater constructed at the SE side of a larger crater forms the volcano's high point. Many lava flows have reached the coastline. Eruptions recorded since 1660 have consisted of explosive activity from the summit crater.

Information Contacts: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as Indonesian Center for Volcanology and Geological Hazard Mitigation, CVGHM), Jalan Diponegoro 57, Bandung 40122, Indonesia (URL: http://www.vsi.esdm.go.id/); MAGMA Indonesia, Kementerian Energi dan Sumber Daya Mineral (URL: https://magma.esdm.go.id/v1); Darwin Volcanic Ash Advisory Centre (VAAC), Bureau of Meteorology, Northern Territory Regional Office, PO Box 40050, Casuarina, NT 0811, Australia (URL: http://www.bom.gov.au/info/vaac/); MIROVA (Middle InfraRed Observation of Volcanic Activity), a collaborative project between the Universities of Turin and Florence (Italy) supported by the Centre for Volcanic Risk of the Italian Civil Protection Department (URL: http://www.mirovaweb.it/); Copernicus Browser, Copernicus Data Space Ecosystem, European Space Agency (URL: https://dataspace.copernicus.eu/browser/).


Barren Island (India) — April 2023 Citation iconCite this Report

Barren Island

India

12.278°N, 93.858°E; summit elev. 354 m

All times are local (unless otherwise noted)


Thermal activity during December 2022-March 2023

Barren Island is part of a N-S-trending volcanic arc extending between Sumatra and Burma (Myanmar). The caldera, which is open to the sea on the west, was created during a major explosive eruption in the late Pleistocene that produced pyroclastic flow and surge deposits. Eruptions dating back to 1787, have changed the morphology of the pyroclastic cone in the center of the caldera, and lava flows that fill much of the caldera floor have reached the sea along the western coast. Previous activity was detected during mid-May 2022, consisting of intermittent thermal activity. This report covers June 2022 through March 2023, which included strong thermal activity beginning in late December 2022, based on various satellite data.

Activity was relatively quiet during June through late December 2022 and mostly consisted of low-power thermal anomalies, based on the MIROVA (Middle InfraRed Observation of Volcanic Activity) graph. During late December, a spike in both power and frequency of thermal anomalies was detected (figure 58). There was another pulse in thermal activity in mid-March, which consisted of more frequent and relatively strong anomalies.

Figure (see Caption) Figure 58. Occasional thermal anomalies were detected during June through late December 2022 at Barren Island, but by late December through early January 2023, there was a marked increase in thermal activity, both in power and frequency, according to this MIROVA graph (Log Radiative Power). After this spike in activity, anomalies occurred at a more frequent rate. In late March, another pulse in activity was detected, although the power was not as strong as that initial spike during December-January. Courtesy of MIROVA.

The Suomi NPP/VIIRS sensor data showed five thermal alerts on 29 December 2022. The number of alerts increased to 19 on 30 December. According to the Darwin VAAC, ash plumes identified in satellite images captured at 2340 on 30 December and at 0050 on 31 December rose to 1.5 km altitude and drifted SW. The ash emissions dissipated by 0940. On 31 December, a large thermal anomaly was detected; based on a Sentinel-2 infrared satellite image, the anomaly was relatively strong and extended to the N (figure 59).

Figure (see Caption) Figure 59. Thermal anomalies of varying intensities were visible in the crater of Barren Island on 31 December 2022 (top left), 15 January 2023 (top right), 24 February 2023 (bottom left), and 31 March 2023 (bottom right), as seen in these Sentinel-2 infrared satellite images. The anomalies on 31 December and 31 March were notably strong and extended to the N and N-S, respectively. Images using “Atmospheric penetration” rendering (bands 12, 11, 8a). Courtesy of Sentinel Hub Playground.

Thermal activity continued during January through March. Sentinel-2 infrared satellite data showed some thermal anomalies of varying intensity on clear weather days on 5, 10, 15, 20, and 30 January 2023, 9, 14, 19, and 24 February 2023, and 21, 26, and 31 March (figure 59). According to Suomi NPP/VIIRS sensor data, a total of 30 thermal anomalies were detected over 18 days on 2-3, 7, 9-14, 16-17, 20, 23, 25, and 28-31 January. The sensor data showed a total of six hotspots detected over six days on 1, 4-5, and 10-12 February. During March, a total of 33 hotspots were visible over 11 days on 20-31 March. Four MODVOLC thermal alerts were issued on 25, 27, and 29 March.

Geologic Background. Barren Island, a possession of India in the Andaman Sea about 135 km NE of Port Blair in the Andaman Islands, is the only historically active volcano along the N-S volcanic arc extending between Sumatra and Burma (Myanmar). It is the emergent summit of a volcano that rises from a depth of about 2250 m. The small, uninhabited 3-km-wide island contains a roughly 2-km-wide caldera with walls 250-350 m high. The caldera, which is open to the sea on the west, was created during a major explosive eruption in the late Pleistocene that produced pyroclastic-flow and -surge deposits. Historical eruptions have changed the morphology of the pyroclastic cone in the center of the caldera, and lava flows that fill much of the caldera floor have reached the sea along the western coast.

Information Contacts: Darwin Volcanic Ash Advisory Centre (VAAC), Bureau of Meteorology, Northern Territory Regional Office, PO Box 40050, Casuarina, NT 0811, Australia (URL: http://www.bom.gov.au/info/vaac/); MIROVA (Middle InfraRed Observation of Volcanic Activity), a collaborative project between the Universities of Turin and Florence (Italy) supported by the Centre for Volcanic Risk of the Italian Civil Protection Department (URL: http://www.mirovaweb.it/); Hawai'i Institute of Geophysics and Planetology (HIGP) - MODVOLC Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/); Sentinel Hub Playground (URL: https://www.sentinel-hub.com/explore/sentinel-playground); NASA Worldview (URL: https://worldview.earthdata.nasa.gov/).


Villarrica (Chile) — April 2023 Citation iconCite this Report

Villarrica

Chile

39.42°S, 71.93°W; summit elev. 2847 m

All times are local (unless otherwise noted)


Nighttime crater incandescence, ash emissions, and seismicity during October 2022-March 2023

Villarrica, located in central Chile, consists of a 2-km-wide caldera that formed about 3,500 years ago, located at the base of the presently active cone. Historical eruptions date back to 1558 and have been characterized by mild-to-moderate explosive activity with occasional lava effusions. The current eruption period began in December 2014 and has recently consisted of ongoing seismicity, gas-and-steam emissions, and thermal activity (BGVN 47:10). This report covers activity during October 2022 through March 2023 and describes Strombolian explosions, ash emissions, and crater incandescence. Information for this report primarily comes from the Southern Andes Volcano Observatory (Observatorio Volcanológico de Los Andes del Sur, OVDAS), part of Chile's National Service of Geology and Mining (Servicio Nacional de Geología y Minería, SERNAGEOMIN) and satellite data.

Seismicity during October consisted of discrete long-period (LP)-type events, tremor (TR), and volcano-tectonic (VT)-type events. Webcam images showed eruption plumes rising as high as 460 m above the crater rim; plumes deposited tephra on the E, S, and SW flanks within 500 m of the crater on 2, 18, 23, and 31 October. White gas-and-steam emissions rose 80-300 m above the crater accompanied by crater incandescence during 2-3 October. There was a total of 5 VT-type events, 10,625 LP-type events, and 2,232 TR-type events detected throughout the month. Sulfur dioxide data was obtained by the Differential Absorption Optical Spectroscopy Equipment (DOAS) installed 6 km in an ESE direction. The average value of the sulfur dioxide emissions was 535 ± 115 tons per day (t/d); the highest daily maximum was 1,273 t/d on 13 October. These values were within normal levels and were lower compared to September. During the night of 3-4 October Strombolian activity ejected blocks as far as 40 m toward the NW flank. Small, gray-brown ash pulses rose 60 m above the crater accompanied white gas-and-steam emissions that rose 40-300 m high during 4-5 October. In addition, crater incandescence and Strombolian explosions that ejected blocks were reported during 4-5 and 9-11 October. Based on satellite images from 12 October, ballistic ejecta traveled as far as 400 m and the resulting ash was deposited 3.2 km to the E and SE and 900 m to the NW.

Satellite images from 14 October showed an active lava lake that covered an area of 36 square meters in the E part of the crater floor. There was also evidence of a partial collapse (less than 300 square meters) at the inner SSW crater rim. POVI posted an 18 October photo that showed incandescence above the crater rim, noting that crater incandescence was visible during clear weather nights. In addition, webcam images at 1917 showed lava fountaining and Strombolian explosions; tourists also described seeing splashes of lava ejected from a depth of 80 m and hearing loud degassing sounds. Tephra deposits were visible around the crater rim and on the upper flanks on 24 October. On 25 October SERNAGEOMIN reported that both the number and amplitude of LP earthquakes had increased, and continuous tremor also increased; intense crater incandescence was visible in satellite images. On 31 October Strombolian explosions intensified and ejected material onto the upper flanks.

Activity during November consisted of above-baseline seismicity, including intensifying continuous tremor and an increase in the number of LP earthquakes. On 1 November a lava fountain was visible rising above the crater rim. Nighttime crater incandescence was captured in webcam images on clear weather days. Strombolian explosions ejected incandescent material on the NW and SW flanks during 1, 2, and 6-7 November. POVI reported that the width of the lava fountains that rose above the crater rim on 2 November suggested that the vent on the crater floor was roughly 6 m in diameter. Based on reports from observers and analyses of satellite imagery, material that was deposited on the upper flanks, primarily to the NW, consisted of clasts up to 20 cm in diameter. During an overflight on 19 November SERNAGEOMIN scientists observed a cone on the crater floor with an incandescent vent at its center that contained a lava lake. Deposits of ejecta were also visible on the flanks. That same day a 75-minute-long series of volcano-tectonic earthquakes was detected at 1940; a total of 21 events occurred 7.8 km ESE of the crater. Another overflight on 25 November showed the small cone on the crater floor with an incandescent lava lake at the center; the temperature of the lava lake was 1,043 °C, based data gathered during the overflight.

Similar seismicity, crater incandescence, and gas-and-steam emissions continued during December. On 1 December incandescent material was ejected 80-220 m above the crater rim. During an overflight on 6 December, intense gas-and-steam emissions from the lava lake was reported, in addition to tephra deposits on the S and SE flanks as far as 500 m from the crater. During 7-12 December seismicity increased slightly and white, low-altitude gas-and-steam emissions and crater incandescence were occasionally visible. On 24 December at 0845 SERNAGEOMIN reported an increase in Strombolian activity; explosions ejected material that generally rose 100 m above the crater, although one explosion ejected incandescent tephra as far as 400 m from the crater onto the SW flank. According to POVI, 11 explosions ejected incandescent material that affected the upper SW flank between 2225 on 25 December to 0519 on 26 December. POVI recorded 21 Strombolian explosions that ejected incandescent material onto the upper SW flank from 2200 on 28 December to 0540 on 29 December. More than 100 Strombolian explosions ejected material onto the upper W and NW flanks during 30-31 December. On 30 December at 2250 an explosion was detected that generated an eruptive column rising 120 m above the crater and ejecting incandescent material 300 m on the NW flank (figure 120). Explosions detected at 2356 on 31 December ejected material 480 m from the crater rim onto the NW flank and at 0219 material was deposited on the same flank as far as 150 m. Both explosions ejected material as high as 120 m above the crater rim.

Figure (see Caption) Figure 120. Webcam image of a Strombolian explosion at Villarrica on 30 December 2022 (local time) that ejected incandescent material 300 m onto the NW flank, accompanied by emissions and crater incandescence. Courtesy of SERNAGEOMIN (Reporte Especial de Actividad Volcanica (REAV), Region De La Araucania y Los Rios, Volcan Villarrica, 30 de diciembre de 2022, 23:55 Hora local).

During January 2023, Strombolian explosions and lava fountaining continued mainly in the crater, ejecting material 100 m above the crater. Gas-and-steam emissions rose 40-260 m above the crater and drifted in different directions, and LP-type events continued. Emissions during the night of 11 January including some ash rose 80 m above the crater and as far as 250 m NE flank. POVI scientists reported about 70 lava fountaining events from 2130 on 14 January to 0600 on 15 January. At 2211 on 15 January there was an increase in frequency of Strombolian explosions that ejected incandescent material 60-150 m above the crater. Some ashfall was detected around the crater. POVI noted that on 19 January lava was ejected as high as 140 m above the crater rim and onto the W and SW flanks. Explosion noises were heard on 19 and 22 January in areas within a radius of 10 km. During 22-23 January Strombolian explosions ejected incandescent material 60-100 m above the crater that drifted SE. A seismic event at 1204 on 27 January was accompanied by an ash plume that rose 220 m above the crater and drifted E (figure 121); later that same day at 2102 an ash plume rose 180 m above the crater and drifted E.

Figure (see Caption) Figure 121. Webcam image of an ash plume at Villarrica on 27 January rising 220 m above the crater and drifting E. Courtesy of SERNAGEOMIN (Reporte Especial de Actividad Volcanica (REAV), Region De La Araucania y Los Rios, Volcan Villarrica, 27 de enero de 2023, 12:35 Hora local).

Seismicity, primarily characterized by LP-type events, and Strombolian explosions persisted during February and March. POVI reported that three explosions were heard during 1940-1942 on 6 February, and spatter was seen rising 30 m above the crater rim hours later. On 9 February lava fountains were visible rising 50 m above the crater rim. On 17 February Strombolian explosions ejected material 100 m above the crater rim and onto the upper SW flank. Webcam images from 20 February showed two separate fountains of incandescent material, which suggested that a second vent had opened to the E of the first vent. Spatter was ejected as high as 80 m above the crater rim and onto the upper NE flank. A sequence of Strombolian explosions was visible from 2030 on 20 February to 0630 on 21 February. Material was ejected as high as 80 m above the crater rim and onto the upper E flank. LP-type earthquakes recorded 1056 and at 1301 on 27 February were associated with ash plumes that rose 300 m above the crater and drifted NE (figure 122). Crater incandescence above the crater rim was observed in webcam images on 13 March, which indicated Strombolian activity. POVI posted a webcam image from 2227 on 18 March showing Strombolian explosions that ejected material as high as 100 m above the crater rim. Explosions were heard up to 8 km away. On 19 March at 1921 an ash emission rose 340 m above the crater and drifted NE. On 21 and 26 March Strombolian explosions ejected material 100 and 110 m above the crater rim, respectively. On 21 March Strombolian explosions ejected material 100 m above the crater rim. Low-intensity nighttime crater incandescence was detected by surveillance cameras on 24 March.

Figure (see Caption) Figure 122. Photo of an ash plume rising 300 m above the crater of Villarrica and drifting NE on 27 February 2023. Courtesy of SERNAGEOMIN (Reporte Especial de Actividad Volcanica (REAV), Region De La Araucania y Los Rios, Volcan Villarrica, 27 de febrero de 2023, 11:10 Hora local).

Infrared MODIS satellite data processed by MIROVA (Middle InfraRed Observation of Volcanic Activity) detected an increase in thermal activity during mid-November, which corresponds to sustained Strombolian explosions, lava fountaining, and crater incandescence (figure 123). This activity was also consistently captured on clear weather days throughout the reporting period in Sentinel-2 infrared satellite images (figure 124).

Figure (see Caption) Figure 123. Low-power thermal anomalies were detected during August through October 2022 at Villarrica, based on this MIROVA graph (Log Radiative Power). During mid-November, the power and frequency of the anomalies increased and remained at a consistent level through March 2023. Thermal activity consisted of Strombolian explosions, lava fountains, and crater incandescence. Courtesy of MIROVA.
Figure (see Caption) Figure 124. Consistent bright thermal anomalies were visible at the summit crater of Villarrica in Sentinel-2 infrared satellite images throughout the reporting period, as shown here on 19 December 2022 (left) and 9 February 2023 (right). Occasional gas-and-steam emissions also accompanied the thermal activity. Images use Atmospheric penetration rendering (bands 12, 11, 8a). Courtesy of Sentinel Hub Playground.

Geologic Background. The glacier-covered Villarrica stratovolcano, in the northern Lakes District of central Chile, is ~15 km south of the city of Pucon. A 2-km-wide caldera that formed about 3,500 years ago is located at the base of the presently active, dominantly basaltic to basaltic-andesite cone at the NW margin of a 6-km-wide Pleistocene caldera. More than 30 scoria cones and fissure vents are present on the flanks. Plinian eruptions and pyroclastic flows that have extended up to 20 km from the volcano were produced during the Holocene. Lava flows up to 18 km long have issued from summit and flank vents. Eruptions documented since 1558 CE have consisted largely of mild-to-moderate explosive activity with occasional lava effusion. Glaciers cover 40 km2 of the volcano, and lahars have damaged towns on its flanks.

Information Contacts: Servicio Nacional de Geología y Minería (SERNAGEOMIN), Observatorio Volcanológico de Los Andes del Sur (OVDAS), Avda Sta María No. 0104, Santiago, Chile (URL: http://www.sernageomin.cl/); Proyecto Observación Villarrica Internet (POVI) (URL: http://www.povi.cl/); MIROVA (Middle InfraRed Observation of Volcanic Activity), a collaborative project between the Universities of Turin and Florence (Italy) supported by the Centre for Volcanic Risk of the Italian Civil Protection Department (URL: http://www.mirovaweb.it/); Sentinel Hub Playground (URL: https://www.sentinel-hub.com/explore/sentinel-playground).


Fuego (Guatemala) — April 2023 Citation iconCite this Report

Fuego

Guatemala

14.473°N, 90.88°W; summit elev. 3763 m

All times are local (unless otherwise noted)


Daily explosions, gas-and-ash plumes, avalanches, and ashfall during December 2022-March 2023

Fuego, one of three large stratovolcanoes overlooking the city of Antigua, Guatemala, has been vigorously erupting since January 2002, with recorded eruptions dating back to 1531 CE. Eruptive activity has included major ashfalls, pyroclastic flows, lava flows, and lahars. Frequent explosions with ash emissions, block avalanches, and lava flows have persisted since 2018. More recently, activity remained relatively consistent with daily explosions, ash plumes, ashfall, avalanches, and lahars (BGVN 48:03). This report covers similar activity during December 2022 through March 2023, based on information from the Instituto Nacional de Sismologia, Vulcanología, Meteorología e Hidrologia (INSIVUMEH) daily reports, Coordinadora Nacional para la Reducción de Desastres (CONRED) newsletters, and various satellite data.

Daily explosions reported throughout December 2022-March 2023 generated ash plumes to 6 km altitude that drifted as far as 60 km in multiple directions. The explosions also caused rumbling sounds of varying intensities, with shock waves that vibrated the roofs and windows of homes near the volcano. Incandescent pulses of material rose 100-500 m above the crater, which caused block avalanches around the crater and toward the Santa Teresa, Taniluyá (SW), Ceniza (SSW), El Jute, Honda, Las Lajas (SE), Seca (W), and Trinidad (S) drainages. Fine ashfall was also frequently reported in nearby communities (table 27). MIROVA (Middle InfraRed Observation of Volcanic Activity) analysis of MODIS satellite data showed frequent, moderate thermal activity throughout the reporting period; however, there was a brief decline in both power and frequency during late-to-mid-January 2023 (figure 166). A total of 79 MODVOLC thermal alerts were issued: 16 during December 2022, 17 during January 2023, 23 during February, and 23 during March. Some of these thermal evets were also visible in Sentinel-2 infrared satellite imagery at the summit crater, which also showed occasional incandescent block avalanches descending the S, W, and NW flanks, and accompanying ash plumes that drifted W (figure 167).

Table 27. Activity at Fuego during December 2022 through March 2023 included multiple explosions every hour. Ash emissions rose as high as 6 km altitude and drifted generally W and SW as far as 60 km, causing ashfall in many communities around the volcano. Data from daily INSIVUMEH reports and CONRED newsletters.

Month Explosions per hour Ash plume altitude (max) Ash plume distance (km) and direction Drainages affected by block avalanches Communities reporting ashfall
Dec 2022 1-12 6 km WSW, W, SW, NW, S, SE, NE, and E, 10-30 km Santa Teresa, Taniluyá, Ceniza, El Jute, Honda, Las Lajas, Seca, and Trinidad Panimaché I and II, Morelia, Santa Sofía, El Porvenir, Finca Palo Verde, Yepocapa, Yucales, Sangre de Cristo, La Rochela, Ceilán, San Andrés Osuna, and Aldea La Cruz
Jan 2023 1-12 5 km W, SW, NW, S, N, NE, E, and SE, 7-60 km Ceniza, Las Lajas, Santa Teresa, Taniluyá, Trinidad, Seca, Honda, and El Jute Panimaché I and II, Morelia, Santa Sofía, El Porvenir, Palo Verde, Yucales, Yepocapa, Sangre de Cristo, La Rochela, Ceylon, Alotenango, and San Andrés Osuna
Feb 2023 1-12 4.9 km SW, W, NW, and N, 10-30 km Santa Teresa, Taniluyá, Ceniza, Las Lajas, Seca, Trinidad, El Jute, and Honda Panimaché I and II, Morelia, Santa Sofía, Palo Verde, San Pedro Yepocapa, El Porvenir, Sangre de Cristo, La Soledad, Acatenango, El Campamento, and La Asunción
Mar 2023 3-11 5 km W, SW, NW, NE, N, S, SE, and E, 10-30 km Seca, Ceniza, Taniluyá, Las Lajas, Honda, Trinidad, El Jute, and Santa Teresa Yepocapa, Sangre de Cristo, Panimaché I and II, Morelia, Santa Sofía, El Porvenir, La Asunción, Palo Verde, La Rochela, San Andrés Osuna, Ceilán, and Aldeas
Figure (see Caption) Figure 166. Thermal activity at Fuego shown in the MIROVA graph (Log Radiative Power) was at moderate levels during a majority of December 2022 through March 2023, with a brief decline in both power and frequency during late-to-mid-January 2023. Courtesy of MIROVA.
Figure (see Caption) Figure 167. Frequent incandescent block avalanches descended multiple drainages at Fuego during December 2022 through March 2023, as shown in these Sentinel-2 infrared satellite images on 10 December 2022 (top left), 4 January 2023 (top right), 18 February 2023 (bottom left), and 30 March 2023 (bottom right). Gray ash plumes were also occasionally visible rising above the summit crater and drifting W, as seen on 4 January and 30 March. Avalanches affected the NW and S flanks on 10 December, the SW and W flanks on 18 February, and the NW, W, and SW flanks on 30 March. Images use Atmospheric penetration rendering (bands 12, 11, 8a). Courtesy of Sentinel Hub Playground.

Daily explosions ranged between 1 and 12 per hour during December 2022, generating ash plumes that rose to 4.5-6 km altitude and drifted 10-30 km in multiple directions. These explosions created rumbling sounds with a shock wave that vibrated the roofs and windows of homes near the volcano. Frequent white gas-and-steam plumes rose to 4.6 km altitude. Strombolian activity resulted in incandescent pulses that generally rose 100-500 m above the crater, which generated weak-to-moderate avalanches around the crater and toward the Santa Teresa, Taniluyá, Ceniza, El Jute, Honda, Las Lajas, Seca, and Trinidad drainages, where material sometimes reached vegetation. Fine ashfall was recorded in Panimaché I and II (8 km SW), Morelia (9 km SW), Santa Sofía (12 km SW), El Porvenir (8 km ENE), Finca Palo Verde, Yepocapa (8 km NW), Yucales (12 km SW), Sangre de Cristo (8 km WSW), La Rochela, Ceilán, San Andrés Osuna, and Aldea La Cruz. INSIVUMEH reported that on 10 December a lava flow formed in the Ceniza drainage and measured 800 m long; it remained active at least through 12 December and block avalanches were reported at the front of the flow. A pyroclastic flow was reported at 1100 on 10 December, descending the Las Lajas drainage for several kilometers and reaching the base of the volcano. Pyroclastic flows were also observed in the Ceniza drainage for several kilometers, reaching the base of the volcano on 11 December. Ash plumes rose as high as 6 km altitude, according to a special bulletin from INSIVUMEH. On 31 December explosions produced incandescent pulses that rose 300 m above the crater, which covered the upper part of the cone.

Activity during January 2023 consisted of 1-12 daily explosions, which produced ash plumes that rose to 4.2-5 km altitude and drifted 7-60 km in multiple directions (figure 168). Incandescent pulses of material were observed 100-350 m above the crater, which generated avalanches around the crater and down the Ceniza, Las Lajas, Santa Teresa, Taniluyá, Trinidad, Seca, Honda, and El Jute drainages. Sometimes, the avalanches resuspended older fine material 100-500 m above the surface that drifted W and SW. Ashfall was recorded in Panimaché I and II, Morelia, Santa Sofía, El Porvenir, Palo Verde, Yucales, Yepocapa, Sangre de Cristo, La Rochela, Ceylon, Alotenango, and San Andrés Osuna. Intermittent white gas-and-steam plumes rose to 4.5 km altitude and drifted W and NW.

Figure (see Caption) Figure 168. Webcam image showing an ash plume rising above Fuego on 15 January 2023. Courtesy of INSIVUMEH.

There were 1-12 daily explosions recorded through February, which generated ash plumes that rose to 4.2-4.9 km altitude and drifted 10-30 km SW, W, NW, and N. Intermittent white gas-and-steam emissions rose 4.5 km altitude and drifted W and SW. During the nights and early mornings, incandescent pulses were observed 100-400 m above the crater. Weak-to-moderate avalanches were also observed down the Santa Teresa, Taniluyá, Ceniza, Las Lajas, Seca, Trinidad, El Jute, and Honda drainages, sometimes reaching the edge of vegetated areas. Occasional ashfall was reported in Panimaché I and II, Morelia, Santa Sofía, Palo Verde, San Pedro Yepocapa, El Porvenir, Sangre de Cristo, La Soledad, Acatenango, El Campamento, and La Asunción. On 18 February strong winds resuspended previous ash deposits as high as 1 km above the surface that blew 12 km SW and S.

During March, daily explosions ranged from 3-11 per hour, producing ash plumes that rose to 4-5 km altitude and drifted 10-30 km W, SW, NW, NE, N, S, SE, and E. During the night and early morning, crater incandescence (figure 169) and incandescent pulses of material were observed 50-400 m above the crater. Weak-to-moderate avalanches affected the Seca, Ceniza, Taniluyá, Las Lajas, Honda, Trinidad, El Jute, and Santa Teresa drainages, sometimes reaching the edge of vegetation. Frequent ashfall was detected in Yepocapa, Sangre de Cristo, Panimaché I and II, Morelia, Santa Sofía, El Porvenir, La Asunción, Palo Verde, La Rochela, San Andrés Osuna, Ceilán, and Aldeas. Weak ashfall was recorded in San Andrés Osuna, La Rochela, Ceylon during 8-9 March. A lahar was reported in the Ceniza drainage on 15 March, carrying fine, hot volcanic material, tree branches, trunks, and blocks from 30 cm to 1.5 m in diameter. On 18 March lahars were observed in the Las Lajas and El Jute drainages, carrying fine volcanic material, tree branches and trunks, and blocks from 30 cm to 1.5 m in diameter. As a result, there was also damage to the road infrastructure between El Rodeo and El Zapote.

Figure (see Caption) Figure 169. Sentinel-2 infrared satellite image showing Fuego’s crater incandescence accompanied by a gas-and-ash plume that drifted SW on 25 March 2023. Images use bands 12, 11, 5. Courtesy of INSIVUMEH.

Geologic Background. Volcán Fuego, one of Central America's most active volcanoes, is also one of three large stratovolcanoes overlooking Guatemala's former capital, Antigua. The scarp of an older edifice, Meseta, lies between Fuego and Acatenango to the north. Construction of Meseta dates back to about 230,000 years and continued until the late Pleistocene or early Holocene. Collapse of Meseta may have produced the massive Escuintla debris-avalanche deposit, which extends about 50 km onto the Pacific coastal plain. Growth of the modern Fuego volcano followed, continuing the southward migration of volcanism that began at the mostly andesitic Acatenango. Eruptions at Fuego have become more mafic with time, and most historical activity has produced basaltic rocks. Frequent vigorous historical eruptions have been recorded since the onset of the Spanish era in 1524, and have produced major ashfalls, along with occasional pyroclastic flows and lava flows.

Information Contacts: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia e Hydrologia (INSIVUMEH), Unit of Volcanology, Geologic Department of Investigation and Services, 7a Av. 14-57, Zona 13, Guatemala City, Guatemala (URL: http://www.insivumeh.gob.gt/ ); MIROVA (Middle InfraRed Observation of Volcanic Activity), a collaborative project between the Universities of Turin and Florence (Italy) supported by the Centre for Volcanic Risk of the Italian Civil Protection Department (URL: http://www.mirovaweb.it/); Hawai'i Institute of Geophysics and Planetology (HIGP) - MODVOLC Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/); Sentinel Hub Playground (URL: https://www.sentinel-hub.com/explore/sentinel-playground).

Search Bulletin Archive by Publication Date

Select a month and year from the drop-downs and click "Show Issue" to have that issue displayed in this tab.

   

The default month and year is the latest issue available.

Bulletin of the Global Volcanism Network - Volume 43, Number 12 (December 2018)

Managing Editor: Edward Venzke

Chillan, Nevados de (Chile)

Dome growth and destruction with several explosive events, June-November 2018

Dukono (Indonesia)

Regular ash explosions continuing as of September 2018

Ebeko (Russia)

Frequent ash explosions continue during June-November 2018

Etna (Italy)

Lava flows emerge from NSEC in late August and late November 2018; Strombolian activity continues from multiple vents

Fournaise, Piton de la (France)

Eruption from 15 September to 1 November produced a lava flow to the E

Ibu (Indonesia)

Thermal anomalies and ash explosions from the crater continue during May-November 2018

Kilauea (United States)

Lava fountains on the Lower East Rift Zone build 50-m-high pyroclastic cone and 13-km-long lava flow that engulfs Kapoho Bay during June 2018; 533 homes destroyed since 1 May

Sabancaya (Peru)

Frequent ash plumes continued during June-November 2018

Santa Maria (Guatemala)

Ash plumes, degassing, and avalanches continue during May-October 2018 with occasional lahars

Stromboli (Italy)

Explosive activity produced ash, lapilli, and bombs, with occasional spattering during July-October 2018



Nevados de Chillan (Chile) — December 2018 Citation iconCite this Report

Nevados de Chillan

Chile

36.868°S, 71.378°W; summit elev. 3180 m

All times are local (unless otherwise noted)


Dome growth and destruction with several explosive events, June-November 2018

Nevados de Chillán is a complex of late-Pleistocene to Holocene stratovolcanoes in the Chilean Central Andes. An eruption started with a phreatic explosion and ash emission on 8 January 2016 from a new crater (Nicanor) on the E flank of the Nuevo crater, which lies on the NW flank of the cone of the large stratovolcano referred to as Volcán Viejo. Strombolian explosions and ash emissions continued throughout 2016 and 2017. The presence of a lava dome within the Nicanor crater was confirmed in early January 2018; it continued to grow through May 2018. This report covers continuing activity from June-November 2018 when growth and destruction of the dome alternated in a series of explosive events. Information for this report is provided primarily by Chile's Servicio Nacional de Geología y Minería (SERNAGEOMIN)-Observatorio Volcanológico de Los Andes del Sur (OVDAS), and by the Buenos Aires Volcanic Ash Advisory Center (VAAC).

Activity at the Nevados de Chillán volcanic complex from June-November 2018 consisted of continued steam-and-gas emissions and periodic explosions with ash plumes and incandescent ejecta; these caused frequent changes to the size and shape of the Gil-Cruz dome within the Nicanor crater. Incandescent material as far as 300 m down the flank was seen in nighttime and thermal webcam images on multiple occasions. Larger explosive events during 13-15 July, 7-8 August, 11-12 September, 13 October, and 7 November produced significant ash plumes that rose a few kilometers above the summit, covered much of the area around the crater with fresh ash and blocks as large as a meter in diameter, and caused noticeable changes to the size and shape of the dome. A 400-m-long pyroclastic flow traveled down the E flank on 12 September 2018. The highest ash plume, on 7 November, rose almost 4 km above the summit and drifted SE.

Intermittent seismic and effusive activity continued during June 2018. Seismicity consisted of long-period earthquakes (LP) and tremor episodes (TR) related to the growth of the viscous lava dome located in the Nicanor crater, and occasional volcano-tectonic (VT) seismic events. Gray emissions and dark ash covering the snow were reported several times during the month. The dome was visible on clear days from the webcam located in Portezuelo (70 km NW); the thermal camera there showed intermittent evidence of emissions as well, usually as nighttime incandescence and ejecta scattered around the crater. Incandescent material traveled 300 m down the slope on 22 June. The Buenos Aires VAAC reported a brief emission on 23 June that rose to 4.6 km altitude and drifted NE before dissipating. It was accompanied briefly by a hotspot detected in thermal imagery.

Low-altitude steam and gas plumes were visible throughout July 2018 with periodic nighttime incandescence and ejecta blocks occasionally visible around the crater. Three explosions on 13, 14, and 15 July produced seismic events and significant ejecta, and resulted in partial destruction of the dome (figure 26). The event on 13 July was recorded as a M 3.7 located 430 m below the summit. During the night of 13-14 July images showed incandescence and ejecta on the NE flank near the crater ranging from centimeter to meter in size. The thermal webcam measured temperatures around 300?C. The second explosion on 14 July was recorded as a M 3.9 event located 1.4 km below the summit; webcam images in clear weather the following afternoon showed the extent of the new material on the NNE flank (figure 27). The third explosion in the early morning of 15 July was measured as a M 3.8 event and produced an incandescent column 340 m high. Additional ejecta on the NNE slope was visible in the webcam that afternoon. The Buenos Aires VAAC reported a pulse of ash moving ESE on 15 July at 6.4 km altitude. A video taken by SERNAGEOMIN during an overflight on 16 July showed ejecta around the flanks and steam rising from the partly destroyed dome. Intermittent, low-altitude steam-and-gas emissions continued for the rest of the month; light gray emissions were reported from 26 July through the end of the month.

Figure (see Caption) Figure 26. Images of the Gil-Cruz dome inside the Nicanor crater at Nevados de Chillán show changes in the character of the dome between 4 April and 16 July 2018 after a series of explosions on 13, 14, and 15 July 2018. The arrows show the main area covered by incandescent ejecta during the explosions. Left image courtesy of Nicolás Luengo V. and used with permission, right image taken during a SERNAGEOMIN overflight and copyright by Carabineros de Chile.
Figure (see Caption) Figure 27. Images from a SERNAGEOMIN webcam showing the NE slope of Nevados de Chillán on several dates in July 2018. Significant ejecta from an explosion during the night of 13-14 July covered the rim of the crater and traveled down the NNE slope over the snow (top). Additional new ejecta appeared on the NNE slope on 15 July 2018 after a third explosion in three days (bottom left). Steam and gas plumes rose from the crater on 24 July 2018 (bottom right) and for the remainder of the month after the explosions during 13-15 July. Courtesy of SERNAGEOMIN.

An explosion midday on 7 August 2018 produced abundant high-temperature ejecta around the crater and a 1.5 km high ash plume, according to SERNAGEOMIN. Intermittent gray plumes were reported the next day and for the remainder of August, along with incandescence at night from high-temperature degassing and smaller explosive events (figure 28). The Buenos Aires VAAC reported sporadic and small puffs of ash visible in the webcam on 27 August.

Figure (see Caption) Figure 28. Activity during August 2018 included a number of ash plumes and incandescent explosions at Nevados de Chillán. Skier Birgit Erti captured this image of an ash plume rising after an explosion on 8 August (left); courtesy of Jaime S. Sincioco. Incandescence from explosions at Nevados de Chillán on 16 August (right) was typical of activity throughout the month; courtesy of SERNAGEOMIN.

Intermittent gray emissions and minor incandescence at night were typical of the activity during September 2018, except for a series of explosive events during 11-13 September (figures 29). An explosion on 11 September produced ejecta that traveled 300 m down the slope. The largest event, on 12 September, produced a 2.5-km-high dense ash plume and a pyroclastic flow that went 400 m down the E slope. Communities within 1 km of the crater reported ashfall. Drone video footage from 13 September posted by Nicolas Luengo V. showed the path of a block-and-ash flow down the flank and dense steam emissions with ash rising from the partially destroyed dome (figure 30) (Luengo and Palma, 2018). The Buenos Aires VAAC reported a small ash plume at 4.3-4.9 km altitude drifting SSW on 14 September. Satellite images from 16 September again showed partial destruction of the growing dome at the summit from the explosive events.

Figure (see Caption) Figure 29. Incandescent explosions on 12 September 2018 (left) generated significant ash and ejecta, including a pyroclastic flow, that spread down the flank of Nevados de Chillán. Fresh deposits from the explosions were visible on 14 September (right) from the webcam. Courtesy of SERNAGEOMIN.
Figure (see Caption) Figure 30. Dense steam-and-ash rose from the dome inside the Nicanor crater at Nevados de Chillán on 13 September 2018 in multiple explosive events. Courtesy of Nicolás Luengo, used with permission.

The Buenos Aires VAAC reported an ash emission to 6.1 km altitude on 13 October 2018 seen in multispectral imagery under mostly clear skies moving SSE, and another isolated emission at the same altitude moving SE on 31 October. SERNAGEOMIN reported abundant ejecta scattered around the crater after the 13 October event. Another explosive event on 7-8 November produced incandescent ejecta and ash plumes that were the highest of the reporting period, rising to 7 km altitude and moving SE as reported by the Buenos Aires VAAC (figure 31).

Figure (see Caption) Figure 31. Explosive events at Nevados de Chillán on 7 and 8 November 2018 were recorded by the SERNAGEOMIN webcam on the NE flank (left, 8 November), and by Samuel Opazo T (right, 7 November), likely taken from a community about 40 km NW. Courtesy of SERNAGEOMIN and Samuel Opazo T.

For most of November 2018, pulsating emissions from the crater were accompanied by nighttime incandescence with small explosions and short-range ejecta. The SERNAGEOMIN webcam captured images of explosions on 23, 27, and 29 November. The Buenos Aires VAAC observed weak pulses of ash in satellite imagery at 3.9 km altitude on 23 and 27 November. The intermittent explosions with incandescent blocks and ash from June through November 2018 produced occasional low to moderate thermal anomalies that were captured by the MIROVA project (figure 32).

Figure (see Caption) Figure 32. Low to moderate power thermal anomalies at Nevados de Chillán were intermittent between June and November 2018, increasing slightly in both intensity and frequency towards the end of the period. Courtesy of MIROVA.

Reference: Luengo, Nicolas and Palma, Jose Luis, 2018, Morfometría y tasas de extrusión del domo de lava del Complejo Volcánico Nevados de Chillán mediante el uso de drones eimágenes satelitales, Concepción, Chile, XV Congreso Geológico Chileno, University of Concepción, DOI:10.13140/RG.2.2.35386.64966/1.

Geologic Background. The compound volcano of Nevados de Chillán is one of the most active of the Central Andes. Three late-Pleistocene to Holocene stratovolcanoes were constructed along a NNW-SSE line within three nested Pleistocene calderas, which produced ignimbrite sheets extending more than 100 km into the Central Depression of Chile. The dominantly andesitic Cerro Blanco (Volcán Nevado) stratovolcano is located at the NW end of the massif. Volcán Viejo (Volcán Chillán), which was the main active vent during the 17th-19th centuries, occupies the SE end. The Volcán Nuevo lava-dome complex formed during 1906-1945 on the NW flank of Viejo. The Volcán Arrau dome complex was then constructed on the SE side of Volcán Nuevo between 1973 and 1986, and eventually exceeded its height. Smaller domes or cones are present in the 5-km valley between the two major edifices.

Information Contacts: Servicio Nacional de Geología y Minería (SERNAGEOMIN), Observatorio Volcanológico de Los Andes del Sur (OVDAS), Avda Sta María No. 0104, Santiago, Chile (URL: http://www.sernageomin.cl/), 16 July 2018 overflight video on YouTube (https://www.youtube.com/watch?v=SVFklfEnWXI); MIROVA (Middle InfraRed Observation of Volcanic Activity), a collaborative project between the Universities of Turin and Florence (Italy) supported by the Centre for Volcanic Risk of the Italian Civil Protection Department (URL: http://www.mirovaweb.it/); Nicolas Luengo, University of Concepcion (Twitter: @nluengov), 13 September drone video footage on YouTube (https://www.youtube.com/watch?v=BZt5X3rWoFM); Jaime S. Sincioco (Twitter: @jaimessincioco); Samuel Opazo T (Twitter: @OpazoSamuel).


Dukono (Indonesia) — December 2018 Citation iconCite this Report

Dukono

Indonesia

1.6992°N, 127.8783°E; summit elev. 1273 m

All times are local (unless otherwise noted)


Regular ash explosions continuing as of September 2018

The long-term eruption at Dukono has been characterized by frequent ash explosions through at least March 2018 (BGVN 43:04). The current report shows that this pattern continued through at least September 2018. The data below were provided by the Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG), also known as the Center for Volcanology and Geological Hazard Mitigation (CVGHM), and the Darwin Volcanic Ash Advisory Centre (VAAC).

Between April and September 2018 there were about five reports per month about ash plumes. Altitudes generally ranged from 1.4-2.1 km, although 3 km was reported during 2-8 May and 3.4 km was reported during 25-31 July (table 18).

Table 18. Monthly summary of reported ash plumes from Dukono for April-September 2018. The direction of drift for the ash plume through each month was highly variable. Data courtesy of the Darwin VAAC and PVMBG.

Month Plume Altitude (km) Notable Plume Drift
Apr 2018 1.5-2.1 --
May 2018 1.5-3 Ash plumes drifted as far as 225 km NW on 28 May
Jun 2018 1.4-2.1 --
Jul 2018 1.8-3.4 --
Aug 2018 1.8-2.4 --
Sep 2018 1.8-2.1 --

No thermal anomalies at Dukono, based on MODIS satellite instruments analyzed using the MODVOLC algorithm, were detected during the reporting period. The MIROVA (Middle InfraRed Observation of Volcanic Activity) volcano hotspot detection system, also based on analysis of MODIS data, detected a low-power hotspot in early April (about 2.5 km from the volcano) and a possible low-power hotspot in late August 2018 (about 5 km from the volcano).

Geologic Background. Reports from this remote volcano in northernmost Halmahera are rare, but Dukono has been one of Indonesia's most active volcanoes. More-or-less continuous explosive eruptions, sometimes accompanied by lava flows, have occurred since 1933. During a major eruption in 1550 CE, a lava flow filled in the strait between Halmahera and the N-flank Gunung Mamuya cone. This complex volcano presents a broad, low profile with multiple summit peaks and overlapping craters. Malupang Wariang, 1 km SW of the summit crater complex, contains a 700 x 570 m crater that has also been active during historical time.

Information Contacts: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as Indonesian Center for Volcanology and Geological Hazard Mitigation, CVGHM), Jalan Diponegoro 57, Bandung 40122, Indonesia (URL: http://www.vsi.esdm.go.id/); Darwin Volcanic Ash Advisory Centre (VAAC), Bureau of Meteorology, Northern Territory Regional Office, PO Box 40050, Casuarina, NT 0811, Australia (URL: http://www.bom.gov.au/info/vaac/); Hawai'i Institute of Geophysics and Planetology (HIGP) - MODVOLC Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/); MIROVA (Middle InfraRed Observation of Volcanic Activity), a collaborative project between the Universities of Turin and Florence (Italy) supported by the Centre for Volcanic Risk of the Italian Civil Protection Department (URL: http://www.mirovaweb.it/).


Ebeko (Russia) — December 2018 Citation iconCite this Report

Ebeko

Russia

50.686°N, 156.014°E; summit elev. 1103 m

All times are local (unless otherwise noted)


Frequent ash explosions continue during June-November 2018

Typical activity during the current eruption at Ebeko that began in October 2016 consists of numerous explosions and associated ash plumes (BGVN 43:06). The Kamchatkan Volcanic Eruption Response Team (KVERT) is responsible for monitoring this remote volcano, and has an observation site at Severo-Kurilsk, 7 km E. The current report reviews events from June through November 2018. During the reporting period, the Aviation Color Code remained at Orange, the second highest level of the four-color scale.

According to KVERT, numerous moderate explosions every month generated ash plumes (figure 18 an d19) that rose between 2.5-6 km in altitude, with most between 3 and 4.5 km (table 7). Occasionally, ashfall was reported in Severo-Kurilsk. KVERT reported that thermal anomalies began about mid-August and continued through November.

Figure (see Caption) Figure 18. Ash explosion at Ebeko on 1 August 2018. Image from video by SVERT (IMGG FEB RAS) and KB GS RAS, courtesy of Institute of Volcanology and Seismology FEB RAS, KVERT.
Figure (see Caption) Figure 19. Aerial photo showing an explosive eruption of Ebeko at 2322 UTC on 21 August 2018. Photo by Roskosmos (color corrected), courtesy of Institute of Volcanology and Seismology FEB RAS, KVERT.

Table 7. Summary of activity at Ebeko from June-November 2018. TA is thermal anomaly, S-K is Severo-Kurilsk (7 km E of the volcano). Data courtesy of KVERT.

Date Plume Altitude Plume Distance Plume Direction Other observations
05 Jun 2018 -- 8 km E Diffuse ash plume.
15 Jun 2018 -- 14 km SE --
17-18 Jun 2018 2.5-3 km -- -- Explosions.
26-27 Jun 2018 3 km -- -- Explosions.
30 Jun-01 Jul 2018 3.2 km 57 km SE Explosions.
08-12 Jul 2018 4 km 37 km W Explosions.
13-20 Jul 2018 3.4 km -- -- Explosions.
20-21, 25-26 Jul 2018 4 km 15 km E Explosions.
29 Jul-01 Aug 2018 6 km -- -- Explosions.
03-10 Aug 2018 3.7 km 65 km E Explosions.
11-17 Aug 2018 4.5 km 52 km SE Explosions. TA on 12 Aug.
17-24 Aug 2018 5.2 km 235 km SE Explosions. TA on 21-23 Aug.
24-31 Aug 2018 3.6 km 135 km SE, S, SW Explosions. TA 24-25, 30 Aug. Ashfall on 29-30 Aug.
31 Aug-07 Sep 2018 4.5 km 75 km N, S Explosions. TA on 4-5 Sep.
07-13 Sep 2018 3.4 km 113 km SE, NE Explosions. TA on 7, 9, 12-13 Sep. Occasional incandescence on 10-13 Sep.
14-21 Sep 2018 4.2 km 80 km E Explosions. TA occasionally visible.
21-28 Sep 2018 4 km 68 km SE Explosions. TA on 23, 27 Sep.
28 Sep-05 Oct 2018 4.5 km 80 km SW, SE, E Explosions. TA on 27-28 Sep.
05-12 Oct 2018 4.5 km 125 km SE Explosions. TA on 8 Oct.
12-19 Oct 2018 4.5 km Multiple Explosions. Ashfall in S-K.
19-26 Oct 2018 4.7 km 80 km E Explosions. TA on 24 Oct. Ashfall in S-K.
26 Oct-02 Nov 2018 3.7 km -- Multiple Explosions. TA on 24, 29 Oct. Ashfall in S-K on 29-31 Oct.
02-09 Nov 2018 3.7 km -- Multiple Explosions. Ashfall in S-K.
09-15 Nov 2018 4.5 km -- E Explosions. Weak TA on 12-13 Nov.
15-23 Nov 2018 3.2 km -- NE, S Explosions.
23-30 Nov 2018 4 km -- E Explosions. Weak TA on 24 Nov. Ashfall in S-K on 27, 29 Nov.

Thermal anomalies, based on MODIS satellite instruments analyzed using the MODVOLC algorithm, were observed only twice during the reporting period, on 30 August and 29 September 2018. The MIROVA (Middle InfraRed Observation of Volcanic Activity) volcano hotspot detection system, also based on analysis of MODIS data, detected a few scattered anomalies, almost all of which were concentrated during the latter half of August through September. These data are consistent with KVERT's observations of thermal anomalies beginning in mid-August.

Geologic Background. The flat-topped summit of the central cone of Ebeko volcano, one of the most active in the Kuril Islands, occupies the northern end of Paramushir Island. Three summit craters located along a SSW-NNE line form Ebeko volcano proper, at the northern end of a complex of five volcanic cones. Blocky lava flows extend west from Ebeko and SE from the neighboring Nezametnyi cone. The eastern part of the southern crater contains strong solfataras and a large boiling spring. The central crater is filled by a lake about 20 m deep whose shores are lined with steaming solfataras; the northern crater lies across a narrow, low barrier from the central crater and contains a small, cold crescentic lake. Historical activity, recorded since the late-18th century, has been restricted to small-to-moderate explosive eruptions from the summit craters. Intense fumarolic activity occurs in the summit craters, on the outer flanks of the cone, and in lateral explosion craters.

Information Contacts: Kamchatka Volcanic Eruptions Response Team (KVERT), Far Eastern Branch, Russian Academy of Sciences, 9 Piip Blvd., Petropavlovsk-Kamchatsky, 683006, Russia (URL: http://www.kscnet.ru/ivs/kvert/); Institute of Volcanology and Seismology, Far Eastern Branch, Russian Academy of Sciences (IVS FEB RAS), 9 Piip Blvd., Petropavlovsk-Kamchatsky 683006, Russia (URL: http://www.kscnet.ru/ivs/eng/); Hawai'i Institute of Geophysics and Planetology (HIGP) - MODVOLC Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/); MIROVA (Middle InfraRed Observation of Volcanic Activity), a collaborative project between the Universities of Turin and Florence (Italy) supported by the Centre for Volcanic Risk of the Italian Civil Protection Department (URL: http://www.mirovaweb.it/).


Etna (Italy) — December 2018 Citation iconCite this Report

Etna

Italy

37.748°N, 14.999°E; summit elev. 3357 m

All times are local (unless otherwise noted)


Lava flows emerge from NSEC in late August and late November 2018; Strombolian activity continues from multiple vents

Italy's Mount Etna on the island of Sicily has had historically recorded eruptions for the past 3,500 years and has been erupting continuously since September 2013 through at least November 2018. Lava flows, explosive eruptions with ash plumes, and Strombolian lava fountains commonly occur from its summit areas that include the Northeast Crater (NEC), the Voragine-Bocca Nuova (or Central) complex (VOR-BN), the Southeast Crater (SEC) (formed in 1978), and the New Southeast Crater (NSEC) (formed in 2011). A new crater, referred to as the "cono della sella" (saddle cone), emerged during early 2017 in the area between SEC and NSEC and has become the highest part of the SEC-NSEC complex. Activity during late 2017 and early 2018 consisted mostly of sporadic Strombolian activity with infrequent minor ash emissions from multiple vents at various summit craters. Lava flow activity resumed in late August 2018 and again in late November and is covered in this report with information provided primarily by the Osservatorio Etneo (OE), part of the Catania Branch of Italy's Istituo Nazionale di Geofisica e Vulcanologica (INGV).

After several months of low-level activity in early 2018, increases in Strombolian activity at several vents began in mid-July (BGVN 43:08). This was followed by new lava flows emerging from the saddle cone and the E vent of the NSEC complex in late August. Discontinuous low-intensity Strombolian activity and intermittent ash emissions were reported from multiple vents at various summit craters during September through November. In late November, renewed Strombolian activity and a new, small flow emerged from a small scoria cone inside the E vent of the NSEC crater and persisted through the end of the month. The MIROVA thermal anomaly correspond to ground observations of increased thermal activity at Etna beginning in mid-July, peaking in late August, and increasing again at the end of November 2018 (figure 222).

Figure (see Caption) Figure 222. MIROVA thermal anomaly graph for Etna from April through early December 2018 shows the increases in thermal activity from lava flows and increased Strombolian activity in late August and late November. Courtesy of MIROVA.

Low-energy Strombolian activity resumed at both of the Bocca Nuova BN-1 vents as well as the vents in the Northeast Crater (NEC) during the second week of July 2018 and continued throughout the month. The activity from BN-1 was nearly continuous, but not always visible; occasionally, lava fragments rose 100 m and could be seen outside of the crater rim. Intermittent ash emissions accompanied the Strombolian activity. Activity at NEC was characterized by strong and prolonged explosions (up to several tens of seconds), sometimes with reddish-brown ash emissions (figure 223). Three vents on the floor of NEC continued to widen due to collapse of the inner walls. A seismic swarm on 18-19 July was located between 4 and 9 km depth.

Figure (see Caption) Figure 223. Ash emissions from the Northeast Crater of Etna on a) 27 July and b) 28 July 2018 rose a few tens of meters and quickly dispersed. Left image by INGV personnel, right image by volcanology guide Francesco Ciancitto. Courtesy of INGV (Rep. 31/2018, ETNA, Bollettino Settimanale, 23/07/2018 - 29/07/2018, data emissione 31/07/2018).

During a field inspection on 30 July INGV personnel noted activity at the three vents at the bottom of Northeast Crater; the farthest west produced ash emissions, the center produced steam, and the vent under the NE crater wall produced Strombolian activity that sent ejecta as high as the crater rim. Frequent ash emissions from NEC were observed on 3, 4, and 5 August. During the first week of August 2018 Strombolian activity also continued at BN-1 (figure 224). The webcam at Montagnola (EMOH) recorded incandescence at night from Bocca Nuova.

Figure (see Caption) Figure 224. Activity during the first half of August 2018 at Etna was concentrated at BN-1, the Northeast Crater (NEC), and the E vent of the New Southeast Crater (NSEC), shown in red. Courtesy of INGV (Rep. 33/2018, ETNA, Weekly Bulletin, 08/06/2018 - 12/08/2018, issue date 08/14/2018).

After several months of calm, explosive activity also resumed at the E vent of the of the New Southeast Crater, high on the E flank, in early August. An explosion in the early morning of 1 August 2018 generated a gray-brown ash plume that rose several hundred meters above the summit (figure 225). Smaller emissions occurred throughout the day, and the EMOH camera recorded sporadic Strombolian explosions at night, which continued through the first week of August.

Figure (see Caption) Figure 225. After several months of calm, a resurgence of explosive activity was observed at the E vent (formed 25 November 2015) on the high E flank of the New Southeast Crater. The activity started with an explosion at 0408 UTC (= local time -2 hours), and generated a gray-brown ash plume that rose several hundred meters above the top of the volcano (a, b). In the following hours other smaller ash emissions occurred, and in the evening, the EMOH camera recorded sporadic Strombolian explosions (c). This activity continued, with fluctuations in the frequency and magnitude of the explosions, for the rest of the month (d, e, f). Courtesy of INGV (Rep. 32/2018, ETNA, Bollettino Settimanale, 30/07/2018 - 05/08/2018, data emissione 07/08/2018).

Similar activity at BN-1, NEC, and the reactivated vent at NSEC continued through the second and third weeks of August. On 16 August 2018 a new vent opened in the BN-2 area on the E side of the Voragine (inactive since December 2015) and exhibited both degassing and Strombolian activity (figure 226). During that week Strombolian activity also continued at the NEC, but activity became more sporadic at the E vent of NSEC. During the last week of August, Strombolian activity and intense degassing continued in the western sector of Bocca Nuova (BN-1). Occasionally, lapilli fragments a few centimeters in diameter were ejected onto the S rim of the crater. Strombolian activity also continued from multiple vents at the bottom of NEC. The frequency and intensity of explosions was variable and increased significantly during 22 August, ejecting coarse pyroclastic material outside the crater rim.

Figure (see Caption) Figure 226. The crater floor of Bocca Nuova at Etna on 16 and 17 August 2018 with thermal (a) and visible (b) images. The incandescent areas are highlighted with colors ranging from yellow to red and white in the thermal image. BN-1 (reactivated in November 2016) is in the foreground, and vent BN-2, which re-opened on 16 August in the south-eastern sector of the Bocca Nuova, is in the back (upper right). Thermal image by Francesco Ciancitto, photograph by Marco Neri. Courtesy of INGV (L'Etna non va in vacanza: aumenta di intensità l'attività eruttiva sommitale, 23 Agosto 2018, INGV Blog).

Beginning on 23 August 2018 about 1800 UTC, activity resumed at the saddle cone located between the old cone of the Southeast Crater (SEC) and the new cone (NSEC). Strombolian activity, initially modest, quickly became more intense, producing almost continuous explosions with the launch of coarse ejecta up to a height of 100-150 m. At 1830 UTC, while Strombolian explosions of modest intensity were also taking place at the E vent of NSEC, a small lava flow emerged from the E vent and traveled a few hundred meters E towards the Valle del Bove. Shortly after 1830 UTC another lava overflow was also observed moving N from the saddle cone (figures 227 and 228).

Figure (see Caption) Figure 227. Strombolian ejecta rose 100 m from the cono della sella (saddle cone) at the New Southeast Crater of Etna and lava flowed from both the E vent (left) and N from the saddle cone (right), shortly before midnight on 23 August 2018. Photo by Boris Behncke, courtesy of INGV blog 25 August 2018 (L'Etna fa gli straordinari: attività eruttiva al Nuovo Cratere di Sud-Est).
Figure (see Caption) Figure 228. Map of the summit crater area (DEM 2014, Aerogeophysics Laboratory - Rome Section 2, modified). BN = Bocca Nuova; VOR = Voragine; NEC = Northeast Crater; SEC = Southeast Crater; NSEC = New Southeast Crater. The yellow dots indicate the position of the degassing vents and those in red are the vents with Strombolian activity. The map also shows the flows produced by the saddle cone and the E vent of NSEC through 27 August 2018. Courtesy of INGV (Rep. N° 35/2018, ETNA, Bollettino Settimanale, 20/08/2018 - 26/08/2018, data emissione 28/08/2018).

Strombolian explosions of moderate intensity continued throughout the night from the saddle cone. The following morning (24 August) a small lava overflow emerged from the vent and stopped after traveling a few tens of meters towards the S flank of the NSEC cone (figure 228, small orange flow within saddle, and figure 229b). The Strombolian activity was accompanied by an abundant and continuous emission of ash, whichformed a small plume that rose a few hundred meters from the vent (figure 229c). The Strombolian activity at the saddle cone decreased gradually on 25 August.

Figure (see Caption) Figure 229. Eruptive activity at Etna during 23-24 August 2018. a) 23 August shortly before midnight; Strombolian activity from the saddle cone and lava flows from the E vent of the NSEC (white arrow) and from the cone of the saddle northwards (red arrow). Photo by B. Behncke taken from Fornazzo. b) 24 August, Strombolian activity and small lava overflow southward taken by the thermal camera of La Montagnola. c) 24 August, ash emitted during the Strombolian activity from the cone of the saddle, taken by the visible camera of La Montagnola. Courtesy of INGV (Rep. 35/2018, ETNA, Bollettino Settimanale, 20/08/2018 - 26/08/2018, data emissione 28/08/2018).

Strombolian activity was continuing on 27 August 2018 at NSEC, and the flow to the N into the Valle del Leone began cooling after lava stopped feeding it that evening. The same day, a new lava overflow emerged from the E vent of NSEC (figure 230) and flowed E towards the Valle del Bove for about 24 hours (figure 231).

Figure (see Caption) Figure 230. Map of the summit crater area of Etna (DEM 2014, Aerogeophysics Laboratory - Rome Section 2, modified). BN = Bocca Nuova; VOR = Voragine; NEC = Northeast Crater; SEC = Southeast Crater; NSEC = New Southeast Crater. The yellow dots are degassing vents and those in red have Strombolian activity. The map also shows the flows produced by NSEC during the last two weeks of August 2018. The yellow flow was cooling by 27 August when the new red flow emerged from the E vent of NSEC and lasted for about 24 hours. Courtesy of INGV (Rep. 36/2018, ETNA, Bollettino Settimanale, 27/08/2018 - 02/09/2018, data emissione 04/09/2018).
Figure (see Caption) Figure 231. A thermal image taken by Pizzi Deneri on 27 August 2018 at Etna shows the two flows on the flanks of NSEC. View is from the N. The flow labelled in red flows E from the E vent, and the other flow travels N from the Cono della sella (saddle cone) into the Valle del Leone and then moves east. Courtesy of INGV (Rep. 36/2018, ETNA, Bollettino Settimanale, 27/08/2018 - 02/09/2018, data emissione 04/09/2018).

Discontinuous Strombolian activity continued from NSEC after the effusive activity ended in late August. Several loud explosions from NSEC were reported by people living near the E flank of Etna during the first week of September. Strombolian activity, modest ash emissions, and significant gas emissions were also produced by BN-1; BN-2 exhibited only continuous degassing activity. Explosive activity declined during the second week of September. Discontinuous low-intensity Strombolian activity and intermittent ash emissions from Bocca Nuova, New Southeast Crater, and Northeast Crater characterized activity for the remainder of September. During the last week of the month, NEC produced frequent gray-brown ash emissions from a vent located in the western part of the crater floor, and included jets of ash, blocks, and volcanic bombs (figure 232).

Figure (see Caption) Figure 232. Ash emissions from Etna's Northeast Crater in late September 2018. The four top images are explosions from a vent at the bottom of NEC on 24 September 2018; the bottom image is one of the many ash emissions observed on 30 September. Courtesy of INGV (Rep. N° 40/2018, ETNA, Bollettino Settimanale, 24/09/2018 - 30/09/2018, data emissione 02/10/2018).

Discontinuous low-intensity Strombolian activity and intermittent ash emissions from the Bocca Nuova, the New Southeast Crater, and Northeast Crater characterized activity during all of October 2018. Two vents remained active at the bottom of Bocca Nuova (BN-1). During a visit on 16 October, INGV-OE geologists noted that the northernmost vent produced nearly continuous Strombolian activity with frequent explosions; occasionally fragments exceeded the crater rim in height but still fell within the crater. The southernmost vent, on the crater floor about 130 m from the edge, was characterized by explosive activity that produced mainly spattering which covered both the crater floor and walls (figure 233). On 25 October the webcam at Bronte recorded an ash emission from Bocca Nuova that resulted from three closely-spaced explosions. The ash was red and dispersed rapidly to the S causing ashfall near Torre del Filosofo and Rifugio Sapienza.

Figure (see Caption) Figure 233. Inside the Bocca Nuova BN-1 crater at Etna on 16 October 2018, two vents were active. The northernmost vent (yellow arrow) had Strombolian activity; the southernmost vent, visible on the right, produced mostly "spattering". Photo by M. Coltelli, courtesy of INGV (Rep. N° 43/2018, ETNA, Bollettino Settimanale, 15/10/2018 - 21/10/2018, data emissione 23/10/2018).

Strombolian activity at NSEC gradually intensified during the first week of November 2018 and was sometimes accompanied by ash emissions that rapidly dispersed, falling mainly near the vent and in the Valle del Bove to the E. Audible explosions from the activity were heard in Zafferana Etnea on the E flank. Several clear views of the summit and details of the active vents were well exposed during an overflight on a clear 9 November day (figure 234).

Figure (see Caption) Figure 234. An aerial view of the Etna summit craters taken on a clear 9 November 2018 day with the assistance of the 2nd Coast Guard Core of Catania. View is to the NW. BN = Bocca Nuova; VOR = Voragine; NEC = Northeast Crater; SEC = Southeast Crater; NSEC = New Southeast Crater. Courtesy of INGV (Rep. N° 46/2018, ETNA, Bollettino Settimanale, 05/11/2018 - 11/11/2018, data emissione 13/11/2018).

Three vents were visible at BN-1 during the 9 November 2018 overflight (figure 235); continuous Strombolian activity occurred at vent 1, whose fallout of pyroclastic debris remained within the crater; discontinuous Strombolian activity was observed at vent 2 associated with weak, pulsing ash emissions; only degassing activities were observed at vent 3. At BN-2, intense degassing accompanied discontinuous Strombolian activity that was associated with weak pulsating ash emissions, and several high temperature gas emission points. Scientists also observed a collapse on a portion of the northern inner wall of BN-1 from the explosion on 25 October.

Figure (see Caption) Figure 235. Aerial view of Bocca Nuova (BN) and Voragine (VOR) at Etna on 9 November 2018 taken with helicopter support of the 2nd Coast Guard Core of Catania. The yellow hatched line indicates the wall of the area that collapsed on 25 October 2018. Inset a) thermal image of Bocca Nuova showing the structure of the three eruptive vents within BN-1 and the eruptive vent within the BN-2. Courtesy of INGV (Rep. N° 46/2018, ETNA, Bollettino Settimanale, 05/11/2018 - 11/11/2018, data emissione 13/11/2018).

Modest outgassing continued at Voragine (VOR) from the 7 August 2016 vent near the rim during November. At NEC, continuous and intense Strombolian activity from the crater floor caused pyroclastic ejecta to land outside the crater rim (figure 236). At the NSEC complex, high-temperature anomalies were visible at the NW crater edge, and the E vent of NSEC had a small scoria cone that produced discontinuous Strombolian explosions and minor ash emissions (figure 237).

Figure (see Caption) Figure 236. Aerial view of Voragine (VOR) and the Northeast Crater (NEC) at Etna taken on 9 November 2018 with helicopter support of the 2nd Coast Guard Core of Catania. The 7 August 2016 vent at VOR had a vigorous steam emission (yellow arrow). Inset a) thermal image showed the Strombolian activity in the bottom of NEC. Courtesy of INGV (Rep. N° 46/2018, ETNA, Bollettino Settimanale, 05/11/2018 - 11/11/2018, data emissione 13/11/2018).
Figure (see Caption) Figure 237. Thermal activity was evident in several places at the SEC-NSEC complex at Etna during the 9 November 2018 overflight with the helicopter of the 2nd Coast Guard Core of Catania (inset a, upper image). The small scoria cone (conetto di scorie) was visible inside the E vent (Bocca orientale) of the New Southeast Crater, seen from the East on 9 November (lower image). Upper image from INGV weekly (Rep. N° 46/2018, ETNA, Bollettino Settimanale, 05/11/2018 - 11/11/2018, data emissione 13/11/2018), lower image by Stefano Branca (INGV-Osservatorio Etneo) from INGV blog (Piccoli coni crescono: aggiornamento sullo stato di attività dell'Etna al 7 dicembre 2018).

A seismic swarm with over 40 events affected the W flank of Etna on 20 November 2018; the hypocenters were located between 15 and 27 km depth. A small lava flow also emerged on 20 November from the scoria cone inside the E vent at NSEC. The flow lasted for a few hours and remained inside the E vent. A new flow from the same scoria cone at the NSEC east vent appeared on 26 November accompanied by continued Strombolian activity. The flow remained high on the E flank at an elevation of about 3,200 m. Flow activity continued into the first days of December with frequent incandescent blocks moving down the NSEC E flank (figure 238). Elsewhere at Etna, Strombolian activity continued accompanied by sporadic and modest ash emissions from Bocca Nuova, the New Southeast Crater and the Northeast Crater through the end of November (figure 239).

Figure (see Caption) Figure 238. Strombolian activity and emission of a small lava flow from the E vent of the New Southeast Crater was seen from the E at dawn on 29 November 2018. The lava flow was very short, but the detachment and rolling of numerous incandescent blocks from the front and sides of the flow created the impression that the flow reached the base of the New Southeast Crater cone. The scoria cone inside the E vent grew considerably compared to its size observed on 9 November (figure 237). Photo by Giò Giusa. Courtesy of INGV, INGV Blog (Piccoli coni crescono: aggiornamento sullo stato di attività dell'Etna al 7 dicembre 2018).
Figure (see Caption) Figure 239. Incandescence from Strombolian activity was visible inside the NSEC (right) and BN (left) craters at Etna on 22 November 2018 as viewed from Tremestieri Etneo. Photo by B. Behncke, courtesy of INGV (Rep. N° 48/2018, ETNA, Bollettino Settimanale, 19/11/2018 - 25/11/2018, data emissione 27/11/2018).

Geologic Background. Mount Etna, towering above Catania on the island of Sicily, has one of the world's longest documented records of volcanism, dating back to 1500 BCE. Historical lava flows of basaltic composition cover much of the surface of this massive volcano, whose edifice is the highest and most voluminous in Italy. The Mongibello stratovolcano, truncated by several small calderas, was constructed during the late Pleistocene and Holocene over an older shield volcano. The most prominent morphological feature of Etna is the Valle del Bove, a 5 x 10 km caldera open to the east. Two styles of eruptive activity typically occur, sometimes simultaneously. Persistent explosive eruptions, sometimes with minor lava emissions, take place from one or more summit craters. Flank vents, typically with higher effusion rates, are less frequently active and originate from fissures that open progressively downward from near the summit (usually accompanied by Strombolian eruptions at the upper end). Cinder cones are commonly constructed over the vents of lower-flank lava flows. Lava flows extend to the foot of the volcano on all sides and have reached the sea over a broad area on the SE flank.

Information Contacts: Sezione di Catania - Osservatorio Etneo, Istituto Nazionale di Geofisica e Vulcanologia (INGV), Sezione di Catania, Piazza Roma 2, 95123 Catania, Italy (URL: http://www.ct.ingv.it/it/ ); MIROVA (Middle InfraRed Observation of Volcanic Activity), a collaborative project between the Universities of Turin and Florence (Italy) supported by the Centre for Volcanic Risk of the Italian Civil Protection Department (URL: http://www.mirovaweb.it/).


Piton de la Fournaise (France) — December 2018 Citation iconCite this Report

Piton de la Fournaise

France

21.244°S, 55.708°E; summit elev. 2632 m

All times are local (unless otherwise noted)


Eruption from 15 September to 1 November produced a lava flow to the E

Piton de la Fournaise, located in the SE part of La Réunion Island in the Indian Ocean, has been producing frequent effusive basaltic eruptions on average twice a year since 1998. The activity is characterized by lava fountains and lava flows, and occasional explosive eruptions that shower blocks over the summit area and produce ash plumes. Almost all of the recent activity has occurred within the Enclos Fouqué caldera, with recent eruptions in 1977, 1986, and 1998 at vents outside of the caldera. The most recent eruptive episode lasted 18 hours on 13 July 2018. This report summarizes activity during September-November 2018 and is based on reports by Observatoire Volcanologique du Piton de la Fournaise (OVPF) and satellite data.

After deformation had ceased in early August, inflation resumed in the beginning of September (figure 145) accompanied by low-level seismicity. From 1 to 12 September CO2 concentrations at the summit had decreased, followed by an increase during 12-20 September. A seismic crisis was reported on 0145 on 15 September that included 995 shallow (less than 2 km depth) volcano-tectonic earthquakes recorded in less than four hours. This was accompanied by rapid deformation of up to 24 cm.

Figure (see Caption) Figure 145. Horizontal displacement at Piton de la Fournaise recorded in October 2018 at the OVPF permanent GPS stations located inside the caldera. The source for the deformation was located at a depth of 1-1.5 km below the Dolomieu crater. Courtesy of and copyright by OVPF/IPGP.

The eruption began at 0435 on 15 September with a fissure opening and erupting lava on the SW flank near Rivals crater. This new fissure was about 300 m downstream, and was a continuation of, the 27 April-1 June 2018 fissure. Volcanic tremor rapidly and steadily declined once the eruption began, which is commonly observed during eruptions of Piton de la Fournaise. An observation flight that day showed five fissures with lava fountains reaching 30 m high in the center of the fissure system (figure 146). By 1100 two main lava flows had merged further downflow and traveled 2 km from the fissures. During the first hours of the eruption the estimated time-averaged discharge rate was 22.7 and 44.7 m3/s.

Figure (see Caption) Figure 146. An overflight at Piton de la Fournaise at 1100 on 15 September 2018 showed that five fissures had opened and two main lava flows had merged and extended to 2 km. The lava fountain in the center of the fissures reached 30 m high. Courtesy of and copyright by OVPF/IPGP (Bulletin d'activité du samedi 15 Septembre 2018 à 16h45).

A survey on the 15th recorded multiple lobes at the end of the lava flow and flow rates of 1-5 m3/s (figures 147 and 148). Three vents remained active on 16 September and a spatter cone was being constructed around them. The lava effusion rate was measured at 2.5-7 m3/s. SO2 levels were elevated and the resulting gas plume was dispersed towards the W. On the 17th the lava flow was still high on the flank and moving E.

Figure (see Caption) Figure 147. The lava flow of the 15 September 2018 eruption of Piton de la Fournaise as seen on 17 September. The top images are photographs of the active fissure and the location of the lava flow as it progresses towards the SE, and the bottom images are thermal infrared images of the lava flow. Courtesy of and copyright by OVPF/IPGP (Bulletin d'activité du samedi 17 Septembre 2018 à 17h30).
Figure (see Caption) Figure 148. The active vent at Piton de la Fournaise producing a lava flow with flow rates of 1-5 m3/s on 15 September 2018. The opening of the vent is towards the south and a degassing plume is visible. Courtesy of and copyright by OVPF/IPGP.

By 18 September a cone had developed and was open to the south, producing lava fountaining and feeding the lava flow (figure 149). The lava flow had extended to 2.8 km from the vent, with the active flow front about 500 m from the southern wall of the caldera. The flows advanced several hundred meters by the 21st and the height of the cone was 30 m on the eastern side where a near-vertical wall had formed (figure 150). The cone contained three active lava fountains.

Figure (see Caption) Figure 149. A spatter cone being built around the new vent on Piton de la Fournaise on 18 September 2018 at 1230 local time. Courtesy of and copyright by OVPF/IPGP (Bulletin d'activité du samedi 18 Septembre 2018 à 17h00).
Figure (see Caption) Figure 150. The active vent on Piton de la Fournaise with spattering activity on 21 September 2018 at 1615. The wall of the cone on the left of the photograph is nearly vertical and was 30 m high. Courtesy of and copyright by OVPF/IPGP (Bulletin d'activité du samedi 21 Septembre 2018 à 20h00).

Fallout of Pele's hair was reported in the Grand Coude area on 22 September. The cone remained open to the south and a deep channel had formed with lava tubes observed close to the cone (figure 151). Three lava fountains continued to feed the lava flow towards the S, then the SE, with a flow rate of 1-3 m3/s.

Figure (see Caption) Figure 151. The eruption fissure at Piton de la Fournaise on 22 September at 1100 local time. Courtesy of and copyright by OVPF/IPGP (Bulletin d'activité du samedi 22 Septembre 2018 à 17h15).

By 26 September the fissure system had evolved into a single cone and the opening towards the south had closed, leaving a circular vent and a lava lake (figure 152). Observations on the 26th showed that lava tubes were developing and feeding outbreak flows 150-300 m away from the cone. During 24-30 September the surface lava flow rate varied from 0.5 to 5.3 m/s, but this was expected to be higher in the lava tubes. By the 27th the majority of the lava was feeding from within the vent area into lava tubes that continued to feed breakout flows several hundred meters from the cone. On the 30th a small lava flow was also visible at the foot of the cone and spattering was seen low above the cone (figure 153).

Figure (see Caption) Figure 152. A view of the active cone and lava flow on Piton de la Fournaise on 25 September 2018. Courtesy of and copyright by OVPF/IPGP (Bulletin d'activité du samedi 26 Septembre 2018 à 17h00).
Figure (see Caption) Figure 153. An explosion producing spatter that is added to the new cone on Piton de la Fournaise. Photographs taken around 1100 on 29 September 2018. Courtesy of and copyright by OVPF/IPGP (Bulletin d'activité du samedi 30 Septmeber 2018 à 15h00).

The surface lava flow rate ranged from less than 1 and up to 4 m3/s on 1-2 October, with the majority of the activity still taking place in lava tubes with some small breakout flows (figure 154). There was a reduction in surface activity on 2-3 October along with a change from continuous degassing to the emission of discrete gas plumes ("gas pistons") that were accompanied by a sharp increase in tremor (figure 155). Observations on the 4th noted that spattering at the vent was minor and rare. No breakouts were observed.

Figure (see Caption) Figure 154. The surface activity of Piton de la Fournaise at 1030 on 2 October 2018. The activity was focused at a single vent and a cone had developed on top of the initial fissure. A white degassing plume and incandescent lava are seen at the vent, but the majority of activity is below the surface in lava tubes. Courtesy of and copyright by OVPF/IPGP (Bulletin d'activité du samedi 3 Octobre 2018 à 14h00).
Figure (see Caption) Figure 155. Thermal infrared imaging of the Piton de la Fournaise eruptive site and active lava flow field taken from Piton Bert at 1050 on 8 October 2018. Courtesy of OVPF/IPGP (Bulletin d'activité du samedi 8 Octobre 2018 à 16h00).

Limited activity continued from the 5 to 7 October surface activity remained low, with minor spattering and few breakouts. Lava continued to flow within the lava tubes and degassing was visible at the surface above them. From 30 September to 8 October the lava had traveled 1.8 km E within lava tubes and emerged as a breakout along the northern flow (figure 156). The south and central flow-fronts had not advanced during this time.

Figure (see Caption) Figure 156. The progression of the Piton de la Fournaise lava flow from 30 September (red) to 8 October 2018 (blue) as determined by InSAR satellite data. There are three main lobes, with the activity focused at the northern lobe during this time. Courtesy of OVPF/IPGP (Bulletin d'activité du samedi 8 Octobre 2018 à 16h00).

On 14 October no lava channels were visible on the surface and only small breakouts were observed (figure 157). Activity continued in lava tubes and strong degassing persisted from both the vent and main lava tubes (figure 158). On the 18th OVPF/IPGP reported continued strong degassing and a small lava channel that had formed out to a few tens of meters from the cone (figures 159 and 160).

Figure (see Caption) Figure 157. OVPF sampling a lava breakout on Piton de la Fournaise 600 m from the lava flow front at 1015 on 14 October 2018. Courtesy of OVPF/IPGP (Bulletin d'activité du samedi 14 Octobre 2018 à 13h00).
Figure (see Caption) Figure 158. The Piton de la Fournaise eruption site at 0945 on 14 October 2018. At this point most of the activity is confined to lava tubes, with the main lava tube marked by degassing moving away from the degassing vent to the left of the photograph. Courtesy of OVPF/IPGP (Bulletin d'activité du samedi 14 Octobre 2018 à 13h00).
Figure (see Caption) Figure 159. A white gas plume at the active vent of Piton de la Fournaise on 18 October 2018. Courtesy of OVPF/IPGP (Bulletin d'activité du samedi 18 Octobre 2018 à 17h00).
Figure (see Caption) Figure 160. The eruptive vent and active lava flow on Piton de la Fournaise at 1130 on 18 October 2018. Courtesy of OVPF/IPGP (Bulletin d'activité du samedi 18 Octobre 2018 à 17h00).

By 25 October the lava flow rate was still low with no further extension of the flow boundary, SO2 emission from the vent were low (close to or below the detection limit), CO2 levels were decreasing, and the intensity of the tremor had stabilized at a very low level for about 24 hours (figure 161). At this point the lava field was essentially composed of lava tubes with a maximum recorded surface temperature (maximum integrated pixel temperature) of 71°C (figure 162). This low level of activity continued during the 26-28th with a small amount of surface lava activity about 1 km from the vent. Over 29-31 October the surface activity was extremely low with no fresh lava observed and only degassing at the vent. The eruption was declared over at 0400 on 1 November after 47 days of activity.

Figure (see Caption) Figure 161. Plot of Real-time Seismic-Amplitude Measurement (RSAM), an indicator of the volcanic tremor and intensity of the Piton de la Fournaise eruption, from 15 September to 25 October 2018. The increase in RSAM beginning on 3 October was due to a change in degassing regime due to the gradual closure of the eruptive vent as the cone grew. The RSAM values stabilized after 24 October; the eruption ended on 1 November. Courtesy of OVPF/IPGP (Bulletin d'activité du samedi 4 Octobre 2018 à 16h30).
Figure (see Caption) Figure 162. An ASTER infrared satellite image of Piton de la Fournaise showing the lava flow in the SE caldera area on 25 October 2018. At this time, the lava field is essentially composed of lava tubes and it has a maximum surface temperature of 71°C. Cooler temperatures are darker and hotter temperatures are shown as white. Courtesy of OVPF/IPGP.

Thermal observations during the September-November eruption showed the evolution of the lava flow and the reduction in surface temperatures when the activity was dominated by lava tubes (figure 163). The sharp increase in thermal anomalies detected by the MIROVA algorithm showed the onset of lava effusion, and the anomalies tapered off as the flow field cooled down (figure 164). The estimated volume of lava produced from 15 September to 17 October was 9-19 million m3, but this is lower than the actual erupted volume due to the lava tube activity. There were 459 MODVOLC thermal alerts from 15 September to 25 October.

Figure (see Caption) Figure 163. Infrared Sentinel-2 images showing the progression of the active areas of the Piton de la Fournaise lava flow (bright yellow-orange) during September and October 2018. Images courtesy of Sentinel Hub Playground.
Figure (see Caption) Figure 164. The MIROVA plot of thermal energy from Piton de la Fournaise shows three eruptive episodes in 2018: 27 April-1 June, a one day event on 13 July, and 15 September-1 November. Thermal signatures continue beyond the eruption dates as the lava flows cool. Courtesy of MIROVA.

Geologic Background. Piton de la Fournaise is a massive basaltic shield volcano on the French island of Réunion in the western Indian Ocean. Much of its more than 530,000-year history overlapped with eruptions of the deeply dissected Piton des Neiges shield volcano to the NW. Three scarps formed at about 250,000, 65,000, and less than 5,000 years ago by progressive eastward slumping, leaving caldera-sized embayments open to the E and SE. Numerous pyroclastic cones are present on the floor of the scarps and their outer flanks. Most recorded eruptions have originated from the summit and flanks of Dolomieu, a 400-m-high lava shield that has grown within the youngest scarp, which is about 9 km wide and about 13 km from the western wall to the ocean on the E side. More than 150 eruptions, most of which have produced fluid basaltic lava flows, have occurred since the 17th century. Only six eruptions, in 1708, 1774, 1776, 1800, 1977, and 1986, have originated from fissures outside the scarps.

Information Contacts: Observatoire Volcanologique du Piton de la Fournaise, Institut de Physique du Globe de Paris, 14 route nationale 3, 27 ème km, 97418 La Plaine des Cafres, La Réunion, France (URL: http://www.ipgp.fr/fr; Twitter: https://twitter.com/ObsFournaise); MIROVA (Middle InfraRed Observation of Volcanic Activity), a collaborative project between the Universities of Turin and Florence (Italy) supported by the Centre for Volcanic Risk of the Italian Civil Protection Department (URL: http://www.mirovaweb.it/); Hawai'i Institute of Geophysics and Planetology (HIGP) - MODVOLC Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/); Sentinel Hub Playground (URL: https://www.sentinel-hub.com/explore/sentinel-playground).


Ibu (Indonesia) — December 2018 Citation iconCite this Report

Ibu

Indonesia

1.488°N, 127.63°E; summit elev. 1325 m

All times are local (unless otherwise noted)


Thermal anomalies and ash explosions from the crater continue during May-November 2018

Continuing activity at Ibu has consisted of numerous thermal anomalies and, except apparently for the period from September 2017 through early March 2018, intermittent ash explosions (BGVN 43:05). This activity continued through November 2018. The Alert Level has remained at 2 (on a scale of 1-4), and the public was warned to stay at least 2 km away from the active crater, and 3.5 km away on the N side.

Ash plumes were seen frequently during May-November 2018 (table 4). Plume heights above the crater were generally 400-80 m. However, ash plumes on 28 and 29 July rose 5.5 and 4.8 km, respectively. Seismicity associated with ash plumes were characterized by explosion and avalanche signals.

Table 4. Ash explosions reported at Ibu, May-November 2018. Data courtesy of PVMBG and Darwin VAAC.

Date Time Ash plume (height above crater rim) Plume Drift
05 May 2018 0622 600 m N, NE
06 Jun 2018 1206 500 m N
12 Jun 2018 1750 600 m N
14-19 Jun 2018 -- 200-600 m N
21 Jun 2018 0857 600 m N
22-26 Jun 2018 -- 850 m WNW, W
27 Jun 2018 -- 500 m W
06 Jul 2018 -- 800 m N
10-15 Jul 2018 -- 200-800 m --
28 Jul 2018 1852 5.5 km SE
29 Jul 2018 1612 4.8 km N, SE
13 Aug 2018 0259 600 m --
20 Aug 2018 1742 1.2 km --
24 Aug 2018 0838 800 m S
28, 30 Sep 2018 -- 500 m N, NE
06 Oct 2018 -- 500 m WSW
19 Oct 2018 1223 400 m N
26 Nov 2018 -- 500 m SE

The number of thermal anomalies during this time, based on MODIS satellite instruments analyzed using the MODVOLC algorithm, ranged from 2 days/month (July) to 9 days/month (September); some events were two pixels. Days with anomalies and ash explosions were not well correlated. The MIROVA (Middle InfraRed Observation of Volcanic Activity) volcano hotspot detection system, also based on analysis of MODIS data, detected numerous hotspots every month of the reporting period, almost all of which were within 5 km of the volcano and of low-to-moderate power. Infrared satellite imagery showed that the volcano had at least two, and sometimes three, active dome or vent locations (figure 14).

Figure (see Caption) Figure 14. Sentinel-2 satellite images of Ibu on 19 August 2018. Top image (infrared, bands 12, 11, 8A) shows a large central hotspot and a smaller thermal area immediately to the west. Bottom image (natural color, bands 8, 4, 3) shows both an ash plume (gray) and steam plume (white), along with fresh and older lava in the crater. Courtesy of Sentinel Hub Playground.

Geologic Background. The truncated summit of Gunung Ibu stratovolcano along the NW coast of Halmahera Island has large nested summit craters. The inner crater, 1 km wide and 400 m deep, has contained several small crater lakes. The 1.2-km-wide outer crater is breached on the N, creating a steep-walled valley. A large cone grew ENE of the summit, and a smaller one to the WSW has fed a lava flow down the W flank. A group of maars is located below the N and W flanks. The first observed and recorded eruption was a small explosion from the summit crater in 1911. Eruptive activity began again in December 1998, producing a lava dome that eventually covered much of the floor of the inner summit crater along with ongoing explosive ash emissions.

Information Contacts: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as Indonesian Center for Volcanology and Geological Hazard Mitigation, CVGHM), Jalan Diponegoro 57, Bandung 40122, Indonesia (URL: http://www.vsi.esdm.go.id/); Darwin Volcanic Ash Advisory Centre (VAAC), Bureau of Meteorology, Northern Territory Regional Office, PO Box 40050, Casuarina, NT 0811, Australia (URL: http://www.bom.gov.au/info/vaac/); Hawai'i Institute of Geophysics and Planetology (HIGP) - MODVOLC Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/); MIROVA (Middle InfraRed Observation of Volcanic Activity), a collaborative project between the Universities of Turin and Florence (Italy) supported by the Centre for Volcanic Risk of the Italian Civil Protection Department (URL: http://www.mirovaweb.it/); Sentinel Hub Playground (URL: https://www.sentinel-hub.com/explore/sentinel-playground).


Kilauea (United States) — December 2018 Citation iconCite this Report

Kilauea

United States

19.421°N, 155.287°W; summit elev. 1222 m

All times are local (unless otherwise noted)


Lava fountains on the Lower East Rift Zone build 50-m-high pyroclastic cone and 13-km-long lava flow that engulfs Kapoho Bay during June 2018; 533 homes destroyed since 1 May

Kīlauea's East Rift Zone (ERZ) has been intermittently active for at least two thousand years. Open lava lakes and flows from the summit caldera and East Rift Zone have been almost continuously active since the current eruption began in 1983. A marked increase in seismicity and ground deformation at Pu'u 'O'o Cone on the upper East Rift Zone on 30 April 2018 and the subsequent collapse of its crater floor marked the beginning of the largest lower East Rift Zone eruptive episode in at least 200 years.

During the month of May 2018 there were 24 fissures that opened along a 6-km-long NE-trending fracture zone on the lower East Rift Zone spawning lava flows in multiple directions, including several that traveled about 5 km SE to the coast; at least 94 structures were destroyed in the Leilani Estates subdivision and adjacent areas (BGVN 43:10). As lava emerged from the fissures, the lava lake at Halema'uma'u drained and explosions produced plumes that spread minor amounts of ash to downwind communities. At the end of May eruptive activity refocused around fissure 8, which began fountaining lava tens of meters into the air and creating a voluminous incandescent flow that headed downslope to the NE. The eruptive events of June 2018 (figure 386), the second month of this episode, are described below with information provided primarily from the US Geological Survey's (USGS) Hawaiian Volcano Observatory (HVO) in the form of daily reports, volcanic activity notices, and abundant photo, map, and video data.

Figure (see Caption) Figure 386. A timeline of events at Kīlauea for 28 May-30 June 2018. Blue shaded region denotes activity at Halema'uma'u crater at the summit. Green shaded area describes activity on the lower East Rift Zone (LERZ). HST is Hawaii Standard Time. Black summit symbols indicate earthquakes (diamonds) and ash plumes (stars); red LERZ symbols indicate lava fountains (stars), lava flows (triangles) and lava ocean entry.

Summary of events during June 2018. Lava fountains from fissure 8 were reaching 60 m in height on 29 May 2018 and producing a vigorous stream of lava that traveled rapidly downslope. Several lobes of lava advanced ENE, some at rates of several hundred meters per hour. Fissure 18 was also generating a narrow flow that headed SE for 3 km before stopping. A spatter cone began growing at fissure 8 and reached 30 m in height in just a few days. On the morning of 2 June the fissure 8 flow covered the Four Corners Intersection of Highways 132 and 137, and continued E and then SE around Kapoho Crater; lava flowed into the crater and evaporated the fresh water lake inside. Traveling at a rate of about 75 m per hour, the flow moved towards the shore and reached Kapoho Bay late on 3 June, where it began building a delta. In just a few days the delta was a kilometer in width, and lava was entering the ocean in many streams along the flow front, generating dense plumes of steam and laze.

By 15 June the fissure 8 cone had reached just over 50 m in height. Fissure 8 lava fountains persisted at 40-70 m high for all of June, feeding the 13-km-long channel to Kapoho Bay. Periodic overflows along the channel built up the levees on either side of the fast-moving river of lava; they were short-lived and traveled only a few meters. Flow speeds slowed as the lava spread out over the delta, which reached 150 hectares (380 acres) in size by 20 June. The ocean-entry points migrated north and south along the delta over the course of the month, expanding the width of the ocean entry area to over 3 km. Towards the end of June, lava was crusted over in the delta up to 1 km back from the ocean, and molten material was traveling within the interior of the earlier flows to the ocean. Minor oozing of lava was reported from a few other fissures during the month, but no other significant flow activity was observed.

Within Halema`uma`u crater at the summit a near-daily pattern of collapse explosion events was due to the subsidence caused by the magma withdrawal. As the crater subsided, its rim and walls slumped inward and large blocks dropped down along growing fractures around the caldera with seismic energy releases greater than M 5.0 almost every day. The deepest part of the crater had reached 400 m below the caldera floor by late June.

Activity at the Lower East Rift Zone during 29 May-4 June 2018. By 29 May, activity on Kīlauea's lower East Rift Zone was focused on the vigorous eruption of lava from fissure 8 advancing rapidly downslope towards Highway 132. Lava fountains from fissure 8 reached 60 m in height on 29 May, feeding a flow that advanced NE over a flow from a few days earlier. The first lobe of the flow crossed Highway 132 just before 1400 that afternoon and continued NE. Most of the flow remained on the S side of the highway as it moved downslope. Visual observations in the early afternoon also confirmed continued weak activity at fissures 18 and 16. Fissure 18 had produced channelized flows which advanced about 2.6 km toward the coast during the previous day. At the ocean entry on the SE coast, only a few small channels of lava were still entering the ocean. Fissure 8 maintained high fountains throughout the day and into the overnight of 29-30 May with sustained heights exceeding 60 m and multiple secondary fountains that reached 20 m. As the flow moved downslope along the highway, the advance rates accelerated overnight, reaching approximately 550 m/hour. Overnight, sporadic bursts of activity were also observed from fissures 7 and 15.

Fissure 8 maintained fountains that rose 60-75 m high on 30 May. The flow split into three lobes; the two easternmost lobes advanced in a more ENE direction while the westernmost lobe advanced in a NE direction (figure 387). The flow rate had dropped to around 90 m/hour by late afternoon and slowed further to 45 m/hour by late evening. The fissure 18 flow also remained active, moving downslope toward Highway 137 at rates of less than 90 m/hour. By late afternoon, the front of the fissure 18 flow was about 1 km from Highway 137 and was spreading and slowing (figure 388). In the late afternoon, a new flow lobe began branching from the S side of the fissure 18 flow approximately 2 km upslope from the flow front. Throughout the day, sporadic bursts of activity were also observed from fissures 22, 6, and 13.

Figure (see Caption) Figure 387. A major lava flow that first emerged from Kīlauea's fissure 8 on 28 May was moving rapidly downslope to the NE when photographed during HVO's early morning overflight on 30 May 2018. The lava channel was estimated to be about 35 m wide; 60-m-high fountains from the fissure are visible in the upper right. Courtesy of HVO.
Figure (see Caption) Figure 388. Kīlauea's Lower East Rift Zone had many active flow fronts as of 1500 HST on 30 May 2018. Active fissures and flows are shown in dark red. Shaded purple areas indicate lava flows erupted in 1840, 1955, and 1960. Courtesy of HVO.

Four lobes of the fissure 8 flow advanced on 31 May (figure 389), fed by persistent fountaining that reached heights up to 80 m. A spatter cone was forming on the downwind side of the fountain and was approximately 30 m high. The fountains were feeding the flow to the NE, and minor overflows from the growing fissure 8 channel were occurring along its length, covering several of the remaining roads in Leilani Estates. The front of the flow advanced at about 90 m/hour through agricultural lands and was within 1.7 km of the Four Corners area (the intersection of Highways 132 and 137) by the evening. The fissure 18 flow that had advanced to within 1 km of Highway 137 had stalled. The new flow that branched from the fissure 18 channel 2 km upslope appeared to have captured most of the lava output from fissure 18. It descended downslope just to the S of the previous flow. Lava was pooling around the vent of fissure 22 throughout the day.

Figure (see Caption) Figure 389. Four advancing lobes from Kīlauea's LERZ fissure 8 were moving 75 m per hour to the NE on the morning of 31 May 2018 in this view to the E. The flow moved north of Highway 132 in the vicinity of Noni Farms and Halekamahina roads, from which the two easternmost lobes advanced in a more ENE direction while the westernmost lobe advanced in a NE direction. Courtesy of HVO.

The advance rates of the distal part of the fissure 8 flow were low overnight on 31 May-1 June as lava ponded in a flat area, but flow continued throughout the day to within 0.5 km of the Four Corners intersection of Highways 132 and 137 by evening; fissures 18 and 22 were inactive. By 0645 on 2 June it was about 100 m from the intersection (figure 390). Around 0930 on 2 June a broad front over 275 m in width extending both north and south of Highway 132 (figures 391) crossed the intersection and continued advancing into Kapoho Crater (sometimes called Green Lake Crater) and Kapoho Beach Lots. It entered Green Lake within the crater, creating a large steam plume that was visible until 1330. The Hawaii County Fire Department reported around 1500, after an overflight, that lava had filled the lake and apparently boiled away all the water.

Figure (see Caption) Figure 390. This thermal map of Kīlauea's LERZ fissure 8 flow shows the location of the lava front as of 0645 on 2 June 2018 shortly before it reached the Four Corners intersection. At that point it was roughly 10 km from the vent. The black and white area is the extent of the thermal map. Temperature is displayed as gray-scale values, with the brightest pixels indicating the hottest areas. The map was constructed by stitching many overlapping oblique images collected by a handheld thermal camera during a helicopter overflight of the flow field. The base is a copyrighted color satellite image (used with permission) provided by Digital Globe. Courtesy of HVO.
Figure (see Caption) Figure 391. Around 0715 on 2 June 2018 Kīlauea's LERZ fissure 8 flow was a 275-m-wide lava front advancing on both sides of Highway 132 (left); the flow front was approximately 90 m west of the Four Corners Intersection when USGS scientists on HVO's morning overflight captured this image. Note trees and highway for scale. Courtesy of HVO.

The flow continued to advance overnight on 2-3 June along an 800-m-wide front towards the ocean at Kapoho Bay between Kapoho Beach Road and Kapoho Kai Drive. As of 0700 on 3 June, the lava flow was around 450 m from the ocean (figures 392 and 393) traveling at a rate of about 75 m/hour. By 1745 it had advanced to within 225 m of the ocean at its closest approach point. The other branches of the fissure 8 lava flow were inactive, and all other fissures were inactive, although observers on the late afternoon overflight noted abundant gas emission from fissures 9 and 10 and incandescence without fountaining at fissures 16 and 18.

Figure (see Caption) Figure 392. At 0700 HST on 3 June 2018 Kīlauea's LERZ fissure 8 flow front was about 450 m from the ocean, advancing at about 75 m/hour. View is to the W looking up the flow front. Nearly all of the front was active and advancing. Courtesy of HVO.
Figure (see Caption) Figure 393. The flow front of Kīlauea's LERZ fissure 8 on the morning of 3 June 2018 was advancing around 75 m/hour along a broad front towards Kapoho Bay. Dark red areas are active flow expansion, shaded purple areas indicate lava flows erupted in 1840, 1955, and 1960. Courtesy of HVO.

Fountaining lava 45-75 m high at fissure 8 continued overnight on 3-4 June, feeding the growing lava channel flowing NE along Highway 132 to the Kapoho area. Throughout 30 May-3 June tephra landing downwind from the fountaining produced a growing pyroclastic cone at fissure 8 (figure 394). Local videographers reported that lava entered the ocean at Kapoho Bay at about 2230 HST on 3 June and began constructing a delta (figure 395); by late afternoon the next day the delta extended about 640 m into the bay. A laze plume (a corrosive seawater steam plume laden with hydrochloric acid and fine volcanic particles) was blowing inland from the ocean entry but dissipating quickly. The lava flow front was about 800 m wide. A lava breakout was also occurring upslope (N) of the Kapoho cone cinder pit. A lava breakout from the S margin of the flow near the intersection of Highway 132 and Railroad Avenue had completely encircled Kapoho Cone by the end of the day.

Figure (see Caption) Figure 394. A comparison of thermal images of the fountains and fast-growing pyroclastic cone at Kīlauea's LERZ fissure 8 from 30 May to 3 June 2018 indicated the increase in height of the lava fountains from 45 to over 75 m, as well as the growth of a cone (pu'u) downwind to about 30 m height. HVO reported the lava fountain temperatures were reaching up to about 1,115°C (2,040°F). The composition of the lava erupted had high MgO (magnesium oxide) values, which came from olivine crystals that were being pulled from deep within the rift zone. Courtesy of HVO.
Figure (see Caption) Figure 395. The flow front of Kīlauea's LERZ fissure 8 flow reached the ocean at Kapoho Bay late in the evening of 3 June; by 0613 HST on 4 June 2018 when this image was taken during an HVO overflight, the lava was creating a large laze plume and beginning to form a delta into the bay. Courtesy of HVO.

Activity at the Lower East Rift Zone during 5-12 June 2018. The intensity of the fountaining at fissure 8 declined overnight on 4-5 June to between 40-50 m in height, not far above the top of the cone formed during the previous several days (figure 396). By the early morning of 5 June the fissure 8 flow had completely filled Kapoho Bay, extending 1.1 km from the former coastline (figure 397). On the south side of the ocean entry, lava was entering the water at the Vacationland tidepools, having inundated most of that subdivision. To the north, lava had covered all but the northern part of Kapoho Beach Lots. The northernmost lobe of the fissure 8 flow, in the Noni Farms Road area, advanced downslope about 180 m overnight (figure 398) and continued to slowly advance during the day on 5 June.

Figure (see Caption) Figure 396. Lava fountains continued at Kīlauea's LERZ fissure 8, although overnight on 4-5 June 2018 USGS field crews reported reduced fountain heights. The lava fountain had built a 35 m (115 ft) high spatter cone, and an actively-growing spatter rampart on its eastern side. The lava channel leading from the cone was filled to the top of its levees at the time of this photo. The white objects in the upper left are the roofs of houses adjacent to the edge of the flow levee. Courtesy of HVO.
Figure (see Caption) Figure 397. Kapoho Bay was filled with lava from Kīlauea's LERZ fissure 8 flow by the morning of 5 June 2018, as seen in this view looking S during the morning HVO overflight. Hundreds of homes around the bay were buried within the lava flow. Courtesy of HVO.
Figure (see Caption) Figure 398. By 1000 HST on 5 June 2018 there were two growing areas of active ocean entry on the delta at the front of Kīlauea's LERZ fissure 8 lava flow. Dark red areas are active flows and shaded purple areas indicate lava flows erupted in 1840, 1955, 1960, and 2014-2015. Courtesy of HVO.

By the morning of 6 June 2018, the lava fountaining at fissure 8 continued to reach heights of 45-55 m and feed a stable channel to the NE and E (figure 399) to the ocean entry in the Kapoho Bay area. The lava delta that formed at the bay had also extended slightly outward overnight; during the day on 6 June a lateral lobe of the flow pushed slowly N through what remained of the Kapaho Beach Lots subdivision. Overnight on 6-7 June and throughout the following day the fountain heights from fissure 8 fluctuated between 58 and 70 m feeding the channel with vigorous flow (figure 400). The delta was about 1.9 km wide in the Vacationland/Waopae area and the flow was expanding northward (figure 401). By the late afternoon overflight on 8 June, two vigorous steam plumes were rising from the ocean flow front and being blown inland. Strong thermal upwelling was noted in the ocean extending up to 900 m out to sea from the visible lava front. Heavy gas and steam emissions were noted at fissures 9 and 10, but lava emission was occurring only at fissure 8.

Figure (see Caption) Figure 399. HVO used drones, referred to as Unmanned Aircraft Systems (UAS), to gather high-resolution video and images throughout the eruption on Kīlauea's lower East Rift Zone. On 6 June 2018 a UAS flight collected video of flowing lava in the upper lava channel of fissure 8. The view is to the S towards the fissure 8 cone in the upper left. The houses on the right provide a sense of scale for the fissure 8 flow. Scientists used the video to assess lava flow velocities, which are measured by tracking surface features in the stationary video view. This still image was taken from video captured by the U.S. Geological Survey and Office of Aviation Services, Department of the Interior, with support from the Hawaiian Volcano Observatory. Courtesy of HVO.
Figure (see Caption) Figure 400. In this early morning view to the E on 7 June 2018, fountains of lava rise 50 m from Kīlauea's LERZ fissure 8 and the lava channel travels NE to the ocean, a distance of about 12.5 km. Steam plumes in the distance rise from inactive fissures that opened during May. Courtesy of HVO.
Figure (see Caption) Figure 401. By 8 June 2018, Kīlauea's LERZ fissure 8 flow had created a lava delta approximately 77 hectares (190 acres) in size, filling Kapoho Bay and shallow reefs along the nearby coastline. Dark red areas are active flows, shaded purple areas indicate lava flows erupted in 1840, 1955, 1960, and 2014-2015. Courtesy of HVO.

Overnight on 8-9 July the fountains at fissure 8 were slightly lower, reaching heights of 40-55 m. Fissure 22 was incandescent and there was minor lava activity at fissures 16/18 while the fuming from fissures 24, 9, and 10 had decreased from the previous day. The fissure 8 flow had created a lava delta approximately 80 hectares (200 acres) in size by the morning of 9 June, filling Kapoho Bay and covering shallow reefs along the nearby coastline (figure 402); observers that night also noted vigorous convection taking place up to 1.5 km offshore from the entry points. Minor levee overflows along the upper part of the channel occurred on 10 June from the strong channelized flow (figure 403). Near the Four Corners region the channel was incandescent and flowing vigorously.

Figure (see Caption) Figure 402. A view from offshore of the Kapoho ocean entry of Kīlauea's LERZ fissure 8 flow as of 0630 HST on 9 June 2018 shows the extent of the lava delta, about 80 hectares (200 acres) in size, that formed over the previous six days. Across the front of the delta plumes of laze, created by molten lava interacting with seawater, appeared diminished that morning, but this was probably due to a change in atmospheric conditions rather than a change in the amount of fissure 8 lava reaching the ocean. Courtesy of HVO.
Figure (see Caption) Figure 403. Overflows of the upper channel at Kīlauea's LERZ fissure 8 lava flow on 10 June 2018 sent small flows of lava down the levee walls. These overflows did not extend far from the channel, so they posed no immediate threat to nearby areas. Channel overflows, like the ones shown here, add layers of lava to the channel levees, increasing their height and thickness. In the lower right of the photo, a paved road and power lines provide a scale for the size of the flow channel and levees. Courtesy of HVO.

By the evening on 10 June, three closely spaced lava fountains at fissure 8 were erupting with maximum heights reaching 35-40 m (figure 404), feeding the fast moving channelized and braided flow that now traveled 13 km to the ocean at Kapoho Bay (figure 405). A strong steam plume was observed on the S end of the ocean entry with frequent steam explosions at the flow front. Weak lava activity continued during 10-12 June at fissures 16/18 as it had for the previous several days (figure 406). Incandescence was noted at fissures 15 and 22 on 12 June. Lava was entering the ocean over a broader area than before with several minor incandescent points and small plumes, and two larger entries and corresponding plumes. The fissure 8 cinder cone had reached about 43 m in height by the evening of 12 June.

Figure (see Caption) Figure 404. The three closely spaced lava fountains at Kīlauea's LERZ fissure 8 reached maximum heights of 35-40 m overnight 10-11 June 2018. Lava fragments falling from the fountains were building a substantial cinder-and-spatter cone around the erupting vent, with the bulk of the fragments falling on the downwind side of the cone. The cone had reached 43 m in height by 12 June. Courtesy of HVO.
Figure (see Caption) Figure 405. Braided channels of lava from Kīlauea's LERZ fissure 8 covered a wide swath of the NW side of the LERZ in the morning on 12 June 2018. Incandescence from the fountain feeding the flow is visible several kilometers in the distance in this image looking upstream. The 13-km-long flow traveled NE then E and flowed into Kapho Bay. Courtesy of HVO.
Figure (see Caption) Figure 406. The fountains at Kīlauea's LERZ fissure 8 remained active as of 1400 HST on 12 June 2018, with the 13-km-long lava flow entering the ocean at Kapoho Bay along a growing delta. Very small, weak lava flows were also active near the fissure 18 area (center). The black and white area is the extent of the thermal map. Temperature in the thermal image is displayed as gray-scale values, with the brightest pixels indicating the hottest areas. The map was constructed by stitching many overlapping oblique images collected by a handheld thermal camera during a helicopter overflight of the flow field. The base is a copyrighted color satellite image (used with permission) provided by Digital Globe. Courtesy of HVO.

Activity on the Lower East Rift Zone during 13-19 June 2018. Lava fountaining at fissure 8 during 13-19 June generally rose 30-50 m with intermittent bursts as high as 60 m. The growing cone was 52 m at its highest point on 15 June (figure 407). From fissure 8, lava flowed freely over small cascades (rapids) into a well-established channel (figure 408). Near the vent, channel lava was traveling about 24 km/hour; it slowed as it traveled the 13 km-long-channel (figure 409) to about 2 km/hour near the ocean entry at Kapoho Bay. Minor amounts of lava periodically spilled over the channel levees.

Figure (see Caption) Figure 407. Lava fountains were still rising higher than the 52-m-high cone at Kīlauea's LERZ fissure 8 on 15 June 2018. Courtesy of HVO.
Figure (see Caption) Figure 408. Cascades of lava from 50-m-high fountains flowed over rapids into the channel of Kīlauea's LERZ fissure 8 lava flow on 17 June 2018. Near the vent, lava was traveling about 24 km per hour; lava slowed to about 2 km per hour near the ocean entry at Kapoho.
Figure (see Caption) Figure 409. Lava flowed in an open channel 13 km long to the ocean from Kīlauea's LERZ fissure 8 on 18 June 2018. Kapoho Crater, which partly filled with lava on 2 June, is the vegetated hill on the right side of the photograph. The lava evaporated Green Lake inside the crater. The ocean entry plume can be seen in the distance on the left. The small white objects on either side of the flow are large buildings about 75 m long. Highway 137 emerges from underneath the flow and heads S into the distance in the upper center of the image. Courtesy of HVO.

Several laze plumes rose along the ocean entry margin as break outs fed many small and large flows during mid-June. The largest pahoehoe breakout area was on the northern margin of the flow (figure 410). A small amount of expansion continued at the southern boundary of the flow near the coast and south of Vacationland. By 17 June, lava flowing into the ocean had built a delta of flows, rock rubble, and black sand, which was over 121 hectares (320 acres) in size. The flow front at the coast was about 2.4 km wide by 18 June. Limited spattering and small flows were also observed at fissures 16 and 18 during 13-19 June; mild spattering from fissure 15 was observed late in the day on 16 June, and incandescence and mild spattering were observed from fissure 6 on 17 June.

Figure (see Caption) Figure 410. A large breakout of lava created several laze plumes as it entered the ocean along the northern ocean entry margin of Kīlauea's LERZ fissure 8 flow delta on 14 June 2018. Courtesy of HVO.

Fissure 8 lava fountains 52-70 m tall showered spatter onto the cone overnight into 19 June (figure 411). Small overflows were observed on the N side of the channel near Pohoiki Road overnight and in the morning, with one breakout spreading slowly beyond the flow boundary. Field crews on the ground near fissure 8 midday on 19 June observed a still-vigorous channelized lava flow being fed by fountains at the vent. Standing waves were visible within the channel and cascades/rapids were visible near the base of the 50-m-high cone. The maximum flow velocity in the channel was measured at 28 km/hour. During the morning overflight, several small overflows could be seen along the channel margins. The flow of lava was faster in the center of the channel and decreased in speed toward the margins where friction with the channel walls increased. A small, sluggish overflow along a section of Luana Street was advancing NW. Fissures 6, 15, 16 were still oozing lava and fuming.

Figure (see Caption) Figure 411. Kīlauea's LERZ fissure 8 vigor increased overnight on 18-19 June 2019 with lava fountains reaching up to 60 m. Spatter continued to build up on the E flank of cone and lava flowed into the channel. Courtesy of HVO.

Activity at Halema'uma'u crater during June 2018. Throughout June intermittent explosions and earthquakes continued at Halema'uma'u crater as the summit area subsided and adjusted to the withdrawal of magma from below. Inward slumping of the rim and walls of Halema`uma`u continued in response to the persistent subsidence. A near-daily pattern of explosive events was characterized by seismicity at the summit that would gradually increase to tens of events per hour, culminating with a larger explosion, often with an energy release equivalent magnitude greater than M 5.0. Seismicity would usually then drop significantly before gradually rising until the next explosion. Ash plumes from the explosions often rose to altitudes of 2.4-4.6 km. With each explosion, Halema'uma'u crater subsided, generating fractures and down-dropped blocks within and around the crater floor, dramatically reshaping the morphology of the summit caldera in just a few weeks (figures 412 and 413).

Figure (see Caption) Figure 412. HVO scientists captured this aerial view of a much-changed Halema'uma'u during their overflight of Kīlauea's summit on the afternoon of 5 June 2018. Explosions and collapses had enlarged the crater (foreground) that previously hosted a lava lake, and the far rim of Halema'uma'u had also dropped with continued summit deflation. The parking area for the former overlook (closed since early 2008 due to volcanic hazards) is to the left of the crater with small fractures trending across it. Courtesy of HVO.
Figure (see Caption) Figure 413. Explosions and collapses continued throughout June 2018, enlarging Halema'uma'u crater almost daily. In this view on 12 June (one week after the previous image (figure 412)), the scale and rate of change at the summit of Kīlauea was clear. The obvious flat surface (center) was the former Halema'uma'u crater floor, which had subsided at least 100 m during the previous two weeks. Large ground cracks circumferential to the crater rim can be seen cutting across the parking lot (left) for the former Halema'uma'u visitor overlook, which is beginning to fall into the crater. The deepest part of Halema'uma'u (foreground) was about 300 m below the crater rim. Courtesy of HVO.

Overnight on 10-11 June there were two explosions at the summit separated by about four hours, followed by a decrease in seismicity. Video recorded during a UAS (Unmanned Aircraft Systems) flight HVO on 24 June 2018 revealed details of the extensive changes occurring within Halema'uma'u crater since explosive eruptions of ash and gas and ongoing wall collapse had begun in mid-May. Clearly visible were the steep crater walls that continued to slump inward and downward with ongoing subsidence. The deepest part of Halema'uma'u had dropped over 400 m below the caldera floor. There were two obvious flat surfaces within the crater that had slumped downward as nearly intact blocks; the shallower one was the former caldera floor and the deeper one was the former Halema'uma'u crater floor. HVO reduced the Aviation Color code from Red to Orange on 24 June, citing the fact that the episodic plumes from the summit rarely exceeded 3 km altitude where the might pose a risk to aviation.

Activity on the Lower East Rift Zone during 20-30 June 2018. For the remainder of June, vigorous fountaining nearly 60 m high from fissure 8 fed the established channel that transported incandescent lava to the ocean at the Kapoho coastline where several entries were active (figure 414). The largest entry area was at the S end of the flow front, but the locations of the ocean entry points migrated back and forth along the delta over time. Periodic overflows from the channel were short-lived and produced sluggish pahoehoe flows that only traveled a few meters (figure 415). Minor effusion of lava was observed from fissures 6, 15, and 16. Activity ceased at fissure 6 by 22 June. During an overflight in the early morning of 23 June, only incandescence was noted at fissure 22.

Figure (see Caption) Figure 414. Lava from Kīlauea's LERZ fissure 8 remained incandescent on its 13-km-long journey to the ocean in an open channel during the last part of June 2018. Plumes of steam and laze at the ocean entry were visible in the upper right of the left image on 20 June 2018. Small streams of lava entered the ocean across a broad area the same day, shown by the multiple white steam and laze plumes. Lava had added about 155 hectares (380 acres) of new land by 20 June 2018. Courtesy of HVO.
Figure (see Caption) Figure 415. Sluggish pahoehoe briefly spilled over a section the levee along the well-established channel of Kīlauea's LERZ fissure 8 lava flow on 20 June 2018. The overflows generally traveled short distances measured in meters. Geologists tracked the extent of overflows and looked for potential areas of weakness and seepages along the sides of the perched channel in order to assess potential breakouts from the channel. The small blades of grass in the lower left suggest the scale of this photo is about one meter across. Courtesy of HVO.

The spatter cone grew to 55 m tall by 24 June, after which the lava fountains only occasionally rose above its highest point. Geologists measured lava entering the channel traveling as fast as 30 km/hour. By 25 June, most of the lava was entering the sea on the southern side of the flow front along a 1-km wide area marked by billowing laze plumes, although the lava front extended for more than 3 km along the coast (figure 416). Beginning on 27 June geologists observed fresh lava oozing at several points along the northern margin of the flow field in the area of the Kapoho Beach Lots. By then, the lava channel had crusted over about 0.8 km inland of the ocean entry; lava was moving beneath the crust and into the still-molten interior of earlier flows before it entered the sea (figure 417). The same day, small overflows on both sides of the channel occurred in the uppermost part of channel, but none of these overflows extended past the existing flow field (figure 418).

Figure (see Caption) Figure 416. Most of the lava from Kīlauea's LERZ fissure 8 flow was entering the ocean at the southern edge of the delta flow field on 25 June 2018, although the whole delta extended for more than 3 km along the coast. Dark red areas were active flows, shaded purple areas indicate lava flows erupted in 1840, 1955, 1960, and 2014-2015. Courtesy of HVO.
Figure (see Caption) Figure 417. At Kīlauea's LERZ fissure 8 delta, small breakouts were observed in the morning of 27 June 2018 in the area of Kapoho Beach Lots on the N flank of the flow delta near the ocean. The lava channel had crusted over about 0.8 km inland of the ocean entry; lava was moving beneath the crust and into the still-molten interior of earlier flows before it entered the sea. This thermal map shows the fissure system and lava flows as of 0600 on 27 June 2018. The fountain at fissure 8 remained active, with the lava flow entering the ocean at Kapoho. Very small, short flows were observed near fissure 22. The black and white area is the extent of the thermal map. Temperature in the image is displayed as gray-scale values, with the brightest pixels indicating the hottest areas. The map was constructed by stitching many overlapping oblique images collected by a handheld thermal camera during a helicopter overflight of the flow field. The base is a copyrighted color satellite image (used with permission) provided by Digital Globe. Courtesy of HVO.
Figure (see Caption) Figure 418. A small overflow from the lava channel of Kīlauea's LERZ fissure 8 flow, visible on the left, was recorded by an Unmanned Aircraft System (UAS) flight. Small overflows on both sides of the channel occurred shortly after midnight on 27 June 2018 in the uppermost part of channel. None of these overflows extended past the existing flow field. The 'arm' is likely about 10 m long. Image by the U.S. Geological Survey and Office of Aviation Services, Department of the Interior. Courtesy of HVO.

The northern margin of the ocean entry flow field was the most active during the last few days of the month with lava entering the sea over a broad area (figure 419). A few burning areas were also observed on the S side of the flow and W of Highway 137. Field crews were able to make rough estimates of the velocity of the flow in the channel by timing the large blocks in the flow as they passed by islands within the channel and known points along the edges (figure 420). Volcanic gas emissions were very high from fissure 8 eruptions throughout June 2018 causing trade winds to bring Vog (volcanic air pollution, a hazy mixture of SO2 gas and aerosols) to the central, south, and western parts of the Island of Hawaii on many occasions. Substantial SO2 plumes were recorded daily (figure 421).

Figure (see Caption) Figure 419. At the Kapoho coast, lava from Kīlauea's LERZ fissure 8 entered the ocean over a broad area along the northern margin of the flow field on 30 June 2018. Courtesy of HVO.
Figure (see Caption) Figure 420. Lava flowed rapidly around islands in the lava channel of Kīlauea's LERZ fissure 8 flow on 30 June 2018. The direction of flow was from the upper right to lower left. Field crews were able to make a rough calculation of velocity by timing large blocks as they passed between two landmarks that were a known distance apart. Courtesy of HVO.
Figure (see Caption) Figure 421. Volcanic gas emissions were very high from Kīlauea's LERZ fissure 8 eruptions throughout June 2018 causing trade winds to bring VOG to the central, south, and western parts of the Island of Hawaii on many occasions. Large plumes of SO2 were identified with satellite instruments on numerous days of the month; 4, 13, 20, and 22 June, shown here, were just a few of the days where large SO2 plumes drifted SW on trade winds across the southern and western margins of the island of Hawaii. The island of Hawaii is 150 km from the N tip to the S tip. Courtesy of NASA Goddard Space Flight Center.

Thermal observations during May-June 2018. The MODVOLC thermal alert system captures infrared data from satellite instruments (MODIS) that indicate the location of hot-spots around the planet. The data collected for Kīlauea for May and June 2018 clearly indicated the size and scope of the eruptive episode (figures 422 and 423). At the end of April, infrared data indicated strong activity at Halema'uma'u and weak activity from the episode 61g flow that originated on the flank of Pu'u 'O'o (figure 422). The first MODVOLC thermal alert of activity on the LERZ appeared 6 May; even though the lava lake had begun to drop, there was still a strong thermal signal at Halema'uma'u that day as well. As the eruption progressed during May, the increasing size of the effusive activity that included lava flows reaching the SE coast was apparent.

Figure (see Caption) Figure 422. Selected maps showing MODVOLC thermal alert pixels at Kīlauea for May 2018. An overflowing lava lake at Halema'uma'u and the episode 61g flow that originated on the flank of Pu'u 'O'o were captured in the infrared data in late April. The first MODVOLC alert on the LERZ appeared in the first week of May, and continued to grow throughout the month; the signal at Halema'uma'u was gone by mid-May. Courtesy of MODVOLC.

By early June, just a few days after the flow-volume increase on the LERZ from the channel emerging from fissure 8, the new pattern of heat flow to the N and NE around Kapoho Cone was recorded in the satellite data. The growing delta filling Kapoho Bay generated a strong infrared signal throughout the month. Although the fissure 8 flow was essentially unchanged in its thermal output on 22 and 23 June based on ground observations, the infrared data for those two days was significantly different, likely reflecting atmospheric conditions that blocked satellite views. In spite of this, the general nature of the flow activity is still clear in the data. By the end of June, the extent of the MODVOLC thermal alert pixels clearly indicated the robust nature of the continuing eruption.

Figure (see Caption) Figure 423. In early June 2018 the new pattern of heat flow to the N and NE around Kapoho Cone was recorded in satellite thermal data. The growing delta filling Kapoho Bay generated a strong infrared signal throughout the month. A change in meteoric conditions, not a change in flow activity, was likely responsible for the change in signal on 22 and 23 June. By the end of June, the extent of the MODVOLC thermal alert pixels clearly indicated the robust nature of the continuing eruption.

Geologic Background. Kilauea overlaps the E flank of the massive Mauna Loa shield volcano in the island of Hawaii. Eruptions are prominent in Polynesian legends; written documentation since 1820 records frequent summit and flank lava flow eruptions interspersed with periods of long-term lava lake activity at Halemaumau crater in the summit caldera until 1924. The 3 x 5 km caldera was formed in several stages about 1,500 years ago and during the 18th century; eruptions have also originated from the lengthy East and Southwest rift zones, which extend to the ocean in both directions. About 90% of the surface of the basaltic shield volcano is formed of lava flows less than about 1,100 years old; 70% of the surface is younger than 600 years. The long-term eruption from the East rift zone between 1983 and 2018 produced lava flows covering more than 100 km2, destroyed hundreds of houses, and added new coastline.

Information Contacts: Hawaiian Volcano Observatory (HVO), U.S. Geological Survey, PO Box 51, Hawai'i National Park, HI 96718, USA (URL: http://hvo.wr.usgs.gov/); NASA Goddard Space Flight Center (NASA/GSFC), Global Sulfur Dioxide Monitoring Page, Atmospheric Chemistry and Dynamics Laboratory, 8800 Greenbelt Road, Goddard, Maryland, USA (URL: https://so2.gsfc.nasa.gov/); Hawai'i Institute of Geophysics and Planetology (HIGP) - MODVOLC Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/).


Sabancaya (Peru) — December 2018 Citation iconCite this Report

Sabancaya

Peru

15.787°S, 71.857°W; summit elev. 5960 m

All times are local (unless otherwise noted)


Frequent ash plumes continued during June-November 2018

Sabancaya has been continuously active in recent years after renewed unrest began in February 2013 following almost 10 years of quiescence. After an increase in seismicity and an increase in the volume and frequency of fumarole emissions, the first explosion of the current eruption occurred in November 2016. Since then, activity has largely consisted of ash plumes and fumarolic activity.

This report summarizes activity during June-November 2018 (table 3) and is based on reports by the Observatorio Vulcanológico division of El Instituto Geológico, Minero y Metalúrgico (OVI-INGEMMET) and Instituto Geofísico del Perú (IGP), and satellite data. During this time the average daily number of explosions was 22, and ranged from 13 to 30. Maximum ash plume heights varied between 1.3 to 4.5 km above the crater, with the maximum plume heights each month usually between 2.5 and 3.7 km. SO2 emissions were variable and reached a maximum of 14,859 tons per day and the drift directions were wind dependent (figure 51).

Table 3. Summary of eruptive activity at Sabancaya during June-November 2018 based on OVI-INGEMMET weekly reports and the HIGP MODVOLC hotspot monitoring algorithm.

Month Avg. Daily Explosions by week Max Plume Heights (m above crater) Plume Drift MODVOLC Alerts Max SO2 tons/day
Jun 2018 24, 19, 29, 24 1,300-2,500 20-30 km, E, S, SE 19 3,000-5,600
Jul 2018 22, 23, 25, 24 1,300-2,500 20-30 km, S, SE, E 12 4,715-14,859
Aug 2018 19, 23, 27, 25, 25 2,600-4,500 30-50 km, N, NE, S, SE 27 2,230-5,000
Sep 2018 17, 13, 16, 21 2,500-3,700 30-50 km, N, NE, S, SE, NW 28 1,600-3,970
Oct 2018 24, 17, 23, 30 2,500-3,500 30-50 km, N, NE, SE, S, SW, W 21 2,200-5,027
Nov 2018 30, 18, 20, 20, 21 2,500-3,700 30-40 km, N, E, SE, S, SW, W, NW 35 2,300-4,600
Figure (see Caption) Figure 51. Examples of SO2 plumes from Sabancaya detected by the NASA Ozone Monitoring Instrument (OMI) in July, September, and October 2018 (dates, times, and SO2 max values are given in the header of each image). Courtesy of NASA Goddard Flight Center.

During June, Sabancaya produced 19-29 explosions per day that ejected ash plumes up to heights of 1.3-2.5 km above the crater (figure 52). These ash plumes extended to 20-30 km away from the volcano. The maximum emissions of SO2 throughout the month ranged from 3,500 to 5,600 tons per day. There was a total of 19 MIROVA thermal anomalies.

Figure (see Caption) Figure 52. An IGP webcam recorded an ash plume at Sabancaya that reached 1,500 m above the crater on 21 June 2018. Courtesy of IGP via OVI-INGEMMET (RSSAB-25-2018 18-24 June 2018 report).

Throughout July there were on average 22-25 explosions per day. Ash plumes reached heights of 1.3-2.5 km above the crater, and drifted 20-30 km to the S, SE, and E (figure 53). On 23 July, Sabancaya produced a continuous ash plume that traveled over 100 km to the SE (figure 54). SO2 emissions were higher this month, with maximum emissions reaching 14,859 tons per day. Twelve MODVOLC thermal alerts were issued.

Figure (see Caption) Figure 53. An ash plume rising through meteorological clouds at Sabancaya on 16 July 2018. Courtesy of IGP via OVI-INGEMMET (RSSAB-29-2018 16-22 July 2018 report).
Figure (see Caption) Figure 54. The ash plume at Sabancaya on 23 July 2018 traveled over Chachani, Misti, and Ubinas volcanoes, and the Quinistaquillas, Carumas, and Calacoa districts. Courtesy of OVI-INGEMMET (13 August 2018 report).

There were an average of 19-27 explosions per day throughout August (figure 55). Ash plumes reached maximum heights of 2.6-4.5 km, and drifted 30-50 km away in various directions. Activity generated two ash plumes on 24 August, one to 4 km above the crater at 0800 and the other to 4.5 km at 0945 (figure 56). The ash was dispersed to the NE, N, and E for 30 km over the towns of Chivay, Yanque, Coporaque, Ichupampa, Achoma, Maca and Pinchollo. On the 25th, an explosion at 1020 produced an ash plume to over 3 km above the crater that resulted in ashfall in the towns of Achoma, Maca and Pinchollo. There were 28 MODVOLC thermal alerts throughout the month. The maximum SO2 emissions reached 2,230-5,000 tons per day.

Figure (see Caption) Figure 55. Photograph of an explosion producing an ash plume at Sabancaya in early August 2018, taken while OVI-INGEMMET installed monitoring equipment. Courtesy of OVI-INGEMMET (10 August 2018 report).
Figure (see Caption) Figure 56. An ash plume at Sabancaya on 24 August 2018 at 0947 that reached a 4.5 km above the crater. The ash was dispersed 30 km to the NE, N, and E, and impacted the towns of Chivay, Yanque, Coporaque, Ichupampa, Achoma, Maca, and Pinchollo. Courtesy of OVI-INGEMMET (27 August 2018 report).

There was an average of 13-21 explosions per day during September, with ash plumes reaching 2.5-3.5 km above the crater. The ash traveled 30-50 km away in different directions (figure 57). There were 28 MODVOLC thermal alerts issued throughout the month, consistent with elevated thermal activity that is visible in Sentinel-2 satellite images (figure 58). The maximum measured SO2 emissions were 1,600-3,970 tons per day. A drone overflight by the IGP and the Pontifical Catholic University of Peru (PUCP) in the third week of September gave the first view of the crater since the eruption began in 2016 (figure 59), revealing lava in the crater and at least six ash emission points.

Figure (see Caption) Figure 57. Sentinel-2 satellite image of an ash plume at Sabancaya on 17 September 2018. The ash plume was directed towards the NE, then the SE. Natural color (bands 4, 3, 2) image courtesy of Sentinel Hub Playground.
Figure (see Caption) Figure 58. Sentinel-2 satellite images showing elevated thermal activity (bright orange-red) in the Sabancaya crater on the 7 and 22 September 2018. False color (urban) images (bands 12, 11, 4) courtesy of Sentinel Hub Playground.
Figure (see Caption) Figure 59. Drone video of the Sabancaya crater was taken in September 2018 showed lava on the crater floor and ash emissions from six locations. This image is a screenshot taken from video collected during the collaborative overflight by IGP and the Pontifical Catholic University of Peru. Courtesy of IGP (24 September 2018 report).

Similar activity continued through October, with an average of 17-30 reported explosions per day. Ash plumes reached maximum heights of 2.5-3.5 km and dispersed 30-50 km in various directions (figure 60). Ashfall was reported in the Huanca area during the week of 1-7 October. Maximum SO2 emissions were 2,200-5,027 tons per day. There were 21 MODVOLC thermal alerts issued for the month.

Figure (see Caption) Figure 60. An example of an ash plume at Sabancaya on 28 October 2018. Courtesy of OVI-INGEMMET (RSSAB-43-2018 22-28 October weekly report).

November 2018 marked two years of uninterrupted activity at Sabancaya (figure 61). Between November 2016 and November 2017 there were 14,000 registered explosions with an average of 39 per day. From November 2017 to November 2018 there were more than 9,800 explosions recorded with an average of 27 per day. During the month there was an average of 18-30 explosions per day, with ash plumes reaching maximum heights of 2.5-3.7 km above the crater and dispersing 30-40 km in all directions. This month saw the highest number of MODVOLC thermal alerts with a total of 35. The maximum detected SO2 emissions were 2,300-4,600 tons per day.

Figure (see Caption) Figure 61. Graph showing the number of explosions per day at Sabancaya from November 2017 through to November 2018. Courtesy of IGP (6 November 2018 report).

Geologic Background. Sabancaya, located in the saddle NE of Ampato and SE of Hualca Hualca volcanoes, is the youngest of these volcanic centers and the only one to have erupted in historical time. The oldest of the three, Nevado Hualca Hualca, is of probable late-Pliocene to early Pleistocene age. The name Sabancaya (meaning "tongue of fire" in the Quechua language) first appeared in records in 1595 CE, suggesting activity prior to that date. Holocene activity has consisted of Plinian eruptions followed by emission of voluminous andesitic and dacitic lava flows, which form an extensive apron around the volcano on all sides but the south. Records of historical eruptions date back to 1750.

Information Contacts: Observatorio Volcanologico del INGEMMET, (Instituto Geológical Minero y Metalúrgico), Barrio Magisterial Nro. 2 B-16 Umacollo - Yanahuara Arequipa, Peru (URL: http://ovi.ingemmet.gob.pe; video URL: https://www.youtube.com/watch?v=CpLhruMwuxQ); Instituto Geofisico del Peru, Observatoria Vulcanologico del Sur (IGP-OVS), Arequipa Regional Office, Urb La Marina B-19, Cayma, Arequipa, Peru (URL: http://ovs.igp.gob.pe/); NASA Goddard Space Flight Center (NASA/GSFC), Global Sulfur Dioxide Monitoring Page, Atmospheric Chemistry and Dynamics Laboratory, 8800 Greenbelt Road, Goddard, Maryland, USA (URL: https://so2.gsfc.nasa.gov/); Sentinel Hub Playground (URL: https://www.sentinel-hub.com/explore/sentinel-playground).


Santa Maria (Guatemala) — December 2018 Citation iconCite this Report

Santa Maria

Guatemala

14.757°N, 91.552°W; summit elev. 3745 m

All times are local (unless otherwise noted)


Ash plumes, degassing, and avalanches continue during May-October 2018 with occasional lahars

Santa Maria is one of the most active volcanoes of Guatemala. The volcano is composed of a large edifice that reaches over 3.7 km above sea level; the Santiaguito dacitic dome complex to the SW, with the active Caliente dome, rises to a height of over 2.5 km (figure 77). The Santiaguito dome complex is situated in a large crater that formed during a catastrophic eruption in 1902. Growing since 1922, this complex has recently been characterized by dome-growth activity that includes degassing, ash plumes, avalanches, pyroclastic flows, lava flows, and lahars. This report summarizes activity from May through October 2018, and is based on reports by Guatemala's INSIVUMEH (Instituto Nacional de Sismologia, Vulcanologia, Meterologia e Hidrologia) and satellite data. During this period, activity consisted of degassing, ash plumes, and avalanches at the Caliente dome, and lahars in multiple tributaries. Intermittent low-power thermal anomalies were detected throughout this period (figure 78).

Figure (see Caption) Figure 77. Santa Maria volcano consists of an older, larger peak to the NW and the Santiaguito dome complex to the SW. Top: The currently-active dome, Caliente, is situated in the 1.5-km-wide collapse crater. Bottom: The Caliente dome has fresh, unstable material accumulating in the crater that is prone to avalanches; image of the dome on 8 August 2018 (4-10 August 2018 weekly report). Courtesy of INSIVUMEH.
Figure (see Caption) Figure 78. Log radiative power MIROVA plot of MODIS infrared data at Santa Maria for May through November 2018. Courtesy of MIROVA.

Throughout May, active degassing of the dome produced white plumes up to 3.2 km above sea level. Frequent weak to moderate explosions produced white and gray ash plumes up to 3.3 km that were dispersed to the SW, W, and SE. As many as 15 explosions were recorded per day. Avalanches frequently occurred on the SE flank of the Caliente dome. The first lahar of the year was generated by rainfall on 10 May and traveled down the Cabello de Angel-Nimá I river. The lahar was composed of abundant fine material with larger branches and blocks up to 1 m in diameter, and it smelled of sulfur. The lahar deposit was 15 m wide and 1.2 m thick. A second lahar descended along the same path on 24 May and emplaced a deposit with a width of 18 m, a depth of 2 m, and blocks up to 2 m in diameter.

During June, white plumes associated with degassing of the Caliente dome often reached altitudes of 2.9 km, with a maximum of 3.9 km on 5 June. An average of 9-11 weak to moderate explosions per day ejected white and gray ash plumes up to 3.1-3.3 km altitude that were dispersed to the SW, W, and SE (figures 79 and 80). Ashfall was reported in Monte Claro on 26 June. Avalanches were recorded most days on the SE side of the dome due to ongoing growth. Lahars were reported on 13, 14, and 16 June down the Nimá I and Cabello de Ángel tributaries of the Samalá River (figures 81 and 82).

Figure (see Caption) Figure 79. A moderate explosion from the Caliente dome at Santa Maria generated an ash plume on 10 June 2018. Courtesy of INSIVUMEH (9-15 June 2018 weekly report).
Figure (see Caption) Figure 80. During the week of 23-30 June 2018 there was an average of 11 weak to moderate explosions per day at Santa Maria, as well as short avalanches on the S side of the dome. Left: a moderate explosion producing a plume from the Caliente dome. Right: Seismicity associated with activity of the dome including weak to moderate explosions. Courtesy of INSIVUMEH (modified from 23-30 2018 June report).
Figure (see Caption) Figure 81. Real-time Seismic-Amplitude Measurement (RSAM) graph showing four peaks corresponding to lahars on the 13 and 14 June 2018. The lahars traveled from Santa Maria down the Nimá I and Cabello de Ángel tributaries of the Samalá River. Courtesy of INSIVUMEH (9-15 June 2018 weekly report).
Figure (see Caption) Figure 82. The seismic signal produced by a lahar at Santa Maria on 16 June 2018. The lahar traveled down the Nimá I river channel. Courtesy of INSIVUMEH (16-22 June 2018 weekly report).

Throughout July, degassing of the dome and fumarolic activity produced white plumes reaching 3 km. These plumes were dominantly directed towards the SW and SE, and on a few days towards the N and W. Explosions frequently produced white and gray ash plumes up to 11 times per day (figure 83). Ash plumes often reached approximately 3.2 km altitude, drifted SE, SW, and W, and frequently deposited ash on the flanks. On 4 July an explosion produced incandescent material up to 150 m above the crater and the accompanying sound was heard in areas including El Palmar, Pueblo Nuevo, and San Felipe Retalhuleu. Avalanches most often occurred on the SE flank of the dome, with some occurring on the N, NE, and W flanks (figure 84). Incandescence was observed on the 11 July.

Figure (see Caption) Figure 83. Examples of plumes from moderate (top) and weak (bottom) explosions at Santa Maria's Caliente dome in July 2018. Courtesy of INSIVUMEH (July 1-6 and 21-27 July 2018 weekly reports, respectively).
Figure (see Caption) Figure 84. Avalanches on Santa Maria's Caliente dome during July 2018. Top: A small avalanche on the SE flank of the dome (7-13 July 2018 weekly report). Bottom: A moderate avalanche on the SE flank of the dome (21-17 July 2018 weekly report). Courtesy of INSIVUMEH.

Through August, degassing of the dome regularly produced white plumes up to a maximum observed altitude of 3.2 km (figure 85). Explosions generated white and gray ash plumes up to 3.1-3.3 km on most days, with a maximum of 13 explosions recorded per day. Gas-and-steam and ash plumes were often dispersed to the SE and sometimes towards the W. Ashfall often occurred on the slopes. Avalanches on the dome were recorded most days on the SE flank and sometimes on the E, NE, and W flanks. On 17 August at 1330 a lahar emplaced a deposit 18 m wide and 2.5 m thick, with blocks up to 3 m in diameter.

Figure (see Caption) Figure 85. Degassing of the Santa Maria Caliente dome forming white plumes during August 2018. Courtesy of INSIVUMEH (27 July-3 August 2018 and 4-10 August 2018, respectively).

Throughout September, degassing and fumarole activity of the Caliente dome produced white plumes up to 3.1 km. Explosions produced ash plumes that reached altitudes of 3.3 km up to 13 times per day. Degassing and ash plumes were most often dispersed to the SW, and sometimes to the W and SE. Red discoloration of ash was noted on 4 September due to the oxidation of the dome rock where the explosion was generated (figure 86). Ashfall often occurred within the proximity of the volcano. Avalanches were often reported as constant on the SE flank of the dome and sometimes occurring on the NE and E flanks. On 12 September a lahar was recorded traveling down both tributaries of the Samalá River. A larger lahar was generated on 20 September in the San Isidro-Tambor tributaries of the Samala River with a width of 25 m and a thickness of 2 m. The lahar carried tree trunks and branches, and blocks up to 2 m in diameter. A third lahar occurred on 24 September down the Cabello de Ángel River, with a width of 15 m, a thickness of 1.5 m, and carrying blocks up to 2 m in diameter.

Figure (see Caption) Figure 86. Oxidation in and around the crater of Caliente dome (top) at Santa Maria occurs due to the high temperatures and causes red discoloration of the rock. This leads to discolored plumes as seen on 4 September 2018 (bottom). Courtesy of INSIVUMEH (1-7 October 2018 weekly report).

Degassing at the dome during October produced white plumes to a maximum altitude of 3.2 km (figure 87). Explosions generated white and gray ash plumes up to 3.2 km, with up to 11 explosions recorded per day and an average of 8-9 per day. Plumes were often directed towards the SE, and sometimes to the W and NW. Ashfall frequently occurred on the slopes and was reported in Monte Claro on 16 and 26 October. Avalanches were frequent on the SE flank of the dome, and sometimes occurred on the W and NE flanks (figure 88). Incandescent material was observed during explosions on the 23rd. Two lahars were generated on 9 October; one traveled down the Cabello de Ángel river channel with a width of 20 m, a thickness of 2 m, and carrying blocks as large as 3 m in diameter. The second was 15-m-wide with a thickness of 1 m and blocks as large as 2 m in diameter which traveled down the San Isidro River.

Figure (see Caption) Figure 87. The Caliente dome of Santa Maria, the active dome of the Santiaguito dome complex. Top: degassing at the edge of the crater on 15 October 2018. Bottom: A moderate explosion that produced an ash plume with abundant gas on 16 October. Courtesy of INSIVUMEH (13-19 October 2018 weekly report).
Figure (see Caption) Figure 88. An avalanche on the NE flank of the Caliente dome of Santa Maria on 25 October 2018 with the corresponding seismic signal that lasted 3 minutes and 40 seconds. Courtesy of INSIVUMEH (20-26 October 2018 weekly report).

Geologic Background. Symmetrical, forest-covered Santa María volcano is part of a chain of large stratovolcanoes that rise above the Pacific coastal plain of Guatemala. The sharp-topped, conical profile is cut on the SW flank by a 1.5-km-wide crater. The oval-shaped crater extends from just below the summit to the lower flank, and was formed during a catastrophic eruption in 1902. The renowned Plinian eruption of 1902 that devastated much of SW Guatemala followed a long repose period after construction of the large basaltic-andesite stratovolcano. The massive dacitic Santiaguito lava-dome complex has been growing at the base of the 1902 crater since 1922. Compound dome growth at Santiaguito has occurred episodically from four vents, with activity progressing E towards the most recent, Caliente. Dome growth has been accompanied by almost continuous minor explosions, with periodic lava extrusion, larger explosions, pyroclastic flows, and lahars.

Information Contacts: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia e Hydrologia (INSIVUMEH), Unit of Volcanology, Geologic Department of Investigation and Services, 7a Av. 14-57, Zona 13, Guatemala City, Guatemala (URL: http://www.insivumeh.gob.gt/ ); MIROVA (Middle InfraRed Observation of Volcanic Activity), a collaborative project between the Universities of Turin and Florence (Italy) supported by the Centre for Volcanic Risk of the Italian Civil Protection Department (URL: http://www.mirovaweb.it/).


Stromboli (Italy) — December 2018 Citation iconCite this Report

Stromboli

Italy

38.789°N, 15.213°E; summit elev. 924 m

All times are local (unless otherwise noted)


Explosive activity produced ash, lapilli, and bombs, with occasional spattering during July-October 2018

Stromboli is a persistently-active volcano that currently has five active vents in the crater terrace area that sits above the steep slope of the Sciara del Fuoco. For several decades, activity has been focused at three main craters, the North crater (N area) and the Central and South craters (CS area), each with multiple frequently-active vents.

This report summarizes activity for July-October 2018 (table 4) and is based on reports by Istituto Nazionale di Geofisica e Vulcanologia (INGV) and satellite data. Intensities associated with explosions are based on the following heights of material ejected from the crater and are as follows. Very low is less than 40 m; low is 40-80 m; medium is 80-150 m; and high is greater than 150 m (figure 131). Overall, the intensity of all vents ranged from very low to medium, with variations in the eruption of ash and lapilli to bomb-sized material (less than 2 mm, 2-64 mm, and over 64 mm, respectively). The variations in activity of the five active vents during July-October is seen in Sentinel-2 thermal satellite data (figure 132).

Table 4. Activity at Stromboli during July-October 2018 summarized by vent areas: N Area (North) with vents N1 and N2; CS Area (central-south) with vents C, S1, and S2. Maximum reported heights for each month are given as meters above the crater. Data courtesy of INGV weekly reports.

Month N Area Activity CS Area Activity
Jul 2018 N1: Explosions ejected lapilli and bombs with some ash up to heights of 200 m. N2: Explosions ejected ash, lapilli, and bombs up to 200 m. The average explosion frequency for the N-Area was 1-19 per hour. C: Continuous degassing with intense Spattering on the 26th. S1: Gas jets with some ash, lapilli, blocks up to 80 m. S2: Explosions with ash, lapilli, blocks up to 150 m. The average explosion frequency for the CS-Area was 1-11 per hour.
Aug 2018 N1: Explosions ejected lapilli and bombs with some ash up to 140 m. N2: Explosions ejected lapilli and bombs with occasional spattering up to 140 m. The average explosion frequency for the N-Area was 2-20 per hour. C: Continuous degassing at two points, intense spattering on the 27th. Some explosions ejected material up to 120 m. S1: Explosive activity and gas jets, incandescent material up to 150 m. S2: Explosive activity ejected material up to 80 m. Major explosion occurred at the CS area on the 18th.The average explosion frequency for the CS-Area was 1-15 per hour.
Sep 2018 N1: Explosions ejected lapilli and bombs with some ash up to 140 m. N2: Explosions ejected mainly ash with some lapilli and bombs up to 150 m. The average explosion frequency for the N-Area was 2-12 per hour. C: Two emission points with continuous degassing, interrupted by explosions and spattering. S1: Jets of incandescent material up to 120 m. S2: Explosive activity with some ash and lapilli up to 120 m, two active vents from the 10th. The average explosion frequency for the CS-Area was 4-20 per hour.
Oct 2018 N1: Explosions ejected lapilli and bombs with some ash up to 150 m. N2: Explosions ejected mostly ash with some lapilli and bombs up to 150 m. The average explosion frequency for the N-Area was 1-13 per hour. C: Two emission points with continuous degassing interrupted by occasional spattering and explosions. S1: Jets of incandescent material up to 120 m. S2: Variable explosive activity ejecting material up to.120 m. The average explosion frequency for the CS-Area was 6-20 per hour.
Figure (see Caption) Figure 131. A thermal image of the active craters of Stromboli showing the Central-South crater (Area CS) and northern crater (Area N), with the active vents S1, S1, C, N1, N2. The white horizontal lines show the heights attributed to explosion intensity: low (bassa), medium (media), and alta (high). Image taken on 29 October 2018, courtesy of INGV (Report No. 44/2018, released on 30 October 2018).
Figure (see Caption) Figure 132. Infrared Sentinel-2 satellite images showing thermal variations at vents on Stromboli during July-October 2018. The active vents are shown in bright yellow-orange and gas plumes appear as light blue-white areas emanating from the vents. Courtesy of Sentinel Hub Playground.

During July Strombolian activity continued with explosions of low to medium-low intensity in the N Area; variable explosions ejected mainly lapilli and bombs along with some ash at the N1 vent, and mainly ash with lapilli and bombs at the N2 vent. Explosive activity was absent or sporadic at the N2 vent during 4-5 July. There was a rapid increase in explosion frequency at the N1 vent on the 14th, and on the 16th lapilli and bombs were ejected. During 16-29 July explosive activity in the N Area was focused at the N2 vent. The average frequency of explosions in the N area ranged from 1-19 per hour. Explosion intensity in the CS Area ranged from low to medium at both the S1 and S2 vents. The C vent produced continuous degassing that was interrupted by intense spattering on the 26th. Activity at the S1 vent was characterized as jets with some ash, lapilli, and blocks, and explosions with ash, lapilli, and blocks occurred at the S2 vent. The average frequency of explosions in the CS area ranged from 1 to 11 per hour during July. The total number of explosions at Stromboli increased in mid-July and remained elevated compared to previous months through the end of October (figure 133).

Figure (see Caption) Figure 133. Graph showing the average number of explosions at Stromboli per day from 1 January to 20 October 2018. The red data are for the N crater area, green are for the CS crater area, and dark blue are the total explosions per day for all active vents. There was a period from mid-January to mid-July when there was a reduction in the frequency of explosions, which then increased to around a total of 15-30 per day. Courtesy of INGV (Report No. 44/2018 released on 30 October 2018).

Similar activity continued through August with the exception of a strong explosion at the C vent that lasted approximately one minute at 1508 on 18 August (figure 134). The explosion ejected an ash plume that rapidly dissipated. Coarse pyroclastic material fell on the crater terrace area and the upper part of the Sciara del Fuoco, and rolled down to the ocean. Occasional intense spattering at the C vent was also observed on the 27th, interrupting the continuous degassing from two vents. Medium to low, and occasionally high-intensity gas jets that incorporated incandescent material were frequent at the S1 vent through August. Low- to medium-intensity explosive activity occurred at the S2 event throughout the month. Explosions averaged 1-11 per hour for the entire CS area during August. The N area produced variable explosions that ejected lapilli and bombs with some ash at the N1 vent. During 8-12 August most of the activity in the N area continued to be focused at the N2 vent, and during this time it produced intense spattering activity. During the rest of the month activity at the N2 vent was characterized by variable explosive activity that produced lapilli and bombs with occasional spattering. The average frequency of explosions for the month was 2-20 per hour.

Figure (see Caption) Figure 134. The major explosion at the Stromboli C vent on 18 August 2018 as seen in thermal and photograph images. The brief (less than one minute) explosion produced an ash plume that deposited material around the vent and on the Sciara del Fuoco. Courtesy of INGV (Report No. 34/2018 released on 21 August 2018).

The typical activity persisted through September with explosions producing ash, lapilli, and blocks (figures 135 and 136), gas jets with incandescent material (figures 137 and 138), and degassing. Over the month there was an average of 2-12 explosive events per hour at the N area, and an average of 4-20 events per hour at the CS area. Variable explosions that ejected lapilli and bombs with some ash characterized activity at the N2 vent, and mainly ash with some lapilli and bombs were typically ejected at the N1 vent. Continuous emissions originated from two points within the C vent and was occasionally interrupted by explosions and spattering. Jets of gas and incandescent material continued at the S1 vent and explosive activity with some ash and lapilli occurred at the S2 vent. The S2 vent had two active points from the 10 September onwards.

Figure (see Caption) Figure 135. Ash plumes and degassing on 10 September. Courtesy of Benjamin Simons, The University of Auckland.
Figure (see Caption) Figure 136. Thermal infrared video screenshots showing multiple active vents in the Stromboli central-south crater area on 10 September 2018. Vents are actively degassing and explosions eject hot lapilli and blocks at two craters. Courtesy of Benjamin Simons, The University of Auckland.
Figure (see Caption) Figure 137. A gas jet with incandescent lapilli and bombs from the Stromboli central-south crater area on 10 September 2018. White gas plumes are visible emanating from other vents in the central-south and north craters. Courtesy of Benjamin Simons, The University of Auckland.
Figure (see Caption) Figure 138. Screenshots of a video showing a gas jet with incandescent lapilli, bombs, and ash from the Stromboli Central-South crater area on 10 September 2018. A large bomb can be seen ejecting from the vent in the top photo. White plumes are a result of degassing of the surrounding vents. Courtesy of Benjamin Simons, The University of Auckland.

During October variable explosions continued to produce low-to medium-intensity explosions that ejected lapilli and bombs, and sometimes ash, at the N1 vent, and very low- to low-intensity explosions that produced mostly ash with some lapilli and bombs at the N2 vent. Explosions averaged 1-13 events per hour through the month. The CS area produced a higher average of 6-20 explosions per hour for October. Sustained degassing continued at two points in the C vent. Low- to medium-low-intensity jets on incandescent material occurred at the S1 vent, and the same intensity of explosive activity was reported at the S2 vent.

Geologic Background. Spectacular incandescent nighttime explosions at Stromboli have long attracted visitors to the "Lighthouse of the Mediterranean" in the NE Aeolian Islands. This volcano has lent its name to the frequent mild explosive activity that has characterized its eruptions throughout much of historical time. The small island is the emergent summit of a volcano that grew in two main eruptive cycles, the last of which formed the western portion of the island. The Neostromboli eruptive period took place between about 13,000 and 5,000 years ago. The active summit vents are located at the head of the Sciara del Fuoco, a prominent scarp that formed about 5,000 years ago due to a series of slope failures which extends to below sea level. The modern volcano has been constructed within this scarp, which funnels pyroclastic ejecta and lava flows to the NW. Essentially continuous mild Strombolian explosions, sometimes accompanied by lava flows, have been recorded for more than a millennium.

Information Contacts: Istituto Nazionale di Geofisica e Vulcanologia (INGV), Sezione di Catania, Piazza Roma 2, 95123 Catania, Italy (URL: http://www.ct.ingv.it/en/); Benjamin Simons, The University of Auckland, 23 Symonds Street, Auckland, 1010, New Zealand (URL: https://unidirectory.auckland.ac.nz/people/profile/bsim836); Sentinel Hub Playground (URL: https://www.sentinel-hub.com/explore/sentinel-playground).

Atmospheric Effects

The enormous aerosol cloud from the March-April 1982 eruption of Mexico's El Chichón persisted for years in the stratosphere, and led to the Atmospheric Effects section becoming a regular feature of the Bulletin. Descriptions of the initial dispersal of major eruption clouds remain with the individual eruption reports, but observations of long-term stratospheric aerosol loading will be found in this section.

Atmospheric Effects (1980-1989)  Atmospheric Effects (1995-2001)

Special Announcements

Special announcements of various kinds and obituaries.

Special Announcements  Obituaries

Misc Reports

Reports are sometimes published that are not related to a Holocene volcano. These might include observations of a Pleistocene volcano, earthquake swarms, or floating pumice. Reports are also sometimes published in which the source of the activity is unknown or the report is determined to be false. All of these types of additional reports are listed below by subject.

Additional Reports  False Reports