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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).

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Bulletin of the Global Volcanism Network - Volume 39, Number 02 (February 2014)

Managing Editor: Richard Wunderman

Ahyi (United States)

Seismic/acoustic signals and bathymetric data validate April-May 2014 eruption

Kelud (Indonesia)

Eruption with plume top over 26 km altitude; ~7 deaths and over 100,000 refugees

Ritter Island (Papua New Guinea)

Report includes past geothermal activity observations

Sangay (Ecuador)

Absence of evidence for ongoing eruption; new hazard maps

Sangeang Api (Indonesia)

Ashfall from 30 May 2014 eruption causes evacuations, airline delays

Telica (Nicaragua)

Small explosions in September 2013; a new intracrater vent

Whakaari/White Island (New Zealand)

Dome extrusion in late 2012 and further eruptions in 2012-2013



Ahyi (United States) — February 2014 Citation iconCite this Report

Ahyi

United States

20.42°N, 145.03°E; summit elev. -75 m

All times are local (unless otherwise noted)


Seismic/acoustic signals and bathymetric data validate April-May 2014 eruption

Ahyi seamount is located ~20 km SE of Farallon de Pajaros and was discussed in the Bulletin associated with volcanic unrest in 1979 (SEAN 04:01) and in 2001 (BGVN 26:05). The evidence for a 2014 eruption at Ahyi seamount includes seismicity, noises heard by divers and felt aboard a vessel in the area, and a follow-up research cruise to Ahyi that measured a hydrothermal plume and significant bathymetric changes since the last survey in 2003. This report is revised from an earlier version.

The U.S. Geological Survey (USGS) reported that, beginning about 0635 local time on 24 April 2014 (2035 on 23 April 2014, UTC), seismometers in various locations in the Mariana Islands began recording T-phase signals interpreted as stemming from an undersea eruption in an area to the N of Pagan island near the island of Uracas (also known as Farallon de Pajaros). Note that throughout this report, at the suggestion of William Chadwick of NOAA, 'T-phase signals' have been used in lieu of 'earthquakes' since all the eruption-related signals were hydroacoustic (from underwater explosions) rather than seismic body-waves. See the final section of this report for a brief definition of T-phase waves. The eruption was ultimately tracked to Ahyi seamount (figures 2 and 3).

Figure (see Caption) Figure 2. Map of the western Pacific margin showing the Northern Mariana Islands with the location of Ahyi volcano added. Original map from Magellan Graphix (1957).
Figure (see Caption) Figure 3. (left) A bathymetric map showing the islands and seamounts making up the Mariana island arc. The rectangular box on that map delineates the N part of the arc that is shown on the map at right. (right) A larger scale bathymetric map that highlights features in the vicinity of Ahyi seamount; within the yellow-lined box is the islands unit of the Mariana Trench Marine National Monument. Maps courtesy of Susan Merle, Oregon State University and NOAA-PMEL.

Seismometers that recorded the 2014 T-phase signals included those on Saipan, Pagan, Sarigan, and Anatahan islands (figure 2). The USGS reported recording T-phases during 24 April through 8 May 2014. During this same period, hydroacoustic sensors on Wake Island (~2,300 km ENE from Ahyi) also received signals. The recorded events all indicated that the source of the hydroacoustic signals was at or near Ahyi seamount, but the accuracy of the initially determined locations remained uncertain because there are other active volcanic seamounts in the area.

On 25 April 2014 the Aviation Color Code was raised by the USGS from Unassigned (Volcanic Alert Level: Unassigned) to Yellow (Volcanic Alert Level: Advisory). As of 29 May, USGS had received no reports of an eruption plume or any evidence that eruptive products had reached the surface. Satellite images showed nothing indicative of a volcanic eruption. On 29 May the Aviation Color Code was lowered by the USGS to Unassigned (Volcanic Alert Level: Unassigned).

At the time of the T-phase signals in April 2014, submarine explosions were heard and felt by scuba divers conducting coral reef research in the area. Chip Young, leader of the Hi'ialakai expedition working in the area as part of a coral reef survey by the NOAA Pacific Islands Fisheries Science Center (PIFSC), provided the following information on 28-29 April 2014. At this stage, the source of the signals was still a mystery.

"While we were diving [on 26 April at Farallon de Pajaros (FDP)] we could hear eruptions underwater. It wasn't casual, in fact, it sounded like bombs exploding with the concussion felt through your body. I don't know how close we were to the event, none of the…divers saw volcanic activity, but at least one explosion was so powerful, that it reverberated through the hull of the ship and the crew onboard thought that something had happened to the ship (at the time they didn't realized we too were hearing these explosions under water)."

"The first divers' comments about hearing something underwater started at Asuncion (4/24-4/25). We were at FDP on [26 April] and to my best guess, the massive explosion that I previously wrote about occurred 0100-0230 26 APR 14 UTC on the SE side of FDP. There were plenty of other explosions throughout the day, but that was the largest one I experienced. There were conglomerates/mats of orange+yellow bubbles on the surface of the water on the SE coastline of FDP as well. We had a very calm day at FDP, so the mats/sludge stretched on for 20-30 ft [~7-9 m] or more. These could have been from Ahyi, but visual disturbances near Ahyi weren't specifically made because we passed there in the early [morning] on the way to FDP and then in the evening on the way to Maug. We did hear explosions underwater at Maug too. I heard distant explosions, which I assumed were from FDP, but there were closer ones too. Not as violent as the sounds we heard at FDP, but 'cracks' for sure."

During the height of the T-phase swarm, explosive signals from the underwater eruption source in the vicinity of Ahyi were occurring at a rate of ~20 per hour. On 16 May 2014, the USGS reported that over the preceding week, T-phase signals had greatly diminished.

Verification of 2014 Ahyi eruption. A subsequent expedition took place during 12-18 May, after the eruption T-phases had stopped. This expedition, led by Chip Young and Dave Butterfield aboard the R/V Hi'ialakai, was working at Maug island (~50 km SSE of Ahyi) and conducted several water-column CTD (conductivity-temperature-depth) casts in the area. They found a hydrothermal plume coming from Ahyi. In addition, they collected new bathymetric data over the summit of Ahyi, which showed the depth changes that confirmed that Ahyi was indeed the source of the 2014 eruption.

According to William Chadwick, NOAA surveyed Ahyi in 2003, measuring a summit depth of 60 m. After the T-phase signals declined in mid-May 2014, the NOAA ship Hi'ialakai went over the summit and the new minimum depth was found to be 75 m. In addition, a new summit crater is evident in the 2014 bathymetry that is ~95 m deep. Bloomer and others (1989) noted a value of 137 m as Ahyi's summit depth, based on U.S. Navy Sonar Array Sounding System (SASS), an early form of multibeam sonar. This pre-2003 summit depth value is probably less accurate and therefore does not necessarily represent a true depth change between the SASS survey and 2003.

Figure 4B shows the results of multibeam sonar bathymetry over Ahyi's summit collected by the Hi'ialakai in 2014. This map was compared to their previous survey in 2003 (figure 4A) and used to compose a third map (figure 4C) showing depth differences between the two surveys. In essence, the summit elevation dropped by 25 m; a crater had developed with a floor at a depth of 195 m; and a conspicuous landslide chute descended to at least 2,300 m depth along the SE slope. Up to 125 m of material was removed from the head of the landslide chute, and constructional deposits downslope were up to 40 m thick. The map analysts noted that even though the 2014 re-survey was limited and produced an incomplete look at the entire Ahyi edifice, the changes were very clear and indicated recent eruptive activity at Ahyi.

Figure (see Caption) Figure 4. Three maps (frames A, B, C) showing multibeam bathymetry and analyses of bathymetric changes between surveys of 2003 and May 2014 of Ahyi volcano (white areas signify lack of data). (A) Bathymetry of Ahyi volcano conducted 2003 showing a cone with summit at a depth of 65 m (Merle and others, 2003). (B) Ahyi map from survey conducted May 2014. The cone was gone and was replaced by a new crater with a rim at 90 m depth and a floor at 195 m depth. The current minimum summit depth for the volcano at 75 m resides near the location on figure 4B labeled "crater rim ~90 m." Extending SSE from the new crater, the research disclosed a new landslide chute descending to at least 2,300 m depth. (C) Depth changes comparing 2003 and 2014 maps. As defined on key at lower left, the cool colors signify material removed; green, no change; and warm colors, material added. Labels indicate elevation changes disclosed in the comparison (e.g. -20 m means this area is 20 m lower on the 2014 map than on the 2003 map). Map courtesy of Susan Merle, Oregon State University and NOAA/PMEL.

T-phase waves: According to Okal (2011) "T phases are defined as seismic recordings of signals having traveled an extended path as acoustic waves in the water body of the oceans. This is made possible by the 'Sound Fixing and Ranging' (SOFAR) channel, a layer of minimum sound velocity acting as a wave guide at average depths of 1,000 m. It allows the efficient propagation of extremely small signals over extremely long distances, in practice limited only by the finite size of the ocean basins."

The use of T-waves has led to much improved diagnosis of submarine vent locations. For example, Fox and Dziak (1998) described the detection of intense seismicity the NE Pacific Ocean using the T-phase Monitoring System developed by NOAA/PMEL to access the U.S. Navy's SOund SUrveillance System (SOSUS) in the North Pacific. Dziak and Fox (2002) discussed monitoring of hydroacoustic signals from the Volcano Islands arc, S of Japan (just N of the N Mariana Islands shown in figure 2), a region with frequent submarine eruptions. The signals are characterized by a narrowband, long-duration, high-amplitude fundamental centered at 10 Hz with three harmonics at 20, 30, and 40 Hz. The hydroacoustic (T-wave) signals are consistent with harmonic tremor signals observed using traditional seismic methods at active subaerial volcanoes throughout the world.

References. Bloomer, S.H., Stern, R.J., and Smoot, N.C., 1989, Physical volcanology of the submarine Mariana and Volcano Arcs, Bulletin of Volcanology, v. 51, pp. 210-224.

Bloomer, S.H., Stern, R.J., Fisk, E., and Geschwind, C.H., 1989, Shoshonitic Volcanism in the Northern Mariana Arc 1. Mineralogic and Major and Trace Element Characteristics, Journal of Geophysical Research, v. 94, no. B4, pp. 4469-4496.

Dziak, R.P., and Fox, C.G., 2002, Evidence of harmonic tremor from a submarine volcano detected across the Pacific Ocean basin, Journal of Geophysical Research, v. 107, no. B5, p. 2085.

Fox, C.G., and Dziak, R.P., 1998 (December), Hydroacoustic detection of volcanic activity on the Gorda Ridge, February-March 1996, Deep Sea Research Part II: Topical Studies in Oceanography, v. 45, no. 12, pp. 2513-2530 (DOI: 10.1016/S0967-0645(98)00081-2).

Magellan Graphix, 1997, Map: Northern Mariana Islands (territory of US) (URL: http://www.infoplease.com/atlas/state/northernmarianaislands.html).

Merle, S., Embley, R., Baker, E., and Chadwick, B., 2003, Submarine Ring of Fire 2003 - Mariana Arc R/V T.G. Thompson Cruise TN-153, February 9-March 5, 2003, Guam to Guam, Cruise Report, NOAA-PMEL (URL: http://www.pmel.noaa.gov/eoi/marianas/marianas-crrpt-03.pdf).

Okal, E.A., 2011, T Waves, in Gupta, H.K. (ed), Encyclopedia of Solid Earth Geophysics, pp. 1421-1423, Springer Netherlands (DOI: 10.1007/978-90-481-8702-7_165).

USGS, 2014 (30 April), Northern Mariana Islands Information Statement, Wednesday, April 30, 2014 5:36 AM ChST (Tuesday, April 29, 2014 19:36 UTC) (URL: http://volcanoes.usgs.gov/activity/archiveupdate.php?noticeid=10031).

USGS, 2014 (1 May), A new submarine eruption in the Northern Mariana Islands: could it happen here?, Hawaii Volcano Observatory (URL: http://hvo.wr.usgs.gov/volcanowatch/view.php?id=226).

USGS, 2014 (16 May), Current Alerts for U.S. Volcanoes, Northern Mariana Islands Weekly Update, 16 May (URL: http://volcanoes.usgs.gov/nmi/activity//status.php).

USGS, 2014 (23 May), Northern Mariana islands Weekly Update, 23 May 2014 (URL: http://volcanoes.usgs.gov/nmi/activity/index.php).

Geologic Background. Ahyi seamount is a large conical submarine volcano that rises to within 75 m of the ocean surface ~18 km SE of the island of Farallon de Pajaros in the northern Marianas. Water discoloration has been observed there, and in 1979 the crew of a fishing boat felt shocks over the summit area, followed by upwelling of sulfur-bearing water. On 24-25 April 2001 an explosive eruption was detected seismically by a station on Rangiroa Atoll, Tuamotu Archipelago. The event was well constrained (+/- 15 km) at a location near the southern base of Ahyi. An eruption in April-May 2014 was detected by NOAA divers, hydroacoustic sensors, and seismic stations.

Information Contacts: NOAA Pacific Marine Environmental Laboratory (NOAA-PMEL), 7600 Sand Point Way NE, Bldg #3, Seattle, WA 98115 (URL: http://www.pmel.noaa.gov/); William W. Chadwick and Susan Merle, NOAA-PMEL Earth-Ocean Interactions Program and Oregon State University; David A. Butterfield, University of Washington and NOAA-PMEL; Charles (Chip) Young, NOAA Fisheries, Pacific Islands Fisheries Science Center (PIFSC); Matt Haney, U.S. Geological Survey (USGS), Alaska Volcano Observatory (AVO), Anchorage, AK 99508; USGS Volcano Hazards Program (URL: http://volcanoes.usgs.gov/nmi/activity/); and CNMI Emergency Management Office (URL: http://www.cnmihomelandsecurity.gov.mp/).


Kelud (Indonesia) — February 2014 Citation iconCite this Report

Kelud

Indonesia

7.935°S, 112.314°E; summit elev. 1730 m

All times are local (unless otherwise noted)


Eruption with plume top over 26 km altitude; ~7 deaths and over 100,000 refugees

On 13 February 2014, the Indonesian National Board for Disaster Management (Badan Nasional Penanggulangan Bencana-BNPB) reported that a major eruption occurred at Kelut (also known as Kelud) volcano in East Java, Indonesia. Ground-based observers had little insight about the ash plume height, but a number of satellite observations helped to constrain the height and other eruption parameters such the direction of plume movement. CALIPSO satellite data revealed that a rapidly rising portion of the plume ejected material up to an altitude exceeding ~26 km, well into the tropical stratosphere. Most of the less rapidly rising portions of the plume remained lower, at 19-20 km altitude. The 2014 eruption destroyed a dome emplaced in the volcano's caldera during the previous eruption in 2007 (BGVN 33:03 and 33:07). According to BNPB in a report issued on 18 February 2014, ~7 people were killed and ~100,000 evacuated. At least one commercial aircraft flew into the plume, later landing successfully but incurring costly engine damage.

This report discusses the pre- and syn-eruption observations from the early January through 25 February 2014. Much of the detailed reporting used here came from the Indonesian Centre for Volcanology and Geological Hazard Mitigation (CVGHM; also known as Pusat Vulkanologi dan Mitigasi Bencana Geologi, PVMBG). Kelut is located just S of Surabaya (Surabaja), Indonesia's second largest city (see figure 8 in BGVN 33:03).

Pre-eruption. According to CVGHM, the lake-water temperature in the crater increased 5.5°C during 10 September 2013 to 2 February 2014. During 1 January-2 February 2014 the number of shallow volcanic earthquakes at Kelut volcano increased. During 3-10 February 2014, seismic activity at Kelut was dominated by both shallow and deep volcanic earthquakes; some hypocenters were 3 km below the summit. Real-time Seismic-Amplitude Measurement (RSAM, a gauge of volcanic seismicity) values increased on 6 and 9 February 2014. Inflation was detected at one station.

Peaks of pre-eruptive seismicity occurred during 15-16 and 28 January, and 2-13 February. Table 3 also portrays the available early 2014 seismic data from CVGHM, but it can be hard to see the aforementioned detail because the various entries on table's rows generally summarize multiple days and some of the time intervals differ. The number of deep volcanic earthquakes fluctuated but generally increased overall. Earthquakes often occurred at 2-8 km depth. Based on these observations, on 2 February the Alert Level was raised to from 1 to 2 (on a scale with increasing severity in the range 1-4). Tiltmeter data on 10 February indicated inflation.

Table 3. Seismicity at Kelut volcano during January and into 13 February 2014. Note that the data stream changed abruptly on 13 February when four of Kelut's 5 seismic stations were destroyed by eruptive material. Courtesy of CVGHM.

Time period 2014 (no. of days) Shallow/deep volcanic earthquakes (VB / VA) Deep/local tectonic earthquakes (TJ) (nr-none reported) Low frequency earthquakes (LF)
1-7 Jan (7) 14 / 1 44 / -- 4
8-14 Jan (7) 18 / 4 32 / -- 2
15-21 Jan (7) 38 / 34 27 / -- 0
22-31 Jan (10) 234 / 74 79 / 2 1
1-3 Feb (3) 111 / 30 3 / -- 0
3-10 Feb (8) 693 / 297 50 / -- 0
13 Feb (1) 440 / 1,135 1 / 3 198

Crater lake water temperatures continued to increase after September 2013, particularly during 23 January-9 February. Temperatures decreased slightly when measured on 10 February. On 10 February, based on the factors noted above, CVGHM increased the Alert Level to 3. This excluded visitors and residents from within a 5-km radius of the crater.

Eruption on 13 February. At 2115 on 13 February the Alert Level for Kelut was raised to 4, extending the exclusionary zone to a 10-km radius. As noted above, BNPB reported that a major eruption occurred less than two hours later at 2250, followed by another large explosion at 2330. NASA reported that satellite images showed the Kelut eruption about 2 hours later on 13 February 2014 at ~2315 local time (1615 UTC).

According to a Darwin VAAC (2014) weekly activity report, the eruption was seen on the hourly MTSAT-2 IR satellite for 1632 UTC (2332 local time) on 13 February, where it appeared as a rapidly expanding cloud. More details came from 10-minute IR data being used on a special basis in the High Ice Project in Darwin, which captured the eruption clearly as a small cluster of cold pixels on a 1610 UTC (2310 local time) IR image. Later analysis found a small low altitude plume as early as 1540 UTC (2240 local time) at Kelut on the MTSAT-1R satellite; this is the earliest reported start time for the eruption.

According to CVGHM, ash plumes rose to an altitude of 17 km and caused ashfall in areas NE, NW, W, and elsewhere as far as Pacitan (133 km WSW), Kulon Progo (236 km W), Temanggung (240 km WNW), and Banyuwangi (228 km E). As ash began to blanket parts of the region, 40 airline flights were cancelled; impacted airports included Juanda (81 km NE), Adi Sucipto Yogya (208 km W), and Adi Sumarmo Solo (175 km WNW). News articles reported that flights in and out of seven airports were cancelled or rerouted.

Figures 15 and 16 show satellite images of the plume taken on 13 February 2014. The image at the top of figure 15 portrays the scene at 0030 local time and the trace of the path across it taken by the satellite. At ~1813 UTC on 13 February. CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation). CALIPSO flew over the plume deploying CALIOP (a lidar instrument, essentially a laser range finder that creates a profile of clouds and particles in the atmosphere). This is one of the favored instruments for cloud height measurement. It is part of the A-Train, a constellation of multiple satellites and instruments that follow the same track on polar orbits and cross the equator within seconds to minutes of each other. This allows near-simultaneous observations. CALIOP data revealed that the Kelut ash cloud was generally at an altitude of 18-19 km, with some cloud/ash material reaching a maximum height of ~26 km. This is sufficiently high, and the A-Train data capabilities are sufficiently large to cause great interest, and more refined estimates of height and other parameters are likely to follow.

Figure (see Caption) Figure 15. Figure 15 (top and bottom). At 0030 local time (1730 UTC 13 February) on 14 February, the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi NPP satellite acquired the top image as the gray circular ash plume over Kelut reached above a lighter-colored weather-cloud deck. Forty minutes later, at 0110 local time (1810 UTC 13 February), the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite flew over the plume with its lidar instrument. The instrument recorded the ash cloud at nearly 20 km altitude, with sections of the plume reaching to nearly 26 km. Courtesy of NASA Earth Observatory; image by Jesse Allen, using data provided by the CALIPSO team; caption by Holli Riebeek.
Figure (see Caption) Figure 16. A cross-section through the Kelut volcanic plume from data acquired on 14 February 2014. The image zooms in on CALIPSO data for the tallest parts of the volcanic cloud (using the CALIOP data). The white line shows the approximate troposphere-stratosphere boundary. Some wave structure (small white oscillations) is apparent in the umbrella region. The vertical scale on the left shows computed altitude, and on the lower right shows the color scale for intensity of the 532 nm wavelength backscatter. The horizontal scale and labels at the bottom of the figure shows the latitude, longitude, and time in UTC for the vertical sounding across the transect. The red trace across the bottom of the figure shows land topography, with the volcano at the center. The AIRS (atmospheric infrared sounder) determined SO2 brightness temperature differences (BTD-scale at upper right) referring to features such as the red stars, where AIRS detected SO2 towards the edge of the cloud. Courtesy of Carn and Telling (2014).

Figure 17 shows a view of an eruption at 0030 local time on 14 February. In Figure 18, a plane, service vehicle, and boarding area are shown covered by ash at Yogyakarta airport, 215 km E of Kelut. Closer to the volcano, ashfall and tephra blocks 5-8 cm in diameter caused structures to collapse, including schools, homes, and businesses.

Figure (see Caption) Figure 17. A photo of the eruption of Kelut at 0030 on 14 February 2014, with lightning being generated in the ash plume. Courtesy of Volcano Discovery web site (URL: http:pic.twitter.com/ypy7kx9615 / @hilmi_dzi).
Figure (see Caption) Figure 18. Image of a tan-colored ash blanket covering the landscape, including a parked jet liner and service vehicle, at Yogyakarta airport, 215 km W of Kelut, taken 14 February 2014. Image from NBC News web site (BIMO SATRIO / EPA).

As a result of this eruption, four of the five Kelut seismic stations were destroyed, after which, volcanic and low-frequency earthquakes were not recorded. Subsequently, available seismicity recorded at the one remaining station, 5 km away, was dominated by continuous tremor with amplitudes ranging from 0.5 to 15 mm. That station later recorded declining seismicity during 14-20 February. Two more seismic stations were installed on 16 February, 2-3 km from the crater.

On 14 February, gray-to-black plumes rose 400-600 m above the crater, and on 15 February grayish white plumes rose as high as 3 km (figure 19).

Figure (see Caption) Figure 19. The eruption of Kelut (labeled just to the right of the image's center) on 13 February 2014 sent a large plume of ash drifting W across Java and over the Indian Ocean. This satellite image, acquired 14 February, shows widespread tan atmospheric discoloration from the ash plume. According to an advisory issued by the Australian Bureau of Meteorology, ash had reached 13 km in altitude, prompting the closure of several airports. Three people were killed, and Indonesian authorities have evacuated more than 75,000 people from their homes. NASA Earth Observatory, image by Jesse Allen and caption by Adam Voiland, using data from the Land Atmosphere Near real-time Capability for EOS (LANCE).

On 14 February BNPB reported that the eruption had killed four people (but later estimates were higher): one died due to a collapsing wall, one from ash inhalation, and two from "shortness of breath." All four victims lived within 7 km of Kelut in the regency of Malang, an area that received ashfall up to 20 cm thick.

By 0600 on 14 February, BNPB reported that the number of displaced people reached 100,248, but the report also noted that volcanic activity had declined. Later that day BNPB noted that 76,388 people remained evacuated. Seismicity continued to decline and was at moderate levels during 15-17 February. During 16-20 February white plumes rose as high as 1 km and drifted N, NE, and E. Data from satellite instruments provided a 14 February 2014 image on sulfur dioxide (SO2) from Kelut (figure 20). The plume had spread primarily W of the volcano.

Figure (see Caption) Figure 20. Sulfur dioxide burdens measured from Kelut (red triangle) over the Indonesian island of Java and Indian Ocean in the early morning of 14 February 2014 following the Kelut eruption. This image is based on data from the IASI instrument on the MetOp mission. Courtesy of European Space Agency (2014).

Heavy rain on 18 February caused lahars in Ngobo, Mangli (Kediri, 35 km WNW), Bladak (Blitar, 20 km SW), and Konto (Malang, 35 km E). BNPB noted that the lahars flooded five houses and one mosque, and destroyed two homes and one bridge. An 18 February BNPB report noted that a total of 7 people in Malang regency had died, and that the ashfall had affected farms, including cattle health and dairy production, and the water supply. Damage to infrastructure in Malang included 3,782 houses, 20 government buildings, 251 schools, 9 hospitals, and 36 churches.

The Alert Level was lowered from 4 to 3 on 20 February and to 2 on 28 February based on decreased amplitude of tremors and thick clouds of white smoke continuously emitted from the crater instead of dark grey. At this point, visitors and residents were prohibited from approaching the crater within a radius of 5 km, but residents outside of this zone were permitted to return home.

Only a single pixel MODVOLC satellite thermal alert was measured during the interval from 13 February through March 2014. The alert occurred at 1515 hours UTC on 20 February 2014, the first alert measured since nearly daily alerts from Kelut's last eruption, 18 November 2007-23 January 2008. During the February 2014 eruption, cloudy weather over Kelut was a major factor that precluded some alerts from being measured, but those visualized suggest that the recent Kelut eruption continued until at least 20 February 2014.

A satellite image made available thanks to the International Charter Space and Major Disasters (2014) was acquired on 18 February and interpreted by the U.S. Geological Survey. The image reveals the impact of the eruption on the summit area and regions peripheral to it (figure 21).

Figure (see Caption) Figure 21. Satellite image of the crater area of Kelud, acquired on 18 February 2014. The former dome was destroyed during the 14 February eruption and significant ash and debris were deposited on the volcano slopes and in the river channels from lahars and pyroclastic flows around the volcano. Steam can be seen rising from the central crater. Courtesy of International Charter Space and Major Disasters (2014); source was WorldView, acquired 18/02/2014 by DigitalGlobe Inc.; map produced by USGS, and found online at Klemetti (2014c).

Later visits disclosed that the 2014 eruption had left a large crater 400 m in diameter and destroyed the 2007 dome, parking area, and access stairs in the crater (see figures 22 and 23).

Figure (see Caption) Figure 22. Photograph of the inner dome in Kelut volcano taken in 2010, showing the then- existing lava dome from the 2007 eruption and the access stairs to the crater, both of which were destroyed by the February 2014 eruption. Image courtesy of Zahidayat / Flickr, from Klemetti (2014b).
Figure (see Caption) Figure 23. (Left) The Kelut lava dome that grew in the crater in 2007, photographed 30 October 2011 by Andersen (2011). In front of the dome was the small portion of what was left of the volcanic lake that used to fill the crater. (Right) The crater of Kelut seen on the morning of 18 February 2014 (photo by Suwarno, a local photographer, via Andersen), showing that the 2014 eruption forcefully removed the dome. Comparison figure came from Andersen (2014).

A group of photographs taken by Oystein Lund Andersen (2014) during a visit from 22 to 23 February show after-eruption images, including steam rising from the crater area, ash and volcanic bombs deposited 2-5 km from Kelut's crater, and damage to trees and other vegetation by pyroclastic flows (for example, Figures 24 and 25). In addition, photographs showed that steam continued to rise from the crater through 25 February 2014. Andersen observed that activity at the volcano has decreased, but it was still unknown what exactly the situation at the vent is, whether or not a new lava dome is forming there.

Figure (see Caption) Figure 24. Steaming pyroclastic flow deposits in one of the valleys below the crater, a once forested area ~1 km SW of the crater .Photo taken at 1157 on 22 February 2014. Courtesy of Andersen (2014).
Figure (see Caption) Figure 25. A lush green forest once stood here, now covered by deposits from a pyroclastic flow and scattered remains of large felled trees. Photo taken at 1205 on 22 February 2014. Courtesy of Andersen (2014).

Airliner encounters plume. A commercial A320 airliner carrying passengers from Perth, Australia, to Jakarta, Indonesia, encountered an ash plume from Kelut near Indonesia on 14 February 2014. The incident was reported by the West Australian (Perth) newspaper and the Sydney Morning Herald (14 February). The reports noted that the airliner left Perth on 14 February 2014 at 0225 local time and flew through the ash cloud before arriving safely in Jakarta at 0550 local time. The estimated cost to replace the two engines of the Airbus aircraft was reported to be $20 million (US dollars). The A320 was grounded after the flight.

Morning Herald reporter Amanda Hoh (2014) reported that a "flight from Perth to Jakarta on Friday morning was filled with smoke after the plane flew into Indonesia's volcanic ash cloud…Richard Craig, from Perth, was on a flight to Jakarta at about 5am on Friday [14 February] when he said the plane suddenly flew into the ash cloud about 30 minutes before landing" Passenger Craig was quoted to have said "It was just starting to get light then it suddenly went quite dark and what I thought was smoke appeared in the cabin out the front, started coming out of the air vent and alarm went off and beeped a few times," he said. "There was an unusual smell. It wasn't like smoke, a slightly sweet smell. More like a very fine smoke…" The smoke cleared within a few minutes and Craig noted that the pilot announced that "it was a volcanic ash cloud and that 'no one was aware of it in the area.'" The plane landed safely.

Summary of damage. According to the International Federation of Red Cross and Red Crescent Societies (IFRC) (2014), "over the first few days the eruption affected 201,228 people (58,341 families) from 35 villages in three districts: Blitar, Kediri, and Malang... As of 14 February 2014, there had been seven fatalities and 70 people in hospitals in serious condition suffering from ash inhalation. Around this time the number of internally displaced persons (IDPs) had reduced to 100,248 people who had evacuated and camped across the province in 172 IDP camps set up to cater for their basic needs... In addition to the volcanic ash, heavy rain fell and produced cold lahar flooding in Malang, Kediri and Blitar districts. This caused further damage to buildings, farm lands, and roads."

Table 4 gives data on damage to structures in the 3 affected districts surrounding Kelut through February 2014. The figures are expected to increase once a more thorough assessment is made.

Table 4. An initial assessment of the damage to housing and other buildings as a result of Kelut eruption volcanic ash. Courtesy of IFRC (2014).

District Totally damaged Moderately damaged Minor damaged
Kediri 8,622 5,426 5,088
Malang 1,514 1,066 1,378
Bitar 957 878 1,578
Totals 11,093 7,370 8,044

As reported on 24 February 2014 in the Jakarta Globe (Pitaloka, 2014), "torrential rain in East Java on 23 February 2014 prompted local officials to impose a safety curfew over some areas affected by the eruption of Mount Kelud for fear that rainwater could mix with volcanic dust, triggering mud flows." The Head of the Malang Disaster Mitigation Agency, Hafi Lutfi, said rain had triggered landslides that damaged several sections of mountain road. "A mud flow in Padansari village on Thursday [13 February] washed away two houses and two bridges, although no casualties were reported... Volcanic mud was carried down the mountain's slopes by the river, which flows through Kasembon, Ngantang and Pujon subdistricts" (figure 26).

Figure (see Caption) Figure 26. Villagers stand on the remains of a bridge washed out in Malang district near Pandansari village. The bridge succumbed to water mixed with volcanic material from Mount Kelut's eruption on 19 February 2014. From Pitaloka (2014); EPA photo by Fully Handoko.

Lutfi was reported to have stated further that the "impact of Mount Kelud's eruption will extend far beyond the initial cleanup efforts. Fruit farmers reportedly lost more than Rp 24 billion ($2 million) in revenue as ash and debris destroyed whole fields of apples, durian and rambutan that were ready for harvest. The trees, covered in a thick coating of ash, had withered from lack of sunlight."

Background. The CVGHM reported that activity at Kelut last occurred in 2007, beginning with an increase in seismic activity and an eruption in October 2007. The activity ended with an effusive eruption on 3-4 November 2007 resulting with a crater lake surrounding a central lava dome (BGVN 33:03, 33:07, and 37:03).

References. Andersen, O.L., 2014 (22 February), Kelud Volcano, East-Java, Indonesia (URL: http://www.oysteinlundandersen.com/Volcanoes/Kelud/Kelud-Volcano-Indonesia-February-2014.html)

Andersen, O.L., 2011 (30 October), Mt. Kelud Volcano, Indonesia, 30 October 2011(URL: http://www.oysteinlundandersen.com/Volcanoes/Kelud/Kelud-Volcano-Indonesia-October-2011.html).

Carn, S., and Telling, J., 2014, Kelut 2014, IAVCEI (International Association of Volcanology and Chemistry of the Earth's Interior) Remote Sensing Commission (RSC) (URL: https://sites.google.com/site/iavceirscweb/eruptions/kelut-2014)

CIMSS Satellite Blog, 2014 (13 February), Eruption of the Kelut volcano in Java, Indonesia (URL: http://cimss.ssec.wisc.edu/goes/blog/archives/14910 ).

European Space Agency (ESA), 2014 (14 February), Kelut volcano grounds air travel, ESA Observing the Earth web site (URL: http://www.esa.int/Our_Activities/Observing_the_Earth/Kelut_volcano_grounds_air_travel).

Hoh, A., 2014 (14 February), Volcano eruption cancels Bali, Phuket flights and closes Indonesian airports, The Sydney Morning Herald (URL: 14http://www.smh.com.au/travel/travel-incidents/volcano-eruption-cancels-bali-phuket-flights-and-closes-indonesian-airports-20140214-32qd8.html)

International Charter Space and Major Disasters, (2014), Mount Kelud volcanic eruption in Indonesia (URL: http://www.disasterscharter.org/web/charter/activation_details?p_r_p_1415474252_assetId=ACT-481)

International Federation of Red Cross and Red Crescent Societies, 2014 (3 March), Emergency plans of action (EPofA), Indonesia: Volcanic eruption - Mt. Kelud (URL: http://reliefweb.int/sites/reliefweb.int/files/resources/MDRID009dref.pdf).

Klemetti, E., 2014a (11 February), Indonesian Eruption Update for February 11, 2014: Kelut and Sinabung (URL: http://www.wired.com/wiredscience/2014/02/indonesias-kelut-placed-highest-alert/)

Klemetti, E., 2014b (13 February), Significant Eruption Started at Indonesia's Kelut (URL: http://www.wired.com/wiredscience/2014/02/significant-eruption-started-indonesias-kelut/).

Klemetti, E., 2014c (24 February), Kelud, Before and After the Eruption (URL: http://www.wired.com/wiredscience/2014/02/kelud-eruption/).

National Aeronautics and Space Administration (NASA) Goddard Space Flight Center, 2014 (13 February), Kelut (Kelud) Eruption- February 13, 2014 (URL: http://so2.gsfc.nasa.gov/pix/special/2014/kelut/Kelut_summary_Feb14_2014.html)

Pitaloka, D.A., 2014 (24 February), Torrential Rain Worsens Kelud Misery, Jakarta Globe (URL: http://www.thejakartaglobe.com/news/torrential-rain-worsens-kelud-misery).

Volcano Discovery, 2014 (2 March), Kelut volcano news (URL: http://www.volcanodiscovery.Kelut volcano news & eruption updates _ 27 Sep 2007 - 2 Mar 2014.htm).

Geologic Background. The relatively inconspicuous Kelud stratovolcano contains a summit crater lake that has been the source of some of Indonesia's most deadly eruptions. A cluster of summit lava domes cut by numerous craters has given the summit a very irregular profile. Satellitic cones and lava domes are also located low on the E, W, and SSW flanks. Eruptive activity has in general migrated in a clockwise direction around the summit vent complex. More than 30 eruptions have been recorded since 1000 CE. The ejection of water from the crater lake during the typically short but violent eruptions has created pyroclastic flows and lahars that have caused widespread fatalities and destruction. After more than 5,000 people were killed during an eruption in 1919, an engineering project to drain the crater lake lowered the surface by more than 50 m. The 1951 eruption deepened the crater by 70 m, leaving 50 million cubic meters of water after the damaged drainage tunnels were repaired. Following more than 200 deaths in the 1966 eruption, a new deeper tunnel was constructed, and the lake's volume before the 1990 eruption was only about 1 million cubic meters.

Information Contacts: Indonesian Centre for Volcanology and Geological Hazard Mitigation – CVGHM (also known as Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG)), Jalan Diponegoro 57, Bandung 40122, Indonesia (URL: http://www.vsi.esdm.go.id/); Darwin Volcanic Ash Advisory Centre (VAAC), Australian Bureau of Meteorology, Northern Territory Regional Office, PO Box 40050, Casuarina NT 0811, Australia (URL: http://www.bom.gov.au/info/vaac); MODVOLC, Hawai'i Institute of Geophysics and Planetology (HIGP) 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/); Badan Nasional Penanggulangan Bencana (BNPB – Indonesian National Board for Disaster Management), Jl. Ir.H.Juanda No. 36 Jakarta Pusat, Indonesia (URL: http://www.bnpb.go.id); CIMSS (NOAA's Cooperative Institute for Meteorological Satellite Studies), University of Wisconsin – Madison's Space Science and Engineering Center (SSEC) (URL: http://cimss.ssec.wisc.edu/goes/blog/about); NOAA Satellite and Information Service, Automated OMI SO2 Alert System, High SO2 Concentration Areas (URL: http://satepsanone.nesdis.noaa.gov/pub/OMI/OMISO2/Alert/alert.html); National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (URL: http://so2.gsfc.nasa.gov); European Space Agency (URL: http://www.esa.int); West Australian (Perth) news (URL: http://au.news.yahoo.com/a/21467336/); Sydney Morning Herald (URL: http://www.smh.com.au); Andersen, Oystein Lund (URL: http://www.oysteinlundandersen.com/); IAVCEI Remote Sensing Commission website (URL: https://sites.google.com/site/iavceirscweb/eruptions/kelut-2014); and Simon Carn, Department of Geological and Mining Engineering and Sciences, Michigan Technical University, Houghton, MI.


Ritter Island (Papua New Guinea) — February 2014 Citation iconCite this Report

Ritter Island

Papua New Guinea

5.519°S, 148.115°E; summit elev. 75 m

All times are local (unless otherwise noted)


Report includes past geothermal activity observations

According to the Rabaul Volcanological Observatory, a "small (probably submarine) eruption was reported to have taken place at Ritter Island on 18 April 2014 (figures 2 and 3). At about 1700 hours, an earthquake was felt at Kampalap village on Umboi Island. At the same time the level of sea rose a little over normal but was confined to the beach at Kampalap. At around 0000 hours on 19 April, another felt earthquake occurred. The earthquakes were estimated to have an intensity at Kampalap of between II to III. No floating debris where seen, and no ash or damage was reported."

Figure (see Caption) Figure 2. Location maps for Ritter Island. The upper map shows the region of Papua New Guinea containing Ritter Island and other volcanoes, and the lower map is enlargement of the center of the upper map focused on Ritter Island. From Saunders and Kuduon (2009).
Figure (see Caption) Figure 3. Oblique aerial view of Ritter Island photographed in 2006 by John Holder (the originator of Oceanic Expeditions) from SW looking NE, with some of the location names. From Saunders and Kuduon (2009).

A Rabaul Volcanological Observatory (RVO) report by Saunder and Kuduon (2009) noted past possible geothermal activity on Ritter Island that had not been previously reported. According to their report, "In 1997 a patrol officer (Hita Mesere) in a media release relayed reports from Councilor Nalong (Kampalap Village?) of an explosive eruption and large waves reaching nearby villages. In the preparation of this report Mr. Mesere was contacted and he confirmed that he and officers from the Morobe PDO flew over Ritter after this event and saw white smoke coming from 'boiling' in the sea, close to land in the South Bay (Mesere, 2009 Pers. Comm.)."

The report concluded that "Ritter is active, both volcanically and geomorphologically. More volcanic activity can be expected. Seismically this will probably not be as intense as in the early 1970's, as the conduit seems now to be open. Volcanic phenomena may however increase in importance if the cone continues to grow towards the surface and magma is erupted into an environment of lower hydrostatic pressures. There seems to be two causes of eruptive activity, one is the rise of fresh magma at the site of the submarine cone and the other is slope instability causing water to come into contact with residual hot rocks leading to small hydrovolcanian events close inshore of Ritter."

The RVO report also included the following table (table 1) showing past observations of possible geothermal activity on Ritter Island.

Table 1. Dates and details of reported post-collapse activity at Ritter. From of Saunders and Kuduon (2009).

Date Seismic Intensity Explosions reported White steam reported Dust/Dark material reported Sound reported Location of emission
9 Oct. 1972 Felt 35 km away; regionally recorded Multiple Y Y Strong rumbling Inshore W (S Cove) & off terminal cusps
17 Oct. 1974 Felt 30 km away: recorded in PNG Multiple Y Y N Offshore ~1 km W
19 Oct. 1996? (Pilot report only) None reported N Y N N ?
1997 None reported Single or few Y N N Inshore W (S Cove)
17 Oct. 2006 Few small, locally felt N Y Y N Offshore ~1 km W
19 May 2007 None reported Several Y Y (and flames) Rumbling & 3 explosions Offshore ~1 km W

Tsunami of 1888. Several recent papers have revisited the 13 March 1888 collapse of Ritter Island volcano that generated a catastrophic tsunami. According to Ward and Day (2003), "In the early morning of 1888 March 13, roughly 5 km3 of Ritter Island Volcano fell violently into the sea northeast of New Guinea. This event, the largest lateral collapse of an island volcano to be recorded in historical time, flung devastating tsunami tens of meters high on to adjacent shores. Several hundred kilometers away, observers on New Guinea chronicled 3 min period waves up to 8 m high, that lasted for as long as 3 h. These accounts represent the best available first-hand information on tsunami generated by a major volcano lateral collapse." Eyewitness accounts noted the lack of explosive activity accompanying the collapse. In this paper, the authors simulated the Ritter Island landslide as constrained by a 1985 sonar survey of its debris field and compare predicted tsunami with historical observations.

Ray and others (2014) reported that, based on primary and secondary eyewitness accounts on the morning of 13 March 1888 "there is no clear evidence for a coincident [to the collapse] or causal magmatic explosive eruption. One report suggests that there was activity (perhaps phreatic or phreatomagmatic explosions?) prior to the collapse that lead some of the resident local communities to seek higher ground, but evidence for precursory flank movements or changes in eruptive style have not been found in the historical accounts."

References. Ray, M.J., Day, S., and Downes, H., 2014, The growth of Ritter Island volcano, Papua New Guinea, and the lateral collapse landslide and tsunami of 1888: new insights from eyewitness accounts, EGU General Assembly 2014, Geophysical Research Abstracts, v. 16, EGU2014-1305.

Saunders, S., and Kuduon, J., 2009, The June 2009 Investigation Of Ritter Volcano, With A Brief Discussion On Its Current Nature, Rabaul Volcanological Observatory Open File Report OFP 003/2009, 25 pp.

Ward, S.N., and Day, S. 2003. Ritter Island—lateral collapse and the tsunami of 1888. Geophysics Journal International, v. 154, pp. 891-902.

Geologic Background. Prior to 1888, Ritter Island was a steep-sided, nearly circular island about 780 m high between Umboi and Sakar Islands. Several historical explosive eruptions had been recorded prior to 1888, when large-scale slope failure destroyed the summit of the conical basaltic-andesitic volcano, leaving the arcuate 140-m-high island with a steep west-facing scarp. Devastating tsunamis were produced by the collapse and swept the coast of Papua New Guinea and offshore islands. Two minor post-collapse explosive eruptions, during 1972 and 1974, occurred offshore within the largely submarine 3.5 x 4.5 km breached depression formed by the collapse.

Information Contacts: Rabaul Volcanological Observatory, P.O. Box 386, Rabaul, Papua New Guinea.


Sangay (Ecuador) — February 2014 Citation iconCite this Report

Sangay

Ecuador

2.005°S, 78.341°W; summit elev. 5286 m

All times are local (unless otherwise noted)


Absence of evidence for ongoing eruption; new hazard maps

Previously reported activity from Sangay volcano (figure 14) included ash plumes as late as 23 May 2013 and satellite infrared thermal alerts ending in early May 2013 (BGVN 36:01). In that previous report, satellite thermal alerts from the MODVOLC system were noted to have persisted and as late as 4 May 2013. That lack of alerts continued as late as 16 July 2013 when the MODVOLC website was last checked. Since that reporting, there have been no new updates regarding Sangay on the website of the Instituto Geofisico (IG), the aviation reports have not mentioned Sangay, and other news of Sangay behavior has also been generally lacking.

Figure (see Caption) Figure 14. (Inset at bottom) A regional map showing Sangay with respect to large rivers and other features surrounding Sangay. Orange line is the PanAmerican highway, which passes near Río Bamba on the map's N. Major rivers (blue) are primary routes of lahars. (Main map) A hazards map for Sangay made with hazards focus and compiling the results of multiple kinds of modeling. Key (in Spanish) notes that the upper three colors were based on slope angle (H/L) with text noting gradation of hazards in those regions from pyroclastic flows, lava flows, ash falls, volcanic bombs, rock falls, and proximal lahars. The lower three colors on the key represent inferred gradations of lahar hazard at distance from the volcano. Dashed envelopes in red refer to boundaries for small and moderate sizes of ash falls. White line shows inferred boundary for an E directed debris avalanche. Base map is from the Instituto Geografico Militar (IGM). Taken from an online poster by Ordóñez and others, 2014).

Absence of MODVOLC and aviation alerts does not necessarily translate to a lack of eruptions. The MODVOLC system imposes a reasonably high threshold to the infrared data acquired from space. Factors such as weather conditions, snow pack, and geometry of the vent area may play a role. Emissions of spatter, ash fall, and small pyroclastic flows could easily be missed. Assessments are generally best made in conjunction with information at the volcano. The current eruption began on 8 August 1934 and is thus far confirmed only through 23 May 2013.

Hazard modeling and products. In late 2013 to early 2014 IG released a poster discussing Sangay hazards (Ordóñez and others, 2014), some of the results of which we reprint here (figures 14, 15, and 16). Figure 14 contains IGEPN's recently published a map of volcanic hazards associated with Sangay, which resides in the Cordillera Real between the cities of Río Bamba and Macas. The IG and others have generally considered Sangay one of the most active volcanoes in South America. The poster noted historical records of its eruptive activity dating back to 1628 (Hall, 1977) and in the last century some important periods of activity were recorded during 1903, 1934-1937, 1941-1942, 1975-1976, and 1995 to the present (Monzier et al.. 1999). Observations of surface activity carried out in the past 40 years allowed scientists to recognize some important morphological changes at the summit of the volcano, including the emergence of new craters, dome growth, extrusion of lava flows, local explosions and ash emissions, and relatively small pyroclastic flows.

Figure (see Caption) Figure 15. Modeled ash fall blanket from a hypothetical eruption at Sangay of moderate size. The key (in Spanish) refers to the colors in the key and on the isopach map, with thicknesses in millimeters. Taken from an online poster by Ordóñez and others (2014).
Figure (see Caption) Figure 16. Modeled ash fall blanket from a hypothetical eruption at Sangay of large size. The key (in Spanish) refers to the colors in the key and on the isopach map, with thicknesses in millimeters. Taken from an online poster by Ordóñez and others (2014).

A larger suite of volcanic hazards models is not shown here but includes results VolcFlow. Ash3D, Tephra2, and LAHARZ. The data used for the simulations were obtained from the few geological studies in this volcano (Hall, 1977; Monzier et al, 1999; Johnson et al, 2003). Sangay is judged in some ways analogous to Tungurahua volcano, because of its chemical composition, and it similar lava rheology and eruptive style of volcanic flows.

During August-September 2013, IG installed seismic monitoring instruments (broad band and infrasound ) and for the measurement of sulfur dioxide (SO2) in the southwestern flank of the volcano Sangay. These tools facilitate the monitoring of internal and surface activity of the volcano which will give an early warning of a potential hazards.

With regard to monitoring, during August-September 2013 IG personnel installed ~4 km southwest of Sangay volcano, permanent telemetered monitoring system consisting of a broadband seismic sensor, infrasound, and gas monitoring.

Figures 15 and 16 show the respective modeled results for a moderate and large eruption. To define the zones affected by ash fall, the modeling used the following computer routines based on assumptions and approaches discussed in the literature: Ash3d (Mastin and others, 2012) and Tephra2 (Banadonna and others, 2005). Some input data came from inferences and interpretations of descriptions by Monzier and others (1999) and from analogy with recent eruptions at Tungurahua. Plume heights were assumed to reach 10-15 km in altitude and the magma volumes in the plumes were assumed to be on the order of 0.001-0.005 km3 (dense-rock equivalent, DRE). Wind field data came from the Global Forecast System (NOAA, US National Weather Service, Environment Modeling Center). LAHARZ (Schilling, 1998), a modeling approach, was also taken to estimate the extent and coverage of lahars seen in figure 14. (The poster includes other maps on this topic as well.)

References. Bonadonna, C, Connor CB, Houghton BF, Byrne M, Laing A, Hincks T., 2005, Probabilistic modeling of tephra dispersal: Hazard assessment of a multi-phase eruption at Tarawera, New Zealand; J. Geophys. Res., 110, B03203.

Hall M. (1977). El Volcanismo en Ecuador. Publicación del Instituto Panamericano de Geografía e Historia, Sección nacional del Ecuador, Quito. 120pp.

Mastin, L, Schwaiger H, Denlinger R., 2012, User's Guide to Ash3d: A 3-D Eulerian Atmospheric Tephra Transportation and Dispersion Model, U.S. Geological Survey Open File Report.

Monzier M, Robin C, Samaniego P, Hall M, Cotten J, Mothes P, Arnaud N., 1999, J. Volcanol. Geotherm. Res. 90, 49-79.

Ordóñez J., Vallejo S., Bustillos J., Hall M., Andrade D., Hidalgo S., and Samaniego P., (Document created, December 2013; Accessed online July 2014), Volcan Sangay---Peligros Volcanicos Potenciales, Instituto Geofísico, Escuela Politécnica Nacional (IG-ESPN) (URL: http://www.igepn.edu.ec/volcan-sangay/mapa-de-peligros.html ).

Schilling S. (1998). LAHARZ: GIS programs for automated mapping of lahar-inundation hazard zones. US Geological Survey Open-File Report 98-638; 79 pp.

Geologic Background. The isolated Sangay volcano, located east of the Andean crest, is the southernmost of Ecuador's volcanoes and its most active. The steep-sided, glacier-covered, dominantly andesitic volcano grew within the open calderas of two previous edifices which were destroyed by collapse to the east, producing large debris avalanches that reached the Amazonian lowlands. The modern edifice dates back to at least 14,000 years ago. It towers above the tropical jungle on the east side; on the other sides flat plains of ash have been eroded by heavy rains into steep-walled canyons up to 600 m deep. The earliest report of an eruption was in 1628. Almost continuous eruptions were reported from 1728 until 1916, and again from 1934 to the present. The almost constant activity has caused frequent changes to the morphology of the summit crater complex.

Information Contacts: Instituto Geofísico-Escuela Politécnica Nacional (IG), Casilla 17-01-2759, Quito, Ecuador (URL: http://www.igepn.edu.ec/); Washington Volcanic Ash Advisory Center (VAAC), Satellite Analysis Branch (SAB), NOAA/NESDIS E/SP23, NOAA Science Center Room 401, 5200 Auth Rd, Camp Springs, MD 20746, USA (URL: http://www.ospo.noaa.gov/Products/atmosphere/vaac/); and 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/).


Sangeang Api (Indonesia) — February 2014 Citation iconCite this Report

Sangeang Api

Indonesia

8.2°S, 119.07°E; summit elev. 1912 m

All times are local (unless otherwise noted)


Ashfall from 30 May 2014 eruption causes evacuations, airline delays

Due to elevated seismic activity, the Indonesian Center for Volcanology and Geologic Hazard Mitigation (CVGHM) issued an alert for Sangeang Api volcano on 21 May 2014. On 30 May 2014 at 1555, CVGHM reported an eruption of the island volcano that generated an explosive eruption column of ash and sulfur dioxide into the atmosphere, extending >3 km above the summit (figure 8). While the 13-km-wide island of Sangeang has no permanent settlements or residents, dozens of farmers cultivate land on the island during the growing and harvest seasons. Photographs of the eruption showed several pyroclastic flows coming down the volcano summit to the S and E that may be hazardous to anyone of the island. On 30 May, the Alert Level was raised from 2 to 3 (on a scale of 1-4). Civil authorities evacuated 135 people from within 1.5 km of the volcano to the mainland (nearby Sumbawa Island), with the result that no one was reported to have been killed or injured during the eruption.

Figure (see Caption) Figure 8. Eruption plume rising from Sangeang Api volcano on 30 May 2014, photographed to the N from Sambawa Island. Note the distinctive lenticular white cloud condensed from uplifted moist air carried by the rising plume. Pyroclastic flows can also be seen moving down along the S and E sides of the volcano. Courtesy of Anonymous (2014).

Based on satellite images, pilot observations, and the Indonesian Meteorological Office, the Darwin VAAC reported that on 30 May an ash plume rose to an maximum altitude of 15.2 km and drifted 440 km E and 750 km SE (figure 9).

Figure (see Caption) Figure 9. After erupting, the Sangeang Api volcano sent an ash plume to the E, along with a distinctive lenticular white cloud condensed from uplifted moist air. Pilots in the area reported seeing the cloud rising to 19.8 km, spreading over a 40 km area. Photograph taken on 30 May 2014 by Sofyan Efendi looking N during a commercial flight from Bali to the fishing town of Labuan Bajo; from Hall (2014).

The Indonesian Regional Disaster Management Agency (BNPB) reported that on 31 May two larger explosions occurred at 1330 and 2242 hrs. According to the VAAC, ash plumes from these two explosions rose to altitudes of 13.7-15.2 km and drifted 280 km NW (and other various directions, including S). Later in the day the ash plumes, including one from the previous day, eventually became detached. Ashfall affected many areas in the Bima Regency on the mainland, including Wera, and prompted the evacuation of 7,328 people from four villages within a radius of 8 km from Sangeang Api. The Bima and Tambolaka airports were temporarily closed. According to a news article, all flights to and from the Darwin International Airport in Australia on 31 May were canceled (figure 10). The VAAC noted that ash plumes rose to an altitude of 4.3 km on 1 June and drifted W and SW (figure 11). During 2-3 June ash plumes rose to altitudes of 3-4.3 km and drifted 45 km W. Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that on 14 June an ash plume from Sangeang Api rose to an altitude of 2.1 km and drifted 55 km NW.

Figure (see Caption) Figure 10. The Moderate Resolution Imaging Spectroradiometer (MODIS) aboard the Terra satellite captured imagery of the eruption plume from Sangeang Api (dark brown line on the image extending from the volcanic island to the SE) at 0235 UTC (1035 local time) on 31 May 2014. Ash drifted SE, shutting down airports in Bima, Indonesia, and Darwin, Australia. Service to Darwin resumed by 1 June, but Bima remained shut down as of 2 June, according to the Jakarta Globe. Other satellites have observed the ash plume as well. A near real-time tool developed by University of Wisconsin and NOAA scientists estimated that the plume reached an altitude of at least 12 to 14 km based on observations from multiple weather satellites. The Ozone Mapping & Profiler Suite on Suomi NPP also observed ash drifting toward Australia on 31 May. NASA image courtesy Jeff Schmaltz LANCE/EOSDIS MODIS Rapid Response Team, GSFC; Caption by Adam Voiland. From NASA Earth Observatory (2014, 3 June).
Figure (see Caption) Figure 11. Landsat 8 satellite collected this true-color image of an ash plume rising from the Sangeang Api, an island volcano just of the coast of Sumbawa Island, Indonesia, on 1 June 2014. Note that on this day the plume is being blown W and then SW as compared with the previous day shown in figure 8. NASA Earth Observatory images by Robert Simmon, using Landsat 8 data from the USGS Earth Explorer. From NASA Earth Observatory (2014, 1 June).

During the period from 2-17 June, thin to thick white smoke was ejected as high as 200-500 m. Seismic activity during the major part of the eruption is shown on Table 4; as of 17 June, seismicity continued to decline. The Alert Level was reduced from 3 to 2 (on a scale of 1-4) on 17 June.

Table 4. Numbers of daily earthquakes measured for 3 days during and after the eruption of Sangeang Api, as reported by CVGHM. 'VB' represents shallow volcanic earthquakes; 'VA' represents deep volcanic earthquakes; 'TL' represents local earthquake tectonics; 'X' indicates activity present; 'nr' is not reported .

Date, 2014 30 May 31 May 1 June
VB 88 143 35
VA 270 157 62
TL nr nr 5
Volcanic swarm X nr nr
Continuous tremor X X X
Tremor eruption X X X
Blowing earthquake nr nr 36

MODVOLC and other satellite imaging. Satellite infrared measurements of thermal alerts over this Sangeang Api volcano eruption first appeared as 2 pixels (an area of thermal anomaly of ≥2 km2) at 1405 UTC on 30 May 2014. These were the first thermal alerts measured over Sangeang Api since 20 October 2013. From 30 May 2014 through 7 July, satellite crossings measured alerts of between 1 and 9 pixels (areas of ≥1 to ≥9 km2, respectively) daily until 1500 UTC on 30 June; the 9-pixel thermal alert was measured 20 June 2014 at 1425 UTC (figure 12). (Note: As an explanation for this technique, the MODVOLC web site states that "Using infrared satellite data provided by the Moderate Resolution Imaging Spectroradiometer (MODIS), scientists at the Hawai'i Institute of Geophysics and Planetology, University of Hawai'i, have developed an automated system [MODVOLC] which maps the global distribution of thermal hot-spots in near-real-time, and displays the results on this web-site." A paper by Wright and others (2004) states that "Although MODIS pixels are nominally 1 km, pixel size increases with distance from nadir and at the edges of the MODIS swath (where the scan angle reaches ±55°) MODIS pixels measure ~2.08 km in the along-track, and ~4.83 km in the across-track direction.")

Figure (see Caption) Figure 12. MODVOLC image for the period 30 May to 7 July 2014 of thermal alerts measured on Sangeang Api volcano. The volcano lies on the island of Sangeang just off the Indonesian island of Sumbawa. The central array of pixels trending E-W are for those alerts measured for the period 30 May - 30 June 2014. Courtesy of MODVOLC.

Figures 13 and 14 show satellite images of ash plume temperature and SO2 plume from Sangeang Api volcano on 30 and 31 May 2014, respectively. The plume is obviously drifting to the E and S toward Australia.

Figure (see Caption) Figure 13. Composite of the Day-Night Band (DNB, red-to-yellow) at 750m resolution and the IR11.45 (I5, color scale at the top) channel at 375m resolution, image made 30 May 2014 at 1745 UTC. The DNB shows two craters at Sangeang Api volcano, Doro Api and Doro Mantoi. The brighter one was emanating the big plume with temperature values down to -196.5 K (76.6 °C) at the top. The secondary crater was emanating some material, but at much lower level so could hardly be seen. Courtesy of EUMETSAT (2014).
Figure (see Caption) Figure 14. SO2 measured from the Sangeang Api volcano plume on 31 May 2014 at 0535 UTC. The volcano is located at the W end of the measured area. Courtesy of NOAA.

References. Anonymous, 2014 (30 May), Massive volcano eruption: Sangeang Api volcano - Sunda Islands, Indonesia, Before Its News web site (http://beforeitsnews.com/environment/2014/05/massive-volcano-eruption-sangeang-api-volcano-sunda-islands-indonesia-2502094.html).

EUMETSAT, 2014, Eruption of Sangeang Api volcano: There were a series of spectacular eruptions from the Indonesian volcano Sangeang Api at the end of the May. URL: http://www.eumetsat.int/website/home/Images/ImageLibrary/DAT_2235292.html

NASA Earth Observatory, 2014 (3 June), Sangeang Api Erupts (URL: http://earthobservatory.nasa.gov/IOTD/view.php?id=83799).

NASA Earth Observatory, 2014 (1 June), Sangeang Api Eruption (URL: http://earthobservatory.nasa.gov/NaturalHazards/view.php?id=83887&eocn=image&eoci=nh_viewall)

Wright, R., Flynn, L.P, Garbeil, H., Harris, A.J.L., and Pilger, E., 2004, MODVOLC: near-real-time thermal monitoring of global volcanism, Journal of Volcanology and Geothermal Research, v. 135, pp. 29-49.

Hall, J., 2014 (30 May), Pictured from a passenger plane: Menacing 12-mile-high ash cloud looms over Indonesia's 'Mountain of Spirits' after volcano erupts, Daily Mail (URL: http://www.dailymail.co.uk/news/article-2644253/Incredible-moment-huge-volcano-erupts-Indonesia-sending-ash-spewing-thousands-feet-sky.html).

Geologic Background. Sangeang Api volcano, one of the most active in the Lesser Sunda Islands, forms a small 13-km-wide island off the NE coast of Sumbawa Island. Two large trachybasaltic-to-tranchyandesitic volcanic cones, Doro Api and Doro Mantoi, were constructed in the center and on the eastern rim, respectively, of an older, largely obscured caldera. Flank vents occur on the south side of Doro Mantoi and near the northern coast. Intermittent eruptions have been recorded since 1512, most of them during in the 20th century.

Information Contacts: Indonesian Centre for Volcanology and Geological Hazard Mitigation – CVGHM (also known as Pusat Vulkanologi dan Mitigasi Bencana Geologi - PVMBG)), Jalan Diponegoro 57, Bandung 40122, Indonesia (URL: http://www.vsi.esdm.go.id/); MODVOLC, Hawai'i Institute of Geophysics and Planetology (HIGP) 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/); DARWIN VAAC (Darwin Volcanic Ash Advisory Centre), Bureau of Meteorology, Northern Territory Regional Office, PO Box 40050, Casuarina, NT 0811, Australia (URL: http://www.bom.gov.au/info/vaac/); Badan Penanggulangan Bencana Daerah (BPBD), Indonesian Regional Disaster Management Agency (URL: http://bpbd.malangkab.go.id/); and Badan Nasional Penanggulangan Bencana (BNPB), Indonesian National Disaster Management Agency (URL: http://www.bnpb.go.id/).


Telica (Nicaragua) — February 2014 Citation iconCite this Report

Telica

Nicaragua

12.606°N, 86.84°W; summit elev. 1036 m

All times are local (unless otherwise noted)


Small explosions in September 2013; a new intracrater vent

INETER reported that during 2013, Telica was one of the main contributors to Nicaragua's volcanic seismicity (along with Momotombo, San Cristóbal, Cerro Negro, and Concepción). Of the total seismicity detected in Nicaragua, 28% was associated with the volcanic chain.

Throughout 2013, white, low-level gas plumes rose over 200 m above the crater. Field observers saw incandescence from the crater floor and heard jetting sounds. This activity was slightly diminished in May and peaked in late September.

In March 2013, a group of students from Chalmers University of Technology, Switzerland, surveyed the crater with an FTIR spectrometer to determine SO2 flux (figure 34). Overall, during 5-21 March, SO2 flux averaged 175 tons/day with the maximum value of 250 tons/day recorded on 17 March. The group returned to Telica in March 2014 and found fluxes of similar levels (figure 34).

Figure (see Caption) Figure 34. SO2 flux measured from Telica during 5-22 March 2013 by students from the Chalmers University of Technology, Switzerland. Courtesy of Vladimir Conde, Chalmers University of Technology.

On 25 September 2013, small explosions were detected from the crater that released gas and ash. There were four explosions during 0725-1605; the largest occurred at 0725 and generated a plume 50 m above the crater rim. The other three explosions were less energetic and did not eject material beyond the crater. During a field visit that day, INETER scientists observed incandescence from a new vent within the crater as well as small fractures crossing the crater floor. An infrared thermometer measured a maximum of 505°C from the active vent.

A field survey team observed strong degassing from the crater on 8 October. The main source of the gas was the SW wall and jetting sounds were also noted.

2014. Low-level degassing continued during January-June 2014. Jetting sounds and incandescence from the crater occurred less frequently based on field visits by INETER scientists. Seismicity in January and February was elevated; 11,182 and 26,355 volcano-tectonic (VT) earthquakes were detected respectively. In April 2014, seismicity was greatly reduced (2,454 earthquakes) and was dominated by paired earthquakes known as doublets (also detected in January 2014).

During a field visit on 22 May 2014, INETER scientists noted that, while incandescence was still visible, gas emissions were greatly reduced and the jetting sounds were absent. The active vent within the crater appeared to be covered and possibly blocked by rockfalls originating from the crater walls. Emissions, jetting sounds, and incandescence were also reduced in June 2014.

Geologic Background. Telica, one of Nicaragua's most active volcanoes, has erupted frequently since the beginning of the Spanish era. This volcano group consists of several interlocking cones and vents with a general NW alignment. Sixteenth-century eruptions were reported at symmetrical Santa Clara volcano at the SW end of the group. However, its eroded and breached crater has been covered by forests throughout historical time, and these eruptions may have originated from Telica, whose upper slopes in contrast are unvegetated. The steep-sided cone of Telica is truncated by a 700-m-wide double crater; the southern crater, the source of recent eruptions, is 120 m deep. El Liston, immediately E, has several nested craters. The fumaroles and boiling mudpots of Hervideros de San Jacinto, SE of Telica, form a prominent geothermal area frequented by tourists, and geothermal exploration has occurred nearby.

Information Contacts: Virginia Tenorio, Instituto Nicaragüense de Estudios Territoriales (INETER), Apartado Postal 2110, Managua, Nicaragua (URL: http://www.ineter.gob.ni).


Whakaari/White Island (New Zealand) — February 2014 Citation iconCite this Report

Whakaari/White Island

New Zealand

37.52°S, 177.18°E; summit elev. 294 m

All times are local (unless otherwise noted)


Dome extrusion in late 2012 and further eruptions in 2012-2013

On 5 August 2012, White Island erupted, following rapid water level rises in the crater lake. Minor ash emission continued to as late as 17 August (BGVN 37:06). This report describes activity during September 2012-January 2014. Unless otherwise stated, information was compiled from GeoNet reports. Major events during the reporting interval include a spiny dome first viewed in December 2012, several months of explosive phreatic activity in early 2013, and discrete explosive eruptions during the latter half of 2013. Magma last surfaced at White Island in 2000 in an explosive eruption that ejected molten lava (BGVN 25:08). GeoNet, a monitoring project funded by the Earthquake Commission, is operated by New Zealand's GNS Science which produces an on-line Volcanic Alert Bulletin. It monitors volcano events by webcam, and acoustic and seismic instruments. Periodically, in situ temperature, fumarole and spring chemical sampling, deformation, gas data, and visual narratives were also recorded. Surveillance includes a mini DOAS network and may also airborne visual observations, photos, and IR images.

GeoNet currently describes White Island as the most active of New Zealand's volcanoes. During 2012 and 2013 normal seismic activity was interspersed with periods of heightened activity. GeoNet reported minor ash, seismicity, gas emissions, dome building, and changes at the crater and crater lakes. Two significant eruptions occurred after a period of reduced activity in 2013: one in August and the other in October. In January 2014, GeoNet volcanologists reported low seismicity. During a single year, tour companies estimated that over 10,000 tourists visited White Island from NZ's North Island ~45 km to the S. Safety of visitors to the island and surrounding waters depends on Volcanic Alert Bulletins. The NZ volcano alert levels ranged from 0 (low risk) to 5 (high risk); Aviation Alert colors ranged from Green (low risk), to Yellow, to Orange and then to Red (high risk). These two alert types were frequently updated, based on spikes in activity. For example in August 2013, Alert Levels ranged from 1 to 2 and Aviation Colour Codes shifted from Yellow to Green to Red to Orange and back to Yellow.

Ashfall in 2012 and a spiny lava dome. In a Volcanic Alert Bulletin issued on 12 December 2012, GNS reported that after the 5 August eruption, a spiny done was formed. In the 26 July 2013 report, phreatic and steam driven activity was observed beginning in December with minor ash emissions interspersed and continuing into the following year. Degassing and tremors were frequent with varying intensities (figure 55). The figure records seismicity as root square amplitude mean (RSAM) on the ordinate plotted along the time line abscissa from June 2007 to December 2013. The tremors were generally attributed to fluid movement (magma, geothermal water, and steam) at an undetermined depth in the crust.

Figure (see Caption) Figure 55. White Island seismicity as root square amplitude mean (RSAM) on the ordinate plotted along the time line abscissa from June 2007 to December 2013. Figure by Brad Scott; courtesy New Zealand's Geological and Nuclear Sciences (GNS Science).

In December 2012, two airborne observations were conducted. GNS volcanologists on 10 December viewed for the first time a small spiny lava dome in the crater active during August 2012. The dome emerged in the vent active in a spot adjacent to two other venting areas (figure 56). GNS reporting attributed the dome morphology to a cooled carapace thrust upward by injection of magma deeper in the dome. Several spines protruded from the roughly 20-30 m diameter dome base (figure 57). Tour operators to the island commented that the dome was visible weeks before the volcanologists viewed it. The actual date of formation remained unstated and possibly unknown.

Figure (see Caption) Figure 56. Aerial view of White Island's active crater. A lava dome juts up adjacent to the front edge of an active oval vent near the prominent lake in the center of the image. The image was taken from a helicopter on 10 December 2012 looking W at ~600 m from the active vents. Photo by Brad Scott; courtesy GNS Science.
Figure (see Caption) Figure 57. Magnified view of the 10 December 2012 image showing the spiny lava dome (about 20-30 m diameter). The hot lake in the foreground sits adjacent to the active vent. Courtesy of GeoNet. Image by B. J. Scott, GNS Science.

Airborne observations on 20 December 2012 found the lava dome unchanged. Several small lakes occupied parts of the area formally covered by a large lake viewed before the August eruption. Infrared temperatures taken during the flight found the dome to be 187°C, the actively upwelling hot lake S of the dome to be 71°C, and the cool lake on the N side of the dome to be 35°C. 20 December airborne measurements resulted in a gas flux rate for SO2 of 400 metric tons/day (t/d), for CO2: 1,300 t/d, and for H2S2; 10 t/d.

Ashfall after the August 2012 eruption to the end of 2012 was unreported in the 2012 Volcanic Alert Bulletin archive. However, in the 26 July 2013 report, GeoNet summarized the December 2012-February 2013 activity as an eruption sequence interspersed with phreatic, steam driven activity and very minor ash emissions. Ashfall in December 2012 and January-February 2013 are reported in table 12. Exact ashfall dates were unreported due to the minor nature of ashfall events and irregular visits. Table 12 summarizes eruptive activity at White Island during this report period.

Table 12. December 2012-11 October 2013 eruptive activity at White Island. Column headings are eruptions, seismicity, and a brief eruptive narrative. Dates in the second column from the right came from Volcanic Alert Bulletin reports. Notes refer to image and video records found in the Reference section under GNS. Courtesy of GNS.

Date Emissions Seismicity noted Eruptive narrative GeoNet report Notes
1 Dec 2012 Small phreatic explosions, minor ash Elevated RSAM levels Intermittent eruptions 26 Jul 2013 --
Jan-Feb 2013 Phreatic explosions, minor ash Elevated RSAM levels Intermittent emissions 26 Jul 2013 --
23-24 Feb 2013 Phreatic explosions, minor ash Increased tremor Intermittent emissions 25 Feb 2013 --
Early Apr 2013 Mud and ash eruption Tremor, outgassing Crater lake starts to form 29 Apr 2013 --
20 Aug 2013 Small explosive eruption Tremor White plume ~4 km 20 Aug 2013 1,2
4,8,11 Oct 2013 Small explosive eruptions -- Minor ash columns 12 Oct 2013 3

Ashfall in 2013, 20 August eruption, and 11 October eruption. On 1 January 2013, GNS volcanologists reported the spiny lava dome (figure 58) remained unchanged from December 2012. The lava dome temperature was 200-240°C, up from 187°C in December, and the nearby 'hot lake' was 70-80°C, unchanged from December.

GNS volcanologist Brad Scott, who visited the island, commented in the 22 January Volcano Alert Bulletin "the hydrothermal activity is some of the most vigorous I have seen at White Island for many years." Scott also reported the hot lake had disappeared, replaced by a small tuff cone. That cone was the main point of emission for steam and gas. On 30 January 2013, the active vent continued to produce intermittent vigorous bursts of mud, rock, steam, and gas rising 50-100 m high without detectable ash in the plume. On 31 January, gas fluxes were 2,000 metric tons per day (t/d) for carbon dioxide (CO2), 600 t/d for sulfur dioxide (SO2), and 19 t/d for hydrogen sulfide (H2S).

Figure (see Caption) Figure 58. This is the same photo seen in figure 56, but in this case it shows infrared temperatures of White Island's dome and lakes taken on 7 January 2013. The active vent continued to produce vigorous bursts of mud, rock, steam, and gas reaching 50-100 m high. Ash was not carried into the plume at the time of this photo. The small lake to the left is the cool lake (35°C) and the lava-dome crater is partially hidden under the steam plume. Courtesy of GeoNet. Image by Brad Scott, GNS Science.

On 7 February, SO2 and CO2 rates were similar to measurements in January: SO2 was 560 t/d and CO2 was 1,800 t/d. The main steam and gas plume came from the ash cone occupying the previous hot lake crater. Small explosive eruptions in the active crater and seismicity, which had been occurring for three weeks prior to the week of 11 February, became less intense.

During 23-24 February 2013 minor ash erupted from the active vent. Tremor was consistent with the level of unrest seen over the past month. On 25 February, the ash emissions had ceased and had been replaced by steam-and-gas explosions from the active vent. The level of volcanic tremor increased, associated with the reappearance of fluids in the vent area (figure 55). The unrest was among the most vigorous that Scott had observed during visits to White Island. He was quoted in the 25 February report to say "the unrest continues and we continue to see small scale explosive events. Larger explosive eruptions can occur at any time with little or no warning. As always a high level of caution should be taken if visiting the island."

The crater on 4 March 2013 contained an ash cone surrounded by water (figure 59), which replaced the previous hot lake as the primary source of steam in the crater. On 29 April 2013, GNS reported that ash had ceased being emitted at an undisclosed date during the first part of the month. In April, low to moderate seismic tremor was detected, while degassing continued. Rainfall during April caused the two lakes to combine. The maximum lake temperature was ~ 62°C. The lava dome temperature was ~200°C.

Figure (see Caption) Figure 59. A 4 March 2013 image looking W ~600 m from the crater. A new ash cone formed at the hot lake emitted gas and steam. N of the ash cone sits the cool lake. Image by B. J. Scott, GNS Science.

During April, May, and June 2013 the crater lake reformed. On 9 July 2013 GNS reported small volcanic earthquakes occurred approximately every 70 seconds, with changing amplitude and frequency. GNS volcanologists visiting on 26 July observed gas venting through the small lake with debris ejected 20-30 m vertically. By 5 August this minor venting had declined and tremor had decreased to near-background levels (see figure 55).

A small eruption took place in August 2013 detected by a constellation of instruments on White Island which included audio receivers, seismometers, temperature sensors, and IR sensors. The eruption was captured on video media by several cameras near the crater rim and a camera stationed ~45 km S at NZ's North Island (figure 60). The eruption occurred at 1023 on 20 August 2013 (NZ local time) and continued for about 10 minutes. As seen from the mainland, it mainly produced a steam plume rising to ~4 km, and slowly trending W before dispersing (figure 61). The eruption originated from a vent in the active crater that had been experiencing very small mud eruptions in early to mid-August 2013. This eruption was preceded by strong tremor.

Figure (see Caption) Figure 60. Map locating GNS video camera which resides at Whakatane on NZ's North Island ~50 km S of White Island. It recorded the 20 August 2013 eruption seen in the next figure. Map courtesy of 100% New Zealand (2014) and revised by GVP.
Figure (see Caption) Figure 61. Image of White Island taken from Whakatane WebCam video of the 20 August 2013 eruption. The image was in the GNS 22 August 2013 report. Courtesy of Geonet.

The N rim webcam captured visual and thermal infrared images of the eruption. Both the N Island camera and the N rim camera video links were included in the GNS 22 August report. The 20 August eruption ejected mud and rocks a short distance from the vent and produced large volumes of white steam. Weather radar observations suggested that the steam also contained a small proportion of volcanic ash. The hazards posed by the eruption were restricted to the island or possibly vessels anchored nearby. By 21 August 2013, White Island activity had diminished. Volcanologists flying over the island on 23 August observed the return of a small lake. Steam emissions chiefly emerged from the cone area, but their intensity dropped as the small lake reformed. SO2, CO2, and H2S gases recorded during the flight had diminished to pre-eruption levels.

The 7 October GNS report described the changes associated with the August 2013 eruption. A new basin further to the NE of the previous lake filled with water. The lava dome area appeared unchanged while nearby a small pond had formed. Landslides had altered several of the main crater walls, the result of processes most likely related to weather events. Daily SO2 gas flux measured the previous month ranged from 117 to 662 t/d, typical of the last 12-18 months but higher than before July 2012. In early October it remained elevated.

A moderate but potentially dangerous eruption emerged on 11 October 2013. The eruption sequence began 4 October, with a small energetic steam emission followed by intensified tremor. On 8 October, a period of strong seismicity prevailed accompanied by acoustic signals, and a minor steam and mud eruption that produced a steam plume. During the evening of 11 October, a moderate explosive eruption lasted ~1 minute based on data from acoustic and seismic sensors. The N rim camera images showed that the eruption emerged from the crater's central vent. The explosive eruption produced an ash cloud that expanded across the main crater floor. New mud deposited on the crater floor was evident in the web camera images taken the following day (figure 63). The deposit was thick enough to bury much of the small scale topography on parts of the crater floor. This image and the muddy stratigraphic layer established the baseline for subsequent changes created by volcanism and erosion.

Figure (see Caption) Figure 62. On 12 October 2013 at 0650, the crater floor and walls lie draped beneath fresh deposits of dark gray mud from the eruption the night before. Courtesy of Geonet.

The October 2013 mud eruption was the largest of recent events. GNS volcanologists estimated it would have been life threatening to people on the island. Volcanic tremor gradually decreased after 11 October returning to levels equivalent to the middle of the prior week (see figure 55). The mud deposited on 11 October 2013 had clearly begun to erode by early December 2013. Around this time a new camera on the W rim captured active steam-and-gas plumes from several vents and the large lake seen in 2012 (figure 63). On 23 December 2013 GNS reported an absence of eruptive activity since the 11 October eruption. Seismicity remained low; gas flux, variable. Average daily SO2 flux ranged from 300 to over 1,000 t/d. Prior to 2012, daily averages were generally less than 300 t/d.

Figure (see Caption) Figure 63. An 11 December 2013 image showing gullies and rills as erosion set in on the fresh mud coating within the crater formed by the 11 October 2013 eruption. Several vents produced active steam plumes and the lake had returned. Courtesy of GNS.

January 2014 changes to the crater and rate of gas emitted. During several January visits, GNS Science staff observed a continued rise in water level of the crater lake, reaching ~5 m higher than in late 2013. The average daily SO2 flux ranged from 133 to 924 t/d. GNS volcanologists reported an absence of further eruptive activity since the 11 October 2013 eruption.

On 15 January 2014, a thermal infrared image was taken by a portable infrared sensor pointed W from the western crater rim (figure 64). The image shows part of the Crater Lake (oval labeled El1), the area of the 2012 lava extrusion below the lake (large rectangular box labeled Ar1), and a hot fumarole on the S edge of the Crater Lake (small rectangle in the center labeled Ar2). Maximum temperatures were 58°C at the lake, 285°C forAr1, and 297°C for Ar2. These observations confirmed that hot volcanic gases were still passing through these vents.

Figure (see Caption) Figure 64. Thermal infrared image taken on 15 January 2014, with scale at right and areas with analysis at upper left. The oval area (El12) includes part of the Crater Lake, and the area of the 2012 lava extrusion (in rectangular Ar1). The smaller rectangle, Ar2, includes a hot fumarole on the southern edge of the Crater Lake. Courtesy of GeoNet.

References.

100% New Zealand, accessed 5 May 2014, New Zealand Map (URL: http://www.newzealand.com/int/map/).

GNS (22 August 2013), White Island eruption 20 August 2013 - 5x speed, (URL: http://info.geonet.org.nz/display/volc/2013/08/20/White+Island+Eruption.)

GNS (22 August 2013), White Island eruption 20 August 2013 Crater rim - 5x speed, (URL: http://info.geonet.org.nz/display/volc/2013/08/20/White+Island+Eruption).

GNS (14 October 2012), Un-named video clip URL reference in body of GNS report (URL: http://info.geonet.org.nz/pages/viewpage.action?pageId=7241739).

Geologic Background. The uninhabited Whakaari/White Island is the 2 x 2.4 km emergent summit of a 16 x 18 km submarine volcano in the Bay of Plenty about 50 km offshore of North Island. The island consists of two overlapping andesitic-to-dacitic stratovolcanoes. The SE side of the crater is open at sea level, with the recent activity centered about 1 km from the shore close to the rear crater wall. Volckner Rocks, sea stacks that are remnants of a lava dome, lie 5 km NW. Descriptions of volcanism since 1826 have included intermittent moderate phreatic, phreatomagmatic, and Strombolian eruptions; activity there also forms a prominent part of Maori legends. The formation of many new vents during the 19th and 20th centuries caused rapid changes in crater floor topography. Collapse of the crater wall in 1914 produced a debris avalanche that buried buildings and workers at a sulfur-mining project. Explosive activity in December 2019 took place while tourists were present, resulting in many fatalities. The official government name Whakaari/White Island is a combination of the full Maori name of Te Puia o Whakaari ("The Dramatic Volcano") and White Island (referencing the constant steam plume) given by Captain James Cook in 1769.

Information Contacts: GeoNet, a collaboration between the Earthquake Commission and GNS Science (URL: http://www.GeoNet.org.nz/); and GNS Science, Wairakei Research Center, Private Bag 2000, Taupo 3352, New Zealand (URL: http://www.gns.cri.nz/).

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