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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 36, Number 01 (February 2011)

Managing Editor: Richard Wunderman

Bagana (Papua New Guinea)

Occasional ash plumes during 11 February-1 October 2010

Karangetang (Indonesia)

Eruption in August 2010 isolated 20,000 residents and caused four deaths

Kizimen (Russia)

Powerful fissure eruption in November 2010 ends ~82-year repose

Manam (Papua New Guinea)

Ashfall, pyroclastic flows, and seismicity in late December 2010

Merapi (Indonesia)

Eruption started 26 October 2010; 386 deaths, more than 300,000 evacuated

Rumble III (New Zealand)

Eruption in 2009 linked to over 100 m of sea floor collapse

Sangay (Ecuador)

Many plumes seen by pilots during past year ending February 2011

Taal (Philippines)

Intermittent non-eruptive unrest during 2008-2010



Bagana (Papua New Guinea) — February 2011 Citation iconCite this Report

Bagana

Papua New Guinea

6.137°S, 155.196°E; summit elev. 1855 m

All times are local (unless otherwise noted)


Occasional ash plumes during 11 February-1 October 2010

This report discusses thermal anomalies and occasional ash plumes at Bagana during February into October 2010, with some satellite thermal data (MODVOLC) as late as early 2011. Our previous report (BGVN 35:02) also noted small lava flows, occasional ash plumes, and thermal anomalies from October 2009 through February 2010.

Historical records describe frequent eruptions since 1842. Bagana lacks instrumental monitoring and sits far from population centers. Many recent observations are remote-sensing based, although the Rabaul Volcano Observatory (RVO) produces reports with direct air- and ground-based observations. Bagana's flanks are covered with andesitic lava flows up to 50 m thick (Blake, 1968). The flows typically descend the mid-slope within the confines of tall lava levees, but emerge from the levees on the outer flanks to form sub-circular flow fields. Bagana's thick lava flows are visible [from the International Space Station] (figure 11).

Figure (see Caption) Figure 11. An International Space Station photo taken on 2 April 2007 showing a diffuse white vapor plume extending SSW from Bagana's summit. The volcano is known for ongoing activity and lava flows of noteworthy thickness (~50 m thick). The brown-to-olive colors of the volcano stand out amidst the green of tropical rain forest. Astronaut Photo ISS014-E-18844. Courtesy NASA.

Activity. Between 10 February 2010 and 1 October 2010, the Darwin Volcanic Ash Advisory Center (VAAC) reported one or a few ash plumes per month from Bagana. Many rose to ~3 km and drifted from 20-205 km (table 5). According to RVO, ash plumes were seen on 5 February and night-time incandescence was seen on 2, 12, 13, and 19 February. White vapor was emitted during 1-21 February. Sulfur dioxide plumes drifted ENE during 11-20 February and NNW on 20 and 21 February. Consistent with the thick lava flows, MODVOLC detected well over 100 thermal anomalies at Bagana in the year ending 10 February 2011.

Table 5. Summary of ash plumes from Bagana reported during 1 February-October 2010. Courtesy of the Darwin Volcanic Ash Advisory Centre (VAAC).

Date Altitude (km) Drift (distance and direction)
11-15 Feb 2010 2.4 18-150 km E, NE
19-20, 23, 25 and 27 Apr 2010 1.5-3 35-85 km S, SW, W, NW
06, 10-12 May 2010 2.4-3 55-75 km W, SW, WSW
25-28 May 2010 3 30-185 km NW, W, SW
13-14 Jun 2010 3 75-205 km SW, W
04 Jul 2010 2.4 75 km W
10-11 Jul 2010 2.4 75-150 km SW
13-15 Aug 2010 2.4 75 km SW, W
01 Oct 2010 2.4 75 km NW

Reference. Blake D H, 1968. Post Miocene volcanoes on Bougainville Island, Territory of Papua and New Guinea. Bull Volc, 32: 121-140

Geologic Background. Bagana volcano, in a remote portion of central Bougainville Island, is frequently active. This massive symmetrical cone was largely constructed by an accumulation of viscous andesitic lava flows. The entire edifice could have been constructed in about 300 years at its present rate of lava production. Eruptive activity is characterized by non-explosive effusion of viscous lava that maintains a small lava dome in the summit crater, although occasional explosive activity produces pyroclastic flows. Lava flows with tongue-shaped lobes up to 50 m thick and prominent levees descend the flanks on all sides.

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/); Rabaul Volcano Observatory (RVO), PO Box 386, Rabaul, Papua New Guinea; NASA Earth Observatory (URL: http://earthobservatory.nasa.gov/); Hawai'i Institute of Geophysics and Planetology (HIGP) MODVOLC Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/); Image Science and Analysis Laboratory, NASA-Marshall Space Flight Center (URL: http://eol.jsc.nasa.gov).


Karangetang (Indonesia) — February 2011 Citation iconCite this Report

Karangetang

Indonesia

2.781°N, 125.407°E; summit elev. 1797 m

All times are local (unless otherwise noted)


Eruption in August 2010 isolated 20,000 residents and caused four deaths

A sudden eruption at Karangetang on 6 August 2010 occurred without warning and caused considerable damage. This report covers the interval from 6 August 2010 to mid-March 2011. Previously, the Indonesian Center of Volcanology and Geological Hazard Mitigation (CVGHM) had reported that, after explosions and lava flows during May and June 2009 and a pyroclastic flow and lahar in November 2009, seismicity had declined through early February 2010 (BGVN 35:01). On 12 February 2010, CVGHM had lowered the Alert Level to 2 (on a scale of 1-4).

According to news articles, an explosion on 6 August 2010 ejected hot clouds of gas and sent pyroclastic flows down the W flank. At least one house was buried and several other buildings, including a church, were damaged. A damaged bridge isolated about six villages and their ~20,000 residents, and communication links were lost. According to news reports (CNN and Associated Press), four people were confirmed dead and five were injured, and about 65 were evacuated. The Darwin Volcanic Ash Advisory Centre (VAAC) reported that an ash plume rose to an altitude of 9.1 km and drifted W on that same day.

The news reports cited CVGHM official Priyadi Kardono as noting that the volcano erupted just after midnight when water from heavy rains had penetrated the volcano's hot lava dome, causing the explosion. According to these reports, Kardono said volcanologists did not issue a warning about the eruption because there were no indications of increased volcanic activity. Kardono also noted that the explosion was not large, and the flow of volcanic debris had since decreased.

CVGHM reported that during 1-21 September 2010, lava traveled 75-500 m down Karangetang's flanks and avalanches traveled as far as 2 km down multiple drainages, to the S, E, and W. Incandescent material was ejected up to 500 m above the crater. Ashfall was reported in areas to the NW.

On 21 and 22 September incandescent material traveled down multiple drainages. Strombolian activity was observed on 22 September; material ejected 50 m high fell back down around the crater. That same day, the Alert level was raised to 3.

During November and early December 2010, CVGHM noted a drastic decrease in the occurrence of pyroclastic flows on Karangetang's flanks. Seismicity also decreased. The only reports were of white plumes that rose up to 300 m above the craters. The Alert Level was thus lowered to 2 on 13 December 2010.

According to CVGHM, the Alert Level was again raised from 2 to 3 on 11 March 2011 due to increased seismicity. According to news reports, lava flows were visible and blocks originating from the lava dome traveled as far as 2 km down the flanks, along with hot gas clouds. A Reuters News photo published in Okezone News showed a moderate Strombolian eruption venting from the summit on 11 March, with an apron of incandescent spatter dotting the upper slopes, and a swath of red spatter and bombs bouncing down one flank. Darwin VAAC reported that on that same day, an ash plume rose to an altitude of 2.4 km and drifted 55 km SW; on 13 March, another ash plume rose to an altitude of 3.7 km and drifted 37 km.

During 12-16 March, CVGHM stated that bluish gas plumes rose 50-150 m above the main crater. On 17 March lava flows traveled as far as 2 km from the main crater, accompanied by roaring and booming noises.

On 18 and 20 March lava flows traveled 1.5-1.8 km and collapses from the lava flow fronts generated avalanches that moved another 500 m. Avalanches from the crater traveled 3.8 km down the flanks. Multiple pyroclastic flows about 1.5-2.3 km long destroyed a bridge, damaged a house, and trapped 31 people (later rescued) between the flow paths. Later that day, pyroclastic flows traveled 4 km, reaching the shore. The Alert Level was raised to 4. According to news articles, 600-1,200 people were evacuated from villages on the W flank.

During the week after 20 March, seismicity and deformation declined. The number of new lava flows also declined.

MODVOLC Thermal Alerts. Thermal alerts derived from the Hawai'i Institute of Geophysics and Planetology Thermal Alerts System (MODVOLC) were reported through 19 February 2010 in BGVN 35:01. A significant number of alerts were measured on 19 March 2010 (14 pixels at 0215 UCT on Terra) and 23 March (1 pixel on Aqua), followed by ~5 months without measured alerts. Alerts reappeared during 16 August-19 October 2010. Alerts were absent between 20 October 2010 and 10 March 2011, followed by renewed alerts during 11-12 March 2011.

Geologic Background. Karangetang (Api Siau) volcano lies at the northern end of the island of Siau, about 125 km NNE of the NE-most point of Sulawesi. The stratovolcano contains five summit craters along a N-S line. It is one of Indonesia's most active volcanoes, with more than 40 eruptions recorded since 1675 and many additional small eruptions that were not documented (Neumann van Padang, 1951). Twentieth-century eruptions have included frequent explosive activity sometimes accompanied by pyroclastic flows and lahars. Lava dome growth has occurred in the summit craters; collapse of lava flow fronts have produced pyroclastic flows.

Information Contacts: Center of Volcanology and Geological Hazard Mitigation (CVGHM), Jalan Diponegoro 57, Bandung 40122, Indonesia (URL: http://vsi.esdm.go.id/); Darwin Volcanic Ash Advisory Centre (VAAC), Bureau of Meteorology, Northern Territory Regional Office, PO Box 40050, Casuarina, NT 0811, Australia (URL: http://www.bom.gov.au/info/vaac/); Hawai'i Institute of Geophysics and Planetology (HIGP) MODVOLC Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/); Okezone News (URL: http://news.okezone.com/read/2011/03/12/340/434280/gunung-muntahkan-lava-pijar); Associated Press (URL: http://www.ap.org/); Reuters (URL: http://www.reuters.com/); CNN (URL: http://www.cnn.com/); Straits Times (URL: http://www.straitstimes.com/); Novinite (URL: http://www.novinite.com/).


Kizimen (Russia) — February 2011 Citation iconCite this Report

Kizimen

Russia

55.131°N, 160.32°E; summit elev. 2334 m

All times are local (unless otherwise noted)


Powerful fissure eruption in November 2010 ends ~82-year repose

Eruption began here during mid-November 2010, the first since 1927-1928 (Brown and other, 2010). Ash plumes rose to ~10 km and were visible in satellite imagery as they traveled hundreds of kilometers during November 2010 through at least late February 2011. Our previous Bulletin (BGVN 35:02) reported that the number of earthquakes at Kizimen had increased substantially beginning in July 2009 (up to 120 earthquakes per day) through early April 2010 and that fumarolic temperatures increased in August. This report discusses activity since early April 2010.

After early April 2010, seismicity at Kizimen entered a quiescent phase until the Kamchatkan Volcanic Eruption Response Team (KVERT) reported increased seismic activity on 20 August and particularly during early November 2010. Based on information from a tourist center 10 km from Kizimen, KVERT noted that on 11 November 2010, strong gas-and-steam emissions resulted in a plume, possibly containing some ash, that rose to an altitude of 4 km.

According to the Kamchatkan Branch of Geophysical Survey (KG GS RAS), seismicity of the volcano was above background levels all week, and an M 4 earthquake occurred on 16 November 2010. According to information from the Yelizovo Airport (UHPP), the Tokyo VAAC reported that on 17 November an ash plume from Kizimen rose to an altitude of 3 km and drifted NE. KVERT noted the lack of satellite data about ash near Kizimen. The Level of Aviation Color Code remained at Green (on a scale that goes from low to high using these terms: Green, Yellow, Orange, and Red).

Seismic activity was above background levels during 19 November to 24 December 2010. On 20 November, volcanologists flying around Kizimen by helicopter observed several new fumaroles at the summit and SW flank. A small amount of "dust" covered the SW flank, possibly ash from the new fumaroles. Activity at the established old fumarole "Revuschaya" on the volcano's NE flank decreased. No thermal anomaly was noted from satellite images. The Level of Aviation Color Code was raised to Yellow.

On 9 December 2010, seismicity increased significantly and the Aviation Color Code level was raised to Orange. That same day, the Tokyo VAAC reported that, according to KB GS RAS, an explosion produced a plume that rose to an altitude of 2.7 km and drifted N. Ash was not identified in satellite images. A bright thermal anomaly was observed in satellite imagery the next day.

The beginning of the eruption Kizimen was captured in in a photo made by Don Page on 10 December from a commercial flight. The eruption start from long fissure on the SE slope (figure 5).

Figure (see Caption) Figure 5. Photo taken on 10 December 2010 at 0314 UTC (1414 local Kamchatka time; from Seat 36K of Air Canada Flight 063 from Vancouver, Canada, to Incheon-Seoul, Korea). A dark, angled (non-vertical) plume rises from the along the length of an elongate fissure network on the SE slope. [Photo: 981x656 pixels, with a Nikon D80 digital camera and an AF-S Nikkor 18-200 mm zoom lens (probably set at 200 mm).] Photo by Don Nelson Page (University of Alberta).

[On 13 December 2010 (UTC) an explosive eruption generated ash plumes that rose to altitudes of 3-3.5 km and drifted NW. Based on information from KEMSD and analysis of satellite imagery, the Tokyo VAAC reported that an ash plume rose to an altitude of 10 km and drifted N. KVERT noted that lightning in the ash plumes was observed. The Aviation Color Code was raised to Red. Ash deposits in Kozyrevsk and Tigil, 110 and 308 km NW, respectively, were 5 mm thick. Later that day seismic activity decreased; the Aviation Color Code was lowered to Orange.]

Kronotsky National Park staff, residing at Ipuin (~16 km WSW), noted that the water level in Levaya Schapina river rose 60 cm after the explosions and remained elevated for the next two days. The water was also very muddy. During 14-24 December seismicity remained above background and a thermal anomaly over the lava dome was detected in satellite imagery.

KVERT noted that during 17-24 December 2010 the number of shallow seismic earthquakes increased from 110 events on 17 December to 304 events on 22 December. Volcanic tremor was detected on 23 December. During 26-28 December, seismicity also increased and there were possible small ash explosions and hot avalanches. A thermal anomaly over the lava dome was again seen in satellite imagery. On 27 December seismic analysis indicated that ash plumes that day possibly rose to altitudes of 3.5-4.5 km. Satellite imagery showed ash plumes drifting 140 km W at an altitude of 4 km. On 28 December, based on a Yelizovo Airport (UHPP) notice, the Tokyo VAAC reported an ash plume drifting W at an altitude of 3.7 km. The Aviation Color Code was raised to Red.

A thermal anomaly over Kizimen's lava dome was again observed in satellite imagery during 29 December 2010-1 January 2011 and an explosive eruption that began on 13 December continued. On 31 December seismicity increased and volcanic tremor was detected. Explosions occurred sporadically for a period of about 20 minutes. Ash plumes detected in satellite imagery rose to an altitude of 8 km and drifted SW. Ashfall at least 1 mm thick occurred in multiple areas 225-275 km SSW, including Petropavlovsk-Kamchatsky, Yelizovo, Paratunka, and Nalychevo. Ash plumes at an altitude of 4 km drifted 480-500 km SW; ash continued to accumulate in some areas.

Seismic data indicated increased activity on 3 January. Based on analysis of satellite imagery, the Tokyo VAAC reported that possible eruptions during 2-4 January produced plumes that rose to an altitude of 3-4.6 km and drifted S, E, and NE. Subsequent images on those same days showed ash emissions continuing, then dissipating. During 4-7 January seismicity remained high and variable and volcanic tremor continued. A thermal anomaly over the volcano was observed in satellite imagery. Explosions continued through 7 January 2011 producing ash plumes mostly below altitudes of 6-8 km as reported by pilots or observed in satellite imagery. These drifted more than 200 km SE. A large and bright thermal anomaly was observed in satellite imagery.

A pattern of high seismicity and ash emissions was noted during early January 2011. On 5 January ash plumes drifted more than 500 km ENE. Ashfall was reported on the Komandorsky Islands, 350-500 km E (figure 6).

Figure (see Caption) Figure 6. An ash plume rising from Kizimen and blowing to the ENE on 5 January 2011. Courtesy of A. Lobashevsky.

The Tokyo VAAC reported that ash continued to be observed in satellite imagery on 5 January. According to information from KVERT and analyses of satellite imagery, a possible eruption on 6 January produced a plume that rose to an altitude of 3.7 km and drifted E. Subsequent satellite images that same day showed continuing ash emissions. Ash plumes drifted NW on 9 January, and drifted NW again on 11 January 2011, at an altitude of 2.7 km.

KVERT reported that during 7-13 January 2011 they saw both a thermal anomaly over Kizimen in satellite imagery and pyroclastic flow deposits on the E flank. Seismicity recorded during 6-7 and 12 January was high but variable, and many shallow volcanic earthquakes as well as volcanic tremor continued to be detected. Ash plumes that rose to altitudes of 6-8 km during 5-13 January were seen drifting multiple directions, and appeared in satellite imagery to be drifting more than 275 km W and NW. On 12 January ashfall was reported in the villages of Anavgai and Esso, 140 km NW. Seismic data during 14-15 January suggested that ash plumes rose to altitudes of 4-5 km. Satellite images showed a bright thermal anomaly over the volcano and ash plumes drifting more than 180 km W on 15 January 2011. The Aviation Color Code level was lowered to Orange.

From 14 January through 1 February, KVERT reported that seismicity from Kizimen was high but variable, and many shallow volcanic earthquakes as well as volcanic tremor continued to be detected. Seismic data analyses suggested that ash plumes possibly rose to an altitude no higher than 6 km. Satellite images showed a daily bright thermal anomaly over the volcano, and ash plumes that drifted more than 200 km W during 15-16 and 20 January. Based on satellite data, the Tokyo VAAC also reported that during 23-25 January eruptions produced plumes that rose to altitudes of 4.9-10.1 km. Based on analyses of satellite imagery, the Tokyo VAAC reported that a possible eruption on 29 January produced a plume that rose to an altitude of 3.7 km and drifted SW. Photo and satellite images taken during late January through late February showed continuing ash emissions (figures 7 and 8).

Figure (see Caption) Figure 7. Two images of Kizimen taken on 26 January 2011. On the left photo (a), a dark pyroclastic flow rushes down the slopes of the volcano. Photo by Igor Shpilenok. On the right (b), a thermal infra-red (IR) image taken of a pyroclastic flow during an explosion (IR scale temperature appears at right). The pyroclastic flow originated from the summit of the lava dome and swept downward. (The infrared image shows radiated energy as areas of bright glow.) During this eruptive stage a pyroclastic surge spread out over the slopes. IR image by V. Droznin, S. Chirkov, and I. Dubrovskaya (IVS RAS).
Figure (see Caption) Figure 8. This satellite image taken on 25 February 2011 shows a vigorous ash-laden plume extending from Kizimen at an altitude of ~3 km, drifting towards the NE, and visible for more than 170 km. The white portion of the plume is likely rich in steam, while the tan plume is primarily ash. The ground E of Kizimen is coated in newly fallen ash not yet covered by fresh snow. To the S of the summit are several dark streaks. These are probably traces of pyroclastic flows. Thermal anomalies (red in colored versions of this Bulletin) show the presence of recent hot block-and-ash flows from summit dome collapses. The image was acquired by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) aboard the Terra satellite. Courtesy of NASA/GSFC/METI/ERSDAC/JAROS.

Reference: Browne B., Izbekov, P., Eichelberger, J., and Churikova, T., 2010, Pre-eruptive storage conditions of the Holocene dacite erupted from Kizimen Volcano, Kamchatka: International Geology Review, v. 52, Issue 1 January 2010, p. 95-110.

Geologic Background. Kizimen is an isolated, conical stratovolcano that is morphologically similar to St. Helens prior to its 1980 eruption. The summit consists of overlapping lava domes, and blocky lava flows descend the flanks of the volcano, which is the westernmost of a volcanic chain north of Kronotsky volcano. The 2334-m-high edifice was formed during four eruptive cycles beginning about 12,000 years ago and lasting 2000-3500 years. The largest eruptions took place about 10,000 and 8300-8400 years ago, and three periods of long-term lava dome growth have occurred. The latest eruptive cycle began about 3000 years ago with a large explosion and was followed by intermittent lava dome growth lasting about 1000 years. An explosive eruption about 1100 years ago produced a lateral blast and created a 1.0 x 0.7 km wide crater breached to the NE, inside which a small lava dome (the fourth at Kizimen) has grown. Prior to 2010, only a single explosive eruption, during 1927-28, had been recorded in historical time.

Information Contacts: Kamchatka Volcanic Eruptions Response Team (KVERT), Institute of Volcanology and Seismology Russian Academy of Sciences, Far East Division, 9 Piip Blvd., Petropavlovsk-Kamchatsky, 683006, Russia (URL: http://www.kscnet.ru/ivs/); Kamchatka Branch of the Geophysical Service of the Russian Academy of Sciences (KB GS RAS), Piip Ave. 9, Petropavlovsk-Kamchatsky, 683006, Russia (URL: http://www.kscnet.ru/ivs/); Sergey Senukov, Russia (URL: http://www.emsd.ru/) Valery Droznin and Sergey Chirkov, Institute of Volcanology and Seismology Russian Academy of Sciences, Far Eastern Branch, 9 Piip Boulevard, Petropavlovsk-Kamchatsky, 683006, Russia; A. Lobashevsky (URL: http://www.photokamchatka.ru/); I. Shpilenok (URL: http://shpilenok.livejournal.com/44922.html); NASA Earth Observatory (URL: http://earthobservatory.nasa.gov/); Don Nelson Page, Theoretical Physics Institute, 412 Physics Lab., University of Alberta, Edmonton, Alberta T6G 2J1, Canada.


Manam (Papua New Guinea) — February 2011 Citation iconCite this Report

Manam

Papua New Guinea

4.08°S, 145.037°E; summit elev. 1807 m

All times are local (unless otherwise noted)


Ashfall, pyroclastic flows, and seismicity in late December 2010

This report discusses Manam behavior during November 2010 to early 2011. As previously reported, during August-October 2010, lava fragments and ash plumes rose from Manam (BGVN 35:09). Similar activity continued through at least 4 January 2011. Over 10,000 former island residents remain in care centers on the mainland (see below).

During the reporting period, the Rabaul Volcano Observatory (RVO) reported that the Main Crater produced mostly white plumes that were occasionally laden with ash. Incandescent material was ejected at times and mainly fell back in and around the crater, but occasionally spilled into the SE and SW valleys.

Based on analysis of satellite imagery, the Darwin Volcanic Ash Advisory Centre (VAAC) reported that ash plumes during 14-16 November 2010 rose to an altitude of 2.7 km and drifted ~95 km NW.

RVO reported that light brown to dark gray ash plumes rose 400-500 m above the South Crater during late November. People living on the island reported occasional roaring and rumbling noises. A new episode of eruptive activity began at South Crater on 25 December and was characterized during 25-29 December by rising ash plumes and ejections of incandescent lava fragments. Electronic tilt measurements showed a strong inflationary trend during 24-26 December but this slowed down on 26 December.

On 30 December 2010, activity from South Crater increased and was reported by observers in Bogia (on the mainland 20 km SSW). A dense ash plume rose 3 km above the summit crater and drifted NW, causing light ashfall in Tabele (4 km SW of Manam). An observer at Tabele confirmed the eruption and also reported that three pyroclastic flows descended the SE valley, stopping within a few to several hundred meters from the coastline. The first and largest pyroclastic flow devastated a broad unpopulated area between Warisi (E of Manam) and Dugulava (S of Manam) villages. RVO increased the Alert Level to Stage 3. Later that day, both ash emissions and the ejection of incandescent fragments diminished.

During early January 2011, plumes, sometimes containing ash, continued to rise above the South and Main Craters. RVO reported low roaring from the South Crater and incandescence was reported at times. On 8 January, the Alert Level was lowered from Stage 3 to Stage 2.

Seismicity and MODVOLC thermal alerts. Seismic data were not available during late November because of technical problems. Seismicity was low on 24 December, increased slightly after 25 December, then reached a point after 27 December where it fluctuated at and above moderate level. RVO reported seismicity during early January 2011 to be at a moderately low to moderate level.

Between 16 October 2010 and 10 January 2011, MODVOLC detected thermal anomalies on 25 days, mostly during late November and December. After 10 January, no thermal anomalies were detected through at least 16 February.

Multi-year evacuation. The UN's IRIN (Integrated Regional Information Networks) discussed Manam evacuees in reports issued 5 May and 20 December 2010. The 5 May 2010 report stated that "Around 14,000 islanders have been living in three care centres in the mainland province of Madang since November 2004. In March 2010 there was discussion that the displaced persons might be allowed to voluntarily return home to Manam Island."

According to the report, "A July 2009 assessment by the National Disaster Centre, the UN, and Oxfam concluded that living on the island was not a viable option because of a lack of access to arable land and public services, and the risk of further volcanic activity."

"The decision to begin returning residents was taken following heightened tensions between islanders and local residents (they speak the same language), largely over land issues. With little to no assistance, many of the IDPs rely on local gardening as their only source of food and livelihood, meaning they often encroach on nearby land.

"In March 2010, the National Executive Council (NEC) approved the establishment of the Manam Task Force Committee to manage the needs of the displaced islanders, with the primary goal of finding a suitable location for their permanent relocation."

Geologic Background. The 10-km-wide island of Manam, lying 13 km off the northern coast of mainland Papua New Guinea, is one of the country's most active volcanoes. Four large radial valleys extend from the unvegetated summit of the conical basaltic-andesitic stratovolcano to its lower flanks. These valleys channel lava flows and pyroclastic avalanches that have sometimes reached the coast. Five small satellitic centers are located near the island's shoreline on the northern, southern, and western sides. Two summit craters are present; both are active, although most observed eruptions have originated from the southern crater, concentrating eruptive products during much of the past century into the SE valley. Frequent eruptions, typically of mild-to-moderate scale, have been recorded since 1616. Occasional larger eruptions have produced pyroclastic flows and lava flows that reached flat-lying coastal areas and entered the sea, sometimes impacting populated areas.

Information Contacts: Rabaul Volcano Observatory (RVO), PO Box 386, Rabaul, Papua New Guinea; Darwin Volcanic Ash Advisory Centre (VAAC), Bureau of Meteorology, Northern Territory Regional Office, PO Box 40050, Casuarina, NT 0811, Australia (URL: http://www.bom.gov.au/info/vaac/); Hawai'i Institute of Geophysics and Planetology (HIGP) MODVOLC Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/).


Merapi (Indonesia) — February 2011 Citation iconCite this Report

Merapi

Indonesia

7.54°S, 110.446°E; summit elev. 2910 m

All times are local (unless otherwise noted)


Eruption started 26 October 2010; 386 deaths, more than 300,000 evacuated

This report represents a preliminary discussion of the deadly eruption at Merapi that started on 26 October 2010. That eruption included weeks of instability that generated pyroclastic (block-and-ash) flows, which became particularly vigorous and numerous in early November, with at least one surge reportedly traveling along the Gendol drainage to 15-16 km from the summit dome. Of particular note from a hazards perspective, the path of some of these deposits differed at times from those of the recent past (but we have yet to find maps showing the flow directions and associated dates). An abstract by Lavigne and others (2011) reported the volume of tephra erupted in the 2010 eruption at over 100 x 106 m3, ~10-fold higher than similar deposits after typical eruptions in the past few decades, and among the factors why ongoing lahars are likely to be a hazard.

Our summary covers events into late 2010, with recognition of ongoing seismicity, weaker emissions, and repeated lahars in early 2011. The bulk of this report is based on those from the Indonesian Center of Volcanology and Geological Hazard Mitigation (CVGHM) and their observatory dedicated to Merapi (MVO). According to CVGHM, the 2010 eruption was the biggest since the 1872 eruption. Eruptions in 1930 killed around 1,300 people. The last eruption of Merapi occurred during March 2006-August 2007 (BGVN 31:05, 31:06, 32:02, and 33:10). A table appears near the end of this report summarizing some key events and observations. Fatalities and scale of evacuations are discussed in a separate subsection below. Another subsection notes that at least one commercial airliner sustained serious in-flight engine damage.

Regional background and prior eruptive patterns. Merapi (figures 38, 39, and 40) is located in the central part of Java, and this region and the island as a whole have extremely high population density (roughly double that of Japan or Thailand). Substantial numbers of people live or vacation on the mountain. The most densely settled part of the mountain is the dangerous S side (figure 39).

Figure (see Caption) Figure 38. (Bottom) Two maps showing Merapi's location and (on the larger map) the distribution of block-and-ash flows that took place during 1954-1998. During that interval, these deposits went to the NW, W, and SW. From Hort and others (2006).
Figure (see Caption) Figure 39. A map of the S portion of Merapi showing population data in shaded patterns with key at left. The segments of circles depict distances from the summit. The 2010 eruptions sent pyroclastic flows through Merapi's SE quadrant, thus passing areas of elevated population. Taken from OCHA (8 November 2010).
Figure (see Caption) Figure 40. A set of simple diagrams illustrating Merapi in cross section (looking W; S is to the left) summarizing behavior that occurred during 1986-1994 (such a diagram has yet to be published for the 2010 eruption). The 1989 case shows VT earthquakes in the edifice (circles containing crosses). Taken from Ratdomopurbo and Poupinet (2000).

Figure 38 provides a summary of block-and ash-flow deposits from 1954-1998 (Hort and others, 2006; Schwarzkopf, 2001). The eruptions starting in October 2010 sent pyroclastic flows and possible surges at least 15 km in the volcano's W to S quadrant. Block-and-ash flows are pyroclastic flows formed by dome collapse and containing a substantial amount of broken dome fragments.

The inset map at the lower left shows Merapi with respect to the city of Yogyakarta (30 km SSW). Although the metro area of that city has a population of 1.6 million residents, the Indonesian statistical bureau estimated the 2010 populations of the ~30 km2 city of Yogyakarta at ~396,000 residents, and the broader region at ~3.5 million residents.

Figure 39 shows the summit and S part of Merapi, plotting population data by village at distances up to 20-25 km from the summit. This side of the volcano is by far the most densely populated, and was also crossed by numerous pyroclastic flows both historically and in the 2010 eruptions.

Figure 40 illustrates critical processes in Merapi's mode of eruption in the recent past. A significant portion of the dome is unconfined by the summit crater and the S side is free to descend the volcano's upper slopes endangering residents below. In the recent episode, CVGHM benefitted from daily access to satellite radar imagery that reliably depicted dome morphology despite weather and steam clouds. Vöge and Hort (2008) and Hort and others (2006) discuss monitoring dome instability using Doppler radar.

Monitoring and lead-up to the 26 October 2010 eruption. Since 2007, short swarms of volcanic earthquakes occurred (eg., on 31 October 2009, 6 December 2009, and 10 June 2010). Monitored parameters, including earthquakes, deformation, and gas emmisions increased significantly during September 2010. Steeper increases in seismicity appeared during 15-26 October with the main ramp-up during 20-26 October.

Figure 41 shows several histograms that depict Merapi seismic data and summarize the variations in hazard status. The CVGHM scale, which stretches from 1 (low) to 4 (high), makes a complete ascent and partial descent through the full range of those levels during the date range shown. The heavy vertical line between Alert Levels 3 and 4 took place on 25 October, slightly before the onset of the major eruption on 26 October.

Figure (see Caption) Figure 41. Three histograms describing Merapi seismicity during 1 September 2010 to 6 March 2011. Horizontal scale marked in weeks and extends from 1 September 2010 to 5 March 2011. Words along the top line show hazard status (on an increasing scale starting from 1 [Normal] and extending to 2 [Waspada]), to 3 [Siaga]), and finally to 4 [Awas] and then declining). The top panel contains seismically inferred rockfalls and avalanches (guguran in Indonesian). The middle panel shows multiphase (MP) earthquakes (shallow source, dominant frequency ~1.5 Hz). The bottom panel shows volcanic earthquakes of both A- and B-type (where VTA represents deep volcano-tectonic earthquakes, 2.5-5 km below the summit; VTB represents shallow volcano-tectonic earthquakes, less than ~1.5 km below the summit). Taken from CVGHM report of 7 March, with minor revisions by Bulletin editors.

Figure 42 presents typical waveforms for various types of earthquakes and tremor signals previously recorded at Merapi (Ratdomopurbo and Poupinet, 2000). Both multiphase (MP) and volcanic type-A (VTA) showed strong peaks in seismicity prior to the 26 October eruption's onset. Rockfalls on upper panel (labeled guguran) and type-b events on bottom panel both peaked on or near 26 October.

Figure (see Caption) Figure 42. Typical waveforms, tremor signals, and descriptive seismic terminology in use at Merapi. These include tremor, LF-low frequency (earthquakes nominally from shallow sources, dominant frequency between 3 and 4 Hz), VTA and VTB (volcano-tectonic A and B, where VTA represents deeper volcano-tectonic earthquakes, 2.5-5 km below the summit; and VTB represents shallower volcano-tectonic earthquake, less than ~1.5 km below the summit), and MP-multiphase earthquakes. Records are from Station PUS (~0.5 km E of summit), shown in the upper part of the figure, and from Station DEL (~3 km SE of the summit), in the lower part. From Ratdomopurbo and Poupinet (2000).

The onset of the 26 October explosion occurred ~19 hours after an M 7.7 tectonic earthquake along the trench near the Mentawai islands adjacent to Central Sumatra, 1,200 km NW of Merapi. This earthquake was followed by several aftershocks, including two prior to the eruption (M 6.1 and 6.2) and one after the eruption (M 5.8). One or more of these earthquakes triggered tsunamis that hit the remote Mentawai islands, sweeping entire villages to sea and killing at least 428 people. There, too, thousands of people were displaced. The two near-simultaneous crises taxed authorities, NGOs, and the natural hazards community (figure 43).

Figure (see Caption) Figure 43. A map emphasizing the locations of the M 7.7 tsunamigenic (tsunami-generating) earthquake and the eruption onset at Merapi, events of 25 and 26 October, respectively. (The earthquake time stated is incorrect—according to USGS cataloging, it registered at 1442 UTC on the 25th, which corresponds to 2142 local time that day. The eruption began at 1002 UTC on the 26th). Jakara is Indonesia's capital. Courtesy of Relief Web.

Except for the close timing and regional proximity, the linkage between the M 7.7 earthquake and the eruption remains ambiguous. However, many researchers have noted that tectonic earthquakes can seemingly trigger volcanic responses (eg., Delle Donne and others, 2010; Lowenstern, JB, Smith, RB, and Hill, DP, 2006; Manga and Brodsky, 2006).

In early September 2010, the pattern of increased volcanic seismicity began to appear with MP earthquakes averaging 10/day and VTA and VTB averaging 3/day, with a total daily seismic energy of 603 x 1012 erg.

Gas analyses in August 2010 showed concentrations of HCl of 0.8 % mol and H2O of 80 % mol. Declining levels of H2O (less than 90 %) and increased levels of HCl (>0.5 %) were interpreted to indicate increased activity.

In September, summit inflation increased markedly. Seismicity also increased beginning on 12 September, when an M 2.5 VTA earthquake and pyroclastic flows/avalanches occurred. On 13 September, VTA earthquakes occurred twice, and white plumes rose 800 m above the crater.

During 23-26 October, there were small steam-and-ash emissions. Inflation increased sharply on 24 October to a rate of 420 mm/day. The next day, CVGHM raised the Alert Level to 4, and recommended immediate evacuation for several communities within a 10-km radius. A Reuters photo by Dwi Oblo taken at sunrise on 26 October looking up at the dome and the prominent S-trending avalanche channel revealed comparatively calm conditions, with emissions consisting of a thick white steam plume blowing W from the dome.

Initial October eruptions. The first eruption occurred at 1702 on 26 October 2010, an event characterized by explosions and multiple pyroclastic flows that traveled S ~8 km down the Gendol and Kuning drainages, and to some extent WSW down the Bedog drainage. Most of the pyroclastic flows lasted 2-9 minutes, but the eruptions associated with the final two each lasted 35 minutes. The event killed 35 people including the renowned mystical guardian of Merapi, Mbah Mbahmarijan, at 7 km distance.

Figure 44 shows an exposed ridge affected by pyroclastic flows in a photo taken on 27 October.

Figure (see Caption) Figure 44. An exposed ridge at Merapi as it appeared the day after the 26 October eruption. Pyroclastic flows had reduced forest to stumps, leaving stripped and fallen trees. Courtesy of The Boston Globe website of Merapi photos (Ulet Ifansasti/Getty Images).

According to the Darwin Volcanic Ash Advisory Center (VAAC), an ash plume rose to an altitude of 18 km, followed by extrusion of lava in the summit crater.

By 27 October the lava dome had sustained damage and a new 200-m-diameter crater had formed at the summit. After that, lava extrusions built a small dome in the crater. A space-based estimate made from the ozone monitoring instrument (OMI) indicated the eruption on the 26th vented at least 3,000 metric tons of SO2 gas. According to the Darwin VAAC, ground-based reports indicated that another explosion occurred on 28 October 2010. Cloud cover prevented satellite observations.

Following the eruption and continuing through 4 November, intense tremor took place. It was felt by people up to 20 km from the volcano.

CVGHM reported that two pyroclastic flows occurred on 30 October following an early morning explosion, the third since 26 October. According to a news article, ash fell in Yogyakarta, 30 km SSW, causing low visibility. CVGHM noted four pyroclastic flows on 31 October.

Stronger eruptions in November. According to CVGHM, during 31 October-4 November, a lava dome grew rapidly within Merapi's summit crater. Collapses from the S side of the dome fed minor pyroclastic flows that extended several hundred meters into the upper part of the Gendol valley.

On 1 November, an explosion began mid-morning with a low-frequency earthquake, and avalanches occurred. About seven pyroclastic flows occurred during the next few hours (figure 45), traveling SSE a maximum runout distance of 4 km, and in another (possibly later) case that day, 9 km. The Darwin VAAC reported that the explosion produced an ash plume that rose to an altitude of 6.1 km. News reports noted flight diversions and cancellations in and out of the airports serving Solo (40 km E) and Yogyakarta.

Figure (see Caption) Figure 45. On 1 November 2010, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite captured this thermal signature of Merapi's lava dome and hot pyroclastic flows. The thermal information is overlaid on a three-dimensional map of the volcano to show the approximate location of the pyroclastic flow. The three-dimensional data is from a global topographic model created using ASTER stereo observations. Courtesy of NASA Earth Observatory website (credit to Robert Simmon and Jesse Allen and NASA/GSFC/METI/ERSDAC/JAROS, and the U.S./Japan ASTER Science Team). Original caption by Holli Riebeek.

On 2 November, an ash plume was seen in satellite imagery drifting 75 km N at an altitude of 6.1 km. On the same day, CVGHM reported 26 pyroclastic flows. On 3 November, observers stationed at multiple posts reported ash plumes from pyroclastic flows. One pyroclastic flow traveled 10 km, prompting CVGHM to extend the hazard zone from a radius of 10 km to 15 km, and they recommended evacuations from several more communities. Another pyroclastic flow traveled 9 km SE later that day. Figure 46 shows a 2 November view of Merapi.

Figure (see Caption) Figure 46. Incandescent material spilled from Merapi's dome glows orange-red in colored versions of this long-exposure photograph taken on 2 November 2010 from ~25 km SSE of the summit (Klaten district). Condensate droplets in the thin (lenticular) clouds over the summit also reflect considerable light. Courtesy of The Boston Globe (Boston.com website); photo credit to Sonny Timbelaka (AFP/Getty Images).

CVGHM reported that, during 3-8 November, the eruption from Merapi continued at a vigorous pace, characterized by incandescent avalanches from the lava dome, pyroclastic flows, ash plumes, and occasional explosions.

Visual observations were often difficult due to inclement weather and eruption plumes. To overcome these challenges, people working on the crisis gained regular access to satellite radar data of high resolution (RADARSAT2). That data was made available 25 October through an agreement called the International Charter Space and Major Disasters.

According to the NASA Earth Observatory website, the strongest explosion during the 2010 eruption took place on 4-5 November, lasting more than 24 hours, when plumes rose to ~18 km altitude and drifted 110 km W. They claimed that some surges of pyroclastic material reached an 18 km runout distance (direction and damage unstated and several kilometers longer than some other observations). They also said that, according to local geologists, this explosion was the most violent one at Merapi since the 1870's. They noted that, by some estimates, the 4-5 November eruption was five times more intense than the one on 26 October.

A CVGHM report on the 4-5 November eruption stated that 38 pyroclastic flows had occurred before it ended. Although dense fog hampered visual observations, a CVGHM observer from Kaliurang post (~7 km S of the summit) saw 19 of those 38 flows travel ~4 km S. Another traveled 9 km SE. Ashfall was noted in some nearby areas. Satellite data indicated this explosion released much more SO2 than previous recent Merapi eruptions, ~300,000 metric tons.

Residents in towns up to 240 km away reported that 'heavy gray ash' blanketed trees, cars, and roads. On 5 November, rumbling sounds were heard in areas 30 km away, and pyroclastic flows continued to descend the flanks. Ash fell in Yogyakarta and "sand"-sized tephra fell within 15 km. CVGHM recommended evacuations from several more towns within a 20-km radius. Observations shortly after the 5 November eruption showed that the large lava dome of the previous week had been destroyed, and the summit crater had enlarged to a diameter of 300-400 m. However, by 6 November, another lava dome had grown, amassing, according to RADARSAT images 11 hours apart, at a rate of ~35 m3 per second.

Activity remained very intense on 6 November. Pyroclastic flows continued to descend the flanks; one flow traveled 4 km down the Senowo drainage to the W. Incandescent flashes from the lava dome were reported from observations posts, and incandescent material was ejected above the crater. Incandescent avalanches traveled 2 km down multiple drainages to the SSE, S, and SSW. The Darwin VAAC reported that ash plumes seen in satellite imagery rose to an altitude of 16.8 km on 5 and 6 November.

During this period, ashfall was heavy on Merapi's flanks, and was observed in multiple surrounding areas, including the villages of Selo (~5 km NNE) and Magelang (26 km WNW). In Muntilan village (18 km WSW), tephra and ash accumulated up to 4 cm. At the volcano, a new dome formed during 6-7 November 2010; it stood ~240 m in a NW-SE orientation, 140 m wide, and 40-50 m high.

On 7 November, the number of pyroclastic flows increased from the previous day. An explosion was heard, and ash plumes rose 6 km and drifted W. Lightning was seen from Yogyakarta. Pyroclastic flows traveled 5 km, and lava avalanches moved 600 m S and SW. The next day, ash plumes rose to altitudes of 6-7 km and were accompanied by rumbling sounds. According to the Darwin VAAC, satellite imagery during 7-8 November showed ash plumes at an altitude of 7.6 km drifting 165-220 km W and SW.

Figure 47 shows Merapi's erupted SO2 in the atmosphere during 4-8 November 2010. On 9 November, an SO2 cloud was seen over the Indian Ocean at altitudes of 12-15 km.

Figure (see Caption) Figure 47. SO2 concentration-pathlength (in Dobson units, with 100 DU as darkest colors) during 4-8 November 2010, as observed by the OMI on NASA's Aura spacecraft. OMI data provided courtesy of Simon Carn (Michigan Technical University). Courtesy of Natural Hazards NASA Earth Observatory website (image by Jesse Allen, and original caption by Michon Scott).

The European Space Agency (ESA) has created updates on SO2 gas retrieval from their Envisat, Eumetsat's MetOp, and NASA's Aura satellites. For the interval 4-13 November 2010, the peak atmospheric loading of SO2 appeared on 8 November at 227 kT SO2. The estimates can be seen presented as animations that depict complex rotating dispersal patterns. As seen in figure 47, significant portions of the gas blew over Western Australia. In Norwegian Institute for Air Research models shown in the article, many of the Merapi plumes centered around 15 km altitude, with tops and bottoms ~5 km above and below that height.

ESA (2010) quoted Andrew Tupper as saying, "The updates from ESA have been very useful to Darwin VAAC [Volcanic Ash Advisory Center] when received in real time, and we expect that in the post-event analysis we'll be able to show lots more potential value." The SO2 maps can help the aviation community avoid dangerous emissions from volcanoes.

ESA (2010) noted that they send SO2 email alerts in near-real time. The alerts link to a web page with a map showing the location of the sulphur dioxide peak.

Reduced eruptive vigor; lahars. Eruptions and seismicity generally dropped during mid-November 2010 into March 2011, but lahars became a problem. On 9 November, CVGHM noted a reduction in the intensity of activity; a single pyroclastic flow occurred in a 6-hour period. Rumbling sounds were accompanied by an ash plume that rose to an altitude of 4.5 km, and ashfall was reported in Selo (~5 km NNE). Lava-dome incandescence was again observed, and lava avalanches moved 800 m SSE.

During 10-11 November, seismicity continued to decrease. Lahar deposits were seen in multiple drainages, at a maximum distance of 16.5 km from the summit. On 10 November, plumes generally rose 0.8-1.5 km above the crater. Heavy ashfall was reported in areas to the WSW and WNW. A 3.5-km-long pyroclastic flow and a 200-m-long avalanche both traveled S in the Gendol drainage. Incandescence from the crater was observed through a closed-circuit television system at the Merapi museum (in the village of Kaliurang, ~7 km S of the summit). On 11 November, roaring was followed by light ashfall at the Ketep Merapi observation post, ~9 km NW of the summit. Plumes, brownish-black at times, rose 800 m above the crater and drifted W and NW, and one plume rose 1.5 km. Avalanches again proceeded S in the Gendol drainage.

According to the Darwin VAAC, during 12-21 November, ash plumes rose as high as 7.6 km and drifted in multiple directions. The SO2 concentration at high altitudes decreased. About 300,000 residents also began to return home after the "danger zone" was reduced in some areas due to decreased activity.

Between 10 November and 1 December, lahar deposits were seen in multiple drainages and in all rivers flowing from Merapi. CVGHM noted that several bridges had been damaged. On 29 November, a narrow tongue of lava was observed, and light-colored flow deposits extended S down several narrow channels (Gendol and Kuning drainages) at least 5 km from the summit.

According to CVGHM, seismicity declined further during 1-3 December, in number of volcanic earthquakes and their associated energy. Deformation measurements were either stable or did not show significant changes. Although fog often prevented visual observations, gas plumes were seen rising 500 m above the crater and drifting W. SO2 plumes were no longer detected in satellite imagery. On 4 December, the Alert Level was lowered to 3.

On 9 January, as seismicity continued to decrease, CVGHM lowered the Alert Level to 2. Plumes continued to rise above the crater and, on 12 January, avalanches descended the Krasak drainage, traveling 1.5 km SW. Lahars and high water during 15-23 January damaged infrastructure and caused temporary road closures. On 22 January, plumes rose 175 m above the crater and drifted E.

According to a news account (vivanews.com), Merapi spewed thick white plumes as of the first week of February 2011. CVGHM reported that gas plumes rose from Merapi during 28 February-6 March. The highest plume, on 5 March, rose 100 m and drifted E. The number of MP earthquakes was slightly lower compared to the previous week.

Analysis of the lahar problem emerged as this issue went to press. According to Lavigne and others (2011) the volume of pyroclastic debris from the 2010 eruptive episode was in excess of 100 x 106 m3, ~10-fold higher than similar deposits after more conventional eruptions. These deposits and subsequent lahars filled most of the protective Sabo-dam structures. The eruption coincided with the onset of the rainy season, an interval that usually brings 4 m of rain but due to La Niña conditions, is predicted to bring more rain than usual. The 50-year absence of lahars in Kuning and Woro drainages altered the perception of risk in residents there. Thousands of sand miners work in the riverbed of all lahar-prone channels.

Fatalities and scale of evacuations. As previously noted, on 26 October, pyroclastic flows killed ~35 people who 7 km from the summit. They had refused to evacuate the village of Kinahejo (Kinahrejo).

According to the U.S. Agency for International Development (USAID) (quoting the Government of Indonesia's National Disaster Management Agency-Badan Nasional Penanggulangan Bencana or BNPB), the 2010 eruptions killed 386 people, injured 131 people, and displaced initially more than 300,000 residents (USAID, 2011). According to Relief Web, the 11,000 displaced remained unable to return to their homes at least as late as January 2011.

Lahars followed the eruptive processes and caused at least one additional death and one injury. An 11 January IRIN News article stated that " . . . more than 300,000 people have been able to return home, another 11,000 remain displaced, living with family or in camps, according to the government's National Disaster Management Agency."

According to the UN's Integrated Regional Information Networks (IRIN News), a source of humanitarian news and analysis, rainfall triggered lahars on Merapi's flanks on 3 and 9 January 2011. This caused damage to houses, farms, and infrastructure in multiple villages in the Magelang district, 26 km WNW of Merapi. One death and an injury were reported. The flooded area reportedly affected an estimated 3,000 residents but the number evacuated was unstated. The flooding on 9 January was more intense and, according to IRIN News, the Red Cross evacuated dozens of people trapped in their homes.

Referring to the larger 2010 eruption and evacuees, the same 11 January IRIN article stated that " . . . more than 300,000 people have been able to return home, another 11,000 remain displaced, living with family or in camps, according to the government's National Disaster Management Agency." This article also quoted the same agency with regard to the 386 reported deaths and the 131 injuries from the 2010 eruption.

Airlines affected. According the Jakarta Post, a total of 13 international carriers stopped their flights to Jakarta on 6 November, citing concerns about volcanic ash in the air that could cause damage to their aircraft and engines, and thus jeopardize safety. They included Malaysia Airlines, Air Asia, Singapore Airlines, Emirate, Ethihad, Turkish Air, Japan Airlines, Lufthansa, and KLM.

Andrew Tupper at the Australian Bureau of Meteorology notified us that Indonesian media reported that a plane encountered a volcanic cloud N of Java ascribed to Merapi on 28 October 2010. The suspected ash-plume encounter occurred at altitudes in the range 9.1-11.6 km. An engine stall message alerted the crew, who also noted a strong burning odor that disappeared as the plane descended from 9.1 to 6.1 km altitude.

According to another news account (Kompas.com), possibly reporting the same incident, on 28 October, a Garuda Indonesia airplane with 383 passengers from Solo, Central Java, landed safely at Hang Nadim Airport, Batam, a scheduled refueling stop. Enroute, volcanic ash from Merapi had been sucked into the left engine of the Airbus 330 aircraft, disrupting the engine. Richard Wijaya, Operational Duty Manager of Garuda Indonesia in Batam, explained that the pilot had notified ground staff of the disruption before landing, and as soon as they landed in Batam, the engine was checked. The crew cancelled the next leg of the scheduled flight to Jeddah, Saudi Arabia.

On 2 November, an unspecified number of international airlines had to cancel flights to airports at Solo and Yogyakarta, as plumes blackened the sky. Poor visibility and heavy ash on the runway caused the cancellations. According to an ABC news report, Yogyakarta airport reopened on 20 November after being closed for ~2 weeks.

Data table. Table 20 summarizes currently available CVGHM reports on Merapi's behavior during September to 1 December 2010. In the first row, it presents some background values commonly seen at Merapi during non-eruption conditions. Seismic terminology in the table is equivalent to that seen in figure 42 (Ratdomopurbo and Poupinet, 2000). Note the rise in seismic energy on 19 September, various changes in Alert Level, and major events in bolded type. Comparative calm prevailed after early November, but lahars became a problem (see text). The table is intended to give readers an overview of the eruption rather than capture all the details.

Table 20. Preliminary summary of pyroclastic flows as well as some collateral observations, and hazard status changes relating to Merapi during early September through 22 November 2010. Pyroclastic flows (locally termed AP for awan panas, hot clouds) here are tallied both from seismic detection and visual observations, along with direction of travel. The table omits seismic data shown in figure 41. The "ber" (beruntun) refers to episodes of densely spaced signals indistinguishable from each other. Those signals were common beginning 4 November and complicated assessments of tremor (not shown). The pre-eruption seismic energy was less than 342 x 1012 erg (normal, non-eruptive conditions). Courtesy of CVGHM and A. Ratdomopurbo (personal communication).

Date Pyroclastic flows Related comments
Early Sep 2010 -- Seismic energy, 603 x 1012 ergs
19 Sep 2010 -- Seismic energy, ~6,000 x 1012 erg
20 Sep 2010 -- Alert Level raised to 2
21 Oct 2010 -- Alert Level raised to 3
25 Oct 2010 -- Regional M 7.7 earthquake; Alert Level raised to 4
26 Oct 2010 8 [Multiple (WSW, SE)] Initial eruption at 1702 LT
30 Oct 2010 2 Second explosive eruption; ashfall in city of Yogyakarta
31 Oct 2010 4 Eruption
01 Nov 2010 7 during several hr --
02 Nov 2010 26 Eruption; 9 and 10 km runout distances
03 Nov 2010 38 [At least 19 (S)] Eruption
04 Nov 2010 ber [Multiple] Eruption (over 24 hours)
05 Nov 2010 ber [Multiple] 4-5 Nov. eruption was largest 2010 eruption (ash plume to 16.8 km asl); runout distances of ~18 km(?); widespread ash fall; dome destruction
06 Nov 2010 5 [Multiple] Eruption, rapid dome extrusion
07 Nov 2010 ber [Multiple] Eruption
08 Nov 2010 7 Eruption
09 Nov 2010 2 [1 in 6 hr period] Weaker eruption
10 Nov 2010 1 [At least 1 (S)] Weaker eruption
11 Nov 2010 1 [At least 1 (S)] Weaker eruption
14 Nov 2010 2 [0 (none)] Weaker eruption
15 Nov 2010 [1] Weaker eruption
16 Nov 2010 [1] Weaker eruption
22 Nov 2010 [5] Eruption

References. Delle Donne, D., Harris, AJL, Ripepe, M, and Wright, R., 2010, Earthquake-induced thermal anomalies at active volcanoes, Geology, Sept. 2010; v. 38; pp. 771-774 [DOI: 10.1130/G30984.1].

European Space Agency (ESA), 2010, Satellites tracking Mt Merapi volcanic ash clouds, ESA News (online; 15 November 2010) (URL: http://www.esa.int/esaCP/SEMY0Y46JGG_index_0.html).

Hort, M, Vöge, FM., Seyfried, R, and Ratdomopurbo, A, 2006, In situ observation of dome instabilities at Merapi volcano, Indonesia: A new tool for volcanic hazard mitigation, Journal of Volcanology and Geothermal Research, v. 154, no. 3-4, p. 301-312.

Lavigne,F, de Bélizal, E, Cholik, N, Aisyah, N, Picquout, A, and Wulan Mei, ET, 2011, Lahar hazards and risks following the 2010 eruption of Merapi volcano, Indonesia, Geophysical Research Abstracts, v. 13, EGU2011-4400, 2011, EGU General Assembly 2011.

Lowenstern, JB, Smith, RB, and Hill, DP, 2006, Monitoring super-volcanoes: geophysical and geochemical signals at Yellowstone and other large caldera systems, Phil. Trans. R. Soc. A, 15 August 2006, v. 364, no. 1845, p. 2055-2072.

Manga, M. and Brodsky, E, 2006, Seismic triggering of eruptions in the far field: volcanoes and geysers, Annual Review of Earth and Planetary Sciences, v. 34, p. 263-291 [DOI: 10.1146/annurev.earth.34.031405.125125].

Ratdomopurbo, A, and Poupinet, G, 2000, An overview of the seismicity of Merapi volcano (Java, Indonesia), 1983-1994, Journal of Volcanology and Geothermal Research, v. 100, no. 1-4, p.193-214 (DOI: 10.1016/S0377-0273(00)00137-2).

Schwarzkopf, L, 2001, The 1995 and 1998 block and ash flow deposits at Merapi volcano, Central Java, Indonesia: implications for emplacement mechanisms and hazard mitigation. Ph.D. Thesis, University at Kiel, Kiel, Germany.

USAID (U.S. Agency for International Development), 2011 (February 4), Indonesia - Tsunami and Volcano, Fact Sheet 2, Fiscal Year 2011.

Vöge, FM, and Hort, M, 2008, Automatic classification of dome instabilities based on Doppler radar measurements at Merapi volcano, Indonesia: Part I. Geophysical Journal International, v. 172, no. 3, p. 1188-1206 (DOI: 10.1111/j.1365-246X.2007.03605.x).

Geologic Background. Merapi, one of Indonesia's most active volcanoes, lies in one of the world's most densely populated areas and dominates the landscape immediately north of the major city of Yogyakarta. It is the youngest and southernmost of a volcanic chain extending NNW to Ungaran volcano. Growth of Old Merapi during the Pleistocene ended with major edifice collapse perhaps about 2,000 years ago, leaving a large arcuate scarp cutting the eroded older Batulawang volcano. Subsequent growth of the steep-sided Young Merapi edifice, its upper part unvegetated due to frequent activity, began SW of the earlier collapse scarp. Pyroclastic flows and lahars accompanying growth and collapse of the steep-sided active summit lava dome have devastated cultivated lands on the western-to-southern flanks and caused many fatalities.

Information Contacts: Center of Volcanology and Geological Hazard Mitigation (CVGHM), Jalan Diponegoro 57, Bandung 40122, Indonesia (URL: http://vsi.esdm.go.id/); Merapi Volcano Observatory (MVO); 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 Earth Observatory (URL: http://earthobservatory.nasa.gov/); U.S. Agency for International Development (USAID) (URL: https://www.usaid.gov/); Antonius Ratdomopurbo, Nanyang Technological University, Earth Observatory of Singapore, Nanyang Avenue, Singapore (URL: http://www.earthobservatory.sg/); Andrew Tupper, Australian Bureau of Meteorology (URL: http://www.bom.gov.au/); European Geosciences Union (URL: http://www.egu.eu/); Badan Nasional Penanggulangan Bencana (BNPB - Indonesian National Disaster Management Agency) (URL: http://dibi.bnpb.go.id/); Relief Web (URL: https://reliefweb.int/); Kompas News, Jakarta, Indonesia (URL: http://www.Kompas.com); The Jakarta Post (URL: http://www.thejakartapost.com/); Reuters (URL: http://www.reuters.com/); Vivanews.com (URL: http://vivanews.com/); ABC News (Australia) (URL: http://www.abc.net.au/); The Boston Globe (URL: http://www.boston.com/bigpicture/2010/11/mount_merapis_eruptions.html); IRIN News (URL: http://www.IRINnews.org/).


Rumble III (New Zealand) — February 2011 Citation iconCite this Report

Rumble III

New Zealand

35.745°S, 178.478°E; summit elev. -220 m

All times are local (unless otherwise noted)


Eruption in 2009 linked to over 100 m of sea floor collapse

We reported in BGVN 34:07 that New Zealand scientists found evidence during a research cruise in 2009 of a recent large eruption at Rumble III, one of more than 30 big submarine volcanoes on the Kermadec Arc, NE of the Bay of Plenty on the N coast of New Zealand's North Island (figures 3 and 4). A newly available report of the 2009 cruise (Dodge, 2010) noted some new details, including the following: (1) since the last study of Rumble III volcano in 2007, significant volcanic activity had occurred; (2) the bathymetric profile of the seamount had changed since it was last mapped in 2007—the summit of Rumble III had collapsed and was ~100 m deeper, at 310 m, much of the 800-m-wide crater was filled by ash, and much of the W side of the volcano had slid down-slope; (3) volcanic flow deposits were documented in camera tows—lava boulders, hackley flow, truncated lobate or pillows, and talus were common; and (4) there was a massive abundance of ash, in particular draped across substrates in many areas, provided compelling evidence for a large eruption since 2007.

Figure (see Caption) Figure 3. Southwest Pacific from Samoa (NE) to New Zealand (SW), showing the location of Rumble III and other submarine volcanoes along the southern Kermadec Arc. Rumble III volcano is located ~ 350 km NE of the Bay of Plenty, New Zealand, 200 km NE of Auckland, and is one of a number of submarine volcanoes that delineate the active arc front in this region. Bathymetry data were satellite-derived (for deep water) and acquired using an EM 300 multibeam echo sounder (along the arc and Lau Basin). Satellite-derived bathymetry from Sandwell and Smith (1997); EM300 bathymetry data courtesy of New Zealand National Institute of Water and Atmospheric Research (NIWA). Map courtesy of National Oceanic and Atmospheric Agency (NOAA) Ocean Explorer web site; from New Zealand American Submarine Ring of Fire 2005 expedition plan.
Figure (see Caption) Figure 4. Bathymetric map of all available multibeam data as of 2009 for the Southern Havre Trough, between the Colville and Kermadec Ridges and N of the New Zealand's North Island. In the colored version of this figure, the bathymetry key (in meters) ranges from red at the surface to purple at depths of 5 to 6 km. The location of Rumble III submarine volcano is highlighted. The inset indicates the tracks and areas of individual surveys whose data comprise the map. Areas that are not covered use satellite data configured to fit the edges of multibeam data set. Courtesy of Wysoczanski and others (2010).

A press release dated 17 August 2010 by the New Zealand National Institute of Water and Atmospheric Research (NIWA) noted that, during an oceanographic cruise aboard NIWA's research vessel R/V Tangaroa in May-June 2010, scientists confirmed that (a) the W flank of the volcano had collapsed ~100 m or more, (b) collapse of 90 m was observed at its highest (shallowest) point, and (c) as much as 120 m collapse occurred in some places. The release noted that the collapse was caused by an eruption some time in the last 2 years.

Glassy, black basaltic rock filled with vesicles was dredged from the volcano. Richard Wysoczanski (NIWA) noted that the samples are the youngest-known rocks from the Kermadec Arc region, created some time between the years 2007 and 2009. It is notable that andesite samples were previously collected from the flank of the submarine volcano by Brothers (1967). Rumble III was last mapped using multibeam technology in 2002.

NIWA principal scientist Geoffrey Lamarche said that the observation of significant pieces of sea floor moving hundreds of meters in height over a short timespan of 8 years give insight into short-time movements of the seabed. Research of the Kermadec Arc is directed in part by NIWA's survey of the area for massive sulphide deposits that sometimes develop over hydrothermal vents.

On 28 February 2011, NIWA and GNS Science announced an upcoming research cruise of about 3 weeks in 2011 to investigate mineral deposits and hydrothermal activity at five major submarine volcanoes in the Kermadec Arc (Clark, Healy, Brothers, Rumble II West, and Rumble III; see figure 4).

References. Brothers, R.N., 1967, Andesite from Rumble III Volcano, Kermadec Ridge, southwest Pacific, Bulletin of Volcanology, v. 31, no. 1, pp. 17-19.

Dodge, E., 2010, Catastrophic volcanic activity at Rumble III volcano based on EM300 bathymetry and direct sea floor imaging, Senior Thesis for Oceanography 444, University of Washington, School of Oceanography, Seattle, WA.

Smith, W. H. F., and Sandwell, D.T., 1997, Global seafloor topography from satellite altimetry and ship depth soundings, Science, v. 277, p. 1957-1962+.

Todd, E., Gill, J.B., Wysoczanski, R.J., Handler, M.R., Wright, I.C., Gamble, J.A., 2010, Sources of constructional cross-chain volcanism in the southern Havre Trough: New insights from HFSE and REE concentration and isotope systematics, Geochemistrry Geophysics Geosystems. v. 11, Q04009, 31 pp, DOI: 10.1029/2009GC002888.

Wysoczanski, R.J., Todd, E., Wright, I.C., Leybourne, M.I., Hergt, J.M., Adam, C., and Mackay, K., 2010, Backarc rifting, constructional volcanism and nascent disorganised spreading in the southern Havre Trough backarc rifts (SW Pacific), Journal of Volcanology and Geothermal Research, v. 190, issues 1-2, p. 39-57.

Geologic Background. Rumble III seamount, the largest of the Rumbles group of submarine volcanoes along the South Kermadec Ridge, rises 2,300 m from the seafloor to within about 200 m of the surface. Collapse of the edifice produced a scarp open to the west and a large debris-avalanche deposit. Fresh-looking andesitic rocks have been dredged from the summit and basaltic lava from its flanks. It has been the source of several submarine eruptions detected by hydrophone signals.

Information Contacts: Roger Matthews, North Shore City Council, 1 The Strand, Takapuna Private Bag 93500, Takapuna, North Shore City, New Zealand; Richard Wysoczanski, New Zealand National Institute of Water and Atmospheric Research (NIWA) (URL: https://www.niwa.co.nz/); Geoffrey Lamarche, NIWA (URL: https://www.niwa.co.nz/); GNS Science, Wairakei Research Centre, Private Bag 2000, Taupo 3352, New Zealand (URL: http://www.gns.cri.nz/); National Oceanic and Atmospheric Agency (NOAA) Ocean Explorer (URL: http://oceanexplorer.noaa.gov/gallery/gallery.html).


Sangay (Ecuador) — February 2011 Citation iconCite this Report

Sangay

Ecuador

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

All times are local (unless otherwise noted)


Many plumes seen by pilots during past year ending February 2011

The last report discussed observations of ash plumes and MODVOLC thermal alerts at Sangay through February 2010 (BGVN 35:01). Intermittent reporting indicated that similar activity continued through at least February 2011, with plumes reaching up to 7.6 km altitude (table 7). Clouds obscured the view at times, and plumes were reported primarily by pilots and were sometimes visible on satellite imagery.

Table 7. Plumes reported at Sangay during April 2010-February 2011. No plumes were noted during March 2011. Courtesy of the Washington VAAC.

Date Type of plume Altitude Distance and direction Source
21 Apr 2010 Ash 6.7 km -- Pilot observation
06 May 2010 Ash -- -- Pilot observation
06 May 2010 Ash -- W Pilot observation and satellite imagery
22-23 Jul 2010 Diffuse plumes -- 65-115 km W Pilot observation and satellite imagery
21 and 23 Jul 2010 Occasional thermal anomalies -- -- Satellite imagery
19 Aug 2010 Ash-and-gas plumes, intermittent thermal anomalies -- 25 km W Satellite imagery
20 Aug 2010 Emission -- -- Pilot observation
30 Aug 2010 Ash -- -- Pilot observation (near Sangay)
05 Sep 2010 Ash 5.5 km -- Pilot observation
10 Sep 2010 Small plume and thermal anomaly -- -- Satellite imagery
13 Sep 2010 Gas with possible ash and a thermal anomaly -- W Tegucigalpa Meteorological Watch Office (MWO) (Honduras), pilot observation, and satellite imagery
21 Sep 2010 Ash 7.6 km -- Pilot observation
06 Oct 2010 Small ash clouds -- WNW Pilot observation and satellite imagery
14 Oct 2010 Pilot reported ash, only gas plumes drifting NW observed in satellite imagery -- NW Pilot observation and satellite imagery
29 Oct 2010 Steam and gas plume possibly with ash and a thermal anomaly -- -- Satellite imagery
05 Dec 2010 Ash -- -- Guayaquil MWO (Ecuador)
12 Jan 2011 Ash and thermal anomaly 6.7 km >45 km SW Pilot observation and satellite imagery
20 Jan 2011 Ash 7.6 km -- Pilot observation
27 Jan 2011 Small ash clouds -- N Satellite imagery
23 Feb 2011 Pilot reported ash, small cloud drifting NW in satellite imagery with no ash confirmed -- SSE Pilot observation and satellite imagery

On 5 December 2010, the Washington Volcanic Ash Advisory Center (VAAC) stated that Instituto Geofisico reported elevated seismicity.

The MODVOLC alert system issued thermal alerts for Sangay monthly during March 2010 through early October 2010. Then, alerts were absent until 11 January 2011 (table 8).

Table 8. Thermal alerts issued for Sangay by the MODVOLC system during March 2010-20 March 2011 (continued from the list in BGVN 35:01). The system uses the MODIS instrument on the Terra and Aqua satellites. Courtesy MODVOLC Thermal Alerts System.

Date (UTC) Time (UTC) Pixels Satellite
15 Mar 2010 0330 1 Terra
30 Apr 2010 0345 1 Terra
16 May 2010 0345 1 Terra
03 Jun 2010 0330 1 Terra
12 Jul 2010 0340 1 Terra
18 Aug 2010 0655 1 Aqua
28 Sep 2010 0650 2 Aqua
30 Sep 2010 0335 1 Terra
02 Oct 2010 0325 1 Terra
07 Oct 2010 0345 1 Terra
11 Jan 2011 0345 1 Terra
02 Mar 2011 0330 1 Terra

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: 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/); 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/).


Taal (Philippines) — February 2011 Citation iconCite this Report

Taal

Philippines

14.0106°N, 120.9975°E; summit elev. 311 m

All times are local (unless otherwise noted)


Intermittent non-eruptive unrest during 2008-2010

As previously reported (BGVN 32:01), during the last four months of 2006 Taal displayed restlessness. This report discusses Taal seismicity, deformation, and hydrothermal behavior (steaming, and temperature changes in lake water at Main Crater) that occurred intermittently during 2008, 2010, and 2011.

Taal (also known as Talisay) is a lake-filled, 15 x 20 km caldera located on SW Luzon Island 65 km S of Manila (figure 9). The lake engulfs a large island with several thousand residents, Volcano Island, the place where all historical eruptions have vented (figures 10 and 11). Restlessness described herein was not confined to the area beneath the island.

Figure (see Caption) Figure 9. Index map of the Philippines showing Manila (the Capital) and several major volcanoes including Taal. Courtesy of Lyn Topinka (US Geological Survey).
Figure (see Caption) Figure 10. A map showing Taal caldera and surroundings. Notice that the caldera lies at the intersection of major faults and the topographic margin extends well beyond the caldera lake's margin. Courtesy of NASA Earth Observing System (EOS) Volcanology and their slide set compiled by Peter Mouginis-Mark (University of Hawaii).
Figure (see Caption) Figure 11. Photo of the Taal caldera lake and Volcano Island taken from the N in November 1999. Courtesy of NASA Earth Observing System (EOS) Volcanology and their slide set compiled by Peter Mouginis-Mark (University of Hawaii).

The Philippine Institute of Volcanology and Seismology (PHIVOLCS) announced in August 2008 that seismic unrest continued. On 28 August 2008, ten volcanic earthquakes occurred, two of which were felt and heard as rumbling sounds by residents in the Pira-Piraso village on Volcano Island. The earthquakes were located NE of the island near the Daang Kastila area (below Taal caldera's N rim) at estimated depths of 0.6-0.8 km. Surface observations indicated no change in the main crater lake area. The Alert Level remained at 1 (scale is 0-5, with 0 referring to No Alert).

On 8 June 2010, PHIVOLCS raised the Alert Level for Taal to 2 because of changes in several monitored parameters that began in late April. Since 26 April, the number and magnitude of volcanic earthquakes had increased. Most signals were high-frequency earthquakes, but at least one, on 2 June, was low-frequency. Steam emissions from the N and NE sides of Main Crater occasionally intensified. Deformation data showed slight inflation since 2004; measurements taken at the SE side of Taal on 7 June showed further inflation by 3 mm.

In addition to increased seismicity, the temperature of the Main Crater Lake increased from 32°C on 11 May to 34°C on 24 May. According to PHIVOLCS, the ratios of Mg:Cl and SO4:Cl, as well as total dissolved solids in the lake, all increased. Temperature measurements of the main crater lake did not increase further, remaining between 33-34°C.

PHIVOLCS proposed that the high frequency earthquakes could be the result of active rock fracturing associated with magma intrusion beneath the volcano, and that the fractures could serve as passageways through which hot gases from the intruding magma could escape into the lake.

According to news reports (Xinhua, Philippine Daily Inquirer), the more than 5,000 residents living near Taal were advised to evacuate their homes voluntarily. On 10 June, the Philippine Coast Guard sent five teams of divers and rescue swimmers with rubber boats and medical teams to its forward command post to help evacuate, if necessary, these residents. A news report (Philippine Daily Inquirer), however, indicated that most residents refused to leave without an official order.

The number of earthquakes recorded daily gradually declined to background levels beginning the second week of July 2010. Hydrothermal activity in the N and NE sides of the main crater and Daang Kastila also decreased. Precise leveling measurements conducted during 13-21 July along the NE, SE, and SW flanks detected minimal inflation. On 2 August, PHIVOLCS lowered the Alert Level to 1.

According to PHIVOLCS, seismic activity increased during the first week of September 2010. From 1-27 September 2010, a total of 274 volcanic earthquakes, or an average of 10 events/day, was recorded. However, given that field surveys conducted at the Main Crater and at the 1965-1977 "New Eruption" site (SW edge of Main Crater) indicated no anomalous thermal or surface activity.

PHIVOLCS reported that a December 2010 deformation survey showed slight inflation compared to a September 2010 survey. Field observations on 10 and 18 January revealed no significant changes. Weak steaming from a thermal area inside the main crater was noted and the lake temperature, acidity, and color were normal. During 15-16 January 2011, ten volcanic earthquakes were detected, two of which were felt by residents of Pira-Piraso, on the N side of the island. On 17 January three volcanic earthquakes were detected and on 18 January only one was reported. Between 18-30 January, up to seven daily volcanic earthquakes were detected by the seismic network.

Field observations during 23-25 January 2011 revealed an increase in the number of steaming vents inside the main crater and a drop in the lake level there. The lake water temperature and pH values remained normal. Visual observations on 27 January showed weak steaming at a thermal area in the crater.

Geologic Background. Taal is one of the most active volcanoes in the Philippines and has produced some powerful eruptions. The 15 x 20 km Talisay (Taal) caldera is largely filled by Lake Taal, whose 267 km2 surface lies only 3 m above sea level. The maximum depth of the lake is 160 m, with several submerged eruptive centers. The 5-km-wide Volcano Island in north-central Lake Taal is the location of all observed eruptions. The island is composed of coalescing small stratovolcanoes, tuff rings, and scoria cones. Powerful pyroclastic flows and surges have caused many fatalities.

Information Contacts: Philippine Institute of Volcanology and Seismology (PHIVOLCS), University of the Philippines Campus, Diliman, Quezon City, Philippines (URL: http://www.phivolcs.dost.gov.ph).Pete Mouginis-Mark, 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://eos.higp.hawaii.edu/ppages/pinatubo/8.taal/?); Xinhua (URL: http://www.xinhuanet.com/english2010); Philippine Daily Inquirer (URL: http://www.inquirer.net/).

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