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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

Sabancaya (Peru) Explosions, ash and SO2 plumes, thermal anomalies, and lava dome growth during June-November 2019

Karangetang (Indonesia) Lava flows, strong thermal anomalies, gas-and-steam emissions, and ash plumes during May-November 2019

Ulawun (Papua New Guinea) New vent, lava fountaining, lava flow, and ash plumes in late September-October 2019

Nyamuragira (DR Congo) Strong thermal anomalies and fumaroles within the summit crater during June-November 2019

Bagana (Papua New Guinea) Intermittent gas-and-steam emissions and thermal anomalies during June-November 2019

Kerinci (Indonesia) Intermittent gas-and-steam and ash plumes during June-early November 2019

Bezymianny (Russia) Lava dome growth, ongoing thermal anomalies, moderate gas-steam emissions, June-November 2019

Mayon (Philippines) Gas-and-steam plumes and summit incandescence during May-October 2019

Merapi (Indonesia) Low-volume dome growth continues during April-September 2019 with rockfalls and small block-and-ash flows

Manam (Papua New Guinea) Significant eruption on 28 June produced an ash plume up to 15.2 km and pyroclastic flows

Tangkuban Parahu (Indonesia) Phreatic eruption on 27 July followed by intermittent explosions through to 17 September 2019

Sheveluch (Russia) Frequent ash explosions and lava dome growth continue through October 2019



Sabancaya (Peru) — December 2019 Citation iconCite this Report

Sabancaya

Peru

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

All times are local (unless otherwise noted)


Explosions, ash and SO2 plumes, thermal anomalies, and lava dome growth during June-November 2019

Sabancaya is an andesitic stratovolcano located in Peru. The most recent eruptive episode began in early November 2016, which is characterized by gas-and-steam and ash emissions, seismicity, and explosive events (BGVN 44:06). The ash plumes are dispersed by wind with a typical radius of 30 km, which occasionally results in ashfall. Current volcanism includes high seismicity, gas-and-steam emissions, ash and SO2 plumes, numerous thermal anomalies, and explosive events. This report updates information from June through November 2019 using information primarily from the Instituto Geofisico del Peru (IGP) and Observatorio Volcanologico del INGEMMET (Instituto Geológical Minero y Metalúrgico) (OVI-INGEMMET).

Table 5. Summary of eruptive activity at Sabancaya during June-November 2019 based on IGP weekly reports, the Buenos Aires VAAC advisories, the HIGP MODVOLC hotspot monitoring algorithm, and Sentinel-5P/TROPOMI satellite data.

Month Avg. Daily Explosions by week Max plume Heights (km above crater) Plume drift MODVOLC Alerts Min Days with SO2 over 2 DU
Jun 2019 12, 13, 16, 17 2.6-3.8 30 km S, SW, E, SE, NW, NE 15 20
Jul 2019 23, 22, 16, 13 2.3-3.7 E, SE, S, NE 7 25
Aug 2019 12, 30, 25, 26 2-4.5 30 km NW, W S, NE, SE, SW 7 25
Sep 2019 29, 32, 24, 15 1.5-2.5 S, SE, E, W, NW, SW 14 26
Oct 2019 32, 36, 44, 48, 28 2.5-3.5 S, SE, SW, W 11 25
Nov 2019 58, 50, 47, 17 2-4 W, SW, S, NE, E 13 22

Explosions, ash emissions, thermal signatures, and high concentrations of SO2 were reported each week during June-November 2019 by IGP, the Buenos Aires Volcanic Ash Advisory Centre (VAAC), HIGP MODVOLC, and Sentinel-2 and Sentinel-5P/TROPOMI satellite data (table 5). Thermal anomalies were visible in the summit crater, even in the presence of meteoric clouds and ash plumes were occasionally visible rising from the summit in clear weather (figure 68). The maximum plume height reached 4.5 km above the crater drifting NW, W, and S the week of 29 July-4 August, according to IGP who used surveillance cameras to visually monitor the plume (figure 69). This ash plume had a radius of 30 km, which resulted in ashfall in Colca (NW) and Huambo (W). On 27 July the SO2 levels reached a high of 12,814 tons/day, according to INGEMMET. An average of 58 daily explosions occurred in early November, which is the largest average of this reporting period.

Figure (see Caption) Figure 68. Sentinel-2 satellite imagery detected ash plumes, gas-and-steam emissions, and multiple thermal signatures (bright yellow-orange) in the crater at Sabancaya during June-November 2019. Sentinel-2 atmospheric penetration (bands 12, 11, 8A) images courtesy of Sentinel Hub Playground.
Figure (see Caption) Figure 69. A webcam image of an ash plume rising from Sabancaya on 1 August 2019 at least 4 km above the crater. Courtesy of IGP.

Seismicity was also particularly high between August and September 2019, according to INGEMMET. On 14 August, roughly 850 earthquakes were detected. There were 280 earthquakes reported on 15 September, located 6 km NE of the crater. Both seismic events were characterized as seismic swarms. Seismicity decreased afterward but continued through the reporting period.

In February 2017, a lava dome was established inside the crater. Since then, it has been growing slowly, filling the N area of the crater and producing thermal anomalies. On 26 October 2019, OVI-INGEMMET conducted a drone overflight and captured video of the lava dome (figure 70). According to IGP, this lava dome is approximately 4.6 million cubic meters with a growth rate of 0.05 m3/s.

Figure (see Caption) Figure 70. Drone images of the lava dome and degassing inside the crater at Sabancaya on 26 (top) and 27 (bottom) October 2019. Courtesy of INGEMMET (Informe Ténico No A6969).

MIROVA (Middle InfraRed Observation of Volcanic Activity) analysis of MODIS satellite data shows strong, consistent thermal anomalies occurring all throughout June through November 2019 (figure 71). In conjunction with these thermal anomalies, the October 2019 special issue report by INGEMMET showed new hotspots forming along the crater rim in July 2018 and August 2019 (figure 72).

Figure (see Caption) Figure 71. Thermal anomalies at Sabancaya for 3 January through November 2019 as recorded by the MIROVA system (Log Radiative Power) were frequent, strong, and consistent. Courtesy of MIROVA.
Figure (see Caption) Figure 72. Thermal hotspots on the NW section of the crater at Sabancaya using MIROVA images. These images show the progression of the formation of at least two new hotspots between February 2017 to August 2019. Courtesy of INGEMMET, Informe Técnico No A6969.

Sulfur dioxide emissions also persisted at significant levels from June through November 2019, as detected by Sentinel-5P/TROPOMI satellite data (figure 73). The satellite measurements of the SO2 emissions exceeded 2 DU (Dobson Units) at least 20 days each month during this time. These SO2 plumes sometimes occurred for multiple consecutive days (figure 74).

Figure (see Caption) Figure 73. Consistent, large SO2 plumes from Sabancaya were seen in TROPOMI instrument satellite data throughout June-November 2019, many of which drifted in different directions based on the prevailing winds. Courtesy of NASA Goddard Space Flight Center.
Figure (see Caption) Figure 74. Persistent SO2 plumes from Sabancaya appeared daily during 13-16 September 2019 in the TROPOMI instrument satellite data. Courtesy of NASA Goddard Space Flight Center.

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), Calle Badajoz N° 169 Urb. Mayorazgo IV Etapa, Ate, Lima 15012, Perú (URL: https://www.gob.pe/igp); Observatorio Volcanologico del INGEMMET (Instituto Geológical Minero y Metalúrgico), Barrio Magisterial Nro. 2 B-16 Umacollo - Yanahuara Arequipa, Peru (URL: http://ovi.ingemmet.gob.pe); 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/); 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/); 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); Sentinel Hub Playground (URL: https://www.sentinel-hub.com/explore/sentinel-playground).


Karangetang (Indonesia) — December 2019 Citation iconCite this Report

Karangetang

Indonesia

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

All times are local (unless otherwise noted)


Lava flows, strong thermal anomalies, gas-and-steam emissions, and ash plumes during May-November 2019

Karangetang (also known as Api Siau), located on the island of Siau in the Sitaro Regency, North Sulawesi, Indonesia, has experienced more than 40 recorded eruptions since 1675 in addition to many smaller undocumented eruptions. In early February 2019, a lava flow originated from the N crater (Kawah Dua) traveling NNW and reaching a distance over 3 km. Recent monitoring showed a lava flow from the S crater (Kawah Utama, also considered the "Main Crater") traveling toward the Kahetang and Batuawang River drainages on 15 April 2019. Gas-and-steam emissions, ash plumes, moderate seismicity, and thermal anomalies including lava flow activity define this current reporting period for May through November 2019. The primary source of information for this report comes from daily and weekly reports by the Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM, or the Center of Volcanology and Geological Hazard Mitigation), the Darwin Volcanic Ash Advisory Center (VAAC), and satellite data.

PVMBG reported that white gas-and-steam emissions were visible rising above both craters consistently between May through November 2019 (figures 30 and 31). The maximum altitude for these emissions was 400 m above the Dua Crater on 27 May and 700 m above the Main Crater on 12 June. Throughout the reporting period PVMBG noted that moderate seismicity occurred, which included both shallow and deep volcanic earthquakes.

Figure (see Caption) Figure 30. A Sentinel-2 image of Karangetang showing two active craters producing gas-and-steam emissions with a small amount of ash on 7 August 2019. Courtesy of Sentinel Hub Playground.
Figure (see Caption) Figure 31. Webcam images of gas-and-steam emissions rising from the summit of Karangetang on 14 (top) and 25 (bottom) October 2019. Courtesy of PVMBG via Øystein Lund Andersen.

Activity was relatively low between May and June 2019, consisting mostly of gas-and-steam emissions. On 26-27 May 2019 crater incandescence was observed above the Main Crater; white gas-and-steam emissions were rising from both craters (figures 32 and 33). At 1858 on 20 July, incandescent avalanches of material originating from the Main Crater traveled as far as 1 km W toward the Pangi and Kinali River drainages. By 22 July the incandescent material had traveled another 500 m in the same direction as well as 1 km in the direction of the Nanitu and Beha River drainages. According to a Darwin VAAC report, discreet, intermittent ash eruptions on 30 July resulted in plumes drifting W at 7.6 km altitude and SE at 3 km, as observed in HIMAWARI-8 satellite imagery.

Figure (see Caption) Figure 32. Photograph of summit crater incandescence at Karangetang on 12 May 2019. Courtesy of Dominik Derek.
Figure (see Caption) Figure 33. Photograph of both summit crater incandescence at Karangetang on 12 May 2019 accompanied by gas-and-steam emissions. Courtesy of Dominik Derek.

On 5 August 2019 a minor eruption produced an ash cloud that rose 3 km and drifted E. PVMBG reported in the weekly report for 5-11 August that an incandescent lava flow from the Main Crater was traveling W and SW on the slopes of Karangetang and producing incandescent avalanches (figure 34). During 12 August through 1 September lava continued to effuse from both the Main and Dua craters. Avalanches of material traveled as far as 1.5 km SW toward the Nanitu and Pangi River drainages, 1.4-2 km to the W of Pangi, and 1.8 km down the Sense River drainage. Lava fountaining was observed occurring up to 10 m above the summit on 14-20 August.

Figure (see Caption) Figure 34. Photograph of summit crater incandescence and a lava flow from Karangetang on 7 August 2019. Courtesy of MAGMA Indonesia.

PVMBG reported that during 2-22 September lava continued to effuse from both craters, traveling SW toward the Nanitu, Pangi, and Sense River drainages as far as 1.5 km. On 24 September the lava flow occasionally traveled 0.8-1.5 km toward the West Beha River drainage. The lava flow from the Main Crater continued through at least the end of November, moving SW and W as far as 1.5 km toward the Nanitu, Pangi, and Sense River drainages. In late October and onwards, incandescence from both summit craters was observed at night. The lava flow often traveled as far as 1 km toward the Batang and East Beha River drainage on 12 November, the West Beha River drainage on 15, 22, 24, and 29 November, and the Batang and West Beha River drainages on 25-27 November (figure 35). On 30 November a Strombolian eruption occurred in the Main Crater accompanied by gas-and-steam emissions rising 100 m above the Main Crater and 50 m above the Dua Crater. Lava flows traveled SW and W toward the Nanitu, Sense, and Pangi River drainages as far as 1.5 km, the West Beha and Batang River drainages as far as 1 km, and occasionally the Batu Awang and Kahetang River drainages as far as 2 km. Lava fountaining was reported occurring 10-25 m above the Main Crater and 10 m above the Dua Crater on 6, 8-12, 15, 21-30 November.

Figure (see Caption) Figure 35. Webcam image of gas-and-steam emissions rising from the summit of Karangetang accompanied by incandescence and lava flows at night on 27 November 2019. Courtesy of MAGMA Indonesia via Øystein Lund Andersen.

MIROVA (Middle InfraRed Observation of Volcanic Activity) analysis of MODIS satellite data showed consistent and strong thermal anomalies within 5 km of the summit craters from late July through November 2019 (figure 36). Satellite imagery from Sentinel-2 corroborated this data, showing strong thermal anomalies and lava flows originating from both craters during this same timeframe (figure 37). In addition to these lava flows, satellite imagery also captured intermittent gas-and-steam emissions from May through November (figure 38). MODVOLC thermal alerts registered 165 thermal hotspots near Karangetang's summit between May and November.

Figure (see Caption) Figure 36. Frequent and strong thermal anomalies at Karangetang between 3 January through November 2019 as recorded by the MIROVA system (Log Radiative Power) began in late July and were recorded within 5 km of the summit craters. Courtesy of MIROVA.
Figure (see Caption) Figure 37. Sentinel-2 thermal satellite imagery (bands 12, 11, 8A) confirmed ongoing thermal activity (bright orange) at Karangetang from July into November 2019. The lava flows traveled dominantly in the W direction from the Main Crater. Courtesy of Sentinel Hub Playground.
Figure (see Caption) Figure 38. Sentinel-2 satellite imagery showing gas-and-steam emissions with a small amount of ash (middle and right) rising from both craters of Karangetang during May through November 2019. Courtesy of Sentinel Hub Playground.

Sentinel-5P/TROPOMI satellite data detected multiple sulfur dioxide plumes between May and November 2019 (figure 39). These emissions occasionally exceeded 2 Dobson Units (DU) and drifted in different directions based on the dominant wind pattern.

Figure (see Caption) Figure 39. SO2 emissions from Karangetang (indicated by the red box) were seen in TROPOMI instrument satellite data during May through November 2019, many of which drifted in different directions based on the prevailing winds. Top left: 27 May 2019. Top middle: 26 July 2019. Top right: 17 August 2019. Bottom left: 27 September 2019. Bottom middle: 3 October 2019. Bottom right: 21 November 2019. Courtesy of NASA Goddard Space Flight Center.

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 island. 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 in the historical record (Catalog of Active Volcanoes of the World: 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: 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.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/); 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/); 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); Øystein Lund Andersen (Twitter: @OysteinLAnderse, https://twitter.com/OysteinLAnderse, URL: https://www.oysteinlundandersen.com); Dominik Derek (URL: https://www.facebook.com/07dominikderek/).


Ulawun (Papua New Guinea) — December 2019 Citation iconCite this Report

Ulawun

Papua New Guinea

5.05°S, 151.33°E; summit elev. 2334 m

All times are local (unless otherwise noted)


New vent, lava fountaining, lava flow, and ash plumes in late September-October 2019

Ulawun is a basaltic-to-andesitic stratovolcano located in West New Britain, Papua New Guinea, with typical activity consisting of seismicity, gas-and-steam plumes, and ash emissions. The most recent eruption began in late June 2019 involving ash and gas-and-steam emissions, increased seismicity, and a pyroclastic flow (BGVN 44:09). This report includes volcanism from September to October 2019 with primary source information from the Rabaul Volcano Observatory (RVO) and the Darwin Volcanic Ash Advisory Centre (VAAC).

Activity remained low through 26 September 2019, mainly consisting of variable amounts of gas-and-steam emissions and low seismicity. Between 26 and 29 September RVO reported that the seismicity increased slightly and included low-level volcanic tremors and Real-Time Seismic Amplitude Measurement (RSAM) values in the 200-400 range on 19, 20, and 22 September. On 30 September small volcanic earthquakes began around 1000 and continued to increase in frequency; by 1220, they were characterized as a seismic swarm. The Darwin VAAC advisory noted that an ash plume rose to 4.6-6 km altitude, drifting SW and W, based on ground reports.

On 1 October 2019 the seismicity increased, reaching RSAM values up to 10,000 units between 0130 and 0200, according to RVO. These events preceded an eruption which originated from a new vent that opened on the SW flank at 700 m elevation, about three-quarters of the way down the flank from the summit. The eruption started between 0430 and 0500 and was defined by incandescence and lava fountaining to less than 100 m. In addition to lava fountaining, light- to dark-gray ash plumes were visible rising several kilometers above the vent and drifting NW and W (figure 21). On 2 October, as the lava fountaining continued, ash-and-steam plumes rose to variable heights between 2 and 5.2 km (figures 22 and 23), resulting in ashfall to the W in Navo. Seismicity remained high, with RSAM values passing 12,000. A lava flow also emerged during the night which traveled 1-2 km NW. The main summit crater produced white gas-and-steam emissions, but no incandescence or other signs of activity were observed.

Figure (see Caption) Figure 21. Photographs of incandescence and lava fountaining from Ulawun during 1-2 October 2019. A) Lava fountains along with ash plumes that rose several kilometers above the vent. B) Incandescence and lava fountaining seen from offshore. Courtesy of Christopher Lagisa.
Figure (see Caption) Figure 22. Photographs of an ash plume rising from Ulawun on 1 October 2019. In the right photo, lava fountaining is visible. Courtesy of Christopher Lagisa.
Figure (see Caption) Figure 23. Photograph of lava fountaining and an ash plume rising from Ulawun on 1 October 2019. Courtesy of Joe Metto, WNB Provincial Disaster Office (RVO Report 2019100101).

Ash emissions began to decrease by 3 October 2019; satellite imagery and ground observations showed an ash cloud rising to 3 km altitude and drifting N, according to the Darwin VAAC report. RVO reported that the fissure eruption on the SW flank stopped on 4 October, but gas-and-steam emissions and weak incandescence were still visible. The lava flow slowed, advancing 3-5 m/day, while declining seismicity was reflected in RSAM values fluctuating around 1,000. RVO reported that between 23 and 31 October the main summit crater continued to produce variable amounts of white gas-and-steam emissions (figure 24) and that no incandescence was observed after 5 October. Gas-and-steam emissions were also observed around the new SW vent and along the lava flow. Seismicity remained low until 27-29 October; it increased again and peaked on 30 October, reaching an RSAM value of 1,700 before dropping and fluctuating around 1,200-1,500.

Figure (see Caption) Figure 24. Webcam photo of a gas-and-steam plume rising from Ulawun on 30 October 2019. Courtesy of the Rabaul Volcano Observatory (RVO).

In addition to ash plumes, SO2 plumes were also detected between September and October 2019. Sentinel-5P/TROPOMI data showed SO2 plumes, some of which exceeded 2 Dobson Units (DU) drifting in different directions (figure 25). MIROVA (Middle InfraRed Observation of Volcanic Activity) analysis of MODIS satellite data showed strong, frequent thermal anomalies within 5 km of the summit beginning in early October 2019 and throughout the rest of the month (figure 26). Only one thermal anomaly was detected in early December.

Figure (see Caption) Figure 25. Sentinel-5P/TROPOMI data showing a high concentration of SO2 plumes rising from Ulawun between late September-early October 2019. Top left: 11 September 2019. Top right: 1 October 2019. Bottom left: 2 October 2019. Bottom right: 3 October 2019. Courtesy of the NASA Space Goddard Flight Center.
Figure (see Caption) Figure 26. Frequent and strong thermal anomalies at Ulawun for February through December 2019 as recorded by the MIROVA system (Log Radiative Power) began in early October and continued throughout the month. Courtesy of MIROVA.

Activity in November was relatively low, with only a variable amount of white gas-and-steam emissions visible and low (less than 200 RSAM units) seismicity with sporadic volcanic earthquakes. Between 9-22 December, a webcam showed intermittent white gas-and-steam emissions were observed at the main crater, accompanied by some incandescence at night. Some gas-and-steam emissions were also observed rising from the new SW vent along the lava flow.

Geologic Background. The symmetrical basaltic-to-andesitic Ulawun stratovolcano is the highest volcano of the Bismarck arc, and one of Papua New Guinea's most frequently active. The volcano, also known as the Father, rises above the N coast of the island of New Britain across a low saddle NE of Bamus volcano, the South Son. The upper 1,000 m is unvegetated. A prominent E-W escarpment on the south may be the result of large-scale slumping. Satellitic cones occupy the NW and E flanks. A steep-walled valley cuts the NW side, and a flank lava-flow complex lies to the south of this valley. Historical eruptions date back to the beginning of the 18th century. Twentieth-century eruptions were mildly explosive until 1967, but after 1970 several larger eruptions produced lava flows and basaltic pyroclastic flows, greatly modifying the summit crater.

Information Contacts: Rabaul Volcano Observatory (RVO), Geohazards Management Division, Department of Mineral Policy and Geohazards Management (DMPGM), PO Box 3386, Kokopo, East New Britain Province, 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/); 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/); 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/); Christopher Lagisa, West New Britain Province, Papua New Guinea (URL: https://www.facebook.com/christopher.lagisa, images posted at https://www.facebook.com/christopher.lagisa/posts/730662937360239 and https://www.facebook.com/christopher.lagisa/posts/730215604071639).


Nyamuragira (DR Congo) — December 2019 Citation iconCite this Report

Nyamuragira

DR Congo

1.408°S, 29.2°E; summit elev. 3058 m

All times are local (unless otherwise noted)


Strong thermal anomalies and fumaroles within the summit crater during June-November 2019

Nyamuragira (also known as Nyamulagira) is a high-potassium basaltic shield volcano located in the Virunga Volcanic Province (VVP) in the Democratic Republic of the Congo. Previous volcanism consisted of the reappearance of a lava lake in the summit crater in mid-April 2018, lava emissions, and high seismicity (BGVN 44:05). Current activity includes strong thermal signatures, continued inner crater wall collapses, and continued moderate seismicity. The primary source of information for this June-November 2019 report comes from the Observatoire Volcanologique de Goma (OVG) and satellite data and imagery from multiple sources.

OVG reported in the July 2019 monthly that the inner crater wall collapses that were observed in May continued to occur. During this month, there was a sharp decrease in the lava lake level, and it is no longer visible. However, the report stated that lava fountaining was visible from a small cone within this crater, though its activity has also decreased since 2014. In late July, a thermal anomaly and fumaroles were observed originating from this cone (figure 85). Seismicity remained moderate throughout this reporting period.

Figure (see Caption) Figure 85. Photograph showing the small active cone within the crater of Nyamuragira in late July 2019. Fumaroles are also observed within the crater originating from the small cone. Courtesy of Sergio Maguna.

MIROVA (Middle InfraRed Observation of Volcanic Activity) analysis of MODIS satellite data shows strong, frequent thermal anomalies within 5 km of the summit between June through November (figure 86). The strength of these thermal anomalies noticeably decreases briefly in September. MODVOLC thermal alerts registered 54 thermal hotspots dominantly near the N area of the crater during June through November 2019. Satellite imagery from Sentinel-2 corroborated this data, showing strong thermal anomalies within the summit crater during this same timeframe (figure 87).

Figure (see Caption) Figure 86. The MIROVA graph of thermal activity (log radiative power) at Nyamuragira during 30 January through November 2019 shows strong, frequent thermal anomalies through November with a brief decrease in activity in late April-early May and early September. Courtesy of MIROVA.
Figure (see Caption) Figure 87. Sentinel-2 thermal satellite imagery (bands 12, 11, 8A) confirmed ongoing thermal activity at Nyamuragira into November 2019. Courtesy of Sentinel Hub Playground.

Geologic Background. Africa's most active volcano, Nyamuragira, is a massive high-potassium basaltic shield about 25 km N of Lake Kivu. Also known as Nyamulagira, it has generated extensive lava flows that cover 1500 km2 of the western branch of the East African Rift. The broad low-angle shield volcano contrasts dramatically with the adjacent steep-sided Nyiragongo to the SW. The summit is truncated by a small 2 x 2.3 km caldera that has walls up to about 100 m high. Historical eruptions have occurred within the summit caldera, as well as from the numerous fissures and cinder cones on the flanks. A lava lake in the summit crater, active since at least 1921, drained in 1938, at the time of a major flank eruption. Historical lava flows extend down the flanks more than 30 km from the summit, reaching as far as Lake Kivu.

Information Contacts: Observatoire Volcanologique de Goma (OVG), Departement de Geophysique, Centre de Recherche en Sciences Naturelles, Lwiro, D.S. Bukavu, DR Congo; Sentinel Hub Playground (URL: https://www.sentinel-hub.com/explore/sentinel-playground); 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/); Sergio Maguna (Facebook: https://www.facebook.com/sergio.maguna.9, images posted at https://www.facebook.com/sergio.maguna.9/posts/1267625096730837).


Bagana (Papua New Guinea) — December 2019 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)


Intermittent gas-and-steam emissions and thermal anomalies during June-November 2019

Bagana volcano is found in a remote portion of central Bougainville Island in Papua New Guinea. The most recent eruptive phase that began in early 2000 has produced ash plumes and thermal anomalies (BGVN 44:06, 50:01). Activity has remained low between January-July 2019 with rare thermal anomalies and occasional steam plumes. This reporting period updates information for June-November 2019 and includes thermal anomalies and intermittent gas-and-steam emissions. Thermal data and satellite imagery are the primary sources of information for this report.

MIROVA (Middle InfraRed Observation of Volcanic Activity) analysis of MODIS satellite data showed an increased number of thermal anomalies within 5 km from the summit beginning in late July-early August (figure 38). Two Sentinel-2 thermal satellite images showed faint, roughly linear thermal anomalies, indicative of lava flows trending EW and NS on 7 July 2019 and 6 August, respectively (figure 39). Weak thermal hotspots were briefly detected in late September-early October after a short hiatus in September. No thermal anomalies were recorded in Sentinel-2 past August due to cloud cover; however, gas-and-steam emissions were visible on 7 July and in September (figures 39, 40, and 41).

Figure (see Caption) Figure 38. Thermal anomalies near the crater summit at Bagana during February-November 2019 as recorded by the MIROVA system (Log Radiative Power) increased in frequency and power in early August. A small cluster was detected in early October after a brief pause in activity in early September. Courtesy of MIROVA.
Figure (see Caption) Figure 39. Sentinel-2 thermal satellite imagery showing small thermal anomalies at Bagana between July-August 2019. Left: A very faint thermal anomaly and a gas-and-steam plume is seen on 7 July 2019. Right: Two small thermal anomalies are faintly seen on 6 August 2019. Both Sentinel-2 satellite images with "Atmospheric penetration" (bands 12, 11, 8A) rendering; courtesy of Sentinel Hub Playground.
Figure (see Caption) Figure 40. A gas-and-steam plume rising from the summit of Bagana on 18 September 2019. Courtesy of Brendan McCormick Kilbride (University of Manchester).

The Deep Carbon Observatory (DCO) scientific team partnered with the Rabaul Volcano Observatory and the Bougainville Disaster Office to observe activity at Bagana and collect gas data using drone technology during two weeks of field work in mid-September 2019. For this field work, the major focus was to understand the composition of the volcanic gas emitted at Bagana and measure the concentration of these gases. Since Bagana is remote and difficult to climb, research about its gas emissions has been limited. The recent advancements in drone technology has allowed for new data collection at the summit of Bagana (figure 41). Most of the emissions consisted of water vapor, according to Brendan McCormick Kilbride, one of the volcanologists on this trip. During 14-19 September there was consistently a strong gas-and-steam plume from Bagana (figure 42).

Figure (see Caption) Figure 41. Degassing plumes seen from drone footage 100 m above the summit of Bagana. Top: Zoomed out view of the summit of Bagana degassing. Bottom: Closer perspective of the gases emitted from Bagana. Courtesy of Kieran Wood (University of Bristol) and the Bristol Flight Laboratory.
Figure (see Caption) Figure 42. Photos of gas-and-steam plumes rising from Bagana between 14-19 September 2019. Courtesy of Brendan McCormick Kilbride (University of Manchester).

Geologic Background. Bagana volcano, occupying a remote portion of central Bougainville Island, is one of Melanesia's youngest and most active volcanoes. 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 frequent and characterized by non-explosive effusion of viscous lava that maintains a small lava dome in the summit crater, although explosive activity occasionally producing pyroclastic flows also occurs. Lava flows form dramatic, freshly preserved tongue-shaped lobes up to 50 m thick with prominent levees that descend the flanks on all sides.

Information Contacts: 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); Brendan McCormick Kilbride, University of Manchester, Manchester M13 9PL, United Kingdom (URL: https://www.research.manchester.ac.uk/portal/brendan.mccormickkilbride.html, Twitter: https://twitter.com/BrendanVolc); Kieran Wood, University of Bristol, Bristol BS8 1QU, United Kingdom (URL: http://www.bristol.ac.uk/engineering/people/kieran-t-wood/index.html, Twitter: https://twitter.com/DrKieranWood, video posted at https://www.youtube.com/watch?v=A7Hx645v0eU); University of Bristol Flight Laboratory, Bristol BS8 1QU, United Kingdom (Twitter: https://twitter.com/UOBFlightLab).


Kerinci (Indonesia) — December 2019 Citation iconCite this Report

Kerinci

Indonesia

1.697°S, 101.264°E; summit elev. 3800 m

All times are local (unless otherwise noted)


Intermittent gas-and-steam and ash plumes during June-early November 2019

Kerinci, located in Sumatra, Indonesia, is a highly active volcano characterized by explosive eruptions with ash plumes and gas-and-steam emissions. The most recent eruptive episode began in April 2018 and included intermittent explosions with ash plumes. Volcanism continued from June-November 2019 with ongoing intermittent gas-and-steam and ash plumes. The primary source of information for this report comes from 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 MAGMA Indonesia.

Brown- to gray-colored ash clouds drifting in different directions were reported by PVMBG, the Darwin VAAC, and MAGMA Indonesia between June and early November 2019. Ground observations, satellite imagery, and weather models were used to monitor the plume, which ranged from 4.3 to 4.9 km altitude, or about 500-1,100 m above the summit. On 7 June 2019 at 0604 a gray ash emission rose 800 m above the summit, drifting E, according to a ground observer. An ash plume on 12 July rose to 4 km altitude and drifted SW, as determined by satellite imagery and weather models. An eruption produced a gray ash cloud on 31 July that rose to 4.6 km altitude and drifted NE and E, according to PVMBG and the Darwin VAAC (figure 17). Another ash cloud rose up to 4.3 km altitude on 3 August. On 2 September a possible ash plume rose to a maximum altitude of 4.9 km and drifted WSW, according to the Darwin VAAC advisory.

Figure (see Caption) Figure 17. A gray ash plume at Kerinci rose roughly 800 m above the summit on 31 July 2019 and drifted NE and E. Courtesy of MAGMA Indonesia.

Brown ash emissions rose to 4.4 km altitude at 1253 on 6 October, drifting WSW. Similar plumes reached 4.6 km altitude twice on 30 October and moved NE, SE, and E at 0614 and WSW at 1721, based on ground observations. On 1-2 November, ground observers saw brown ash emissions rising up to 4.3 km drifting ESE. Between 3 and 5 November the brown ash plumes rose 100-500 m above the summit, according to PVMBG.

Gas emissions continued to be observed through November, as reported by PVMBG and identified in satellite imagery (figure 18). Seismicity that included volcanic earthquakes also continued between June and early November, when the frequency decreased.

Figure (see Caption) Figure 18. Sentinel-2 thermal satellite imagery showing a typical white gas-and-steam plume at Kerinci on 9 August 2019. Sentinel-2 satellite image with "Atmospheric penetration" (bands 12, 11, 8A) rendering; courtesy of Sentinel Hub Playground.

Geologic Background. Gunung Kerinci in central Sumatra forms Indonesia's highest volcano and is one of the most active in Sumatra. It is capped by an unvegetated young summit cone that was constructed NE of an older crater remnant. There is a deep 600-m-wide summit crater often partially filled by a small crater lake that lies on the NE crater floor, opposite the SW-rim summit. The massive 13 x 25 km wide volcano towers 2400-3300 m above surrounding plains and is elongated in a N-S direction. Frequently active, Kerinci has been the source of numerous moderate explosive eruptions since its first recorded eruption in 1838.

Information Contacts: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as Indonesian Center for Volcanology and Geological Hazard Mitigation, CVGHM), Jalan Diponegoro 57, Bandung 40122, Indonesia (URL: http://www.vsi.esdm.go.id/); Darwin Volcanic Ash Advisory Centre (VAAC), Bureau of Meteorology, Northern Territory Regional Office, PO Box 40050, Casuarina, NT 0811, Australia (URL: http://www.bom.gov.au/info/vaac/); MAGMA Indonesia, Kementerian Energi dan Sumber Daya Mineral (URL: https://magma.vsi.esdm.go.id/); Sentinel Hub Playground (URL: https://www.sentinel-hub.com/explore/sentinel-playground).


Bezymianny (Russia) — December 2019 Citation iconCite this Report

Bezymianny

Russia

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

All times are local (unless otherwise noted)


Lava dome growth, ongoing thermal anomalies, moderate gas-steam emissions, June-November 2019

The long-term activity at Bezymianny has been dominated by almost continuous thermal anomalies, moderate gas-steam emissions, dome growth, lava flows, and an occasional ash explosion (BGVN 44:06). The volcano is monitored by the Kamchatka Volcanic Eruptions Response Team (KVERT. Throughout the reporting period of June to November 2019, the Aviation Colour Code remained Yellow (second lowest of four levels).

According to KVERT weekly reports, lava dome growth continued in June through mid-July 2019. Thereafter the reports did not mention dome growth, but indicated that moderate gas-and-steam emissions (figure 32) continued through November. The MIROVA (Middle InfraRed Observation of Volcanic Activity) volcano hotspot detection system, based on analysis of MODIS data, detected hotspots within 5 km of the summit almost every day. KVERT also reported a thermal anomaly over the volcano almost daily, except when it was obscured by clouds. Infrared satellite imagery often showed thermal anomalies generated by lava flows or dome growth (figure 33).

Figure (see Caption) Figure 32. Photo of Bezymianny showing fumarolic activity on 4 July 2019. Photo by O. Girina (IVS FEB RAS, KVERT); courtesy of KVERT.
Figure (see Caption) Figure 33. Typical infrared satellite images of Bezymianny showing thermal anomalies in the summit crater, including a lava flow to the WNW. Top: 21 August 2019 with SWIR filter (bands 12, 8A, 4). Bottom: 17 September 2019 with Atmospheric Penetration filter (bands 12, 11, 8A). Courtesy of Sentinel Hub Playground.

Geologic Background. Prior to its noted 1955-56 eruption, Bezymianny had been considered extinct. The modern volcano, much smaller in size than its massive neighbors Kamen and Kliuchevskoi, was formed about 4700 years ago over a late-Pleistocene lava-dome complex and an ancestral edifice built about 11,000-7000 years ago. Three periods of intensified activity have occurred during the past 3000 years. The latest period, which was preceded by a 1000-year quiescence, began with the dramatic 1955-56 eruption. This eruption, similar to that of St. Helens in 1980, produced a large horseshoe-shaped 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/); 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/); 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).


Mayon (Philippines) — November 2019 Citation iconCite this Report

Mayon

Philippines

13.257°N, 123.685°E; summit elev. 2462 m

All times are local (unless otherwise noted)


Gas-and-steam plumes and summit incandescence during May-October 2019

Mayon, located in the Philippines, is a highly active stratovolcano with recorded historical eruptions dating back to 1616. The most recent eruptive episode began in early January 2018 that consisted of phreatic explosions, steam-and-ash plumes, lava fountaining, and pyroclastic flows (BGVN 43:04). The previous report noted small but distinct thermal anomalies, gas-and-steam plumes, and slight inflation (BGVN 44:05) that continued to occur from May into mid-October 2019. This report includes information based on daily bulletins from the Philippine Institute of Volcanology and Seismology (PHIVOLCS) and Sentinel-2 satellite imagery.

Between May and October 2019, white gas-and-steam plumes rose to a maximum altitude of 800 m on 17 May. PHIVOLCS reported that faint summit incandescence was frequently observed at night from May-July and Sentinel-2 thermal satellite imagery showed weaker thermal anomalies in September and October (figure 49); the last anomaly was identified on 12 October. Average SO2 emissions as measured by PHIVOLCS generally varied between 469-774 tons/day; the high value of the period was on 25 July, with 1,171 tons/day. Small SO2 plumes were detected by the TROPOMI satellite instrument a few times during May-September 2019 (figure 50).

Figure (see Caption) Figure 49. Sentinel-2 thermal satellite imagery of Mayon between May-October 2019. Small thermal anomalies were recorded in satellite imagery from the summit and some white gas-and-steam plumes are visible. Top left: 30 May 2019. Top right: 9 June 2019. Bottom left: 22 September 2019. Bottom right: 12 October 2019. Sentinel-2 satellite images with "Atmospheric penetration" (bands 12, 11, 8A) rendering; courtesy of Sentinel Hub Playground.
Figure (see Caption) Figure 50. Small SO2 plumes rising from Mayon during May-September 2019 recorded in DU (Dobson Units). Top left: 28 May 2019. Top right: 26 July 2019. Bottom left: 16 August 2019. Bottom right: 23 September 2019. Courtesy of NASA Goddard Space Flight Center.

Continuous GPS data has shown slight inflation since June 2018, corroborated by precise leveling data taken on 9-17 April, 16-25 July, and 23-30 October 2019. Elevated seismicity and occasional rockfall events were detected by the seismic monitoring network from PHIVOLCS from May to July; recorded activity decreased in August. Activity reported by PHIVOLCS in September-October 2019 consisted of frequent gas-and-steam emissions, two volcanic earthquakes, and no summit incandescence.

Geologic Background. Beautifully symmetrical Mayon, which rises above the Albay Gulf NW of Legazpi City, is the Philippines' most active volcano. The structurally simple edifice has steep upper slopes averaging 35-40 degrees that are capped by a small summit crater. Historical eruptions date back to 1616 and range from Strombolian to basaltic Plinian, with cyclical activity beginning with basaltic eruptions, followed by longer term andesitic lava flows. Eruptions occur predominately from the central conduit and have also produced lava flows that travel far down the flanks. Pyroclastic flows and mudflows have commonly swept down many of the approximately 40 ravines that radiate from the summit and have often devastated populated lowland areas. A violent eruption in 1814 killed more than 1,200 people and devastated several towns.

Information Contacts: Philippine Institute of Volcanology and Seismology (PHIVOLCS), Department of Science and Technology, University of the Philippines Campus, Diliman, Quezon City, Philippines (URL: http://www.phivolcs.dost.gov.ph/); Sentinel Hub Playground (URL: https://www.sentinel-hub.com/explore/sentinel-playground); 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/).


Merapi (Indonesia) — October 2019 Citation iconCite this Report

Merapi

Indonesia

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

All times are local (unless otherwise noted)


Low-volume dome growth continues during April-September 2019 with rockfalls and small block-and-ash flows

Merapi is an active volcano north of the city of Yogyakarta (figure 79) that has a recent history of dome growth and collapse, resulting in block-and-ash flows that killed over 400 in 2010, while an estimated 10,000-20,000 lives were saved by evacuations. The edifice contains an active dome at the summit, above the Gendol drainage down the SE flank (figure 80). The current eruption episode began in May 2018 and dome growth was observed from 11 August 2018-onwards. This Bulletin summarizes activity during April through September 2019 and is based on information from Balai Penyelidikan dan Pengembangan Teknologi Kebencanaan Geologi (BPPTKG, the Center for Research and Development of Geological Disaster Technology, a branch of PVMBG), Sutopo of Badan Nasional Penanggulangan Bencana (BNPB), MAGMA Indonesia, along with observations by Øystein Lund Andersen and Brett Carr of the Lamont-Doherty Earth Observatory.

Figure (see Caption) Figure 79. Merapi volcano is located north of Yogyakarta in Central Java. Photo courtesy of Øystein Lund Andersen.
Figure (see Caption) Figure 80. A view of the Gendol drainage where avalanches and block-and-ash flows are channeled from the active Merapi lava dome. The Gendol drainage is approximately 400 m wide at the summit. Courtesy of Brett Carr, Lamont-Doherty Earth Observatory.

At the beginning of April the rate of dome growth was relatively low, with little morphological change since January, but the overall activity of Merapi was considered high. Magma extrusion above the upper Gendol drainage resulted in rockfalls and block-and-ash flows out to 1.5 km from the dome, which were incandescent and visible at night. Five block-and-ash flows were recorded on 24 April, reaching as far as 1.2 km down the Gendol drainage. The volume of the dome was calculated to be 466,000 m3 on 9 April, a slight decrease from the previous week. Weak gas plumes reached a maximum of 500 m above the dome throughout April.

Six block-and-ash flows were generated on 5 May, lasting up to 77 seconds. Throughout May there were no significant changes to the dome morphology but the volume had decreased to 458,000 by 4 May according to drome imagery analysis. Lava extrusion continued above the Gendol drainage, producing rockfalls and small block-and-ash flows out to 1.2 km (figure 81). Gas plumes were observed to reach 400 m above the top of the crater.

Figure (see Caption) Figure 81. An avalanche from the Merapi summit dome on 17 May 2019. The incandescent blocks traveled down to 850 m away from the dome. Courtesy of Sutopo, BNPB.

There were a total of 72 avalanches and block-and-ash flows from 29 January to 1 June, with an average distance of 1 km and a maximum of 2 km down the Gendol drainage. Photographs taken by Øystein Lund Andersen show the morphological change to the lava dome due to the collapse of rock and extruding lava down the Gendol drainage (figures 82 and 83). Block-and-ash flows were recorded on 17 and 20 June to a distance of 1.2 km, and a webcam image showed an incandescent flow on 26 June (figure 84). Throughout June gas plumes reached a maximum of 250 m above the top of the crater

Figure (see Caption) Figure 82. The development of the Merapi summit dome from 2 June 2018 to 17 June 2019. Courtesy of Øystein Lund Andersen.
Figure (see Caption) Figure 83. Photos taken of the Merapi summit lava dome in June 2019. Top: This nighttime time-lapse photograph shows incandescence at the south-facing side of the dome on the 16 June. Middle: A closeup of a small rockfall from the dome on 17 June. Bottom: A gas plume accompanying a small rockfall on 17 June. Courtesy of Øystein Lund Andersen.
Figure (see Caption) Figure 84. Blocks from an incandescent rockfall off the Merapi dome reached out to 1 km down the Gendol drainage on 26 June 2019. Courtesy of MAGMA Indonesia.

Analysis of drone images taken on 4 July gave an updated dome volume of 475,000 m3, a slight increase but with little change in the morphology (figure 85). Block-and-ash flows traveled 1.1 km down the Gendol drainage on 1 July, 1 km on the 13th, and 1.1 km on the 14th, some of which were seen at night as incandescent blocks fell from the dome (figure 86). During the week of 19-25 July there were four recorded block-and-ash flows reaching 1.1 km, and flows traveled out to around 1 km on the 24th, 27th, and 31st. The morphology of the dome continued to be relatively stable due to the extruding lava falling into the Gendol drainage. Gas plumes reached 300 m above the top of the crater during July.

Figure (see Caption) Figure 85. The Merapi dome on 30 July 2019 producing a weak plume. Courtesy of MAGMA Indonesia.
Figure (see Caption) Figure 86. Incandescent rocks from the hot lava dome at the summit of Merapi form rockfalls down the Gendol drainage on 14 July 2019. Courtesy of Øystein Lund Andersen.

During the week of 5-11 August the dome volume was calculated to be 461,000 m3, a slight decrease from the week before with little morphological changes due to the continued lava extrusion collapsing into the Gendol drainage. There were five block-and-ash flows reaching a maximum of 1.2 km during 2-8 August. Two flows were observed on the 13th and 14th reaching 950 m, out to 1.9 km on the 20th and 22nd, and to 550 m on the 24th. There were 16 observed flows that reached 500-1,000 m on 25-27 August, with an additional flow out to 2 km at 1807 on the 27th (figure 87). Gas plumes reached a maximum of 350 m through the month.

Figure (see Caption) Figure 87. An incandescent rockfall from the Merapi dome that reached 2 km down the Gendol drainage on 27 August 2019. Courtesy of BPPTKG.

Brett Carr was conducting field work at Merapi during 12-26 September. During this time the lava extrusion was low (below 1 m3 per second). He observed small rockfalls with blocks a couple of meters in size, traveling about 50-200 m down the drainage every hour or so, producing small plumes as they descended and resulting in incandescence on the dome at night. Small dome collapse events produced block-and-ash flows down the drainage once or twice per day (figure 88) and slightly larger flows just over 1 km long a couple of times per week.

Figure (see Caption) Figure 88. A rockfall on the Merapi dome, towards the Gendol drainage at 0551 on 20 September 2019. Courtesy of Brett Carr, Lamont-Doherty Earth Observatory.

The dome volume was 468,000 m3 by 19 September, a slight increase from the previous calculation but again with little morphological change. Two block-and-ash flows were observed out to 600 m on 9 September and seven occurred on the 9th out to 500-1,100 m. Two occurred on the 14th down to 750-900 m, three occurred on 17, 20, and 21 September to a maximum distance of 1.2 km, and three more out to 1.5 km through the 26th. A VONA (Volcano Observatory Notice for Aviation) was issued on the 22nd due to a small explosion producing an ash plume up to approximately 3.8 km altitude (about 800 m above the summit) and minor ashfall to 15 km SW. This was followed by a block-and-ash flow reaching as far as 1.2 km and lasting for 125 seconds (figure 89). Preceding the explosion there was an increase in temperature at several locations on the dome. Weak gas plumes were observed up to 100 m above the crater throughout the month.

Figure (see Caption) Figure 89. An explosion at Merapi on 22 September 2019 was followed by a block-and-ash flow that reached 1.2 km down the Gendol drainage. Courtesy of BPPTKG.

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 2000 years ago, leaving a large arcuate scarp cutting the eroded older Batulawang volcano. Subsequently growth of the steep-sided Young Merapi edifice, its upper part unvegetated due to frequent eruptive 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 during historical time.

Information Contacts: Balai Penyelidikan dan Pengembangan Teknologi Kebencanaan Geologi (BPPTKG), Center for Research and Development of Geological Disaster Technology (URL: http://merapi.bgl.esdm.go.id/, Twitter: @BPPTKG); 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.vsi.esdm.go.id/); Badan Nasional Penanggulangan Bencana (BNPB), National Disaster Management Agency, Graha BNPB - Jl. Scout Kav.38, East Jakarta 13120, Indonesia (URL: http://www.bnpb.go.id/, Twitter: https://twitter.com/BNPB_Indonesia); Øystein Lund Andersen? (Twitter: @OysteinLAnderse, URL: http://www.oysteinlundandersen.com); Sutopo Purwo Nugroho, BNPB (Twitter: @Sutopo_PN, URL: https://twitter.com/Sutopo_PN); Brett Carr, Lamont-Doherty Earth Observatory, Columbia University, 61 Route 9W, Palisades, NY, USA (URL: https://www.ldeo.columbia.edu/user/bcarr).


Manam (Papua New Guinea) — October 2019 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)


Significant eruption on 28 June produced an ash plume up to 15.2 km and pyroclastic flows

Manam is a frequently active volcano forming an island approximately 10 km wide, located 13 km north of the main island of Papua New Guinea. At the summit are the Main Crater and South Crater, with four valleys down the NE, SE, SW, and NW flanks (figure 57). Recent activity has occurred at both summit craters and has included gas and ash plumes, lava flows, and pyroclastic flows. Activity in December 2018 prompted the evacuation of nearby villages and the last reported activity for 2018 was ashfall on 8 December. Activity from January through September 2019 summarized below is based on information from the Rabaul Volcano Observatory (RVO), the Darwin Volcanic Ash Advisory Center (VAAC), the University of Hawai'i's MODVOLC thermal alert system, Sentinel-5P/TROPOMI and NASA Aqua/AIRS SO2 data, MIROVA thermal data, Sentinel-2 satellite images, and observations by visiting scientists. A significant eruption in June resulted in evacuations, airport closure, and damage to local crops and infrastructure.

Figure (see Caption) Figure 57. A PlanetScope image of Manam showing the two active craters with a plume emanating from the South Crater and the four valleys at the summit on 29 August 2019. Image copyright 2019 Planet Labs, Inc.

Activity during January-May 2019. Several explosive eruptions occurred during January 2019 according to Darwin VAAC reports, including an ash plume that rose to around 15 km and dispersed to the W on the 7th. RVO reported that an increase in seismic activity triggered the warning system shortly before the eruption commenced (figure 58). Small explosions were observed through to the next day with ongoing activity from the Main Crater and a lava flow in the NE valley observed from around 0400. Intermittent explosions ejected scoria after 0600, depositing ejecta up to 2 cm in diameter in two villages on the SE side of the island. Incandescence at both summit craters and hot deposits at the terminus of the NE valley are visible in Sentinel-2 TIR data acquired on the 10th (figure 59).

Figure (see Caption) Figure 58. Real-Time Seismic-Amplitude Measurement graph representing seismicity at Manam over 7-9 January 2019, showing the increase during the 7-8 January event. Courtesy of RVO.
Figure (see Caption) Figure 59. Sentinel-2 thermal infrared (TIR) imagery shows incandescence in the two Manam summit craters and at the terminus of the NE valley near the shoreline on 10 January 2019. Courtesy of Sentinel-Hub Playground.

Another explosion generated an ash plume to around 15 km on the 11th that dispersed to the SW. An explosive eruption occurred around 4 pm on the 23rd with the Darwin VAAC reporting an ash plume to around 16.5 km altitude, dispersing to the E. Activity continued into the following day, with satellites detecting SO2 plumes on both 23 and 24 January (figure 60). Activity declined by February with one ash plume reported up to 4.9 km altitude on 15 February.

Figure (see Caption) Figure 60. SO2 plumes originating from Manam detected by NASA Aqua/AIRS (top) on 23 January 2019 and by Sentinel-5P/TROPOMI on 24 January (bottom). Images courtesy of Simon Carn, Michigan Technological University.

Ash plumes rose up to 3 km between 1 and 5 March, and dispersed to the SE, ESE, and E. During 5-6 March the plumes moved E, and the events were accompanied by elevated seismicity and significant thermal anomalies detected in satellite data. During 19-22 March explosions produced ash plumes up to 4.6 km altitude, which dispersed to the E and SE. Simon Carn of the Michigan Technological University noted a plume in Aqua/AIRS data at around 15 km altitude at 0400 UTC on 23 January with approximately 13 kt measured, similar to other recent eruptions. Additional ash plumes were detected on 29 March, reaching 2.4-3 km and drifting to the E, NE, and N. Multiple SO2 plumes were detected throughout April (figure 61).

Figure (see Caption) Figure 61. Examples of elevated SO2 (sulfur dioxide) emissions from Manam during April 2019, on 9 April (top left), 21 April (top right), 22 April (bottom left), 28 April (bottom right). Courtesy of the NASA Space Goddard Flight Center.

During 19-28 May the Deep Carbon Observatory ABOVE (Aerial-based Observations of Volcanic Emissions) scientific team observed activity at Manam and collected gas data using drone technology. They recorded degassing from the South Crater and Main Crater (figure 63 and 64), which was also detected in Sentinel-5P/TROPOMI data (figure 65). Later in the day the plumes rose vertically up to 3-4 km above sea level and appeared stronger due to condensation. Incandescence was observed each night at the South Crater (figure 66). The Darwin VAAC reported an ash plume on 10 May, reaching 5.5 km altitude and drifting to the NE. Smaller plumes up to 2.4 km were noted on the 11th.

Figure (see Caption) Figure 62. Degassing plumes from the South Crater of Manam, seen from Baliau village on the northern coast on 24 May 2019. Courtesy of Emma Liu, University College London.
Figure (see Caption) Figure 63. A strong gas-and-steam plume from Manam was observed moving tens of kilometers downwind on 19 May 2019, viewed here form the SSW at dusk. Photo courtesy of Julian Rüdiger, Johannes Gutenberg University Mainz.
Figure (see Caption) Figure 64. Sentinel-5P/TROPOMI SO2 data acquired on 22 May 2019 during the field observations of the Deep Carbon Observatory ABOVE team. Image courtesy of Simon Carn, Michigan Technological University.
Figure (see Caption) Figure 65. Incandescence at the South Crater of Manam was visible during 19-21 May 2019 from the Baliau village on the northern coast of the island. Photos courtesy of Tobias Fischer, University of New Mexico (top) and Matthew Wordell (bottom).

Activity during June 2019. Ash plumes rose to 4.3 km and drifted SW on 7-8 June, and up to 3-3.7 km and towards the E and NE on 18 June. Sentinel-2 thermal satellite data show hot material around the Main Crater on 24 June (figure 66). On 27 June RVO reported that RSAM (Real-time Seismic Amplitude Measurement, a measure of seismic activity through time) increased from 540 to over 1,400 in 30 minutes. "Thundering noise" was noted by locals at around 0100 on the 28th. An ash plume drifting SW was visible in satellite images acquired after 0620, coinciding with reported sightings by nearby residents (figure 67). The Darwin VAAC noted that by 0910 the ash plume had reached 15.2 km altitude and was drifting SW. When seen in satellite imagery at 1700 that day the large ash plume had detached and remained visible extending SW. There were 267 lightning strokes detected within 75 km during the event (figure 68) and pyroclastic flows were generated down the NE and W flanks. At 0745 on 29 June an ash plume reached up to 4.8 km.

Villages including Dugulava, Yassa, Budua, Madauri, Waia, Dangale, and Bokure were impacted by ashfall and approximately 3,775 people had evacuated to care centers. Homes and crops were reportedly damaged due to falling ash and scoria. Flights through Madang airport were also disrupted due to the ash until they resumed on the 30th. The Office of the Resident Coordinator in Papua New Guinea reported that as many as 455 homes and gardens were destroyed. Humanitarian resources were strained due to another significant eruption at nearby Ulawun that began on 26 June.

Figure (see Caption) Figure 66. Sentinel-2 thermal satellite data show hot material around the Main Crater and a plume dispersing SE through light cloud cover on 24 June 2019. Courtesy of Sentinel Hub Playground.
Figure (see Caption) Figure 67. Himawari-8 satellite image showing the ash plume rising above Manam and drifting SW at 0840 on 28 June. Satellite image courtesy of NCIT ScienceCloud.
Figure (see Caption) Figure 68. There were 267 lightning strokes detected within 75 km of Manam between 0729 on 27 June and 0100 on 29 June 2019. Sixty of these occurred within the final two hours of this observation period, reflecting increased activity. Red dots are cloud to ground lightning strokes and black dots are in-cloud strokes. Courtesy of Chris Vagasky, Vaisala Inc.

Activity during July-September 2019. Activity was reduced through July and September. The Darwin VAAC reported an ash plume to approximately 6 km altitude on 6 July that drifted W and NW, another plume that day to 3.7 km that drifted N, and a plume on the 21st that rose to 4.3 km and drifted SW and W. Diffuse plumes rose to 2.4-2.7 km and drifted towards the W on 29 September. Thermal anomalies in the South Crater persisted through September.

Fresh deposits from recent events are visible in satellite deposits, notably in the NE after the January activity (figure 69). Satellite TIR data reflected elevated activity with increased energy detected in March and June-July in MODVOLC and MIROVA data (figure 70).

Figure (see Caption) Figure 69. Sentinel-2 thermal infrared images acquired on 12 October 2018, 20 May 2019, and 12 September 2019 show the eruption deposits that accumulated during this time. A thermal anomaly is visible in the South Crater in the May and September images. Courtesy of Sentinel Hub Playground.
Figure (see Caption) Figure 70. MIROVA log radiative power plot of MODIS thermal infrared at Manam during February through September 2019. Increases in activity were detected in March and June-July. Courtesy of MIROVA.

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 1807-m-high basaltic-andesitic stratovolcano to its lower flanks. These "avalanche 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 historical eruptions have originated from the southern crater, concentrating eruptive products during much of the past century into the SE valley. Frequent historical 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), Geohazards Management Division, Department of Mineral Policy and Geohazards Management (DMPGM), PO Box 3386, Kokopo, East New Britain Province, Papua New Guinea; 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); 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/); Office of the Resident Coordinator, United Nations, Port Moresby, National Capital District, Papua New Guinea (URL: https://papuanewguinea.un.org/en/about/about-the-resident-coordinator-office, https://reliefweb.int/report/papua-new-guinea/papua-new-guinea-volcanic-activity-office-resident-coordinator-flash-2); Himawari-8 Real-time Web, developed by the NICT Science Cloud project in NICT (National Institute of Information and Communications Technology), Japan, in collaboration with JMA (Japan Meteorological Agency) and CEReS (Center of Environmental Remote Sensing, Chiba University) (URL: https://himawari8.nict.go.jp/); 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); Chris Vagasky, Vaisala Inc., Louisville, Colorado, USA (URL: https://www.vaisala.com/en?type=1, Twitter: @COweatherman, URL: https://twitter.com/COweatherman); Emma Liu, University College London Earth Sciences, London WC1E 6BS (URL: https://www.ucl.ac.uk/earth-sciences/people/academic/dr-emma-liu); Matthew Wordell, Boise, ID, USA (URL: https://www.matthhew.com/biocontact); Julian Rüdiger, Johannes Gutenberg University Mainz, Saarstr. 21, 55122 Mainz, Germany (URL: https://www.uni-mainz.de/).


Tangkuban Parahu (Indonesia) — October 2019 Citation iconCite this Report

Tangkuban Parahu

Indonesia

6.77°S, 107.6°E; summit elev. 2084 m

All times are local (unless otherwise noted)


Phreatic eruption on 27 July followed by intermittent explosions through to 17 September 2019

Tangkuban is located in the West Bandung and Subang Regencies in the West Java Province and has two main summit craters, Ratu and Upas (figure 3). Recent activity has largely consisted of phreatic explosions and gas-and-steam plumes at the Ratu crater. Prior to July 2019, the most recent activity occurred in 2012-2013, ending with a phreatic eruption on 5 October 2013 (BGVN 40:04). Background activity includes geothermal activity in the Ratu crater consisting of gas and steam emission (figure 4). This area is a tourist destination with infrastructure, and often people, overlooking the active crater. This report summarizes activity during 2014 through September 2019 and is based on official agency reports. Monitoring is the responsibility of Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as Indonesian Center for Volcanology and Geological Hazard Mitigation, CVGHM).

Figure (see Caption) Figure 3. Map of Tangkuban Parahu showing the Sunda Caldera rim and the Ratu, Upas, and Domas craters. Basemap is the August 2019 mosaic, copyright 2019 Planet Labs, Inc.
Figure (see Caption) Figure 4. Background activity at the Ratu crater of Tangkuban Parahu is shown in these images from 1 May 2012. The top image is an overview of the crater and the bottom four images show typical geothermal activity. Copyrighted photos by Øystein Lund Andersen, used with permission.

The first reported activity in 2014 consisted of gas-and-steam plumes during October-December, prompting PVMBG to increase the alert level from I to II on 31 December 2014. These white plumes reached a maximum of 50 m above the Ratu crater (figure 5) and were accompanied by elevated seismicity and deformation. This prompted the implementation of an exclusion zone with a radius of 1.5 km around the crater. The activity decreased and the alert level was lowered back to I on 8 January 2015. There was no further reported activity from January 2015 through mid-2019.

Figure (see Caption) Figure 5. Changes at the Ratu crater of Tangkuban Parahu during 25 December 2014 to 8 January 2015. Rain water accumulated in the crater in December and intermittent gas-and-steam plumes were observed. Courtesy of PVMBG (8 January 2015 report).

From 27 June 2019 an increase in activity was recorded in seismicity, deformation, gas chemistry, and visual observations. By 24 July the responsible government agencies had communicated that the volcano could erupt at any time. At 1548 on 26 July a phreatic (steam-driven) explosion ejected an ash plume that reached 200 m; a steam-rich plume rose to 600 m above the Ratu crater (figures 6, and 7). People were on the crater rim at the time and videos show a white plume rising from the crater followed by rapid jets of ash and sediment erupting through the first plume. Deposition of eruption material was 5-7 cm thick and concentrated within a 500 m radius from the point between the Rata and Upas craters, and wider deposition occurred within 2 km of the crater (figures 8 and 9). According to seismic data, the eruption lasted around 5 minutes and 30 seconds (figure 10). Videos show several pulses of ash that fell back into the crater, followed by an ash plume moving laterally towards the viewers.

Figure (see Caption) Figure 6. These screenshots are from a video taken from the Ratu crater rim at Tangkuban Parahu on 26 July 2019. Initially there is a white gas-and-steam plume rising from the crater, then a high-velocity black jet of ash and sediment rises through the plume. This video was widely shared across multiple social media platforms, but the original source could not be identified.
Figure (see Caption) Figure 7. The ash plume at Tangkuban Parahu on 26 July 2019. Courtesy of BNPB.
Figure (see Caption) Figure 8. Volcanic ash and lapilli was deposited around the Ratu crater of Tangkuban Parahu during a phreatic eruption on 26 July 2019. Note that the deposits have slumped down the window and are thicker than the actual ashfall. Courtesy of BNPB.
Figure (see Caption) Figure 9. Ash was deposited on buildings that line the Ratu crater at Tangkuban Parahu during a phreatic eruption on 26 July 2019. Photo courtesy of Novrian Arbi/via Reuters.
Figure (see Caption) Figure 10. A seismogram showing the onset of the 26 July 2019 eruption of Tangkuban Parahu and the elevated seismicity following the event. Courtesy of PVMBG via Øystein Lund Andersen.

On 27 July, the day after the eruption, Øystein Lund Andersen observed the volcano using a drone camera, operated from outside the restricted zone. Over a period of two hours the crater produced a small steam plume; ashfall and small blocks from the initial eruption are visible in and around the crater (figure 11). The ashfall is also visible in satellite imagery, which shows that deposition was restricted to the immediate vicinity to the SW of the crater (figure 12).

Figure (see Caption) Figure 11. Photos of the Ratu crater of Tangkuban Parahu on 27 July 2019, the day after a phreatic eruption. A small steam plume continued through the day. Courtesy of Øystein Lund Andersen.
Figure (see Caption) Figure 12. PlanetScope satellite images showing the Ratu crater of Tangkuban Parahu before (17 July 2019) and after (28 July 2019) the explosion that took place on 26 July 2019. Natural color PlanetScope Imagery, copyright 2019 Planet Labs, Inc.

Another eruption occurred at 2046 on 1 August 2019 and lasted around 11 minutes, producing a plume up to 180 m above the vent. Additional explosions occurred at 0043 on 2 August, lasting around 3 minutes according to seismic data, but were not observed. Explosions continued to be recorded at 0145, 0357, and 0406 at the time of the PVMBG report when the last explosion was ongoing, and a photo shows an explosion at 0608 (figure 13). The explosions produced plumes that reached between 20 and 200 m above the vent. Due to elevated activity the Alert Level was increased to II on 2 August. Ash emission continued through the 4th. During 5-11 August events ejecting ash continued to produce plumes up to 80 m, and gas-and-steam plumes up to 200 m above the vent. Ashfall was localized around Ratu crater. The following week, 12-18 August, activity continued with ash and gas-and-steam plumes reaching 100-200 m above the vent. During 19-25 August, similar activity sent ash to 50-180 m, and gas-and-steam plumes to 200 m. A larger phreatic explosion occurred at 0930 on 31 August with an ash plume reaching 300 m, and a gas-and-steam plume reaching 600 m above the vent, depositing ash and sediment around the crater.

Figure (see Caption) Figure 13. A small ash plume below a white gas-and-steam plume erupting from the Ratu crater of Tangkuban Parahu on 2 August 2019 at 0608. Courtesy of PVBMG (2 August 2019 report).

In early September activity consisted of gas-and-steam plumes up to 100-180 m above the vent with some ash plumes observed (figure 14). Two larger explosions occurred at 1657 and 1709 on 7 September with ash reaching 180 m, and gas-and-steam up to 200 m above the vent. Ash and sediment deposited around the crater. Due to strong winds to the SSW, the smell of sulfur was reported around Cimahi City in West Bandung, although there was no detected increase in sulfur emissions. A phreatic explosion on 17 September produced an ash plume to 40 m and a steam plume to 200 m above the crater. Weak gas-and-steam emissions reaching 200 m above the vent continued through to the end of September.

Figure (see Caption) Figure 14. A phreatic explosion at Tangkuban Parahu in the Ratu crater at 0724 on 4 September 2019, lasting nearly one minute. The darker ash plume reached around 100 m above the vent. Courtesy of PVGHM (4 September 2019 report).

Geologic Background. Gunung Tangkuban Parahu is a broad shield-like stratovolcano overlooking Indonesia's former capital city of Bandung. The volcano was constructed within the 6 x 8 km Pleistocene Sunda caldera, which formed about 190,000 years ago. The volcano's low profile is the subject of legends referring to the mountain of the "upturned boat." The Sunda caldera rim forms a prominent ridge on the western side; elsewhere the rim is largely buried by deposits of the current volcano. The dominantly small phreatic eruptions recorded since the 19th century have originated from several nested craters within an elliptical 1 x 1.5 km summit depression.

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/); Badan Nasional Penanggulangan Bencana (BNPB), National Disaster Management Agency, Graha BNPB - Jl. Scout Kav.38, East Jakarta 13120, Indonesia (URL: http://www.bnpb.go.id/); Øystein Lund Andersen (Twitter: @OysteinLAnderse, https://twitter.com/OysteinLAnderse, URL: https://www.oysteinlundandersen.com/tangkuban-prahu/tangkuban-prahu-volcano-west-java-one-day-after-the-26th-july-phreatic-eruption/); Reuters (URL: https://www.reuters.com/news/picture/editors-choice-pictures-idUSRTX71F3E).


Sheveluch (Russia) — November 2019 Citation iconCite this Report

Sheveluch

Russia

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

All times are local (unless otherwise noted)


Frequent ash explosions and lava dome growth continue through October 2019

After a lull in activity at Sheveluch, levels intensified again in mid-December 2018 and remained high through April 2019, with lava dome growth, strong explosions that produced ash plumes, incandescent lava flows, hot avalanches, numerous thermal anomalies, and strong fumarolic activity (BGVN 44:05). This report summarizes activity between May and October 2019. The volcano is monitored by the Kamchatka Volcanic Eruptions Response Team (KVERT).

According to KVERT, explosive activity continued to generate ash plumes during May-October 2019 (table 13). Strong fumarolic activity, incandescence and growth of the lava dome, and hot avalanches accompanied this process. There were also reports of plumes caused by re-suspended ash rather than new explosions. Plumes frequently extended a few hundred kilometers downwind, with the longest ones remaining visible in imagery as much as 1,000-1,400 km away. One of the larger explosions, on 1 October (figure 52), also generated a pyroclastic flow. Some of the stronger explosions sent the plume to an altitude of 10-11 km, or more than 7 km above the summit. The Aviation Color Code remained at Orange (the second highest level on a four-color scale) throughout the reporting period, except for several hours on 6 October when it was raised to Red (the highest level).

Table 13. Explosions and ash plumes at Sheveluch during May-October 2019. Dates and times are UTC, not local. Data courtesy of KVERT.

Dates Plume altitude (km) Drift Distance and Direction Remarks
30 Apr-02 May 2019 -- 200 km SE Resuspended ash.
03-10 May 2019 -- 50 km SE, SW Gas-and-steam plumes containing some ash.
13 May 2019 -- 16 km SE Resuspended ash.
11-12 Jun 2019 -- 60 km WNW Explosions and hot avalanches seen in video and satellite images.
24, 27 Jun 2019 4.5 E, W Ash plumes.
05 Aug 2019 2.5 40 km NW Diffuse ash plume.
25 Aug 2019 4.5-5 500 km NW Ash plumes.
29 Aug 2019 10 Various; 550 km N Explosions at 1510 produced ash plumes.
30 Aug 2019 7-7.5 50 km SSE Explosions at 1957 produced ash plumes.
03 Sep 2019 5.5 SE --
02-03, 05 Sep 2019 10 660 km SE Ash plumes seen in satellite images.
05 Sep 2019 -- -- Resuspended ash.
11-12 Sep 2019 -- 250 km ESE Resuspended ash plumes. Satellite and webcam data recorded ash emissions and a gas-and-steam plume with some ash drifting 50 km ESE on 12 Sep.
12-15, 17, 19 Sep 2019 -- 200 km SW, SE, NE Ash plumes.
20-21, 23, 26 Sep 2019 7 580 km ESE Explosions produced ash plumes.
29 Sep, 01-02 Oct 2019 9 1,400 km SE, E Explosions produced ash plumes. Notable pyroclastic flow traveled SE on 1 Oct.
04 Oct 2019 -- 170 km E Resuspended ash.
06 Oct 2019 10 430 km NE; 1,080 km ENE Ash plumes. Aviation Color Code raised to Red for several hours.
08 Oct 2019 -- 170 km E Resuspended ash.
06, 09 Oct 2019 6.5-11 1,100 km E --
11-13, 15 Oct 2019 6.5-7 620 km E, SE Explosions produced ash plumes.
16-17 Oct 2019 -- 125 km E Resuspended ash.
19-20 Oct 2019 -- 110 km SE Resuspended ash.
21 Oct 2019 10-11 1,300 km SE Explosions produced ash plumes.
Figure (see Caption) Figure 52. An explosion of Sheveluch on 1 October 2019. A pyroclastic flow was also reported by KVERT this day. Courtesy of Yu. Demyanchuk, IVS FEB RAS, KVERT.

Numerous thermal anomalies, based on MODIS satellite instruments analyzed using the MODVOLC algorithm, were observed every month. Consistent with this, the MIROVA (Middle InfraRed Observation of Volcanic Activity) system recorded thermal anomalies almost daily. According to KVERT, a thermal anomaly over Sheveluch was identified in satellite images during the entire reporting period, although cloudy weather sometimes obscured observations.

Geologic Background. The high, isolated massif of Sheveluch volcano (also spelled Shiveluch) rises above the lowlands NNE of the Kliuchevskaya volcano group. The 1300 km3 volcano is one of Kamchatka's largest and most active volcanic structures. 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 dot its outer flanks. The Molodoy Shiveluch lava dome complex was constructed during the Holocene within the large horseshoe-shaped caldera; Holocene lava dome extrusion also took place on the flanks of Stary Shiveluch. At least 60 large eruptions have occurred during the Holocene, making it the most vigorous andesitic volcano of the Kuril-Kamchatka arc. 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/); 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/).

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Bulletin of the Global Volcanism Network - Volume 33, Number 01 (January 2008)

Managing Editor: Richard Wunderman

Etna (Italy)

Tall sustained lava fountains, lava flows, and tephra blanket on 22-24 November 2007

Heard (Australia)

Rare thermal anomalies through March 2008 suggest eruptions

Huila, Nevado del (Colombia)

Eruptions in February, April, and May 2007; lahars take out bridges

Krakatau (Indonesia)

Repeated minor eruptions during October-November 2007

Llaima (Chile)

Ash plumes observed in May and August 2007; new eruption beginning 1 January 2008

Sheveluch (Russia)

Lava-dome growth and block-and-ash flows continue April-December 2007

Turrialba (Costa Rica)

Fumarolic increases during August 2007-January 2008

Ubinas (Peru)

Continuing ashfall during 2006-2007



Etna (Italy) — January 2008 Citation iconCite this Report

Etna

Italy

37.748°N, 14.999°E; summit elev. 3295 m

All times are local (unless otherwise noted)


Tall sustained lava fountains, lava flows, and tephra blanket on 22-24 November 2007

After the 10-hour-long episode of sustained lava fountaining from the Southeast Crater (SEC) on 4-5 September 2007 (BGVN 32:09), Etna remained quiescent for about three weeks. Ash emissions then resumed from the vent on the eastern flank of the SEC cone, which had been the main focus of activity since mid-August 2007. During October, ash emissions occurred intermittently, at times with minor incandescent ejections. This activity persisted until mid-November, after which there was a week-long pause until the early morning of 22 November. That day around 0500, weak Strombolian activity and ash emission started from the vent on the E flank of the SEC and continued with increasing strength for the following 36 hours.

A series of explosions occurred at the Bocca Nuova between 1658 and 1705 on 23 November, ejecting dark gray ash plumes, and producing strong seismic signals on nearby stations. During the following hours, Strombolian explosions occurred from the SEC vent, ejecting incandescent bombs to several tens of meters high.

After 2020, the vigor increased, with bursts of bombs rising to 100 m high, accompanied by a sharp rise in tremor amplitude. By 2130, a broad, pulsating lava fountain rose from the vent. Then, 15 min later, observers saw sustained fountaining up to 600 m high. The fountains discharged from what appeared to be two closely spaced sources within the depression, often making a V-shape.

Lava spilled over the vent's rim in at least three locations (figure 129), feeding three narrow branches of lava that ran E and coalesced, before spreading down the steep W slope of the Valle del Bove. A fourth lava flow started from an area ~ 150 m NE of the active vent, where fountain-fed spatter rapidly accumulated and ultimately began to flow. This flow joined the main lava flow toward the Valle del Bove at about 2,500 m elevation.

Figure (see Caption) Figure 129. Preliminary map of the lava flows emitted during Etna's lava-fountaining episodes of and 4-5 September 2007 and 23-24 November 2007. Both sets of flows discharged from the active vent on the E flanks of Southeast Crater (SEC). Courtesy of INGV-Catania.

The November lava flowed mostly on top of, or immediately adjacent to, the lava emitted during the eruption of early September 2007 (figure 129). At the base of the Valle del Bove slope, the November eruption's lava fanned out to form several minor lobes, the longest of which advanced to 1,670 m elevation, 4.2 km from the vent (figure 130; Burton and Neri, 2007).

Figure (see Caption) Figure 130. Aerial view, taken on 25 November 2007 from a helicopter of the Italian Civil Protection, of the lava flows erupted at Etna during 23-24 November 2007. View is from SE across the Valle del Bove (foreground). From Burton and Neri (2007), courtesy of INGV-Catania.

The explosive activity fed a dense tephra plume. It blew NE and caused ash and lapilli falls as far as 80 km away in southern Calabria, (Andronico and Cristaldi, 2007). At Piano Provenzana (~ 6.5 km NNE of the summit), the deposit was about 3 cm thick. Coarse scoriae, up to 5 cm across, fell ~ 10 km NNE from the SEC (in Linguaglossa) during the first hour of the eruption. During the following hours, finer ash fell in areas adjacent Etna and to the W.

Shortly after 0300 on 24 November, the eruptive activity and volcanic tremor amplitude began to diminish gradually, and during the next 20 min the fountain height dropped from ~ 600 m to under 200 m. Subsequently, the fountaining gave way to a series of powerful explosions, which showered the entire SEC cone with meter-sized bombs. The last of these explosions occurred at 0338, and for another 45 min after this, only minor explosive ejections occurred from the vent.

During the following hours, material continued to crumble and collapse on the steep slopes around the vent, exposing incandescent rock in countless spots. By 0600, the tremor amplitude had dropped to background levels, and no further eruptive activity was noted at the vent.

For several days after the eruption, gravitational instability of the new pyroclastic deposit, which had accumulated to thicknesses of several tens of meters, especially on the N side of the vent, caused occasional slides of material, exposing the still-incandescent interior of the deposit. A particularly large collapse from the overhanging W rim of the vent at 1713 on 27 November may have been accompanied by minor explosive activity, with incandescent material rolling to the base of the SEC cone (Calvari, 2007).

Ash emissions from the same vent occurred on 10 January 2008 and again on 1-3 February (figure 131). In mid-February such emissions became more frequent; some produced plumes several hundreds of meters high.

Figure (see Caption) Figure 131. Ash plume rising about 1 km high above the active vent on the eastern slope of Etna's Southeast Crater cone, on the morning of 10 January 2008. View is from Trecastagni, ~ 16 km SSE of the active vent. Courtesy of INGV-Catania.

References. Andronico, D. and Cristaldi, A., 2007, Il parossismo del 23-24 novembre 2007 al Cratere di SE: caratteristiche del deposito di caduta. Report published on-line at: http://www.ct.ingv.it/Report/RPTVETCEN20071123.pdf

Burton, M. and Neri, M., 2007, Stato attuale e osservazione dell'Etna 25 novembre 2007. Report published on-line at: http://www.ct.ingv.it/Report/WKRVGREP20071125.pdf

Calvari, S., 2007, Rapporto sull'attivit? dell'Etna del 27 novembre 2007. Report published on-line at: http://www.ct.ingv.it/Report/WKRVGREP20071127.pdf

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

Information Contacts: Boris Behncke, Sonia Calvari, and Marco Neri, Istituto Nazionale di Geofisica e Vulcanologia (INGV), Sezione di Catania, Piazza Roma 2, 95123 Catania, Italy.


Heard (Australia) — January 2008 Citation iconCite this Report

Heard

Australia

53.106°S, 73.513°E; summit elev. 2745 m

All times are local (unless otherwise noted)


Rare thermal anomalies through March 2008 suggest eruptions

Due to its isolated location in the S Indian Ocean on the Kerguelen Plateau, Heard Island is rarely visited, and satellite imagery provides the only regular information on eruptive activity. The Hawai'i Institute of Geophysics and Planetology (HIGP) Thermal Alerts System MODVOLC provides an analysis of MODIS (Moderate Resolution Imaging Spectroradiometer) satellite thermal anomaly data, with 1-2 daily observations. That system remains the best source of evidence at isolated, glacier-covered volcanoes like Heard, though it is difficult to determine how often meteorological clouds may obscure thermal anomalies.

The last report summarized activity beginning in March 2000 (BGVN 32:06), describing three eruptive episodes (based on thermal anomalies). The last thermal anomaly mentioned was on 6 April 2007. As seen on table 5, the MODVOLC system recorded the next thermal anomaly on 24 July 2007. For the rest of 2007, there were anomalies recorded on two days in August and two days in November. During 2008 as late as 2 March, anomalies occurred in February and March.

Table 5. Thermal anomalies measured by MODIS/MODVOLC over Heard Island during 7 April 2007 through 2 March 2008. Courtesy of HIGP Thermal Anomalies Team.

Date Time (UTC) Pixels Satellite
24 Jul 2007 1750 1 Aqua
12 Aug 2007 1820 1 Terra
30 Aug 2007 1955 1 Aqua
11 Nov 2007 1800 1 Terra
11 Nov 2007 1945 2 Aqua
22 Feb 2008 1955 3 Aqua
02 Mar 2008 1950 1 Aqua

Geologic Background. Heard Island on the Kerguelen Plateau in the southern Indian Ocean consists primarily of the emergent portion of two volcanic structures. The large glacier-covered composite basaltic-to-trachytic cone of Big Ben comprises most of the island, and the smaller Mt. Dixon lies at the NW tip of the island across a narrow isthmus. Little is known about the structure of Big Ben because of its extensive ice cover. The historically active Mawson Peak forms the island's high point and lies within a 5-6 km wide caldera breached to the SW side of Big Ben. Small satellitic scoria cones are mostly located on the northern coast. Several subglacial eruptions have been reported at this isolated volcano, but observations are infrequent and additional activity may have occurred.

Information Contacts: Hawai'i Institute of Geophysics and Planetology (HIGP) Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/).


Nevado del Huila (Colombia) — January 2008 Citation iconCite this Report

Nevado del Huila

Colombia

2.93°N, 76.03°W; summit elev. 5364 m

All times are local (unless otherwise noted)


Eruptions in February, April, and May 2007; lahars take out bridges

Nevado del Huila was the scene of elevated seismicity during February and May 2000 (BGVN 25:05). In 1994, the M 6.4 Paéz earthquake triggered avalanches and lahars along the Paéz river, which took many lives (BGVN 19:05, 19:07). A more recent abstract summarized the losses from the Paéz earthquake as 271 reported deaths, 1,700 people missing, and more than 32,000 people evacuated during the crisis (Schuster, 1996). Correa and Pulgarín (2002a, b) wrote reviews of the volcano's geology, hazards, and related topics.

This report discusses the onset of eruptions during February 2007 and repeated eruptions during April and May 2007. During the most active intervals during February and April there were substantial ash plumes, lahars, earthquake swarms (and some individual earthquakes up to M ~ 3), and the growth of fissures, crevasses, and new fumaroles on the volcano's upper, glacier-covered slopes. During the April eruption thousands of residents evacuated. This report draws heavily on material issued by the Instituto Colombiano de Geología y Minería (INGEOMINAS), Observatory Vulcanológico and Sismológico de Popayán.

The andesitic-dacitic edifice (figure 6) is large and elongate (with a footprint of ~ 170 km2 ). Located in the Central Cordillera (figure 7), it forms Colombia's highest peak. This area only 3 degrees from the equator experiences periods of high precipitation. In 1995 its alpine glaciers covered ~ 13.4 km2 with an approximate volume of 800 x 106 m3 (Pulgarín and others, 2005).

Figure (see Caption) Figure 6. An aerial photo showing the upper slopes of Nevado del Huila from the W. The photo was taken at unknown date prior to 2002 when the volcano was in a non-eruptive state. From N to S the four main peaks consist of Pico Norte ("N"), Pico la Cresta ("LC"), Pico Central ("C"), and Pico Sur ("S"). Heavy cloud banks such as those in the foreground are common, adding to the difficulty of monitoring this remote, high stratovolcano. Taken from Correa and Pulgarín (2002a).
Figure (see Caption) Figure 7. A sketch map showing the three distinct ranges (cordillera) of the Andes in Colombia, with Nevado del Huila indicated. Between the Western and Central cordillera, the valley contains the Cauca river (not shown). It flows N and ultimately joins the Magdalena river (not shown), traveling ~ 1,350 km beyond its starting point to reach Northern Colombia. Between the Central and Eastern cordillera, the valley contains the Magdalena river (not shown). It flows N and travels ~ 1,500 km before entering the Caribbean sea at Barranquilla. After a digital elevation map prepared by the USGS; courtesy of the International Charter "Space and Major Disasters."

The April 2007 activity impacted not only the immediate vicinity of the volcano, but also ten's of kilometers to the S, where rivers carried debris. In order to assess the impact of the lahars, INGEOMINAS compared calibrated Landsat images from before and after the 19 February eruption. They found clear visual evidence that the lahars had discolored the Betania Reservoir, ~ 150 km downstream.

The Símbola joins the Paéz river ~ 28 km (straight-line distance) S of Pico Central (figure 8). Adjacent that intersection sits the town of Belacázar (figure 9). Another ~ 15 km downstream, the Paéz merges into the Magdalena river, the 6th largest river the world in terms of sediment yield (~ 690 t / (km2 ? yr); Restrepo and others, 2005). A straight-line distance of ~ 50 km downslope from the intersection of the Paéz and Magdalena rivers, the Magdalena enters the Betania Reservoir.

Figure (see Caption) Figure 8. A false-color Landsat TM5 mosaic image showing the Magdalena river and some of its headwaters (eg. the Paéz and Símbola rivers) that feed from Nevado del Huila (upper left corner). Images are Landsat-5, 30-m resolution. Left image acquired 7 August 1989. Right image acquired 2 January 1988. The annotations include the epicenter for the Paéz earthquake (star) and the Betania Reservoir. On the colored version, snow is shown by the elongate magenta region around Huila.Created March 2007 by INGEOMINAS; courtesy of the International Charter "Space and Major Disasters."
Figure (see Caption) Figure 9. Map indicating the topography and naming conventions on the Huila edifice and some surrounding regions. The inset shows the volcano's location at the triangle labeled CVNH. Note epicenter for the Paéz earthquake. This was modified from a larger map in Correa and Pulgarín (2002a).

Beyond the reservoir, the Magdalena flows NNE; it ultimately reaches the Carribean Sea at a large delta in N Colombia by the large city of Barranquilla (figure 7). According to Restrepo and Kjerfve (2000), "the Magdalena is the largest river discharging directly into the Caribbean sea [228 km3 water annually], and it has the highest sediment yield of any medium-sized or large river along the entire E coast of South America."

Unrest and 19 February eruption. Since 1994 the volcano has been monitored by multiple telemetered seismometers with data sent to the city of Popayán (~ 100 km SSW). Mumucué (2007) pointed out that people living around the volcano saw the appearance of fumaroles in October 2006.

From 22 November 2006, INGEOMINAS assigned an elevated hazard of Level II ('Eruption probable in the coming days or weeks'). Some fracture-related earthquakes took place at depths of 2 km below the summit. Some of these earthquakes reached MR 1.6-1.9.

A 13 February flight mainly found steam escaping both secondary craters and fumarole fields on the main crater's margin. The previous day, observers W of the volcano in Consacá saw steam emissions outside the crater.

A seismometer recorded an earthquake swarm during 1030-1259 on 18 February. The seismometer, located 2 km S of Pico Central (at station 'Cerro Negro') measured 108 earthquakes interpreted as rock fracture events in the upper part of the volcano. An M 3 earthquake followed, and at 0137 on 19 February a new swarm of 53 earthquakes occurred. In this swarm fracture earthquakes were accompanied by those of longer period; the amplitude and number of events increased into the next morning.

Seismic records also contained some long-period earthquakes called tornillos (events with long, gradually decreasing codas or tails, so that their seismic trace resembles the tapering profile of a wood screw; tornillo is Spanish for screw). During March 2006-February 2007, instruments had recorded 105 tornillos (an average of 9 per month). In contrast, during 1-19 February 2007, instruments recorded 20 tornillos, more than double the number usually seen during a full month.

INGEOMINAS reported two earthquakes on 19 February 2007, at 0830 and 0853, with probable explosive character. Aviation authorities reported ash-bearing columns over the edifice reaching ~ 0.6-0.7 km above the summit.

A later INGEOMINAS summary of events stated that the eruption began at 0856 on 19 February, manifested as a ~ 1.5 km tall eruption column blowing mainly W. Ashfall was noted by inhabitants of Toribio, Silvia, and Páez (in the Department of Cauca). Small mudflows came down the Bellavista and Azufrada rivers feeding into the Paéz river, but airborne observers found significant fresh deposits at higher elevations. Authorities advised inhabitants to move to higher ground. Inhabitants noticed the rise of the Paéz river at 1150 on 19 February.

A 20 February flight detected significant fresh ash, abundant crevasses in the ice, and a steaming fissure near the summit (figure 10). The fissure extended ~ 2 km between Pico Central and Pico la Cresta to the N. Observers noted that the fissure continually emitted gases along its entire length. The flight was a collaboration between INGEOMINAS and IGEFA (Inspección General de la Fuerza Aérea).

Figure (see Caption) Figure 10. (a-f) Six aerial photos of Nevado del Huila taken from multiple angles and distances on 20 February 2007. A) A view with the Paéz river basin in the foreground and with Nevado del Huila steaming in the background. B) A close up of the SE flank looking NW, showing dark snow on the W side of the volcano and a thinner coating on the E side. C) Contrasting ash-free and thickly ash-covered ice at the N-central side of the summit (Pico Central to the right), with the elongate fissure emitting steam near the ridgeline. D) Pico Central seen at comparatively close range from the E side of the mountain, where a thin coating of ash is apparent over many of the upper slopes. E) A view looking S across Pico la Cresta slightly off the trend of the ridge axis, highlighting steam emissions from the fissure, areas of ash-covered snow, and abundant fresh crevasses in the upslope ice. F) A photo looking NW at the gray ash deposits on glacial ice of Pico Central and again illustrating venting steam. Courtesy of the Colombian Air Force and INGEOMINAS.

A VAAC report noted an eruption at about 1400 UTC on the 19th to approximately FL 200 (~ 6.1 km altitude) moving W and dissipating quickly. No ash was seen in satellite imagery the next day at either 0045 or 1100 UTC, however, around this latter time, a pilot observed an ash cloud. In addition, a local aircraft reported ash to ~ 6.1 km at 0500 UTC on the 21st.

During 30 March-16 April 2007 INGEOMINAS observers reported the initiation of noteworthy seismicity indicating rock fractures and movement of fluids. The fracture events were located at depths of 4-8 km E and SW from the central peak and at magnitudes of less than 1.0. Low gas columns were again seen on 11 April, moving W.

Seismicity further increased on 17 April, leading up to an eruption on the 18th. Early on 18 April, a cluster of 25 rock-fracture earthquakes occurred, M 0.5 to 1.5. These were located at a depth less than 2 km. Seismicity again increased later that morning.

April 2007 eruption. A brief summary of the 18 April eruption appeared on the website hosted by the International Charter "Space and Major Disasters" on 20 April). It stated, "The Nevado del Huila volcano erupted at 02:57 local time 18 April, causing avalanches and floods [lahars] which affected the villages of La Plata, Paicol, Tesalia, Natagá, [and] Belalcázar. About 5,000 people were evacuated." (That same website hosted more than 10 (Landsat, Radarsat, and Envisat) images shedding light on this remote volcano's behavior, hazards, and impacts).

According to an 18 April 2007 report from the Washington Volcanic Ash Advisory Center (VAAC), a pilot in Colombia saw an ash cloud. Two ash plumes were evident on GOES-10 (split window) satellite imagery for an eruption starting at 0815 UTC on 18 April. They rose to poorly constrained altitudes of ~ 9 and 11 km and drifted E at 9 km/hour. The lower ash cloud was ~ 37 km across and moved SW at 9-18 km/hour. The higher ash cloud was ~ 19 km across and moved E at 0-9 km/hour. These clouds had dissipated by 1034 UTC.

The 18 April eruption sent an a torrent of brown water and rocks down the volcano's sides and into the Paéz and Símbola rivers (figures 11 and 12), causing them to flood, destroying several kilometers of highway and endangering or sweeping away what some government reports stated were 15 bridges (although it is uncertain how many of those were footbridges, and new reports tended to indicate a slightly higher numbers). In an evaluation the lahars of 18 April, INGEOMINAS staff found them quite similar, though smaller, than those of the earthquake and disaster of 1994.

Figure (see Caption) Figure 11. Photo from hillside overlooking the confluence of the Paéz and Símbola rivers, viewed upstream towards Nevado del Huila. One of the battered and partly lahar-covered bridges lies in the left-foreground. Photo was taken 25 April 2007 and came from Mumucué (2007).
Figure (see Caption) Figure 12. An aerial photo of part of the Huila lahar shot in sub-vertical orientation on 22 April 2007. Name and location of this settlement is uncertain. Lahars were apparently insufficiently thick to overrun established settlements. Courtesy of INGEOMINAS.

Videos. At least three videos taken chiefly from Colombian military or national guard helicopters were posted on the web during April-May 2007 (see Videos, under References). They featured either the volcano or the powerful lahars or both, as follows.

Video 1("Avalancha . . ."; posted 18 April 2007) contains lahar footage from a television newscast, much of it taken from a helicopter. The shots include several bridges destroyed or impacted by lahars and the dialog mentioned nineteen bridges affected. Segments also show closeups of sediments and considerable flooding. Few if any flooded or damaged buildings were shown. Footage shows segments of the river with various gradients; the dark water carrying considerable debris. In one scene of a threatened bridge taken from shore, the turbulent river races by and among the passing logs seemingly floats a large farm animal.

Video 2 ("Sobrevuelo . . ." [Overflight . . .]) was taken by INGEOMINAS on 3 March 2007. It shows the volcano in modest eruption. A dense, dark plume emerges from the complex ice-bound summit area. Somewhat surprisingly, the plume immediately descends one flank of the volcano.

Video 3 (Erupcion . . . 18 Abril) shows vigorous white plumes escaping from multiple vents and forming a dense white plume. The text says that the footage was taken hours after the eruption on 18 April 2007. The base of the volcano is shrouded in weather clouds. The footage credits "Ejercito Nacional-INGEOMINAS-FAC."

Further observations and assessments. Seismicity escalated during 19-20 April but decreased on the 21st. Two larger earthquakes soon took place, on the 22nd and 27th. Their respective seismic signals appeared to come from rock fracturing at shallow depths; they had epicenters at Pico Central, and they were M 3.0 and M 3.2. On 23 April instruments detected continuous low-frequency tremor, interpreted as continuing instability and possible eruptions.

On 22 April, the Colombian Air Force flew INGEOMINAS staff past the volcano. They observed the N-trending fissure seen in February and found it had extended to reach a length of 2.3 km and a width of ~ 200 m. It emitted a white, sulfurous smelling gas column to 5 km altitude. The 22 April observers also saw a second new fissure ~ 2 km long across the same region. Strong fumaroles also discharged. Some lahars remained active down both E and W flank drainages.

Associated with the eruptions and as recent as 28 April 2007, there had been a total of 5,708 seismic events. Of those, 2,861 had signals suggesting rock fracture and 2,847 had signals suggesting movement of fluids.

During late April and early May 2007 the seismicity generally decreased (except for a 6 May, M 3.2 earthquake). On 5 May, INGEOMINAS staff, using a land-based correlation spectrometer, measured an SO2 flux from the volcano at 3,000 tons per day.

Early on 14 May, INGEOMINAS recorded a cluster of 54 low magnitude earthquake events, possibly triggering or associated with an ash emission. Based on satellite imagery of 14 May, the Washington VAAC reported an ash plume 8 km wide in an area 45 km W; it drifted SW and dissipated.

Based on seismic interpretation, INGEOMINAS inferred ash emissions during 27 May. Aerial observations later that day confirmed the emissions. Tremor recorded on 28 May possibly indicated another pulse of ash emissions. The SO2 flux measured on 1 June continued at 3,000 metric tons per day and on 2 June increased to ~ 6,900 metric tons per day. Flights on 3, 6, and 10 June indicated no changes in the existing fissures nor changes in the fumarolic field. Seismicity was relatively quiet during June 2007.

Humanitarian concerns. Luz Amanda Pulido, director of the national disaster office said that there were no reports of deaths or injuries. According to a 22 May report of the UN Office for the Coordination of Human Affairs (OHCA), by 26 April authorities resolved to evacuate 2,307 families affected by the crisis.

A government document issued May 2007 discussed the displaced residents. According to that report (Mumucué, 2007) the number of indigenous inhabitants living around the volcano and affected by lahars or emissions or both totaled 26,949 people. The affected territory he discussed (the Municipio de Páez, which has Belacazar as the main urban center) had an area of ~ 161,000 hectares. The inhabitants losses included cultivated areas and farm animals, including horses and smaller livestock. Photos showed displaced families living in temporary camps with outdoor cooking facilities. Another photo showed workers installing a footbridge where a vehicle bridge was lost to the torrent. That photo, taken ~5 days after the 18 April lahars began showed that by this time the river had greatly receded. The report was also a plea for supplies, including children's clothing and two-way radios with solar panels. Total days of community work devoted to reconstruction after the disaster and as late as May 2007 amounted to 4,264 (Mumucué, 2007).

References. Correa, A.M., and Pulgarín, B.A, 2002a, Revisión histórica de los estudios geológicos y otros aspectos, sobre el volcán Nevado del Huila y su área de influenza, Instituto Colombiano de Geologia y Mineria, INGEOMINAS; Observatorio Vulcanológico y Sismológico, Popayán; Junio de 2002, 51 p.

Correa, A., and Pulgarín, B., 2002b, Morfología, estratigrafía y petrografía general del Complejo Volcánico Nevado del Huila (énfasis en el flanco occidental): INGEOMINAS, Centro Operativo, Popayán, Informe Interno, 104 p.

Mumucué, J.A., May 2007, Analisis de los diversos eventos de erupción volcánica en la región de Tierradentro Páez Cauca hasta el momento: Republica de Colombia, Departamento del Cauca - Region de Tierradentro, Asociación de Cabildos Nasa ?xh??xha.

Pulagarín, B.A., Jordan, E., and Linder, W., 2005, Aspectos geológicos y cambio glaciar del volcán Nevado del Huila entre 1961 y 1995: Proceedings I Conferencia Cambio Climático, Bogotá 2005, 17 p.

Restrepoa, J.D., Kjerfveb, B., Hermelina, M., and Restrepoa, J.C., 2005, Factors controlling sediment yield in a major South American drainage basin: the Magdalena River, Colombia: Journal of Hydrology, v. 316, nos. 1-4, 10 January 2006, p. 213-232.

Restrepoa, J.D., and Kjerfve, B., 2000, Magdalena river: interannual variability (1975-1995) and revised water discharge and sediment load estimates: Journal of Hydrology, v. 235, nos. 1-2, 22 August 2000, p. 137-149, Elsevier.

Schuster, R. L., 1996, Recent earthquake-induced catastrophic landslides in the Andes of Ecuador and Colombia; Abstract, Colorado Scientific Society (URL: http://www.coloscisoc.org/abstracts).

Video References. (1) "Avalancha del Volcan Nevado del Huila" [A newscast from a Colombian television station, www.youtube.com/watch?v=k6nW1DP5mqg

(2) INGEOMINAS, 3 March 2007, Sobrevuelo Ingeominas Nevado Huila pocos dias despues de la erupción" (posted 8 May 2007) [Overflight of summit area] http://www.youtube.com/watch?v=UPP0vzBzZ38 (00:39)

(3) INGEOMINAS, 2007, Erupcion Nevado del Huila Colombia 18 Abril; Video stamped with "Ejercito Nacional-INGEOMINAS-FAC"; http://www.youtube.com/watch?v=xUnYOALOCWg; (00:56) (Posted 8 May 2007)

Geologic Background. Nevado del Huila, the highest peak in the Colombian Andes, is an elongated N-S-trending volcanic chain mantled by a glacier icecap. The andesitic-dacitic volcano was constructed within a 10-km-wide caldera. Volcanism at Nevado del Huila has produced six volcanic cones whose ages in general migrated from south to north. The high point of the complex is Pico Central. Two glacier-free lava domes lie at the southern end of the volcanic complex. The first historical activity was an explosive eruption in the mid-16th century. Long-term, persistent steam columns had risen from Pico Central prior to the next eruption in 2007, when explosive activity was accompanied by damaging mudflows.

Information Contacts: Instituto Colombiano de Geología y Minería (INGEOMINAS), Observatorio Vulcanológico y Sismológico de Popayán, Popayán, Colombia; Washington Volcanic Ash Advisory Center (VAAC), Satellite Analysis Branch (SAB), NOAA/NESDIS E/SP23, NOAA Science Center Room 401, 5200 Auth road, Camp Springs, MD 20746, USA (URL: http://www.ospo.noaa.gov/Products/atmosphere/vaac/); Jorge Castilla Echenique, Salud para desplazados, Programa de Emergencias y Desastres OPS/OMS, PWR Colombia; Jorge E. Victoria R., Salud en Desastres y Emergencias Complejas, Organización Panamericana De La Salud, Oficina de Neiva, Carrera 10 No. 4-72, Huila, Colombia; International Charter-Space and Major Disasters (URL: http://www.disasterscharter.org/).


Krakatau (Indonesia) — January 2008 Citation iconCite this Report

Krakatau

Indonesia

6.102°S, 105.423°E; summit elev. 155 m

All times are local (unless otherwise noted)


Repeated minor eruptions during October-November 2007

During 23-26 October 2007, minor eruptions occurred at Anak Krakatau (BGVN 32:09), an island and active vent on the rim of the famous larger caldera whose name often is misspelled as "Krakatoa." This report continues coverage from late October through November 2007. The Center of Volcanology and Geological Hazard Mitigation (CVGHM) raised the Alert Level to 3 (on a scale of 1-4) for Krakatau on 26 October because of the presence of multiple gray plumes from the volcano and an increase in seismicity. Plumes rose to an altitude of ~ 1 km during 23-26 and 30 October. Villagers and tourists were advised not go within 3 km of the summit.

According to an Associated Press news article, "red-hot lava flares" from Anak Krakatau rose 500-700 m above the S crater on 6 November. Multiple ash clouds were also observed. On 9 November, CVGHM officials in Bandung, West Java, conducted seismic and visual monitoring. Officials said, that on that day there were 182 eruptions coupled with 11 volcanic earthquakes, 54 shallow volcanic shocks, eight deep volcanic tremors and 44 shallower tremors. The volcano spewed "smoke" 29 times. On 13-14 November, as reported by CVGHM, lava flows and incandescent rocks traveled 400 m down the flanks.

As reported by VolcanoDiscovery's Tom Pfeiffer, who visited there from 21-26 November, emissions were relatively constant. He noted that all activity occurred from the newly formed crater on the upper S flank just below the old summit crater (figure 18). On 21 November, the new crater had an oval shape, approximately 50 x 70 m. Dense, dark brown, billowing ash clouds escaped in pulses from the crater at near-constant intervals of about 2 minutes, rising typically 100-200 m above the crater and drifting E. A few blocks were ejected along with the ash clouds (figure 19).

Figure (see Caption) Figure 18. A sudden explosion ejecting rocks and ash on the S flank of the old Anak Krakatau crater on 22 November, 2007. Courtesy Tom Pfeiffer of Volcano Discovery.
Figure (see Caption) Figure 19. Ballistic blocks land all over the cone of Anak Krakatau where the impacts stir up dust on 22 November 2007. A few also flew as far as the sea. Courtesy Tom Pfeiffer of Volcano Discovery.

Pfeiffer also reported that at more irregular intervals, about 10-30 min apart, more violent, small vulcanian explosions interrupted the weaker ash venting events. The more violent explosions consisted of a sudden spray of mostly solid rocks and few incandescent scoria, followed by more powerful and turbulent ash plumes that rose up to 1 km above the crater (figure 20). Generally, these vulcanian explosions occurred after a slightly longer quiet period and, in most cases, the length of the quiet period correlated with the force of the explosion.

Figure (see Caption) Figure 20. Eruption plume at Anak Krakatau rising to ~ 1 km on 23 November 2007. Courtesy Tom Pfeiffer of Volcano Discovery.

Pfeiffer noted that several more powerful explosions occurred at intervals of approximately 16-24 hours. The strongest, on 21-22 November, showered the whole island with incandescent blocks, ignited bush fires, and produced a very loud cannon-shot noise that rattled windows on the W coast of Java, 40 km away (figure 21).

Figure (see Caption) Figure 21. On the evening of 21 November 2007, a powerful blast throws bombs and blocks all over the old cone of Anak Krakatau. Courtesy Tom Pfeiffer of Volcano Discovery.

Other, unusually large blasts occurred at around 0200 on 21 November and at around 0900 and 1320 on 23 November (figure 22). Early on 23 November, activity became more ash-rich and the vigor of the individual events increased slightly over the next two days. The pace of single explosions stayed at near-constant intervals of about 2 minutes. During 24-25 November, ash plumes typically rose to over 1 km above the crater and were easily visible from the W coast of Java. Based on a pilot report, on 24 November, the Darwin Volcanic Ash Advisory Center noted that an ash plume rose to an altitude of 3 km and drifted NE.

Figure (see Caption) Figure 22. Another very powerful blast occurs at around 0300 on 24 November 2007. Incandescent blocks reach the lower western flanks of the island. Courtesy Tom Pfeiffer of Volcano Discovery.

Based on the University of Hawaii's Institute of Geophysics and Planetology (HIGP) Thermal Alerts System MODVOLC analysis of MODIS (Moderate Resolution Imaging Spectroradiometer) satellite thermal anomaly data, occasional hot spots were identified by Terra or Aqua satellites. The thermal alerts occurred on twelve occasions between 27 October and 9 December 2007. Seven of these took place between 16 and 26 November 2007.

Geologic Background. The renowned volcano Krakatau (frequently misstated as Krakatoa) lies in the Sunda Strait between Java and Sumatra. Collapse of the ancestral Krakatau edifice, perhaps in 416 or 535 CE, formed a 7-km-wide caldera. Remnants of this ancestral volcano are preserved in Verlaten and Lang Islands; subsequently Rakata, Danan, and Perbuwatan volcanoes were formed, coalescing to create the pre-1883 Krakatau Island. Caldera collapse during the catastrophic 1883 eruption destroyed Danan and Perbuwatan, and left only a remnant of Rakata. This eruption, the 2nd largest in Indonesia during historical time, caused more than 36,000 fatalities, most as a result of devastating tsunamis that swept the adjacent coastlines of Sumatra and Java. Pyroclastic surges traveled 40 km across the Sunda Strait and reached the Sumatra coast. After a quiescence of less than a half century, the post-collapse cone of Anak Krakatau (Child of Krakatau) was constructed within the 1883 caldera at a point between the former cones of Danan and Perbuwatan. Anak Krakatau has been the site of frequent eruptions since 1927.

Information Contacts: Center of Volcanology and Geological Hazard Mitigation (CVGHM), Saut Simatupang, 57, Bandung 40122, Indonesia (URL: http://vsi.esdm.go.id/); Darwin Volcanic Ash Advisory Center, Bureau of Meteorology, Australia (URL: http://www.bom.gov.au/info/vac); Tom Pfeiffer, Volcano Discovery (URL: http://www.decadevolcano.net/, http://www.volcanodiscovery.com/volcano-tours/krakatau/photos.html); Associated Press (URL: http://www.ap.org/).


Llaima (Chile) — January 2008 Citation iconCite this Report

Llaima

Chile

38.692°S, 71.729°W; summit elev. 3125 m

All times are local (unless otherwise noted)


Ash plumes observed in May and August 2007; new eruption beginning 1 January 2008

From January 2002 through April 2003 (BGVN 29:02) there were increases in seismicity and fumarolic activity, along with minor eruptions, pronounced glacial melting, and substantial ash and gas plumes. Renewed activity consisting of minor eruptions was reported in May and possibly August 2007, but a larger eruption began on 1 January 2008. The source for most of the following is the Observatorio Volcanológico de los Andes del Sur (OVDAS)-SERNAGEOMIN (Volcano Observatory of the Southern Andes-Chile National Service of Geology and Mining).

On 26 May 2007, the Buenos Aires Volcanic Ash Advisory Center (VAAC) reported that ash plumes from Llaima rose to altitudes of 3-4.3 km and were visible on satellite imagery drifting E. A pilot reported another ash plume on 28 May that rose to an altitude of 5.5-6.7 km and drifted E. On 29 May, an ash plume rose to an altitude of 3 km and drifted E. No further activity was reported until 8 August, when pilots observed a plume to an altitude of 5.2 km drifting E. Ash was not identified on satellite imagery for this date.

Eruption during January 2008. Based on pilot reports and observations of satellite imagery, the Buenos Aires VAAC reported that on 1 January 2008 an ash plume rose to an altitude of 12.5 km and drifted E and ESE. The eruption began at 1820 hours, according to the Chile National Emergency Office. Lava was reported to be visible on the E flank and fumaroles at the summit were noted. The strong explosive activity prompted authorities to raise the Alert level to Yellow. According to news media reports, around 700 people were evacuated from local communities following the initial eruption, including about 200 tourists and National Forest Service employees from the Conguillo National Park. Most of the residents returned the following day when activity declined.

SERNAGEOMIN reported that tremor coincided with the onset of the gas and pyroclastic emissions on 1 January. Lava and incandescent material initially emitted were confined to the crater, but within a few hours, a Strombolian phase began. Soon, brightly glowing material covered much of the previously ice-covered summit (figure 14). Around the time of the eruption, an increase in volume of the Captrén river on the N flank was observed; this was likely a response to the glacial melting.

Figure (see Caption) Figure 14. Llaima as seen in eruption on 1 January 2008. Photo taken from W of the volcano between Temuco and Vilcun, Chile. Photo by Antonio Vergara via the flikr website (Creative Commons license).

On the following day, observers on an overflight saw small emissions of ash and gas (mainly steam) and three small lahars on the N and W flanks. Tremor decreased, though explosions continued. Based on pilot reports and satellite imagery, the Buenos Aires VAAC reported that an ash plume rose to an altitude of 12.5 km and drifted E (figure 15). A later overflight revealed that the explosion on 2 January occurred at an area high on the E flank, outside the summit crater. A lava flow on the E flank was also noted. On 3 January an ash plume was visible on satellite imagery at an altitude of 3.7 km drifting NE. Airborne observers noted small sporadic gas-and-ash emissions.

Figure (see Caption) Figure 15. A GOES-12 visual image of Llaima plume, captured at 1039 UTC on 2 January 2008. North is toward the top of the image, and the plume blew to the ESE. Courtesy of Charles Holliday, U.S. Air Force Weather Agency.

In addition to ash, Llaima's eruption released considerable sulfur dioxide (SO2), identified by satellite instruments in the days following the 1 January eruption (figure 16). The initially intense SO2 plume dispersed as it moved E. On 4 January, the plume passed over Tristan da Cunha, a remote archipelago in the South Atlantic Ocean (figure 16). According to Charles Holliday, Simon Carn, and Michon Scott, the SO2 dissipated after 6 January 2008.

Figure (see Caption) Figure 16. An image acquired by the Ozone Monitoring Instrument (OMI) on NASA's Aura satellite showing the progress of the SO2 plume from Llaima during 2-4 January 2008. The island of Tristan de Cunha is shown along in the southern Atlantic Ocean. (In the colored version of this image, red indicates the greatest concentration-pathlength of SO2 and lavender-pink indicates the lowest concentration-pathlength.) OMI measures the total atmospheric column amount of SO2 in Dobson Units (a common unit used in atmospheric research). NASA image courtesy Simon Carn; text modified from that by Simon Carn and Michon Scott.

Between 1835 and 1915 on 6 January 2008 a helicopter overflight was conducted, coordinated by Jaime Pinto, Director of the Araucania Region Emergency Office (OREMI). Observers noted that main crater vent was clogged with lava (figure 17), which, after the eruption, dropped a few dozen meters inside the crater. During the eruption, lava diverged into two areas in the main crater, draining flows to the W and NE and melting the ice. The melted ice produced three lahars toward the W flank, which merged into one that entered the Calbuco River. To the NE, the melted ice generated a single channel lahar that flowed into the Captrén River, cutting the road in several locations. A small lahar also traveled to the E. The dispersion of ash and gases was mainly to the E, although initially they went ESE. There were abundant cracks seen in the glaciers in the SW and SE of the main crater, particularly in the SE.

Figure (see Caption) Figure 17. Topographic map showing Llaima and features observed during a helicopter overflight on 6 January 2008. The features include lahars (shaded in green), the Calbuco and Captren rivers, detached areas of lava blocks and ashes, fallen pyroclastics, fumaroles, and limit of falling ash (highlighted dashed lines). Courtesy of SERNAGEOMIN.

SERNAGEOMIN reported that during 10-14 January 2008 seismicity decreased in terms of energy, but increased in the number of events. Based on seismic interpretation, weak explosions produced plumes of gas and ash that drifted NE. On 11 January, the upper surface of lava flows on the W flank that were observed during an overflight were cooled and snow-covered near the crater, but snow-free, and therefore still hot, about 500 m farther downslope. Blocks of incandescent material rolled ~ 1.5 km downslope and caused steam emissions where they contacted the glacier. Abundant cracks in glaciers to the SW of the crater were noted. Based on observations of satellite imagery and pilot reports, the Buenos Aires VAAC reported that ash plumes rose to an altitude of 5.5-6.7 km and drifted NE on 11 January and SW on 13 January.

Eruptive activity continued during the second half of January from the main crater and from two craters and a fissure on the E flank. The main crater contained three active pyroclastic cones. On 16 January one of the craters, ~ 15 m in diameter, produced ash plumes that rose to an altitude of ~ 3.6 km. Glaciers on the NE slope and W flank were fractured and dislocated. Ash plumes rising from the E flank attained an altitude of 4.1 km. Ash emissions vented from a NE-trending fissure ~ 80 m long and ~ 10 m wide. On 16-17 January glowing rocks were emitted from the fissure's NE end; ash plumes caused by rolling rocks rose from multiple areas.

At 0732 on 18 January, an explosion from the E flank sent an ash plume to an altitude of 9.1 km that quickly dispersed NE. People later saw a small lateral explosion from the same area, ash-and-gas emissions from several points, and a new fissure.

On 19 January, an explosion produced an ash plume that rose to an altitude of 4.1 km. An overflight revealed Strombolian activity in the main crater from a new pyroclastic cone that was 120 m in diameter and 100 m high; the cone was absent during a 17 January overflight. A second crater to the SW emitted gas. Sporadic ash emissions were noted from the E sector and an explosion produced a pyroclastic flow and an ash plume that quickly dissipated. On 20 January, another explosion produced an ash plume that rose to an altitude of 4.1 km. Gas and ash emissions were again noted from multiple areas. On 21 January, cloud cover prevented visual observations, but one small ash emission was seen at the end of the day.

On 23 January, a brown ash plume rose to an altitude of 3.5 km and drifted W. Observers on an overflight later that day saw Strombolian eruptions from the pyroclastic cone in the main crater accompanied by emissions of brown ash. A small hornito emitting bluish gas and a lava field were noted between the pyroclastic cone and the inner margins of the crater. Explosions from the E flank were detected on 24 January, and on 26 January steam plumes were observed. Strombolian eruptions in the main crater accompanied by gas and ash emissions continued during through 27 January. Ash plumes rose to altitudes of 3.3-4.1 km and drifted NW, E, SE, and S.

MODVOLC Thermal Alerts. Numerous MODIS thermal anomalies were measured almost daily throughout the month of January 2008 (table 2). As shown by the number of pixels for various observing time, the anomalies covered a particularly large area on 2 January (24 pixels). In contrast, anomalies were absent during the previous intervals of 1 January 2002 through 26 April 2007, and 16 June 2007 through 1 January 2008.

Table 2. Thermal anomalies measured by MODIS/MODVOLC over Llaima from 27 April 2007 through 30 January 2008. No anomalies were detected from 2002 through 26 April 2007, or 16 June 2007 through 1 January 2008. Courtesy of HIGP Thermal Anomalies Team.

Date Time (UTC) Pixels Satellite
27 Apr 2007 1910 3 Aqua
14 Jun 2007 1455 5 Terra
15 Jun 2007 0515 1 Aqua
02 Jan 2008 0250 2 Terra
02 Jan 2008 0430 9 Terra
02 Jan 2008 0605 24 Aqua
02 Jan 2008 1355 2 Terra
02 Jan 2008 1535 3 Terra
02 Jan 2008 1810 2 Aqua
03 Jan 2008 0335 4 Terra
03 Jan 2008 0510 2 Aqua
03 Jan 2008 1440 1 Terra
03 Jan 2008 1850 1 Aqua
04 Jan 2008 0555 3 Aqua
05 Jan 2008 0320 1 Terra
06 Jan 2008 0545 1 Aqua
11 Jan 2008 0425 1 Terra
11 Jan 2008 0600 2 Aqua
12 Jan 2008 0330 1 Terra
14 Jan 2008 0630 1 Aqua
15 Jan 2008 0400 1 Terra
15 Jan 2008 0535 1 Aqua
16 Jan 2008 0620 2 Aqua
17 Jan 2008 0345 1 Terra
17 Jan 2008 0525 3 Aqua
17 Jan 2008 1450 2 Terra
18 Jan 2008 0605 1 Aqua
20 Jan 2008 0555 1 Aqua
22 Jan 2008 0405 1 Terra
22 Jan 2008 0545 2 Aqua
23 Jan 2008 0625 1 Aqua
24 Jan 2008 0530 3 Aqua
24 Jan 2008 1455 1 Terra
25 Jan 2008 0255 3 Terra
25 Jan 2008 0615 4 Aqua
26 Jan 2008 0340 2 Terra
26 Jan 2008 0520 2 Aqua
26 Jan 2008 1445 1 Aqua
27 Jan 2008 0425 2 Terra
27 Jan 2008 0600 2 Aqua
27 Jan 2008 1525 1 Terra
28 Jan 2008 0330 4 Terra
28 Jan 2008 0505 4 Aqua
28 Jan 2008 1845 1 Aqua
29 Jan 2008 0410 4 Terra
29 Jan 2008 0550 2 Aqua
30 Jan 2008 0315 2 Terra
30 Jan 2008 0630 4 Aqua
30 Jan 2008 1420 5 Terra
31 Jan 2008 0400 6 Terra
31 Jan 2008 0535 3 Aqua
31 Jan 2008 1915 3 Aqua

Geologic Background. Llaima, one of Chile's largest and most active volcanoes, contains two main historically active craters, one at the summit and the other, Pichillaima, to the SE. The massive, dominantly basaltic-to-andesitic, stratovolcano has a volume of 400 km3. A Holocene edifice built primarily of accumulated lava flows was constructed over an 8-km-wide caldera that formed about 13,200 years ago, following the eruption of the 24 km3 Curacautín Ignimbrite. More than 40 scoria cones dot the volcano's flanks. Following the end of an explosive stage about 7200 years ago, construction of the present edifice began, characterized by Strombolian, Hawaiian, and infrequent subplinian eruptions. Frequent moderate explosive eruptions with occasional lava flows have been recorded since the 17th century.

Information Contacts: Servico Nacional de Geologia y Mineria (SERNAGEOMIN), Avda Sta María N° 0104, Santiago, Chile (URL: http://www.sernageomin.cl/); 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/productos.php); Simon Carn, Joint Center for Earth Systems Technology (JCET), University of Maryland Baltimore County (UMBC); Charles Holliday, U.S. Air Force Weather Agency (AFWA)/XOGM, Offutt Air Force Base, NE 68113, USA; Hawai'i Institute of Geophysics and Planetology (HIGP) Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/); Associated Press (URL: http://www.ap.org/); United Nations Office for the Coordination of Humanitarian Affairs (OCHA) (URL: https://reliefweb.int/); Antonio Vergara, Temuco, Chile (URL: http://www.flickr.com/people/odiofotolog/).


Sheveluch (Russia) — January 2008 Citation iconCite this Report

Sheveluch

Russia

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

All times are local (unless otherwise noted)


Lava-dome growth and block-and-ash flows continue April-December 2007

Shiveluch (also spelled Sheveluch), the scene of lava-dome growth, is one of the most active volcanoes on Kamchatka. It was last reported here discussing events through early April 2007 (BGVN 32:03). The following report covering the interval early April-December 2007 came from multiple sources.

Shiveluch's eruptions are of an explosive nature and the volcano has been in a state of heightened activity since 5 December 2006. Vigorous activity continued to the time of this report (March 2008). Small lava-dome collapse events produced ash plumes and short block-and-ash flows, which in turn generated mudflows when snow was present. This activity was recorded in shallow volcanic earthquakes and tremor and a large, ever-present thermal anomaly on satellite imagery.

The Level of Concern Color Code remained at Orange throughout this report period (early April through December 2007). The Kamchatka Branch of the Geophysical Service of the Russian Academy of Sciences (KB GS RAS) is monitoring the volcano and believes that it poses little danger for nearby populated localities.

During April 2007 growth of the lava dome continued, and hot lava extruded at the top of the dome. Hot avalanches from the top of the dome occurred daily. Ash and ash-and-steam plumes rose to altitudes of ~ 4.6-6.5 km. Some plumes were seen on satellite imagery drifting E, SE, and S. According to satellite data, ash plumes extended ~ 60 km on 28-29 April, mainly to the S and SW, and ~ 50 km to the E on 5 and 7 May. During 27-28 May, plumes were seen on satellite imagery drifting SW.

A large thermal anomaly was conspicious during the last week of April 2007, and hot avalanches originating from the dome were noted on 30 April, 4 May, and 6-7 May. Gas-steam emissions occurred repeatedly. On 7 May a mudflow traveled down Shiveluch's slope, reaching ~ 20 km beyond the lava dome and blocking ~ 30 m of a road, isolating the district center Ust-Kamchatsk on the E of the peninsula. There were no vehicles on this portion of the road when the mudflow descended, and no casualties occurred. Figure 12 contrasts the dome in 2006 and 2007.

Figure (see Caption) Figure 12. The dome at Shiveluch as seen from the SW at two points in time, July 2006 and July 2007. The dome grew to substantially fill the active crater. The most active lava dome growth took place along in the dome's E sector. Photo by Natasha Gorbach (from Gorbach, 2007).

During July, gas-steam plumes frequently reached 4.0-6.1 km altitude. Ash was not always identified on satellite imagery because clouds obscured visibility; however, on 16 July satellite imagery detected gas-steam and ash plumes that extended for about 7-40 km to the S and SW of the volcano. Seismic data suggested that gas-and-ash emissions were concurrent with hot avalanches (figure 13).

Figure (see Caption) Figure 13. The lava dome of Shiveluch volcano as seen from the SW on 11 July 2007. The dark dome contrasts with glowing zones where hot avalanches descended. Photo by Y. Demyanchuk.

On 25 September 2007, video observations indicated ash plumes rising to 6 km altitude and drifting E. According to video for 27 September and 2 October 2007, gas-steam plumes rose up to 4.5 and 3.5 km altitude, respectively. Weak fumarolic activity was noted on both 1 and 8 October. KB GS RAS noted that there was no significant variation in the previous ongoing activity through December 2007 that might indicate any impending activity of greater significance. Frequent MODIS thermal alerts continued throughout 2007 into 2008.

Reference. Gorbach, N., 31 July 2007, Bulletin of activity at Sheveluch volcano, issued 31 July 2007 [title approximate (translated from Russian); available in Russian at URL: http://www.kscnet.ru/ivs/volcanoes/inform_messages/2007/Sheveluch_072007/Sheveluch_072007.html).

Geologic Background. The high, isolated massif of Sheveluch volcano (also spelled Shiveluch) rises above the lowlands NNE of the Kliuchevskaya volcano group. The 1300 km3 volcano is one of Kamchatka's largest and most active volcanic structures. 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 dot its outer flanks. The Molodoy Shiveluch lava dome complex was constructed during the Holocene within the large horseshoe-shaped caldera; Holocene lava dome extrusion also took place on the flanks of Stary Shiveluch. At least 60 large eruptions have occurred during the Holocene, making it the most vigorous andesitic volcano of the Kuril-Kamchatka arc. 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: Yuri Demyanchuk, Natasha Gorbsch, and theKamchatka Volcanic Eruptions Response Team (KVERT), Institute of Volcanology and Seismology, Far East Division, Russian Academy of Sciences, Piip Ave. 9, 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), Russia (URL: http://www.emsd.ru/); Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, 4200 University Drive, Anchorage, AK 99508-4667, USA (URL: http://www.avo.alaska.edu/), Geophysical Institute, University of Alaska, PO Box 757320, Fairbanks, AK 99775-7320, USA, and the Alaska Division of Geological and Geophysical Surveys, 794 University Ave., Suite 200, Fairbanks, AK 99709, USA.


Turrialba (Costa Rica) — January 2008 Citation iconCite this Report

Turrialba

Costa Rica

10.025°N, 83.767°W; summit elev. 3340 m

All times are local (unless otherwise noted)


Fumarolic increases during August 2007-January 2008

Enhanced fumarolic activity accompanied by new fractures at the summit was noted during June-September 2007 (BGVN 32:08). The earlier report noted that the fumaroles had spread over a larger area and contained molten sulfur, a condensate previously not seen here in more than 25 years of continuous monitoring by the Observatorio Vulcanológico y Sismológico de Costa Rica-Universidad Nacional (OVSICORI-UNA). By mid-August 2007, acute chemical burning of important patches of natural forest had occurred. This report covers the period from October 2007 through January 2008.

During October, new sites of gas discharge, small landslides, and accelerated vegetation die-off were noted from various locations within and around the crater. Fumaroles were active and widespread across the central crater. Many exhibited sulfur deposits and those in the S, SE, and SW reached a temperature of 91°C.

Areas burned by acute acidification extended during November. Fieldwork conducted by OVSICORI-UNA confirmed an unusual output of gas from several fumaroles along the S outer wall of the volcano. Pastures turned yellowish near the upper areas, and native and exotic tree species were impacted as well as birch tree patches along most drainage basins.

During December, within the W crater, fumarole temperatures reached 280°C and significant sulfur deposits were noted. Local residents confirmed an unusual output of gas from several fumaroles along the S outer wall of the volcano. Areas burned by acute acidification extended during the month. On 5 December, members of the media and local communities observed a gas-and-steam plume from Turrialba that rose to an altitude greater than 5.3 km (figure 12).

Figure (see Caption) Figure 12. Column from Turrialba observed and photographed from Heredia City, located 40 km W of the volcano taken at 0540 on 5 December 2007. Courtesy OVSICORI-UNA.

On a team visit between 30 and 31 January 2008, OVSICORI staff documented the progression of fumarolic activity in the W crater, the external W crater walls, and distant areas towards the W, NW, and SW. Some of the fumaroles correspond with two fractures. One to the SW of the W crater, trending SW, was 100 m in length and 2 to 3 cm wide, and deposited sulfur. The second crack to the NW of the W crater, also trending SW , had temperatures of 72°C and discharged steam and gas affecting the adjacent vegetation. To the NW of the W crater, the team studied an area of about 20 x 50 m with constant gas emission and a temperature of 88°C.

Geologic Background. Turrialba, the easternmost of Costa Rica's Holocene volcanoes, is a large vegetated basaltic-to-dacitic stratovolcano located across a broad saddle NE of Irazú volcano overlooking the city of Cartago. The massive edifice covers an area of 500 km2. Three well-defined craters occur at the upper SW end of a broad 800 x 2200 m summit depression that is breached to the NE. Most activity originated from the summit vent complex, but two pyroclastic cones are located on the SW flank. Five major explosive eruptions have occurred during the past 3500 years. A series of explosive eruptions during the 19th century were sometimes accompanied by pyroclastic flows. Fumarolic activity continues at the central and SW summit craters.

Information Contacts: Eliécer Duarte, Erick Fernández, and Vilma Barboza, Observatorio Vulcanológico y Sismológico de Costa Rica, Universidad Nacional (OVSICORI-UNA), Apdo. 2346-3000, Heredia, Costa Rica (URL: http://www.ovsicori.una.ac.cr/); Tellez and Francois Robichaud, Université de Sherbrooke, 2500 boul. de l'Université, Sherbrooke, Québec J1K 2R1, Canada.


Ubinas (Peru) — January 2008 Citation iconCite this Report

Ubinas

Peru

16.355°S, 70.903°W; summit elev. 5672 m

All times are local (unless otherwise noted)


Continuing ashfall during 2006-2007

Ubinas began erupting ash on 25 March 2006 (BGVN 31:03 and 31:05). As reported in BGVN 31:10, ash eruptions and steam emissions continued through 31 October 2006. This report discusses ongoing eruptions through December 2007 as drawn from Buenos Aires Volcanic Ash Advisory Center (VAAC) reports and the Instituto Geológical Minero y Metalúrgico (INGEMMET).

From November 2006 through December 2007, emissions of volcanic ash, rocks, and gases with water and steam were essentially continuous. INGEMMET authorities indicated that during March 2007 the volcano generated increased ashfall behavior that significantly affected people and the environment. At the beginning of the month, small explosions occurred every 6-8 days but the rate of activity increased toward the end. On 30 March 2007, nearby residents felt a strong explosion. A large ash plume vented from the volcano's summit and local communities were blanketed beneath falling ash. According to INGEMMET authorities, most of Querapi, a town ~ 4.5 km SE of the crater's active vent, was covered in volcanic ash, and the town of Anascapa, 6 km E, also experienced ashfall.

Volcanic ash clouds blown into the atmosphere also presented a hazard to aviation. As summarized in table 3, ash clouds were nearly continuously reported by the Buenos Aires VAAC and the INGEMMET. Plume heights reached as high as 9.1 km in May and again in November 2007. The aviation warning color code was generally Red through the period. The reports were based on satellite imagery and pilot reports. No thermal alerts were noted from the University of Hawaii's Institute of Geophysics and Planetology (HIGP) MODIS satellite-based thermal alert system during 2006 or 2007.

Table 3. Compilation of Volcanic Ash Advisories for aviation from Ubinas during November 2006 through December 2007. Courtesy of the Buenos Aires Volcanic Ash Advisory Center (VAAC) and the Instituto Geológical Minero y Metalúrgico (INGEMMET).

Date Altitude of Plume (km) Flight Level (thousands of feet) Direction of Plume
3-16 Nov 2006 5.5-7.3 190-260 SW, S, SW
25 Nov 2006 5.5 180 NE
2 Dec 2006 5.5 180 N
27-30 Dec 2006 4.9-8.5 160-280 E
28 Jan 2007 5.5-6.9 180-220 SE
2-5 Feb 2007 5.5 180 S, SW
18-21 Feb 2007 5.5-7.0 180-230 E, SW
11, 14 Mar 2007 5.5-6.4 180-210 N, SW
30 Mar 2007 5.5 180 E
5, 7-9, 10-11 Apr 2007 5.5-7.8 180-270 E, SE, S, SW, W
17-18, 22, 24 Apr 2007 5.5-7.2 180-280 NW, SW, SE
2-5 May 2007 5.5-9.1 180/300 N, S, SE, SW
12, 15-16 May 2007 5.5-8.2 180-270 SE, N, SW
17, 19-22 May 2007 5.5-9.1 180-300 E, SE
22-28 May 2007 5.5-7.3 180-240 NE, SE
30 May-6 Jun 2007 3.7-7.6 120-250 NE, SE
12-17 Jun 2007 5.5-6.7 180-230 NE, E, SW, W
27-28 Jun 2007 5.5-6.7 180-230 SW, NW, E
4 Jul 2007 5.5-6.1 180-200 S
23-25 Jul 2007 5.9-6.1 190-200 SE, S
9 Aug 2007 6.1 200 SE
11-14 Sep 2007 5.5-7.6 180-250 E, SE
20 Sep 2007 5.5-6.4 180-210 E
5-7 Oct 2007 5.5-6.4 180-210 N, S
11-13, 15 Oct 2007 5.5-7.6 180-250 N, SE
19-27 Oct 2007 5.5-8.5 180-280 NW, NE
1, 3-6 Nov 2007 5.5-7.6 180-250 NE, SE
11-12 Nov 2007 5.5-6.7 180-220 NE
16, 18, 20 Nov 2007 5.5-7.9 180-260 NE
24-27 Nov 2007 6.1-9.1 200-300 SE, E, SW
28-29 Nov 2007 6.7-7.6 220-250 SW, NE
4-7, 10 Dec 2007 5.5-8.5 180-280 NE
17 Dec 2007 5.5-6.7 180-220 N

Geologic Background. A small, 1.4-km-wide caldera cuts the top of Ubinas, Perú's most active volcano, giving it a truncated appearance. It is the northernmost of three young volcanoes located along a regional structural lineament about 50 km behind the main volcanic front. The growth and destruction of Ubinas I was followed by construction of Ubinas II beginning in the mid-Pleistocene. The upper slopes of the andesitic-to-rhyolitic Ubinas II stratovolcano are composed primarily of andesitic and trachyandesitic lava flows and steepen to nearly 45 degrees. The steep-walled, 150-m-deep summit caldera contains an ash cone with a 500-m-wide funnel-shaped vent that is 200 m deep. Debris-avalanche deposits from the collapse of the SE flank about 3,700 years ago extend 10 km from the volcano. Widespread Plinian pumice-fall deposits include one of Holocene age about 1,000 years ago. Holocene lava flows are visible on the flanks, but historical activity, documented since the 16th century, has consisted of intermittent minor-to-moderate explosive eruptions.

Information Contacts: Instituto Geológical Minero y Metalúrgico (INGEMMET), Av. Canadá 1470, San Borja, Lima 41, Perú (URL: http://www.ingemmet.gob.pe/); Buenos Aires Volcanic Ash Advisory Center (VAAC), Argentina (URL: http://www.smn.gov.ar/vaac/buenosaires/productos.php).

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

Additional 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 subregion and subject.

Kermadec Islands


Floating Pumice (Kermadec Islands)

1986 Submarine Explosion


Tonga Islands


Floating Pumice (Tonga)


Fiji Islands


Floating Pumice (Fiji)


Andaman Islands


False Report of Andaman Islands Eruptions


Sangihe Islands


1968 Northern Celebes Earthquake


Southeast Asia


Pumice Raft (South China Sea)

Land Subsidence near Ham Rong


Ryukyu Islands and Kyushu


Pumice Rafts (Ryukyu Islands)


Izu, Volcano, and Mariana Islands


Acoustic Signals in 1996 from Unknown Source

Acoustic Signals in 1999-2000 from Unknown Source


Kuril Islands


Possible 1988 Eruption Plume


Aleutian Islands


Possible 1986 Eruption Plume


Mexico


False Report of New Volcano


Nicaragua


Apoyo


Colombia


La Lorenza Mud Volcano


Pacific Ocean (Chilean Islands)


False Report of Submarine Volcanism


Central Chile and Argentina


Estero de Parraguirre


West Indies


Mid-Cayman Spreading Center


Atlantic Ocean (northern)


Northern Reykjanes Ridge


Azores


Azores-Gibraltar Fracture Zone


Antarctica and South Sandwich Islands


Jun Jaegyu

East Scotia Ridge


Additional Reports (database)

08/1997 (BGVN 22:08) False Report of Mount Pinokis Eruption

False report of volcanism intended to exclude would-be gold miners

12/1997 (BGVN 22:12) False Report of Somalia Eruption

Press reports of Somalia's first historical eruption were likely in error

11/1999 (BGVN 24:11) False Report of Sea of Marmara Eruption

UFO adherent claims new volcano in Sea of Marmara

05/2003 (BGVN 28:05) Har-Togoo

Fumaroles and minor seismicity since October 2002

12/2005 (BGVN 30:12) Elgon

False report of activity; confusion caused by burning dung in a lava tube



False Report of Mount Pinokis Eruption (Philippines) — August 1997

False Report of Mount Pinokis Eruption

Philippines

7.975°N, 123.23°E; summit elev. 1510 m

All times are local (unless otherwise noted)


False report of volcanism intended to exclude would-be gold miners

In discussing the week ending on 12 September, "Earthweek" (Newman, 1997) incorrectly claimed that a volcano named "Mount Pinukis" had erupted. Widely read in the US, the dramatic Earthweek report described terrified farmers and a black mushroom cloud that resembled a nuclear explosion. The mountain's location was given as "200 km E of Zamboanga City," a spot well into the sea. The purported eruption had received mention in a Manila Bulletin newspaper report nine days earlier, on 4 September. Their comparatively understated report said that a local police director had disclosed that residents had seen a dormant volcano showing signs of activity.

In response to these news reports Emmanuel Ramos of the Philippine Institute of Volcanology and Seismology (PHIVOLCS) sent a reply on 17 September. PHIVOLCS staff had initially heard that there were some 12 alleged families who fled the mountain and sought shelter in the lowlands. A PHIVOLCS investigation team later found that the reported "families" were actually individuals seeking respite from some politically motivated harassment. The story seems to have stemmed from a local gold rush and an influential politician who wanted to use volcanism as a ploy to exclude residents. PHIVOLCS concluded that no volcanic activity had occurred. They also added that this finding disappointed local politicians but was much welcomed by the residents.

PHIVOLCS spelled the mountain's name as "Pinokis" and from their report it seems that it might be an inactive volcano. There is no known Holocene volcano with a similar name (Simkin and Siebert, 1994). No similar names (Pinokis, Pinukis, Pinakis, etc.) were found listed in the National Imagery and Mapping Agency GEOnet Names Server (http://geonames.nga.mil/gns/html/index.html), a searchable database of 3.3 million non-US geographic-feature names.

The Manila Bulletin report suggested that Pinokis resides on the Zamboanga Peninsula. The Peninsula lies on Mindanao Island's extreme W side where it bounds the Moro Gulf, an arm of the Celebes Sea. The mountainous Peninsula trends NNE-SSW and contains peaks with summit elevations near 1,300 m. Zamboanga City sits at the extreme end of the Peninsula and operates both a major seaport and an international airport.

[Later investigation found that Mt. Pinokis is located in the Lison Valley on the Zamboanga Peninsula, about 170 km NE of Zamboanga City and 30 km NW of Pagadian City. It is adjacent to the two peaks of the Susong Dalaga (Maiden's Breast) and near Mt. Sugarloaf.]

References. Newman, S., 1997, Earthweek, a diary of the planet (week ending 12 September): syndicated newspaper column (URL: http://www.earthweek.com/).

Manila Bulletin, 4 Sept. 1997, Dante's Peak (URL: http://www.mb.com.ph/).

Simkin, T., and Siebert, L., 1994, Volcanoes of the world, 2nd edition: Geoscience Press in association with the Smithsonian Institution Global Volcanism Program, Tucson AZ, 368 p.

Information Contacts: Emmanuel G. Ramos, Deputy Director, Philippine Institute of Volcanology and Seismology, Department of Science and Technology, PHIVOLCS Building, C. P. Garcia Ave., University of the Philippines, Diliman campus, Quezon City, Philippines.


False Report of Somalia Eruption (Somalia) — December 1997

False Report of Somalia Eruption

Somalia

3.25°N, 41.667°E; summit elev. 500 m

All times are local (unless otherwise noted)


Press reports of Somalia's first historical eruption were likely in error

Xinhua News Agency filed a news report on 27 February under the headline "Volcano erupts in Somalia" but the veracity of the story now appears doubtful. The report disclosed the volcano's location as on the W side of the Gedo region, an area along the Ethiopian border just NE of Kenya. The report had relied on the commissioner of the town of Bohol Garas (a settlement described as 40 km NE of the main Al-Itihad headquarters of Luq town) and some or all of the information was relayed by journalists through VHF radio. The report claimed the disaster "wounded six herdsmen" and "claimed the lives of 290 goats grazing near the mountain when the incident took place." Further descriptions included such statements as "the volcano which erupted two days ago [25 February] has melted down the rocks and sand and spread . . . ."

Giday WoldeGabriel returned from three weeks of geological fieldwork in SW Ethiopia, near the Kenyan border, on 25 August. During his time there he inquired of many people, including geologists, if they had heard of a Somalian eruption in the Gedo area; no one had heard of the event. WoldeGabriel stated that he felt the news report could have described an old mine or bomb exploding. Heavy fighting took place in the Gedo region during the Ethio-Somalian war of 1977. Somalia lacks an embassy in Washington DC; when asked during late August, Ayalaw Yiman, an Ethiopian embassy staff member in Washington DC also lacked any knowledge of a Somalian eruption.

A Somalian eruption would be significant since the closest known Holocene volcanoes occur in the central Ethiopian segment of the East African rift system S of Addis Ababa, ~500 km NW of the Gedo area. These Ethiopian rift volcanoes include volcanic fields, shield volcanoes, cinder cones, and stratovolcanoes.

Information Contacts: Xinhua News Agency, 5 Sharp Street West, Wanchai, Hong Kong; Giday WoldeGabriel, EES-1/MS D462, Geology-Geochemistry Group, Los Alamos National Laboratory, Los Alamos, NM 87545; Ayalaw Yiman, Ethiopian Embassy, 2134 Kalorama Rd. NW, Washington DC 20008.


False Report of Sea of Marmara Eruption (Turkey) — November 1999

False Report of Sea of Marmara Eruption

Turkey

40.683°N, 29.1°E; summit elev. 0 m

All times are local (unless otherwise noted)


UFO adherent claims new volcano in Sea of Marmara

Following the Ms 7.8 earthquake in Turkey on 17 August (BGVN 24:08) an Email message originating in Turkey was circulated, claiming that volcanic activity was observed coincident with the earthquake and suggesting a new (magmatic) volcano in the Sea of Marmara. For reasons outlined below, and in the absence of further evidence, editors of the Bulletin consider this a false report.

The report stated that fishermen near the village of Cinarcik, at the E end of the Sea of Marmara "saw the sea turned red with fireballs" shortly after the onset of the earthquake. They later found dead fish that appeared "fried." Their nets were "burned" while under water and contained samples of rocks alleged to look "magmatic."

No samples of the fish were preserved. A tectonic scientist in Istanbul speculated that hot water released by the earthquake from the many hot springs along the coast in that area may have killed some fish (although they would be boiled rather than fried).

The phenomenon called earthquake lights could explain the "fireballs" reportedly seen by the fishermen. Such effects have been reasonably established associated with large earthquakes, although their origin remains poorly understood. In addition to deformation-triggered piezoelectric effects, earthquake lights have sometimes been explained as due to the release of methane gas in areas of mass wasting (even under water). Omlin and others (1999), for example, found gas hydrate and methane releases associated with mud volcanoes in coastal submarine environments.

The astronomer and author Thomas Gold (Gold, 1998) has a website (Gold, 2000) where he presents a series of alleged quotes from witnesses of earthquakes. We include three such quotes here (along with Gold's dates, attributions, and other comments):

(A) Lima, 30 March 1828. "Water in the bay 'hissed as if hot iron was immersed in it,' bubbles and dead fish rose to the surface, and the anchor chain of HMS Volage was partially fused while lying in the mud on the bottom." (Attributed to Bagnold, 1829; the anchor chain is reported to be on display in the London Navy Museum.)

(B) Romania, 10 November 1940. ". . . a thick layer like a translucid gas above the surface of the soil . . . irregular gas fires . . . flames in rhythm with the movements of the soil . . . flashes like lightning from the floor to the summit of Mt Tampa . . . flames issuing from rocks, which crumbled, with flashes also issuing from non-wooded mountainsides." (Phrases used in eyewitness accounts collected by Demetrescu and Petrescu, 1941).

(C) Sungpan-Pingwu (China), 16, 22, and 23 August 1976. "From March of 1976, various large anomalies were observed over a broad region. . . . At the Wanchia commune of Chungching County, outbursts of natural gas from rock fissures ignited and were difficult to extinguish even by dumping dirt over the fissures. . . . Chu Chieh Cho, of the Provincial Seismological Bureau, related personally seeing a fireball 75 km from the epicenter on the night of 21 July while in the company of three professional seismologists."

Yalciner and others (1999) made a study of coastal areas along the Sea of Marmara after the Izmet earthquake. They found evidence for one or more tsunamis with maximum runups of 2.0-2.5 m. Preliminary modeling of the earthquake's response failed to reproduce the observed runups; the areas of maximum runup instead appeared to correspond most closely with several local mass-failure events. This observation together with the magnitude of the earthquake, and bottom soundings from marine geophysical teams, suggested mass wasting may have been fairly common on the floor of the Sea of Marmara.

Despite a wide range of poorly understood, dramatic processes associated with earthquakes (Izmet 1999 apparently included), there remains little evidence for volcanism around the time of the earthquake. The nearest Holocene volcano lies ~200 km SW of the report location. Neither Turkish geologists nor scientists from other countries in Turkey to study the 17 August earthquake reported any volcanism. The report said the fisherman found "magmatic" rocks; it is unlikely they would be familiar with this term.

The motivation and credibility of the report's originator, Erol Erkmen, are unknown. Certainly, the difficulty in translating from Turkish to English may have caused some problems in understanding. Erkmen is associated with a website devoted to reporting UFO activity in Turkey. Photographs of a "magmatic rock" sample were sent to the Bulletin, but they only showed dark rocks photographed devoid of a scale on a featureless background. The rocks shown did not appear to be vesicular or glassy. What was most significant to Bulletin editors was the report author's progressive reluctance to provide samples or encourage follow-up investigation with local scientists. Without the collaboration of trained scientists on the scene this report cannot be validated.

References. Omlin, A, Damm, E., Mienert, J., and Lukas, D., 1999, In-situ detection of methane releases adjacent to gas hydrate fields on the Norwegian margin: (Abstract) Fall AGU meeting 1999, Eos, American Geophysical Union.

Yalciner, A.C., Borrero, J., Kukano, U., Watts, P., Synolakis, C. E., and Imamura, F., 1999, Field survey of 1999 Izmit tsunami and modeling effort of new tsunami generation mechanism: (Abstract) Fall AGU meeting 1999, Eos, American Geophysical Union.

Gold, T., 1998, The deep hot biosphere: Springer Verlag, 256 p., ISBN: 0387985468.

Gold, T., 2000, Eye-witness accounts of several major earthquakes (URL: http://www.people.cornell.edu/ pages/tg21/eyewit.html).

Information Contacts: Erol Erkmen, Tuvpo Project Alp.


Har-Togoo (Mongolia) — May 2003

Har-Togoo

Mongolia

48.831°N, 101.626°E; summit elev. 1675 m

All times are local (unless otherwise noted)


Fumaroles and minor seismicity since October 2002

In December 2002 information appeared in Mongolian and Russian newspapers and on national TV that a volcano in Central Mongolia, the Har-Togoo volcano, was producing white vapors and constant acoustic noise. Because of the potential hazard posed to two nearby settlements, mainly with regard to potential blocking of rivers, the Director of the Research Center of Astronomy and Geophysics of the Mongolian Academy of Sciences, Dr. Bekhtur, organized a scientific expedition to the volcano on 19-20 March 2003. The scientific team also included M. Ulziibat, seismologist from the same Research Center, M. Ganzorig, the Director of the Institute of Informatics, and A. Ivanov from the Institute of the Earth's Crust, Siberian Branch of the Russian Academy of Sciences.

Geological setting. The Miocene Har-Togoo shield volcano is situated on top of a vast volcanic plateau (figure 1). The 5,000-year-old Khorog (Horog) cone in the Taryatu-Chulutu volcanic field is located 135 km SW and the Quaternary Urun-Dush cone in the Khanuy Gol (Hanuy Gol) volcanic field is 95 km ENE. Pliocene and Quaternary volcanic rocks are also abundant in the vicinity of the Holocene volcanoes (Devyatkin and Smelov, 1979; Logatchev and others, 1982). Analysis of seismic activity recorded by a network of seismic stations across Mongolia shows that earthquakes of magnitude 2-3.5 are scattered around the Har-Togoo volcano at a distance of 10-15 km.

Figure (see Caption) Figure 1. Photograph of the Har-Togoo volcano viewed from west, March 2003. Courtesy of Alexei Ivanov.

Observations during March 2003. The name of the volcano in the Mongolian language means "black-pot" and through questioning of the local inhabitants, it was learned that there is a local myth that a dragon lived in the volcano. The local inhabitants also mentioned that marmots, previously abundant in the area, began to migrate westwards five years ago; they are now practically absent from the area.

Acoustic noise and venting of colorless warm gas from a small hole near the summit were noticed in October 2002 by local residents. In December 2002, while snow lay on the ground, the hole was clearly visible to local visitors, and a second hole could be seen a few meters away; it is unclear whether or not white vapors were noticed on this occasion. During the inspection in March 2003 a third hole was seen. The second hole is located within a 3 x 3 m outcrop of cinder and pumice (figure 2) whereas the first and the third holes are located within massive basalts. When close to the holes, constant noise resembled a rapid river heard from afar. The second hole was covered with plastic sheeting fixed at the margins, but the plastic was blown off within 2-3 seconds. Gas from the second hole was sampled in a mechanically pumped glass sampler. Analysis by gas chromatography, performed a week later at the Institute of the Earth's Crust, showed that nitrogen and atmospheric air were the major constituents.

Figure (see Caption) Figure 2. Photograph of the second hole sampled at Har-Togoo, with hammer for scale, March 2003. Courtesy of Alexei Ivanov.

The temperature of the gas at the first, second, and third holes was +1.1, +1.4, and +2.7°C, respectively, while air temperature was -4.6 to -4.7°C (measured on 19 March 2003). Repeated measurements of the temperatures on the next day gave values of +1.1, +0.8, and -6.0°C at the first, second, and third holes, respectively. Air temperature was -9.4°C. To avoid bias due to direct heating from sunlight the measurements were performed under shadow. All measurements were done with Chechtemp2 digital thermometer with precision of ± 0.1°C and accuracy ± 0.3°C.

Inside the mouth of the first hole was 4-10-cm-thick ice with suspended gas bubbles (figure 5). The ice and snow were sampled in plastic bottles, melted, and tested for pH and Eh with digital meters. The pH-meter was calibrated by Horiba Ltd (Kyoto, Japan) standard solutions 4 and 7. Water from melted ice appeared to be slightly acidic (pH 6.52) in comparison to water of melted snow (pH 7.04). Both pH values were within neutral solution values. No prominent difference in Eh (108 and 117 for ice and snow, respectively) was revealed.

Two digital short-period three-component stations were installed on top of Har-Togoo, one 50 m from the degassing holes and one in a remote area on basement rocks, for monitoring during 19-20 March 2003. Every hour 1-3 microseismic events with magnitude <2 were recorded. All seismic events were virtually identical and resembled A-type volcano-tectonic earthquakes (figure 6). Arrival difference between S and P waves were around 0.06-0.3 seconds for the Har-Togoo station and 0.1-1.5 seconds for the remote station. Assuming that the Har-Togoo station was located in the epicentral zone, the events were located at ~1-3 km depth. Seismic episodes similar to volcanic tremors were also recorded (figure 3).

Figure (see Caption) Figure 3. Examples of an A-type volcano-tectonic earthquake and volcanic tremor episodes recorded at the Har-Togoo station on 19 March 2003. Courtesy of Alexei Ivanov.

Conclusions. The abnormal thermal and seismic activities could be the result of either hydrothermal or volcanic processes. This activity could have started in the fall of 2002 when they were directly observed for the first time, or possibly up to five years earlier when marmots started migrating from the area. Further studies are planned to investigate the cause of the fumarolic and seismic activities.

At the end of a second visit in early July, gas venting had stopped, but seismicity was continuing. In August there will be a workshop on Russian-Mongolian cooperation between Institutions of the Russian and Mongolian Academies of Sciences (held in Ulan-Bator, Mongolia), where the work being done on this volcano will be presented.

References. Devyatkin, E.V. and Smelov, S.B., 1979, Position of basalts in sequence of Cenozoic sediments of Mongolia: Izvestiya USSR Academy of Sciences, geological series, no. 1, p. 16-29. (In Russian).

Logatchev, N.A., Devyatkin, E.V., Malaeva, E.M., and others, 1982, Cenozoic deposits of Taryat basin and Chulutu river valley (Central Hangai): Izvestiya USSR Academy of Sciences, geological series, no. 8, p. 76-86. (In Russian).

Geologic Background. The Miocene Har-Togoo shield volcano, also known as Togoo Tologoy, is situated on top of a vast volcanic plateau. The 5,000-year-old Khorog (Horog) cone in the Taryatu-Chulutu volcanic field is located 135 km SW and the Quaternary Urun-Dush cone in the Khanuy Gol (Hanuy Gol) volcanic field is 95 km ENE. Analysis of seismic activity recorded by a network of seismic stations across Mongolia shows that earthquakes of magnitude 2-3.5 are scattered around the Har-Togoo volcano at a distance of 10-15 km.

Information Contacts: Alexei V. Ivanov, Institute of the Earth Crust SB, Russian Academy of Sciences, Irkutsk, Russia; Bekhtur andM. Ulziibat, Research Center of Astronomy and Geophysics, Mongolian Academy of Sciences, Ulan-Bator, Mongolia; M. Ganzorig, Institute of Informatics MAS, Ulan-Bator, Mongolia.


Elgon (Uganda) — December 2005

Elgon

Uganda

1.136°N, 34.559°E; summit elev. 3885 m

All times are local (unless otherwise noted)


False report of activity; confusion caused by burning dung in a lava tube

An eruption at Mount Elgon was mistakenly inferred when fumes escaped from this otherwise quiet volcano. The fumes were eventually traced to dung burning in a lava-tube cave. The cave is home to, or visited by, wildlife ranging from bats to elephants. Mt. Elgon (Ol Doinyo Ilgoon) is a stratovolcano on the SW margin of a 13 x 16 km caldera that straddles the Uganda-Kenya border 140 km NE of the N shore of Lake Victoria. No eruptions are known in the historical record or in the Holocene.

On 7 September 2004 the web site of the Kenyan newspaper The Daily Nation reported that villagers sighted and smelled noxious fumes from a cave on the flank of Mt. Elgon during August 2005. The villagers' concerns were taken quite seriously by both nations, to the extent that evacuation of nearby villages was considered.

The Daily Nation article added that shortly after the villagers' reports, Moses Masibo, Kenya's Western Province geology officer visited the cave, confirmed the villagers observations, and added that the temperature in the cave was 170°C. He recommended that nearby villagers move to safer locations. Masibo and Silas Simiyu of KenGens geothermal department collected ashes from the cave for testing.

Gerald Ernst reported on 19 September 2004 that he spoke with two local geologists involved with the Elgon crisis from the Geology Department of the University of Nairobi (Jiromo campus): Professor Nyambok and Zacharia Kuria (the former is a senior scientist who was unable to go in the field; the latter is a junior scientist who visited the site). According to Ernst their interpretation is that somebody set fire to bat guano in one of the caves. The fire was intense and probably explains the vigorous fuming, high temperatures, and suffocated animals. The event was also accompanied by emissions of gases with an ammonia odor. Ernst noted that this was not surprising considering the high nitrogen content of guano—ammonia is highly toxic and can also explain the animal deaths. The intense fumes initially caused substantial panic in the area.

It was Ernst's understanding that the authorities ordered evacuations while awaiting a report from local scientists, but that people returned before the report reached the authorities. The fire presumably prompted the response of local authorities who then urged the University geologists to analyze the situation. By the time geologists arrived, the fuming had ceased, or nearly so. The residue left by the fire and other observations led them to conclude that nothing remotely related to a volcanic eruption had occurred.

However, the incident emphasized the problem due to lack of a seismic station to monitor tectonic activity related to a local triple junction associated with the rift valley or volcanic seismicity. In response, one seismic station was moved from S Kenya to the area of Mt. Elgon so that local seismicity can be monitored in the future.

Information Contacts: Gerald Ernst, Univ. of Ghent, Krijgslaan 281/S8, B-9000, Belgium; Chris Newhall, USGS, Univ. of Washington, Dept. of Earth & Space Sciences, Box 351310, Seattle, WA 98195-1310, USA; The Daily Nation (URL: http://www.nationmedia.com/dailynation/); Uganda Tourist Board (URL: http://www.visituganda.com/).