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SI/USGS Weekly Volcanic Activity Report 1-7 December 2010
From: "Kuhn, Sally" <KUHNS@xxxxxx>
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SI/USGS Weekly Volcanic Activity Report
1-7 December 2010
Sally Kuhn Sennert - Weekly Report Editor
kuhns@xxxxxx
URL: http://www.volcano.si.edu/reports/usgs/
New Activity/Unrest: | Bulusan, Luzon | Kliuchevskoi, Central Kamchatka (Russia) | Merapi, Central Java (Indonesia) | Tengger Caldera, Eastern Java (Indonesia) | Tungurahua, Ecuador
Ongoing Activity: | Dukono, Halmahera | Fuego, Guatemala | Karymsky, Eastern Kamchatka (Russia) | Kilauea, Hawaii (USA) | Machín, Colombia | Popocatépetl, México | Sakura-jima, Kyushu | Sangay, Ecuador | Shiveluch, Central Kamchatka (Russia) | Soufrière Hills, Montserrat | Suwanose-jima, Ryukyu Islands (Japan)
The Weekly Volcanic Activity Report is a cooperative project between the Smithsonian's Global Volcanism Program and the US Geological Survey's Volcano Hazards Program. Updated by 2300 UTC every Wednesday, notices of volcanic activity posted on these pages are preliminary and subject to change as events are studied in more detail. This is not a comprehensive list of all of Earth's volcanoes erupting during the week, but rather a summary of activity at volcanoes that meet criteria discussed in detail in the "Criteria and Disclaimers" section. Carefully reviewed, detailed reports on various volcanoes are published monthly in the Bulletin of the Global Volcanism Network.
Note: Many news agencies do not archive the articles they post on the Internet, and therefore the links to some sources may not be active. To obtain information about the cited articles that are no longer available on the Internet contact the source.
New Activity/Unrest
BULUSAN Luzon 12.770°N, 124.05°E; summit elev. 1565 m
PHIVOLCS reported that volcanic earthquakes from Bulusan were detected during 1-6 December; no earthquakes were recorded on 7 December. Steam from known thermal vents rose 100 m and drifted SW on 1 December. Cloud cover prevented visual observations during 2-4 and 6-7 December. Diffuse steam rose from the crater and from known vents on 5 December. The Alert Level remained at 1 (on a scale of 0-5).
Geologic Summary. Luzon's southernmost volcano, Bulusan, was constructed within the 11-km-diameter dacitic Irosin caldera, which was formed more than 36,000 years ago. A broad, flat moat is located below the prominent SW caldera rim; the NE rim is buried by the andesitic Bulusan complex. Bulusan is flanked by several other large intracaldera lava domes and cones, including the prominent Mount Jormajan lava dome on the SW flank and Sharp Peak to the NE. The summit of Bulusan volcano is unvegetated and contains a 300-m-wide, 50-m-deep crater. Three small craters are located on the SE flank. Many moderate explosive eruptions have been recorded at Bulusan since the mid-19th century.
Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS) http://www.phivolcs.dost.gov.ph/index.php
KLIUCHEVSKOI Central Kamchatka (Russia) 56.057°N, 160.638°E; summit elev. 4835 m
KVERT reported that seismic activity at Kliuchevskoi was slightly above background levels during 26-27 November, and did not exceed background levels during 28 November-3 December. Satellite imagery showed gas-and-ash plumes drifting 430 km N and NE during 26-29 November and a weak thermal anomaly over the crater on 26, 28, and 29 November. Ash plumes were seen rising to an altitude of 6.3 km (20,700 ft) a.s.l. on 26 and 29 November and 1 December. Ash fell in Kozyrevsk (about 50 km W) on 27 November and in Klyuchi (30 km NNE) on 28 November. Strombolian activity was observed on 1 and 2 December. The Aviation Color Code level remained at Orange.
Geologic Summary. Kliuchevskoi is Kamchatka's highest and most active volcano. Since its origin about 7,000 years ago, the beautifully symmetrical, 4,835-m-high basaltic stratovolcano has produced frequent moderate-volume explosive and effusive eruptions without major periods of inactivity. More than 100 flank eruptions, mostly on the NE and SE flanks of the conical volcano between 500 m and 3,600 m elevation, have occurred during the past 3,000 years. The morphology of its 700-m-wide summit crater has been frequently modified by historical eruptions, which have been recorded since the late-17th century. Historical eruptions have originated primarily from the summit crater, but have also included major explosive and effusive events from flank craters.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php
MERAPI Central Java (Indonesia) 7.542°S, 110.442°E; summit elev. 2968 m
CVGHM reported that activity at Merapi declined during 1-3 December. Seismic data showed a decrease in the number of earthquakes as well as amplitude of the events. Deformation measurements did not show any significant changes. Although fog often prevented visual observations or views through webcams, gas plumes were seen rising 500 m above the crater and drifting W. Sulfur dioxide plumes were no longer detected in satellite imagery. CVGHM noted that lahar deposits were seen in multiple drainages and that several bridges had been recently damaged by lahar activity. On 4 December, the Alert Level was lowered to 3 (on a scale of 1-4).
Geologic Summary. Merapi, one of Indonesia's most active volcanoes, lies in one of the world's most densely populated areas and dominates the landscape immediately N of the major city of Yogyakarta. The steep-sided modern Merapi edifice, its upper part unvegetated due to frequent eruptive activity, was constructed to the SW of an arcuate scarp cutting the eroded older Batulawang volcano. Pyroclastic flows and lahars accompanying growth and collapse of the steep-sided active summit lava dome have devastated cultivated and inhabited lands on the volcano's western-to-southern flanks and caused many fatalities during historical time. The volcano is the object of extensive monitoring efforts by the Merapi Volcano Observatory (MVO).
Source: Center of Volcanology and Geological Hazard Mitigation (CVGHM) http://www.vsi.esdm.go.id/
TENGGER CALDERA Eastern Java (Indonesia) 7.942°S, 112.95°E; summit elev. 2329 m
On 6 December, CVGHM reported that seismicity from Tengger Caldera's Bromo cone had declined since 30 November, and deformation measurements showed deflation. White-to-gray plumes rose 200-300 m above the crater rim and drifted N. The Alert Level was lowered to 3 (on a scale of 1-4). Residents and tourists were not permitted within a 2-km-radius of the active crater.
Geologic Summary. The 16-km-wide Tengger caldera in eastern Java is located at the northern end of a volcanic massif extending from Semeru volcano. The massive Tengger volcanic complex consists of five overlapping stratovolcanoes, each truncated by a caldera. The most recent is the 9 x 10 km wide Sandsea caldera, which formed incrementally during the late Pleistocene and early Holocene. An overlapping cluster of post-caldera cones was constructed on the floor of the Sandsea caldera within the past several thousand years. The youngest of these is Bromo, one of Java's most frequently visited and most active volcanoes. More than 50 mild-to-moderate explosive eruptions have occurred since 1804.
Source: Center of Volcanology and Geological Hazard Mitigation (CVGHM) http://www.vsi.esdm.go.id/
TUNGURAHUA Ecuador 1.467°S, 78.442°W; summit elev. 5023 m
During 2-3 December, IG reported that Strombolian activity from Tungurahua was seen at night. Ash plumes on 3 December rose to an altitude of 8 km (26,200 ft) a.s.l. and ashfall was reported in nearby areas. On 4 December, a sudden increase in tremor detected by the seismic network was followed by intense roaring noises, an increase in the number and intensity of explosions, and window and ground vibrations. Pyroclastic flows descended the N and W drainages at 0939 and continued to occur in those and additional drainages until 1522, including Cusúa, Mandur, and Juive (NW), as well as Rea, Choglontús, and Mapayacu (SW). Ashfall occurred in uninhabited regions to the S and SE. According to news articles, people within 8 km of the summit were evacuated.
On 5 December, satellite images showed ash plumes drifting SW. Ashfall was reported in areas within 8 km SW, W, NNW, and NW. Explosions caused windows to vibrate. During 5-6 December, blocks ejected from Strombolian activity rolled 1 km down the flanks. On 6 December, ash plumes rose to an altitude of 8 km (26,200 ft) a.s.l. and drifted NW, W and SW, causing ashfall downwind. Gas-and-ash plumes on 7 December rose to altitudes of 7-8 km (23,000-26,200 ft) a.s.l. and drifted SW and W. Ashfall resulted in deposits up to 1 mm thick in areas to the W. Ejected blocks rolled 1-2 km down the flanks and explosions vibrated windows.
Geologic Summary. The steep-sided Tungurahua stratovolcano towers more than 3 km above its northern base. It sits ~140 km S of Quito, Ecuador's capital city, and is one of Ecuador's most active volcanoes. Historical eruptions have all originated from the summit crater. They have been accompanied by strong explosions and sometimes by pyroclastic flows and lava flows that reached populated areas at the volcano's base. The last major eruption took place from 1916 to 1918, although minor activity continued until 1925. The latest eruption began in October 1999 and prompted temporary evacuation of the town of Baños on the N side of the volcano.
Sources: Instituto Geofísico-Escuela Politécnica Nacional (IG) http://www.igepn.edu.ec/,
Reuters http://www.bernama.com/bernama/v5/bm/newsworld.php?id=547879
Ongoing Activity
DUKONO Halmahera 1.68°N, 127.88°E; summit elev. 1335 m
Based on analyses of satellite imagery, the Darwin VAAC reported that during 3-5 December ash plumes from Dukono rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted 55-110 km W.
Geologic Summary. Reports from this remote volcano in northernmost Halmahera are rare, but Dukono has been one of Indonesia's most active volcanoes. More-or-less continuous explosive eruptions, sometimes accompanied by lava flows, occurred from 1933 until at least the mid-1990s, when routine observations were curtailed. During a major eruption in 1550, a lava flow filled in the strait between Halmahera and the N-flank cone of Gunung Mamuya. Dukono is a complex volcano presenting a broad, low profile with multiple summit peaks and overlapping craters. Malupang Wariang, 1 km SW of Dukono's summit crater complex, contains a 700 x 570 m crater that has also been active during historical time.
Source: Darwin Volcanic Ash Advisory Centre (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AU/messages.html
FUEGO Guatemala 14.473°N, 90.880°W; summit elev. 3763 m
Based on analysis of satellite imagery, the Washington VAAC reported that on 4 December a diffuse plume of gas and possibly ash drifted SW. On 6 December, INSIVUMEH reported that explosions produced ash plumes that rose 900 m above the crater and drifted 6 km SW.
Geologic Summary. Volcán Fuego, one of Central America's most active volcanoes, is one of three large stratovolcanoes overlooking Guatemala's former capital, Antigua. The scarp of an older edifice, Meseta, lies between 3,763-m-high Fuego and its twin volcano to the N, Acatenango. Construction of Meseta volcano continued until the late Pleistocene or early Holocene, after which growth of the modern Fuego volcano continued the southward migration of volcanism that began at Acatenango. Frequent vigorous historical eruptions have been recorded at Fuego since the onset of the Spanish era in 1524, and have produced major ashfalls, along with occasional pyroclastic flows and lava flows. The last major explosive eruption from Fuego took place in 1974, producing spectacular pyroclastic flows visible from Antigua.
Sources: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH) http://www.insivumeh.gob.gt/,
Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html
KARYMSKY Eastern Kamchatka (Russia) 54.05°N, 159.45°E; summit elev. 1536 m
KVERT reported that seismic activity at Karymsky was above background levels during 26 November-3 December, suggesting that possible ash plumes rose to an altitude of 5.3 km (17,400 ft) a.s.l. during 25-26 and 30 November, and 1-2 December. Thermal anomalies were detected in satellite imagery on 26 and 27 November, and 1 December. The Aviation Color Code level remained at Orange.
Geologic Summary. Karymsky, the most active volcano of Kamchatka's eastern volcanic zone, is a symmetrical stratovolcano constructed within a 5-km-wide caldera that formed about 7,600-7,700 radiocarbon years ago. Construction of the Karymsky stratovolcano began about 2,000 years later. The latest eruptive period began about 500 years ago, following a 2,300-year quiescence. Much of the cone is mantled by lava flows less than 200 years old. Historical eruptions have been Vulcanian or Vulcanian-Strombolian with moderate explosive activity and occasional lava flows from the summit crater. Most seismicity preceding Karymsky eruptions has originated beneath Akademia Nauk caldera, which is located immediately S of Karymsky volcano and erupted simultaneously with Karymsky in 1996.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php
KILAUEA Hawaii (USA) 19.421°N, 155.287°W; summit elev. 1222 m
During 1-7 December, HVO reported that activity at Kilauea continued from the summit caldera and the east rift zone. At the summit caldera, the level of the lava-pool surface in the deep pit within Halema'uma'u crater remained mostly stable at approximately 135 m below the crater floor, periodically rising about 15 m above that level. Nighttime incandescence has been visible from the Jaggar Museum on the NW caldera rim since early 2010. A plume from the vent mostly drifted SW and deposited ash and fresh spatter nearby.
At the east rift zone, lava flowed a short distance through the TEB lava-tube system before breaking out onto the surface at a saddle between two rootless shields at around the 610 m elevation on 1 December. Lava started to build a shield and also extended several hundred meters from both sides of the lava tube. A small breakout lava flow on top of the pali traveled 100 m downslope to within about 6 km of Kalapana Gardens. During 2-7 December, lava flows at the saddle area advanced W, N, and E. Lava was last observed entering the ocean at Puhi-o-Kalaikini during 29-30 November.
Geologic Summary. Kilauea, one of five coalescing volcanoes that comprise the island of Hawaii, is one of the world's most active volcanoes. Eruptions at Kilauea originate primarily from the summit caldera or along one of the lengthy E and SW rift zones that extend from the caldera to the sea. About 90% of the surface of Kilauea is formed of lava flows less than about 1,100 years old; 70% of the volcano's surface is younger than 600 years. A long-term eruption from the East rift zone that began in 1983 has produced lava flows covering more than 100 sq km, destroying nearly 200 houses and adding new coastline to the island.
Source: US Geological Survey Hawaiian Volcano Observatory (HVO) http://hvo.wr.usgs.gov/
MACHIN Colombia 4.48°N, 75.392°W; summit elev. 2650+ m
According to INGEOMINAS, Observatory Vulcanológico and Sismológico de Manizales reported increased seismicity from Cerro Machín on 3 December. About 340 volcano-tectonic earthquakes with low magnitudes were located SW of the main lava dome, at an average depth of 4 km. The largest event, a M 3.7 earthquake located SW of the dome at a depth of about 3.5 km, was felt by local residents. The Alert level remained at III (Yellow; "changes in the behavior of volcanic activity").
Geologic Summary. The small Cerro Machín stratovolcano lies at the southern end of the Ruiz-Tolima massif about 20 km WNW of the city of Ibagué. A 3-km-wide caldera is breached to the S and contains three forested lava domes. Voluminous pyroclastic flows traveled up to 40 km from the volcano during eruptions in the mid-to-late Holocene perhaps associated with formation of the caldera. Late-Holocene eruptions produced block-and-ash flows that traveled through the breach in the caldera rim to the W and S. The latest known eruption of Volcán Cerro Machín took place about 800 years ago.
Source: Instituto Colombiano de Geología y Minería (INGEOMINAS) http://www.ingeominas.gov.co//
POPOCATEPETL México 19.023°N, 98.622°W; summit elev. 5426 m
CENAPRED noted that steam-and-gas emissions rose from Popocatépetl during 1-7 December. Based on a SIGMET notice, the Washington VAAC reported that a small and brief emission of gas and ash on 5 December was too small or diffuse to be detected in satellite images.
Geologic Summary. Popocatépetl, whose name is the Aztec word for smoking mountain, towers to 5,426 m 70 km SE of Mexico City and is North America's second-highest volcano. Frequent historical eruptions have been recorded since the beginning of the Spanish colonial era. A small eruption on 21 December 1994 ended five decades of quiescence. Since 1996 small lava domes have incrementally been constructed within the summit crater and destroyed by explosive eruptions. Intermittent small-to-moderate gas-and-ash eruptions have continued, occasionally producing ashfall in neighboring towns and villages.
Sources: Centro Nacional de Prevencion de Desastres (CENAPRED) http://www.cenapred.unam.mx/es/,
Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html
SAKURA-JIMA Kyushu 31.585°N, 130.657°E; summit elev. 1117 m
Based on information from JMA, the Tokyo VAAC reported that during 1-7 December explosions from Sakura-jima produced plumes that rose to altitudes of 1.2-2.7 km (4,000-9,000 ft) a.s.l. and drifted E, SE, W, NW, and N. During 2 and 4-5 December, pilots reported that ash plumes rose to altitudes of 1.5-4.6 km (5,000-15,000 ft) a.s.l.
Geologic Summary. Sakura-jima, one of Japan's most active volcanoes, is a post-caldera cone of the Aira caldera at the northern half of Kagoshima Bay. Eruption of the voluminous Ito pyroclastic flow was associated with the formation of the 17 x 23-km-wide Aira caldera about 22,000 years ago. The construction of Sakura-jima began about 13,000 years ago and built an island that was finally joined to the Osumi Peninsula during the major explosive and effusive eruption of 1914. Activity at the Kita-dake summit cone ended about 4,850 years ago, after which eruptions took place at Minami-dake. Frequent historical eruptions, recorded since the 8th century, have deposited ash on Kagoshima, one of Kyushu's largest cities, located across Kagoshima Bay only 8 km from the summit. The largest historical eruption took place during 1471-76.
Source: Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html
SANGAY Ecuador 2.002°S, 78.341°W; summit elev. 5230 m
Based on information from Guayaquil MWO, the Washington VAAC reported ash from Sangay on 5 December; weather clouds prevented satellite observations. IG noted elevated seismicity.
Geologic Summary. The isolated Sangay volcano, located E of the Andean crest, is the southernmost of Ecuador's volcanoes, and its most active. It has been in frequent eruption for the past several centuries. The steep-sided, 5,230-m-high glacier-covered volcano grew within horseshoe-shaped calderas of two previous edifices, which were destroyed by collapse to the E, producing large debris avalanches that reached the Amazonian lowlands. The modern edifice dates back to at least 14,000 years ago. Sangay towers above the tropical jungle on the E side; on the other sides flat plains of ash from the volcano have been sculpted by heavy rains into steep-walled canyons up to 600 m deep. The earliest report of an historical eruption was in 1628. More or less continuous eruptions were reported from 1728 until 1916, and again from 1934 to the present. The more or less constant eruptive activity has caused frequent changes to the morphology of the summit crater complex.
Source: Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html
SHIVELUCH Central Kamchatka (Russia) 56.653°N, 161.360°E; summit elev. 3283 m
KVERT reported that moderate seismic activity from Shiveluch was detected during 26 November-3 December. A bright thermal anomaly over the volcano was observed in satellite imagery. Strong gas-and-steam activity was observed on 26 and 29 November. Satellite images showed ash plumes drifting 153 km N and NE during 29-30 November, as well as several ash clouds (as large as 81 by 16 km) at distances up to 351 km N and NE. Seismic data analysis suggested that ash plumes rose to an altitude of 5.5 km (18,000 ft) a.s.l. on 1 December. The Aviation Color Code level remained at Orange.
Geologic Summary. The high, isolated massif of Shiveluch volcano (also spelled Sheveluch) rises above the lowlands NNE of the Kliuchevskaya volcano group and forms one of Kamchatka's largest and most active volcanoes. The currently active Molodoy Shiveluch lava-dome complex was constructed during the Holocene within a large breached caldera formed by collapse of the massive late-Pleistocene Strary Shiveluch volcano. At least 60 large eruptions of Shiveluch have occurred during the Holocene, making it the most vigorous andesitic volcano of the Kuril-Kamchatka arc. Frequent collapses of lava-dome complexes, most recently in 1964, have produced large debris avalanches whose deposits cover much of the floor of the breached caldera. Intermittent explosive eruptions began in the 1990s from a new lava dome that began growing in 1980. The largest historical eruptions from Shiveluch occurred in 1854 and 1964.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php
SOUFRIERE HILLS Montserrat 16.72°N, 62.18°W; summit elev. 915 m
MVO reported that during 26 November-3 December activity from the Soufrière Hills lava dome was at a low level. Part of the large unstable overhanging area on the W side of the lava dome collapsed on 29 November, generating pyroclastic flows that traveled about 2 km W. Small pyroclastic flows also occurred on the E side of the dome. On 2 December, small areas of incandescence were visible on the back wall of the 11 February collapse scar. The Hazard Level remained at 3.
Geologic Summary. The complex dominantly andesitic Soufrière Hills volcano occupies the southern half of the island of Montserrat. The summit area consists primarily of a series of lava domes emplaced along an ESE-trending zone. English's Crater, a 1-km-wide crater breached widely to the E, was formed during an eruption about 4,000 years ago in which the summit collapsed, producing a large submarine debris avalanche. Block-and-ash flow and surge deposits associated with dome growth predominate in flank deposits at Soufrière Hills. Non-eruptive seismic swarms occurred at 30-year intervals in the 20th century, but with the exception of a 17th-century eruption that produced the Castle Peak lava dome, no historical eruptions were recorded on Montserrat until 1995. Long-term small-to-moderate ash eruptions beginning in that year were later accompanied by lava-dome growth and pyroclastic flows that forced evacuation of the southern half of the island and ultimately destroyed the capital city of Plymouth, causing major social and economic disruption.
Source: Montserrat Volcano Observatory (MVO) http://www.mvo.ms/
SUWANOSE-JIMA Ryukyu Islands (Japan) 29.635°N, 129.716°E; summit elev. 799 m
Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima during 1-4 December. Plumes rose to an altitude of 1.2 km (4,000 ft) and drifted SE on 4 December.
Geologic Summary. The 8-km-long, spindle-shaped island of Suwanose-jima in the northern Ryukyu Islands consists of an andesitic stratovolcano with two historically active summit craters. Only about 50 persons live on the sparsely populated island. The summit of the volcano is truncated by a large breached crater extending to the sea on the east flank that was formed by edifice collapse. Suwanose-jima, one of Japan's most frequently active volcanoes, was in a state of intermittent Strombolian activity from On-take, the NE summit crater, that began in 1949 and lasted nearly a half century. The largest historical eruption took place in 1813-14, when thick scoria deposits blanketed residential areas, after which the island was uninhabited for about 70 years. The SW crater produced lava flows that reached the western coast in 1813, and lava flows reached the eastern coast of the island in 1884.
Source: Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html
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