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SI/USGS Weekly Volcanic Activity Report 22-28 September 2010
From: "Kuhn, Sally" <KUHNS@xxxxxx>
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SI/USGS Weekly Volcanic Activity Report
22-28 September 2010
Sally Kuhn Sennert - Weekly Report Editor
URL: http://www.volcano.si.edu/reports/usgs/
New Activity/Unrest: | Karangetang [Api Siau], Siau I | Kliuchevskoi, Central Kamchatka (Russia) | Merapi, Central Java (Indonesia) | Piton de la Fournaise, Reunion Island | Planchón-Peteroa, Central Chile-Argentina border | Sinabung, Sumatra (Indonesia)
Ongoing Activity: | Cleveland, Chuginadak Island | Dukono, Halmahera | Karymsky, Eastern Kamchatka (Russia) | Kilauea, Hawaii (USA) | Reventador, Ecuador | Sakura-jima, Kyushu | 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
KARANGETANG [API SIAU] Siau I 2.78°N, 125.40°E; summit elev. 1784 m
CVGHM reported that during 1-7 September lava seen from the observation post (5 km SSW) traveled 75 m down Karangetang's flanks. Avalanches traveled as far as 1.5 km down the Batang (S), Batu Awang (E), and Nanitu drainages. Incandescent material was ejected 350 m above the crater. During 8-21 September lava traveled 500 m down the flanks. Avalanches originating from the end of the lava flow traveled as far as 2 km down the Batang, Kahetang (E), and Nanitu drainages. During 18-20 September material was ejected 300-500 m above the crater. Ashfall was reported in areas to the NW. On 21 and 22 September incandescent material traveled down multiple drainages. Strombolian activity was observed on 22 September; material ejected 50 m high fell back down around the crater. That same day the Alert level was raised to 3 (on a scale of 1-4).
Geologic Summary. Karangetang (also known as Api Siau) lies at the northern end of the island of Siau, N of Sulawesi, and contains five summit craters strung along a N-S line. One of Indonesia's most active volcanoes, Karangetang has had more than 40 recorded eruptions since 1675. Twentieth-century eruptions have included frequent explosions, sometimes accompanied by pyroclastic flows and lahars.
Source: Center of Volcanology and Geological Hazard Mitigation (CVGHM) http://portal.vsi.esdm.go.id/joomla/
KLIUCHEVSKOI Central Kamchatka (Russia) 56.057°N, 160.638°E; summit elev. 4835 m
KVERT reported that during 17-24 September seismic activity from Kliuchevskoi was above background levels and lava from the summit crater flowed down the SW flank. Satellite imagery analyses showed a large and intense daily thermal anomaly over the volcano. Strombolian activity was observed during 17 and 20-21 September, and ash plumes were seen rising to altitudes of 6.5-7 km (21,300-23,000 ft) a.s.l. on 20 and 21 September. Satellite imagery showed ash plumes drifting about 60 km W on 19 September and about 240 km E on 20 and 21 September. 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 a pattern of increasing seismicity from Merapi began in to emerge in early September. Observers at Babadan (7 km W) and Kaliurang (8 km S) heard an avalanche on 12 September. On 13 September white plumes rose 800 m above the crater. Inflation, detected since March, increased from background levels of 0.1 to 0.3 mm per day to a rate of 11 mm per day on 16 September. On 19 September earthquakes continued to be numerous, and the next day CVGHM raised the Alert Level to 2 (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://portal.vsi.esdm.go.id/joomla/
PITON DE LA FOURNAISE Reunion Island 21.231°S, 55.713°E; summit elev. 2632 m
Starting on 14 August and continuing through 10 September, OVPDLF recorded a slow but steady increase in the number and magnitude of earthquakes from Piton de la Fournaise. Inflation of the summit area began in late August. A report on 13 September noted localized deformation W of Dolomieu crater and a small number of landslides in the crater. On 20 September a significant increase in earthquakes was recorded, although the average magnitude was low. The earthquakes were located at the base of Piton de la Fournaise, W and S of Dolomieu crater. A seismic crisis on 24 September was characterized by several tens of earthquakes located beneath Dolomieu crater, and occurred in conjunction with 3 cm of inflation. The Alert level was raised to 1 ("Probable or Imminent Eruption").
Geologic Summary. Massive Piton de la Fournaise shield volcano on the island of Réunion is one of the world's most active volcanoes. Most historical eruptions have originated from the summit and flanks of a 400-m-high lava shield, Dolomieu, that has grown within the youngest of three large calderas. This depression is 8 km wide and is breached to below sea level on the eastern side. More than 150 eruptions, most of which have produced fluid basaltic lava flows within the caldera, have been documented since the 17th century. The volcano is monitored by the Piton de la Fournaise Volcano Observatory, one of several operated by the Institut de Physique du Globe de Paris.
Source: Observatoire Volcanologique du Piton de la Fournaise (OVPDLF) http://www.ipgp.fr/pages/03030810.php
PLANCHON-PETEROA Central Chile-Argentina border 35.240°S, 70.570°W; summit elev. 4107 m
Based on analyses of satellite imagery, the Buenos Aires VAAC reported that on 26 September an ash plume from Planchón-Peteroa rose to an altitude of 4.3 km (14,000 ft) a.s.l. and drifted SSE.
Geologic Summary. Planchón-Peteroa is an elongated complex volcano along the Chile-Argentina border with several overlapping calderas. Activity began in the Pleistocene with construction of the basaltic-andesite to dacitic Volcán Azufre, followed by formation of basaltic and basaltic-andesite Volcán Planchón, 6 km to the N. About 11,500 years ago, much of Azufre and part of Planchón collapsed, forming the massive Río Teno debris avalanche, which reached Chile's Central Valley. Subsequently, Volcán Planchón II was formed. The youngest volcano, andesitic and basaltic-andesite Volcá Peteroa, consists of scattered vents between Azufre and Planchón. Peteroa has been active into historical time and contains a small steaming crater lake. Historical eruptions from the Planchón-Peteroa complex have been dominantly explosive, although lava flows were erupted in 1837 and 1937.
Source: Buenos Aires Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AG/messages.html
SINABUNG Sumatra (Indonesia) 3.17°N, 98.392°E; summit elev. 2460 m
CVGHM reported that on 22 September a white plume from Sinabung rose as high as 100 m above the crater. On 23 September the Alert Level was lowered to 3 (on a scale of 1-4).
Geologic Summary. Gunung Sinabung is a Pleistocene-to-Holocene stratovolcano with many lava flows on its flanks. The migration of summit vents along a N-S line gives the summit crater complex an elongated form. The youngest crater of this conical, 2460-m-high andesitic-to-dacitic volcano is at the southern end of the four overlapping summit craters. An unconfirmed eruption was noted in 1881, and solfataric activity was seen at the summit and upper flanks of Sinabung in 1912, although no confirmed historical eruptions were recorded prior to 2010.
Source: Center of Volcanology and Geological Hazard Mitigation (CVGHM) http://portal.vsi.esdm.go.id/joomla/
Ongoing Activity
CLEVELAND Chuginadak Island 52.825°N, 169.944°W; summit elev. 1730 m
AVO reported that during 25-26 September a weak thermal anomaly from Cleveland was detected in satellite imagery. Cloud cover prevented views of the volcano during 22-24 and 27-28 September. The Volcano Alert Level remained at Advisory and the Aviation Color Code remained at Yellow. No current seismic information was available because Cleveland does not have a real-time seismic network.
Geologic Summary. Symmetrical Mount Cleveland stratovolcano is situated at the western end of the uninhabited dumbbell-shaped Chuginadak Island in the east-central Aleutians. The 1,730-m-high stratovolcano is the highest of the Islands of Four Mountains group and is one of the most active in the Aleutians. Numerous large lava flows descend its flanks. It is possible that some 18th to 19th century eruptions attributed to Carlisle (a volcano located across the Carlisle Pass Strait to the NW) should be ascribed to Cleveland. In 1944 Cleveland produced the only known fatality from an Aleutian eruption. Recent eruptions from Mt. Cleveland have been characterized by short-lived explosive ash emissions, at times accompanied by lava fountaining and lava flows down the flanks.
Source: Alaska Volcano Observatory (AVO) http://www.avo.alaska.edu/
DUKONO Halmahera 1.68°N, 127.88°E; summit elev. 1335 m
Based on analyses of satellite imagery, the Darwin VAAC reported that during 21-25 September ash plumes from Dukono rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted 35-95 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
KARYMSKY Eastern Kamchatka (Russia) 54.05°N, 159.45°E; summit elev. 1536 m
KVERT reported that seismic activity from Karymsky was above background levels during 16-20 September and suggested possible ash explosions. Seismicity was at background levels on 21 and 22 September. Cloud cover prevented satellite image views. 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 22-28 September 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 around 160 m below the crater floor; periodically the lava rose 15-35 m above that level. Glow from the vent was also visible at night. A plume from the vent drifted SW and deposited ash nearby. At the east rift zone, lava that flowed through the TEB lava-tube system mainly fed the Puhi-o-Kalaikini ocean entry. Weak thermal anomalies detected in satellite imagery suggested little to no lava flow activity on the pali or the coastal plain. On 26 September lava broke out of the lava-tube system W of the end of Highway 130 and produced a flow E toward Kalapana Gardens. The next day lava, flowing at a slower rate, filled in low areas S of the Hawaii County lava viewing area.
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/
REVENTADOR Ecuador 0.077°S, 77.656°W; summit elev. 3562 m
The IG reported that on 28 September three seismic events from Reventador were recorded. Cloud cover prevented observations during the first event. During the second period of increased seismicity, observers noted that a steam plume with a small amount of ash rose 400-500 m above the crater and drifted N. The third episode was accompanied by a steam-and-ash plume that rose 2 km above the crater and drifted NW. Ash fell on Reventador.
Geologic Summary. Reventador is the most frequently active of a chain of Ecuadorian volcanoes in the Cordillera Real, well E of the principal volcanic axis. It is a forested stratovolcano that rises above the remote jungles of the western Amazon basin. A 3-km-wide caldera breached to the E was formed by edifice collapse and is partially filled by a young, unvegetated stratovolcano that rises about 1,300 m above the caldera floor. Reventador has been the source of numerous lava flows as well as explosive eruptions that were visible from Quito in historical time. Frequent lahars in this region of heavy rainfall have constructed a debris plain on the eastern floor of the caldera.
Source: Instituto Geofísico-Escuela Politécnica Nacional (IG) http://www.igepn.edu.ec/
SAKURA-JIMA Kyushu 31.585°N, 130.657°E; summit elev. 1117 m
Based on a pilot observation, the Tokyo VAAC reported that on 22 September an ash plume rose to an altitude of 1.8 km (6,000 ft) a.s.l. and drifted SE.
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
SHIVELUCH Central Kamchatka (Russia) 56.653°N, 161.360°E; summit elev. 3283 m
KVERT reported that during 17-24 September seismic activity from Shiveluch was above background levels and suggested that possible ash plumes rose to an altitude of 3.5 km (11,500 ft) a.s.l. Satellite imagery analysis showed a thermal anomaly on the volcano. Gas-and-ash plumes were observed on 21 September, and satellite imagery showed ash plumes drifting 16 km SE the same day. 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 17-24 September activity from the Soufrière Hills lava dome was at a low level. Heavy rains caused lahars during 19-20 September in the Belham valley to the NW. One pyroclastic flow traveled 1.5 km E down the Tar River valley on 21 September. 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 22, 25, and 27-28 September. A pilot observed an ash plume on 22 September that rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted SE. JMA noted that plumes on 25 September rose to an altitude of 1.5 km (5,000 ft) a.s.l. and drifted E.
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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