Volcanic Weekly World Update Sep 24

By: Smithsonian & USGS
By: Smithsonian & USGS

15 September-21 September 2010

New Activity/Unrest: | Cleveland, Chuginadak Island | Kliuchevskoi, Central Kamchatka (Russia) | Machín, Colombia | Manam, Northeast of New Guinea (SW Pacific) | Planchón-Peteroa, Central Chile-Argentina border | Sinabung, Sumatra (Indonesia)

Ongoing Activity: | Batu Tara, Komba Island (Indonesia) | Dukono, Halmahera | Karymsky, Eastern Kamchatka (Russia) | Kilauea, Hawaii (USA) | Sakura-jima, Kyushu | Sangay, Ecuador | Shiveluch, Central Kamchatka (Russia) | Suwanose-jima, Ryukyu Islands (Japan)

Updated on Wednesdays. Please see www.volcano.si.edu/reports/usgs/
for news of the latest significant activity.

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

CLEVELAND Chuginadak Island 52.825°N, 169.944°W; summit elev. 1730 m

AVO reported that on 15 September a thermal anomaly from Cleveland was detected in satellite imagery. Cloud cover prevented views of the volcano during 16-21 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)

Cleveland Information from the Global Volcanism Program

KLIUCHEVSKOI Central Kamchatka (Russia) 56.057°N, 160.638°E; summit elev. 4835 m

KVERT reported that during 10-17 September seismic activity from Kliuchevskoi was above background levels and lava flowed down the SW flank. Satellite imagery analyses showed a large and intense daily thermal anomaly over the volcano. During 9-15 September ash plumes rose to altitudes of 6-7 km (19,700-23,000 ft) a.s.l. and drifted 575 km S and SE based on analyses of satellite imagery and visual observations. Strombolian activity was seen on 11 September. Based on analyses of satellite imagery and information from KEMSD, the Tokyo VAAC reported that possible eruptions on 21 and 22 September produced ash plumes that rose to altitudes of 5.2-6.1 km (17,000-20,000 ft) a.s.l. and drifted E. 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.

Sources: Kamchatkan Volcanic Eruption Response Team (KVERT), Tokyo Volcanic Ash Advisory Center (VAAC)

Kliuchevskoi Information from the Global Volcanism Program

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 17 September. About 140 volcano-tectonic earthquakes as large as M 1.85 were located S and SW of the main lava dome at depths of 2-4 km. 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)

Machín Information from the Global Volcanism Program

MANAM Northeast of New Guinea (SW Pacific) 4.080°S, 145.037°E; summit elev. 1807 m

RVO reported that during 5-7 September ash plumes were seen rising from Manam's South Crater when the weather did not prevent observations. Light ashfall was reported on the NW part of the island. Variable amounts of white vapor that was sometimes tinted blue rose from Main Crater.

Geologic Summary. 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," regularly spaced 90 degrees apart, channel lava flows and pyroclastic avalanches that have sometimes reached the coast. 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 avalanche valley. Frequent historical eruptions, typically of mild-to-moderate scale, have been recorded at Manam 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.

Source: Rabaul Volcano Observatory (RVO)

Manam Information from the Global Volcanism Program

PLANCHON-PETEROA Central Chile-Argentina border 35.240°S, 70.570°W; summit elev. 4107 m

According to NASA's Earth Observatory, a satellite image of Planchón-Peteroa shows an ash plume drifting 22 km SE on 18 September and ashfall on the snow beneath the plume. The Buenos Aires VAAC reported that according to a SIGMET issued on 21 September an ash plume rose to an altitude of 6.1 km (20,000 ft) a.s.l and drifted SE. Ash was not identified in satellite imagery. The Alert Level remained at 4, Yellow.

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.

Sources: Earth Observatory, Buenos Aires Volcanic Ash Advisory Center (VAAC)

Planchón-Peteroa Information from the Global Volcanism Program

SINABUNG Sumatra (Indonesia) 3.17°N, 98.392°E; summit elev. 2460 m

Based on information from CVGHM and views through a web camera, the Darwin VAAC reported that during 15-18 September ash plumes from Sinabung rose to an altitude of 4.3 km (14,000 ft) a.s.l. and drifted W. CVGHM reported a slow rate of inflation during 15-18 September followed by deflation during 19-21 September. Fog mostly prevented visual observations. On 20 September diffuse white plumes rose 30 m above the crater and drifted NE. The Alert Level remained at 4 (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.

Sources: Center of Volcanology and Geological Hazard Mitigation (CVGHM), Darwin Volcanic Ash Advisory Centre (VAAC)

Sinabung Information from the Global Volcanism Program


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