VOLCANO MADNESS: [ Volcano ] Smithsonian/USGS Weekly Volcanic Activity Report 21-27 November 2012

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Smithsonian/USGS Weekly Volcanic Activity Report 21-27 November 2012
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Smithsonian/USGS Weekly Volcanic Activity Report

21-27 November 2012

Sally Kuhn Sennert - Weekly Report Editor

kuhns@si.edu

URL: http://www.volcano.si.edu/reports/usgs/

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

CHIRPOI Kuril Islands (Russia) 46.525°N, 150.875°E; summit elev. 742 m

SVERT reported that a thermal anomaly was detected over Snow, a volcano of Chirpoi, on 20, 22, and 25 November, possibly indicating a lava flow on the SE flank.

Geologic Summary. Chirpoi, a small island lying between the larger islands of Simushir and Urup, contains a half dozen volcanic edifices constructed within an 8-9 km wide, partially submerged caldera. The southern rim of the caldera is exposed on nearby Brat Chirpoev Island. Two volcanoes on Chirpoi Island have been historically active. The symmetrical Cherny volcano, which forms the 691 m high point of the island, erupted twice during the 18th and 19th centuries. The youngest volcano, Snow, originated between 1770 and 1810. It is composed almost entirely of lava flows, many of which have reached the sea on the southern coast. No historical eruptions are known from 742-m-high Brat Chirpoev, but its youthful morphology suggests recent strombolian activity.

Source: Sakhalin Volcanic Eruption Response Team (SVERT) http://www.imgg.ru/en/home.html

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

On 21 November AVO noted that no explosions at Cleveland had been detected since 10 November, nor evidence of renewed lava-dome growth. The Volcanic Alert Level was lowered to Advisory and the Aviation Color Code was lowered to Yellow. Elevated surface temperatures were detected in satellite imagery during 21-24 November. Clouds obscured satellite and web camera views during 25-27 November.

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/

KILAUEA Hawaii (USA) 19.421°N, 155.287°W; summit elev. 1222 m

During 21-27 November HVO reported that the circulating lava lake periodically rose and fell in the deep pit within Kilauea's Halema'uma'u Crater. Occasional measurements indicated that the gas plume from the vent continued to deposit variable amounts of ash, spatter, and Pele's hair onto nearby areas. At Pu'u 'O'o Crater, lava circulated within the perched lava lake at the NE part of the crater, and glow emanated from vents at the S edge of the crater floor and from a spatter cone at the N edge. A small lava flow issued from the E vent at the S edge of the crater floor on 24 November.

The easternmost of two lava flows on the coastal plain entered the ocean on 24 November in an area 500 m E of the easternmost border of Hawai'i Volcanoes National Park. Steam plumes rose from the entry point during 25-26 November, suggesting lava continued to enter the ocean. A plume was absent on the morning of 27 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/

KIZIMEN Eastern Kamchatka (Russia) 55.130°N, 160.32°E; summit elev. 2376 m

KVERT reported that during 16-23 November moderate seismic activity at Kizimen was detected. Video and satellite images showed lava flows effusing from the summit and the E flank, summit incandescence, strong gas-and-steam activity, and hot avalanches on the S flank. A thermal anomaly was detected in satellite images on 17, 20, and 22 November; cloud cover obscured views on the other days. The Aviation Color Code remained at Orange.

Geologic Summary. Kizimen is an isolated, conical stratovolcano that is morphologically similar to Mount St. Helens prior to its 1980 eruption. The summit of Kizimen consists of overlapping lava domes, and blocky lava flows descend the flanks of the volcano, which is the westernmost of a volcanic chain north of Kronotsky volcano. The 2,376-m-high Kizimen was formed during four eruptive cycles beginning about 12,000 years ago and lasting 2,000-3,500 years. The largest eruptions took place about 10,000 and 8300-8400 years ago, and three periods of longterm lava-dome growth have occurred. The latest eruptive cycle began about 3,000 years ago with a large explosion and was followed by lava-dome growth lasting intermittently about 1,000 years. An explosive eruption about 1,100 years ago produced a lateral blast and created a 1.0 x 0.7 km wide crater breached to the NE, inside which a small lava dome (the fourth at Kizimen) has grown. A single explosive eruption, during 1927-28, has been recorded in historical time.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php

PALUWEH Lesser Sunda Islands (Indonesia) 8.32°S, 121.708°E; summit elev. 875 m

Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that during 21 and 23-27 November ash plumes from Paluweh rose to altitudes of 2.4-3 km (8,000-10,000 ft) a.s.l. and drifted 35-115 km WNW, W, and SW.

Geologic Summary. Paluweh volcano, also known as Rokatenda, forms the 8-km-wide island of Paluweh N of the volcanic arc that cuts across Flores Island. Although the volcano rises about 3,000 m above the sea floor, its summit reaches only 875 m above sea level. The broad irregular summit region contains overlapping craters up to 900 m wide and several lava domes. Several flank vents occur along a NW-trending fissure. The largest historical eruption of Paluweh occurred in 1928, when a strong explosive eruption was accompanied by landslide-induced tsunamis and lava-dome emplacement.

Source: Darwin Volcanic Ash Advisory Centre (VAAC) ftp://ftp.bom.gov.au/anon/gen/vaac

REVENTADOR Ecuador 0.077°S, 77.656°W; summit elev. 3562 m

IG reported that scientists aboard an overflight of Reventador on 23 November observed steam-and-gas emissions with slight amounts of ash rising 500 m above the lava dome and drifting WSW. The lava dome had intense fumarolic activity and there was a new crater at the summit of the dome, which was filled with ash and large blocks. A thermal camera measured temperatures in the dome of about 300 degrees Celsius. Lava flows continued to be active on the dome flanks, and elongated block-and-ash deposits were also visible on the flanks.

According to the Washington VAAC, the IG reported that on 24 November an ash plume from Reventador rose to an altitude of 4.6 km (15,000 ft) a.s.l. Ash was not detected in satellite imagery due to cloud cover, but a thermal anomaly was detected.

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.

Sources: Instituto Geofísico-Escuela Politécnica Nacional (IG) http://www.igepn.edu.ec/,

Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html

RUAPEHU North Island (New Zealand) 39.28°S, 175.57°E; summit elev. 2797 m

On 23 November, GeoNet reported that measurements of Ruapehu's crater lake taken on 21 November suggested that conditions had not changed since the previous week and that Ruapehu was in a state of unrest. The Volcanic Alert Level remained at 1 (signs of volcano unrest) and the Aviation Colour Code remained at Yellow.

Geologic Summary. Ruapehu, one of New Zealand's most active volcanoes, is a complex stratovolcano constructed during at least four cone-building episodes. The 110 cu km volcanic massif is elongated in a NNE-SSW direction and is surrounded by another 100 cu km ring plain of volcaniclastic debris. A single historically active vent, Crater Lake, is located in the broad summit region, but at least five other vents on the summit and flanks have been active during the Holocene. Frequent mild-to-moderate explosive eruptions have occurred in historical time from the Crater Lake vent. Lahars produced by phreatic eruptions from the summit crater lake are a hazard to a ski area on the upper flanks and to river valleys below the volcano.

Source: New Zealand GeoNet Project http://geonet.org.nz/

STROMBOLI Aeolian Islands (Italy) 38.789°N, 15.213°E; summit elev. 924 m

Sezione di Catania - Osservatorio Etneo reported that the persistent explosive activity at Stromboli showed a clear increase on 21 November with episodes of spattering and low lava fountaining from two vents located in the N and central portions of the crater terrace.

Geologic Summary. Spectacular incandescent nighttime explosions at Stromboli volcano have long attracted visitors to the "Lighthouse of the Mediterranean."Stromboli, the NE-most of the Aeolian Islands, has lent its name to the frequent mild explosive activity that has characterized its eruptions throughout historical time. The small, 926-m-high island of Stromboli is the emergent summit of a volcano that grew in two main eruptive cycles, the last of which formed the western portion of the island. The active summit vents are located at the head of the Sciara del Fuoco, a horseshoe-shaped scarp formed as a result of slope failure that extends to below sea level and funnels pyroclastic ejecta and lava flows to the NW. Essentially continuous mild Strombolian explosions, sometimes accompanied by lava flows, have been recorded at Stromboli since Roman times.

Source: Sezione di Catania - Osservatorio Etneo http://www.ct.ingv.it/index.php

TOLBACHIK Central Kamchatka (Russia) 55.830°N, 160.330°E; summit elev. 3682 m

KVERT reported that episodes of volcanic tremor were detected in the area of Plosky Tolbachik during 7-10, 18, and 26 November. The number of shallow volcanic earthquakes increased to 250 on 26 November. A strong event occurred at 1652 on 27 November. The Aviation Color Code was raised to Yellow. That same day observers from Kozyrevsk (40 km NW) and Lazo (50 km SW) villages reported ash explosions and lava flows at Tolbachinsky Dol, in the same area as the 1975 eruption (northern vents). Ashfall, 4 cm thick, was reported in Krasny Yar (60 km NNW). The Aviation Color Code was raised to Orange. Based on information from the Kamchatka Branch of Geophysical Services (KGBS), the Tokyo VAAC reported that ash plumes possibly rose to altitudes of 6.1-10.1 km (20,000-33,000 ft) a.s.l. Ash plumes were not detected in satellite imagery. Plume altitudes were estimated based on seismic data.

Geologic Summary. The massive Tolbachik basaltic volcano is located at the southern end of the dominantly andesitic Kliuchevskaya volcano group. The Tolbachik massif is composed of two overlapping, but morphologically dissimilar volcanoes. The flat-topped Plosky Tolbachik shield volcano with its nested Holocene Hawaiian-type calderas up to 3 km in diameter is located east of the older and higher sharp-topped Ostry Tolbachik stratovolcano. The summit caldera at Plosky Tolbachik was formed in association with major lava effusion about 6500 years ago and simultaneously with a major southward-directed sector collapse of Ostry Tolbachik volcano. Lengthy rift zones extending NE and SSW of the volcano have erupted voluminous basaltic lava flows during the Holocene, with activity during the past two thousand years being confined to the narrow axial zone of the rifts. The 1975-76 eruption originating from the SSW-flank fissure system and the summit was the largest historical basaltic eruption in Kamchatka.

Sources: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php,

Tokyo Volcanic Ash Advisory Center (VAAC) http://ds.data.jma.go.jp/svd/vaac/data/vaac_list.html

TONGARIRO North Island (New Zealand) 39.13°S, 175.642°E; summit elev. 1978 m

A small eruption at Tongariro's Te Maari Craters occurred at 1325 on 21 November, without precursory events, prompting GeoNet to raise the Volcanic Alert Level to 2 and the Aviation Colour Code to Red. A report at 1730 noted that the eruption appeared to be over; the Aviation Colour Code was lowered to Orange.

The eruption occurred in the same area as the previous eruption on 6 August and lasted less than five minutes, although local seismic activity lasted about 15 minutes. GNS staff and hikers saw the eruption. An ash plume rose 3-4 km above the Upper Te Maari crater and produced ashfall across part of State Highway 46 and NE towards Turangi (21 km NE). Two small pyroclastic density currents were produced at the base of the column, to the W and N of the crater, and traveled a limited distance of a few hundred meters downslope. Later that afternoon gas-and-steam plumes drifted SE. On 22 November a sulfur gas odor was reported in Manawatu (S) and Hawke's Bay (115 km ESE), downwind of Tongariro. A substantial amount of gas was emitted during 22-23 November. The Aviation Colour Code was lowered to Yellow on 23 November due to the absence of emitted ash. On 26 November GeoNet noted that no further volcanic activity had occurred since the eruption, gas flux had decreased, and seismic activity remained low.

Geologic Summary. Tongariro is a large andesitic volcanic massif, located immediately NE of Ruapehu volcano, that is composed of more than a dozen composite cones constructed over a period of 275,000 years. Vents along a NE-trending zone extending from Saddle Cone (below Ruapehu volcano) to Te Mari crater (including vents at the present-day location of Ngauruhoe) were active during a several hundred year long period around 10,000 years ago, producing the largest known eruptions at the Tongariro complex during the Holocene. The youngest cone of the complex, Ngauruhoe, has grown to become the highest peak of the massif since its birth about 2500 years ago. The symmetrical, steep-sided Ngauruhoe, along with its neighbor Ruapehu to the south, have been New Zealand's most active volcanoes during historical time.

Source: New Zealand GeoNet Project http://geonet.org.nz/

Ongoing Activity

ETNA Sicily (Italy) 37.734°N, 15.004°E; summit elev. 3330 m

Sezione di Catania - Osservatorio Etneo reported that on the evening of 21 November, weak glow was observed coming from within Etna's New Southeast Crater, caused either by the emission of high-temperature gas and/or Strombolian activity. Incandescence was also visible during the following nights, but was weak and intermittent.

A seismic swarm, consisting of around seventy events, occurred below the NW flank on 22 November, with epicenters located in the area of Monte Maletto. During a field visit to the summit area on the morning of 23 November, scientists did not hear sounds typically associated with Strombolian activity. In addition, volcanic-tremor amplitude did not show any significant variations.

Geologic Summary. 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 BC. Historical lava flows cover much of the surface of this massive basaltic stratovolcano, the highest and most voluminous in Italy. Two styles of eruptive activity typically occur at Etna. Persistent explosive eruptions, sometimes with minor lava emissions, take place from one or more of the three prominent summit craters, the Central Crater, NE Crater, and SE Crater. Flank eruptions, typically with higher effusion rates, occur less frequently and originate from fissures that open progressively downward from near the summit. A period of more intense intermittent explosive eruptions from Etna's summit craters began in 1995. The active volcano is monitored by the Instituto Nazionale di Geofisica e Volcanologia (INGV) in Catania.

Source: Sezione di Catania - Osservatorio Etneo http://www.ct.ingv.it/index.php

KARYMSKY Eastern Kamchatka (Russia) 54.05°N, 159.45°E; summit elev. 1536 m

KVERT reported that moderate seismic activity at Karymsky was detected during 16-23 November. Satellite imagery showed a big thermal anomaly on 20 and 22 November; cloud cover obscured views on the other days. The Aviation Color Code 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

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

RVO reported that during 19-20 November white and blue vapor rose from Manam. Activity increased at 1200 on 20 November characterized by occasional emissions of dark grey ash. Ejected incandescent tephra was observed at night. At 1700 on 21 November a small pyroclastic flow traveled down the upper part of the SW valley. Stronger activity was detected two hours later which lasted until the next morning; incandescent tephra was ejected several hundred meters above the crater, roaring was heard in Bogia (23 km SSW), and a lava flow was extruded into the SE valley from a new vent beneath Southern Crater. The activity slightly decreased at 1700 on 22 November and diffuse ash plumes occasionally rose from the crater. Activity increased again on 24 November. Ash fell on the NW side of the island.

Based on observations of satellite imagery and reports from RVO, the Darwin VAAC reported that an ash plume rose to an altitude of 3.3 km (11,000 ft) a.s.l. on 26 November and drifted 110 km E.

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.

Sources: Rabaul Volcano Observatory (RVO),

Darwin Volcanic Ash Advisory Centre (VAAC) ftp://ftp.bom.gov.au/anon/gen/vaac

PAGAN Mariana Islands 18.13°N, 145.80°E; summit elev. 570 m

Clear satellite views showed steam-and-gas emissions drifting from Pagan during 17-24 November. According to the Washington VAAC, ash from an unknown volcano was reported by a pilot in the vicinity of Pagan on 25 November. Satellite imagery suggested continuing degassing, but it was possible that ash was present in a 30-km-wide plume that was drifting almost 90 km S. Mostly gas was seen drifting S in an image later that day.

Geologic Summary. Pagan Island, the largest and one of the most active of the Mariana Islands volcanoes, consists of two stratovolcanoes connected by a narrow isthmus. Both North and South Pagan stratovolcanoes were constructed within calderas, 7 and 4 km in diameter, respectively. The 570-m-high Mount Pagan at the NE end of the island rises above the flat floor of the caldera, which probably formed during the early Holocene. South Pagan is a 548-m-high stratovolcano with an elongated summit containing four distinct craters. Almost all of the historical eruptions of Pagan, which date back to the 17th century, have originated from North Pagan volcano. The largest eruption of Pagan during historical time took place in 1981 and prompted the evacuation of the sparsely populated island.

Sources: Emergency Management Office of the Commonwealth of the Mariana Islands, Office of the Governor, United States Geological Survey Volcano Hazards Program http://volcanoes.usgs.gov/nmi/activity/,

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

JMA reported that during 19-22 November explosions from Sakura-jima's Showa Crater ejected tephra as far as 1.3 km from the crater. Very small eruptions at Minami-dake Crater occurred during 19-20 November. Based on information from JMA, the Tokyo VAAC reported that explosions during 21-23, 25, and 27 November often produced plumes that rose to altitudes of 1.5-2.7 km (5,000-9,000 ft) a.s.l. and drifted N, NE, E, and 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.

Sources: Japan Meteorological Agency (JMA) http://www.jma.go.jp/jma/index.html,

Tokyo Volcanic Ash Advisory Center (VAAC) http://ds.data.jma.go.jp/svd/vaac/data/vaac_list.html

SANTA MARIA Guatemala 14.756°N, 91.552°W; summit elev. 3772 m

INSIVUMEH reported in a special bulletin on 21 November that collapses of the fronts of lava flows on the NE, SE, S, and SW flanks of Santa María's Santiaguito lava-dome complex generated pyroclastic flows and ash plumes that rose 1 km. Ash plumes drifted 15 km S and SE, producing ashfall in Las Marías, Calaguache (9 km S), and Nuevo Palmar (12 km S). During 24-27 November incandescence was observed, lava flows were active on the SW and SE flanks, and ash plumes rose 500 m and drifted 15 km SW. On 27 November pyroclastic flows traveled short distances, and generated ash plumes that rose 500 m and drifted 10 km S and SE.

Geologic Summary. Symmetrical, forest-covered Santa María volcano is one of a chain of large stratovolcanoes that rises dramatically above the Pacific coastal plain of Guatemala. The stratovolcano has a sharp-topped, conical profile that is cut on the SW flank by a large, 1-km-wide crater, which formed during a catastrophic eruption in 1902 and extends from just below the summit to the lower flank. The renowned Plinian eruption of 1902 followed a long repose period and devastated much of SW Guatemala. The large dacitic Santiaguito lava-dome complex has been growing at the base of the 1902 crater since 1922. Compound dome growth at Santiaguito has occurred episodically from four westward-younging vents, accompanied by almost continuous minor explosions and periodic lava extrusion, larger explosions, pyroclastic flows, and lahars.

Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH) http://www.insivumeh.gob.gt/

SHIVELUCH Central Kamchatka (Russia) 56.653°N, 161.360°E; summit elev. 3283 m

Based on visual observations and analyses of satellite data, KVERT reported that during 16-23 November a viscous lava flow continued to effuse on the NW flank of Shiveluch's lava dome, accompanied by hot avalanches, incandescence, and fumarolic activity. Satellite imagery showed a thermal anomaly on the lava dome during 17-18 and 20-22 November; cloud cover obscured views on the other days. The Aviation Color Code 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

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Sally Kuhn Sennert

SI/USGS Weekly Volcanic Activity Report Editor

Global Volcanism Program

http://www.volcano.si.edu/reports/usgs/

Smithsonian Institution, National Museum of Natural History

Department of Mineral Sciences, MRC-119

Washington, D.C., 20560

Phone: 202.633.1805

Fax: 202.357.2476

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