Smithsonian/USGS Weekly Volcanic Activity Report 26 October-1 November 2011
From: "Kuhn, Sally" <KUHNS@xxxxxx>
**************************************************************************************************
Smithsonian/USGS Weekly Volcanic Activity Report
26 October-1 November 2011
Sally Kuhn Sennert - Weekly Report Editor
URL: http://www.volcano.si.edu/reports/usgs/
New Activity/Unrest: | Cerro Hudson, Southern Chile | Gaua, Banks Islands (SW Pacific) | Hierro, Canary Islands (Spain)
Ongoing Activity: | Batu Tara, Komba Island (Indonesia) | Bezymianny, Central Kamchatka (Russia) | Cleveland, Chuginadak Island | Dukono, Halmahera | Gorely, Southern Kamchatka (Russia) | Karymsky, Eastern Kamchatka (Russia) | Kilauea, Hawaii (USA) | Kizimen, Eastern Kamchatka (Russia) | Lokon-Empung, Sulawesi | Puyehue-Cordón Caulle, Central Chile | Sakura-jima, Kyushu | Santa María, Guatemala | Shiveluch, Central Kamchatka (Russia)
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
CERRO HUDSON Southern Chile 45.90°S, 72.97°W; summit elev. 1905 m
OVDAS-SERNAGEOMIN reported three new craters at Cerro Hudson following increased seismicity that was detected during 25-26 October. At 1908 on 25 October an M 4.6 volcano-tectonic earthquake occurred at a depth of 19 km, followed by a seismic swarm starting at 2149. More than 100 events, with depths ranging from 15 to 25 km, were recorded through the next day; 12 of the events were M 3, and three events were M 4. Scientists aboard an overflight on 26 October observed a white plume with some ash content that rose 1.5 km and lahars in Rio Huemul, to the W. The Alert Level was raised to Level 5 - Red. A very low-frequency M 4.3 earthquake occurred that same day at a depth of 15 km.
Five earthquakes per hour were recorded between 1600 on 26 October and 1600 on 27 October. Most of the earthquakes were volcano-tectonic events with magnitudes lower that 3.6 and located W of the caldera at depths between 3 and 25 km. The earthquake hypocenters became shallower with time. The most significant event, a M 3.6, occurred at 0227 on 27 October and was located in the SW edge of the crater. Very low-frequency earthquakes possibly indicated magma movement.
SERNAGEOMIN staff aboard an overflight on 27 October observed three craters along the S, SE edge of the caldera, with diameters of 200, 300, and 500 m. Mostly white plumes rose above the two smaller craters. The larger, southern-most crater emitted a plume with a greater ash content that rose 5 km above the crater. Satellite imagery showed a plume drifting 12 km SE. In response to the raised Alert Level, ONEMI reported that 128 people were evacuated from areas within a 45-km radius of the volcano, defined as high-risk zone.
One earthquake per hour was recorded between 1600 on 27 October and 1600 on 28 October. The majority of the earthquakes were characterized as long-period with magnitudes less than 2.2. During an overflight on 28 October, scientists observed a gas plume with a very low ash content rise 3-4 km above the craters. Seismicity continued to decrease during 28-29 October. Scientists conducting an overflight noted that a gas plume with some ash rose 1 km above the craters and drifted 5-8 km NE. They also confirmed that a large lahar had traveled down the Rio Huemul and another branch of the river during the initial phase of the eruption. During another observation flight on 30 October, scientists saw plumes with minor ash rising 0.8 km from two of the three craters. ONEMI noted that the total number of evacuees had reached 140. On 31 October scientists observed gas plumes rising 0.5 km above the craters and drifting SE. On 1 November scientists observed an explosion and an accompanying ash plume that rose 1.5 km above the active craters. They also noted subsequent minor explosions and ash emissions.
Geologic Summary. The ice-filled, 10-km-wide caldera of the remote Cerro Hudson volcano was not recognized until its first 20th-century eruption in 1971. Cerro Hudson is the southernmost volcano in the Chilean Andes related to subduction of the Nazca plate beneath the South American plate. The massive, 1905-m-high Cerro Hudson covers an area of 300 sq km. The compound caldera is drained through a breach on its NW rim, which has been the source of mudflows down the Río de Los Huemeles. Two cinder cones occur north of the volcano and others occupy the SW and SE flanks. Hudson has been the source of several major Holocene explosive eruptions. An eruption about 6700 years ago was one of the largest known in the southern Andes during the Holocene; another eruption about 3600 years ago also produced more than 10 cu km of tephra. An eruption in 1991 was Chile's second largest of the 20th century and formed a new 800-m-wide crater in the SW part of the caldera.
Sources: Servicio Nacional de Geología y Minería (SERNAGEOMIN) http://www.sernageomin.cl/,
Oficina Nacional de Emergencia - Ministerio del Interior (ONEMI) http://www.onemi.cl/
GAUA Banks Islands (SW Pacific) 14.27°S, 167.50°E; summit elev. 797 m
Based on a hazards assessment during 17-18 October, the Vanuatu Geohazards Observatory reported that Gaua had been emitting ash since September. Ash fell on western parts of the island. The Alert Level remained at 1 (on a scale of 0-4).
Geologic Summary. The roughly 20-km-diameter Gaua Island, also known as Santa Maria, consists of a basaltic-to-andesitic stratovolcano with an 6 x 9 km wide summit caldera. Small parasitic vents near the caldera rim fed Pleistocene lava flows that reached the coast on several sides of the island; several littoral cones were formed where these lava flows reached the sea. Quiet collapse that formed the roughly 700-m-deep caldera was followed by extensive ash eruptions. Construction of the historically active cone of Mount Garat (Gharat) and other small cinder cones in the SW part of the caldera has left a crescent-shaped caldera lake. The symmetrical, flat-topped Mount Garat cone is topped by three pit craters. The onset of eruptive activity from a vent high on the SE flank of Mount Garat in 1962 ended a long period of dormancy.
Source: Vanuatu Geohazards Observatory http://www.geohazards.gov.vu/
HIERRO Canary Islands (Spain) 27.73°N, 18.03°W; summit elev. 1500 m
Instituto Geográfico Nacional (IGN) reported that during 26 October-1 November tremor continued to be registered by every seismic station on El Hierro Island; 540 seismic events were registered and located, and the mean amplitude increased slightly during the last two days. Most of the events were located offshore to the N of the island, at depths of 16-23 km. The maximum magnitude was 3.9, and 36 of the total events were felt by residents at a maximum intensity value of IV using EMS-98 (European Macroseismic Scale). The total number of located events since 17 July was 10,930.
Preliminary analysis of GPS deformation data showed an inflation-deflation sequence at one station on the N side of the island, with the main deformation trending N-S and in vertical components. GPS stations located in the W and S showed different behavior, with mean deformations to the SW and NE, respectively.
Geologic Summary. The triangular island of Hierro is the SW-most and least studied of the Canary Islands. The massive Hierro shield volcano is truncated by a large NW-facing escarpment formed as a result of gravitational collapse of El Golfo volcano about 130,000 years ago. The steep-sided 1500-m-high scarp towers above a low lava platform bordering 12-km-wide El Golfo Bay, and three other large submarine landslide deposits occur to the SW and SE. Three prominent rifts oriented NW, NE, and south at 120 degree angles form prominent topographic ridges. The subaerial portion of the volcano consists of flat-lying Quaternary basaltic and trachybasaltic lava flows and tuffs capped by numerous young cinder cones and lava flows. Holocene cones and flows are found both on the outer flanks and in the El Golfo depression. Hierro contains the greatest concentration of young vents in the Canary Islands. Uncertainty surrounds the report of an historical eruption in 1793.
Source: Instituto Geográfico Nacional (IGN) http://www.ign.es/ign/layout/volcaVolcanologia.do
Ongoing Activity
BATU TARA Komba Island (Indonesia) 7.792°S, 123.579°E; summit elev. 748 m
Based on analyses of satellite imagery, the Darwin VAAC reported that on 27 October an ash plume from Batu Tara rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted about 45 km W.
Geologic Summary. The small isolated island of Batu Tara in the Flores Sea about 50 km north of Lembata (formerly Lomblen) Island contains a scarp on the eastern side similar to the Sciara del Fuoco of Italy's Stromboli volcano. Vegetation covers the flanks of Batu Tara to within 50 m of the 748-m-high summit. Batu Tara lies north of the main volcanic arc and is noted for its potassic leucite-bearing basanitic and tephritic rocks. The first historical eruption from Batu Tara, during 1847-52, produced explosions and a lava flow.
Source: Darwin Volcanic Ash Advisory Centre (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AU/messages.html
BEZYMIANNY Central Kamchatka (Russia) 55.978°N, 160.587°E; summit elev. 2882 m
KVERT reported that during 21-28 October seismic activity at Bezymianny was low. A thermal anomaly was observed in satellite imagery during 23-25 October, and fumarolic activity was observed during 23 and 25-26 October. The Aviation Color Code remained at Yellow.
Geologic Summary. Prior to its noted 1955-56 eruption, Bezymianny volcano had been considered extinct. Three periods of intensified activity have occurred during the past 3,000 years. The latest period, which was preceded by a 1,000-year quiescence, began with the dramatic 1955-56 eruption. That eruption, similar to the 1980 event at Mount St. Helens, 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.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php
CLEVELAND Chuginadak Island 52.825°N, 169.944°W; summit elev. 1730 m
AVO reported that a radar image from 23 October indicated a lowering of the lava dome surface in Cleveland's summit crater. During 26 October-1 November cloud cover prevented views of the lava dome. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange. 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 27 October-1 November ash plumes from Dukono rose to altitudes of 2.1-2.7 km (7,000-9,000 ft) a.s.l. and drifted 35-110 km W, NW, and NE.
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
GORELY Southern Kamchatka (Russia) 52.558°N, 158.03°E; summit elev. 1829 m
KVERT reported that during 21-28 November seismic activity from Gorely was at moderate levels and volcanic tremor was detected. Satellite imagery showed a weak thermal anomaly over the volcano during 21-25 November. The Aviation Color Code level remained at Yellow.
Geologic Summary. Gorely volcano, one of the most active in southern Kamchatka, consists of five small overlapping stratovolcanoes constructed along a WNW-ESE line within a large 9 x 13.5 km late-Pleistocene caldera. The massive Gorely complex contains 11 summit and 30 flank craters. During the early Holocene, activity was characterized by frequent mild eruptions with occasional larger explosions and lava flows that filled in the caldera. Quiescent periods became longer between 6,000 and 2,000 years ago, after which the activity was mainly explosive. About 600-650 years ago intermittent strong explosions and lava flow effusion accompanied frequent mild eruptions. Historical eruptions have consisted of vulcanian and phreatic explosions of moderate volume.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php
KARYMSKY Eastern Kamchatka (Russia) 54.05°N, 159.45°E; summit elev. 1536 m
KVERT reported that seismic activity continued at a moderate level at Karymsky during 21-28 October, and indicated that possible ash plumes rose to an altitude of 3.7 km (12,100 ft) a.s.l. during 20 and 23-24 October. Satellite imagery showed a daily thermal anomaly on the volcano and an ash plume that rose to an altitude of 1.8 km (6,000 ft) a.s.l. and drifted 15 km NE on 26 October. 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.
Sources: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php,
Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html
KILAUEA Hawaii (USA) 19.421°N, 155.287°W; summit elev. 1222 m
During 26 October-1 November, HVO reported that the lava lake circulated and periodically rose and fell in the deep pit within Kilauea's Halema'uma'u Crater, remaining below the inner ledge (75 m below the crater floor). Almost daily measurements indicated that the gas plume from the vent continued to deposit variable amounts of ash and fresh spatter nearby. Incandescence emanated from the E and W edges of the Pu'u 'O'o crater floor and from the 21 September fissure on the upper E flank of the Pu'u 'O'o cone. On 30 October incandescence was seen from a new area high on the W edge of a depression in the crater floor. Lava flows remained active to the SE of Pu'u 'O'o during 26-30 October, but were more sluggish during 31 October-1 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 21-28 October there was moderate seismic activity at Kizimen; the number of volcanic earthquakes decreased from 105 to 30 during 21-24 October. A thermal anomaly on the volcano was detected daily in satellite images. Video observations on 20 October showed a small pyroclastic flow on the NE flank and later ashfall on the flanks. Gas-and-steam activity was observed during 20-21 and 23-26 October. A large lava flow on the NE flank continued to effuse, and incandescence from both the lava flows and the crater was noted at night. 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
LOKON-EMPUNG Sulawesi 1.358°N, 124.792°E; summit elev. 1580 m
According to a news article, a gray plume rose 1.2 km above Tompaluan crater, in the saddle between the Lokon-Empung peaks, and drifted SW on 26 October, followed by an explosion that sent incandescent material as far as 800 m away from Tompaluan crater. A second eruption produced a plume that rose 500 m above the crater.
Geologic Summary. The twin volcanoes Lokon and Empung, rising about 800 m above the plain of Tondano, are among the most active volcanoes of Sulawesi. Lokon, the higher of the two peaks (whose summits are only 2.2 km apart) has a flat, craterless top. The morphologically younger Empung volcano has a 400-m-wide, 150-m-deep crater that erupted last in the 18th century, but all subsequent eruptions have originated from Tompaluan, a 150 x 250 m wide double crater situated in the saddle between the two peaks. Historical eruptions have primarily produced small-to-moderate ash plumes that have occasionally damaged croplands and houses, but lava-dome growth and pyroclastic flows have also occurred.
Source: Kompas.com http://regional.kompas.com/read/2011/10/27/19525139/Surono.Gunung.Lokon.Masih.Berstatus.Siaga
PUYEHUE-CORDON CAULLE Central Chile 40.590°S, 72.117°W; summit elev. 2236 m
Based on seismicity during 26 October-1 November, OVDAS-SERNAGEOMIN reported that the eruption from the Cordón Caulle rift zone, part of the Puyehue-Cordón Caulle volcanic complex, continued at a low level.
During 26-29 October white plumes observed with an area web camera rose 4.5-5 km above the crater. Satellite imagery showed a plume drifting 30 km SW and W on 26 October, and diffuse ash plumes drifting E during 27-28 October. Small incandescent explosions were observed at night during 28-29 October. A plume observed in satellite imagery drifted 180 km N and NW on 29 October, and ashfall was reported in Lonquimay.
On 30 October seismicity possibly indicated minor lava effusion. A mostly white plume rose 7.5 km above the crater and ash plumes observed in satellite imagery drifted 350 km NW and N. Ashfall was reported in Río Bueno (80 km WNW). Small incandescent explosions were observed at night during 30-31 October. A mostly white plume rose as high as 6.5 km above the crater on 31 October and ash plumes observed in satellite imagery drifted 270 km S and SSW. On 1 November satellite imagery showed an ash plume that drifted 300 km SE. The Alert Level remained at Red.
Geologic Summary. The Puyehue-Cordón Caulle volcanic complex (PCCVC) is a large NW-SE-trending late-Pleistocene to Holocene basaltic-to-rhyolitic transverse volcanic chain SE of Lago Ranco. The 1799-m-high Pleistocene Cordillera Nevada caldera lies at the NW end, separated from Puyehue stratovolcano at the SE end by the Cordón Caulle fissure complex. The Pleistocene Mencheca volcano with Holocene flank cones lies NE of Puyehue. The basaltic-to-rhyolitic Puyehue volcano is the most geochemically diverse of the PCCVC. The flat-topped, 2236-m-high Puyehue volcano was constructed above a 5-km-wide caldera and is capped by a 2.4-km-wide summit caldera of Holocene age. Lava flows and domes of mostly rhyolitic composition are found on the eastern flank of Puyehue. Historical eruptions originally attributed to Puyehue, including major eruptions in 1921-22 and 1960, are now known to be from the Cordón Caulle rift zone. The Cordón Caulle geothermal area, occupying a 6 x 13 km wide volcano-tectonic depression, is the largest active geothermal area of the southern Andes volcanic zone.
Source: Servicio Nacional de Geología y Minería (SERNAGEOMIN) http://www.sernageomin.cl/
SAKURA-JIMA Kyushu 31.585°N, 130.657°E; summit elev. 1117 m
Based on information from JMA, the Tokyo VAAC reported that during 26 October-1 November explosions from Sakura-jima produced plumes that rose to altitudes of 1.8-3.4 km (6,000-11,000 ft) a.s.l. and drifted NW, W, SW, S, and SE. Satellite imagery on 26 October detected ash plumes that later dissipated. A pilot observed an ash plume on 31 October that rose to an altitude of 2.7 km (9,000 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
SANTA MARIA Guatemala 14.756°N, 91.552°W; summit elev. 3772 m
INSIVUMEH reported that during 26-27 October gas plumes from Santa María's Santiaguito lava-dome complex rose 200 m above the crater and lava flows on the SE and SW flanks generated block avalanches that were deposited into the Río Nimá II drainage. Based on analyses of satellite imagery, the Washington VAAC reported that on 26 October an ash plume drifted 16.7 km SW and then rapidly dissipated. The next day satellite imagery showed a possible ash plume and a thermal anomaly.
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/inicio.html
SHIVELUCH Central Kamchatka (Russia) 56.653°N, 161.360°E; summit elev. 3283 m
KVERT reported strong seismic activity at Shiveluch during 21-23 October and indicated that possible ash plumes rose to altitudes of 7.1-10.6 km (23,300-34,800 ft) a.s.l. Technical reasons prevented seismic data collection during 24-28 October. Ground-based observers noted hot avalanches in the lava dome area during 23-26 October; cloud cover prevented observations on the other days. Satellite imagery showed a large daily thermal anomaly over the lava dome and gas-and-steam plumes that drifted 170 km SE on 24 and 25 October. The Aviation Color Code remained at Orange.
Based on information from Yelizovo Airport (UHPP), the Tokyo VAAC reported that on 31 October an ash plume rose to an altitude of 4.6 km (15,000 ft) a.s.l. and drifted E.
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.
Sources: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php,
Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html
+++++++++++++++++++++++++++++++++++++
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: 202.633.1805Fax: 202.357.2476
==============================================================
To unsubscribe from the volcano list, send the message: signoff volcano to: listserv@xxxxxxx, or write to: volcano-request@xxxxxxx.
To contribute to the volcano list, send your message to: volcano@xxxxxxx. Please do not send attachments.
==============================================================
