SI/USGS Weekly Volcano Report 2/3-9/2010 - stymied by weather!

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Sally Sennert from the Smithsonian Institution sent me an email to say that this week’s USGS/Smithsonian Institute Weekly Volcanic Report will be delayed due to the inclement weather in the Washington DC area. She can’t connect with the server, so the report can’t be updated on the Smithsonian website … so here it is! Look for it to show up on the Smithsonian site with all the bells and whistles as soon as DC thaws out.

And a big thanks to Sally for sending me the Report to post.

***PLEASE NOTE: Website posting of the SI/USGS Weekly Volcanic Activity Report for 3-9 February 2010 will be delayed due to closings from inclement weather.

New Activity/Unrest: | Bezymianny, Central Kamchatka ( Russia) | Fukutoku-Okanoba, Japan | Pacaya, Guatemala

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.

nNew Activity/Unrest

nBEZYMIANNY Central Kamchatka (Russia) 55.978°N, 160.587°E; summit elev. 2882 m

KVERT reported that during 29-30 January and 2 February a thermal anomaly from Bezymianny’s lava dome was detected in satellite imagery. The anomaly was larger during 7-8 February, prompting KVERT to raise the Level of Concern Color Code to Orange. Strong activity from Kliuchevskoi volcano had obscured seismic signals from Bezymianny since 4 January.

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

nFUKUTOKU-OKANOBA Japan 24.28°N, 141.485°E; summit elev. -14 m

According to news articles, JMA reported Surtseyan explosions from Fukutoku-Okanoba, 5 km NE of the island of Minami-Iwo-jima, on 3 February. Steam-and-ash plumes rose 100 m a.s.l. and the surrounding sea turned yellow-green. Video footage of the event was captured by people aboard a Japanese Coast Guard patrol boat. One article stated that the sea in the area had regularly changed colors since the 1950s, most recently in December 2009.

Geologic Summary. Fukutoku-Okanoba is a submarine volcano located 5 km NE of the pyramidal island of Minami-Iwo-jima. Water discoloration is frequently observed from the volcano, and several ephemeral islands have formed in the 20th century. The first of these formed Shin-Iwo-jima (“New Sulfur Island”) in 1904, and the most recent island was formed in 1986. Fukutoku-Okanoba is part of an elongated edifice with two major topographic highs trending NNW-SSE and is a trachyandesitic volcano geochemically similar to Iwo-jima.

Sources: ITN http://itn.co.uk/505f1ee85ab8fd460beb70dabaf8421e.html,
nThe Mainichi Daily News http://mdn.mainichi.jp/mdnnews/news/20100204p2a00m0na017000c.html

nPACAYA Guatemala 14.381°N, 90.601°W; summit elev. 2552 m

INSIVUMEH reported that activity from Pacaya consisting of effusion of lava flows, the source of which had migrated towards the S from the N flank since April 2006, ceased on 30 January 2010. On 5 February, Strombolian explosions from MacKenney cone ejected material 30 m into the air and lava from the crater moved down the flank. The activity was heard in the village of San Francisco de Sales, 5 km N. A new lava flow originating from a depression on the NE flank was seen on 6 February.

Geologic Summary. Eruptions from Pacaya, one of Guatemala’s most active volcanoes, are frequently visible from Guatemala City, the nation’s capital. Pacaya is a complex volcano constructed on the southern rim of the 14 x 16 km Pleistocene Amatitlan caldera. A cluster of dacitic lava domes occupies the caldera floor. The Pacaya massif includes the Cerro Grande lava dome and a younger volcano to the SW. Collapse of Pacaya volcano about 1,100 years ago produced a debris-avalanche deposit that extends 25 km onto the Pacific coastal plain and left an arcuate somma rim inside which the modern Pacaya volcano (MacKenney cone) grew. During the past several decades, activity at Pacaya has consisted of frequent Strombolian eruptions with intermittent lava flow extrusion on the flanks of MacKenney cone, punctuated by occasional larger explosive eruptions.

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

nOngoing Activity

nDUKONO Halmahera 1.68°N, 127.88°E; summit elev. 1335 m

The Darwin VAAC reported that during 5-6 February ash plumes from Dukono rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted 55-150 km SW and 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

nGALERAS Colombia 1.22°N, 77.37°W; summit elev. 4276 m

On 9 February, INGEOMINAS lowered the Alert Level for Galeras to III (Yellow; “changes in the behavior of volcanic activity”). During the previous few days, seismicity was low and sulfur dioxide emissions were low to moderate.

Geologic Summary. Galeras, a stratovolcano with a large breached caldera located immediately W of the city of Pasto, is one of Colombia’s most frequently active volcanoes. The dominantly andesitic Galeras volcanic complex has been active for more than 1 million years, and two major caldera collapse eruptions took place during the late Pleistocene. Longterm extensive hydrothermal alteration has affected the volcano. This has contributed to large-scale edifice collapse that has occurred on at least three occasions, producing debris avalanches that swept to the W and left a large horseshoe-shaped caldera inside which the modern cone has been constructed. Major explosive eruptions since the mid Holocene have produced widespread tephra deposits and pyroclastic flows that swept all but the southern flanks. A central cone slightly lower than the caldera rim has been the site of numerous small-to-moderate historical eruptions since the time of the Spanish conquistadors.

Source: Instituto Colombiano de Geología y Minería (INGEOMINAS) http://www.ingeominas.gov.co//

nKARYMSKY Eastern Kamchatka 54.05°N, 159.45°E; summit elev. 1536 m

KVERT reported that during 29 January-5 February seismic activity from Karymsky was above background levels and possibly indicated weak ash explosions. Analyses of satellite imagery revealed a thermal anomaly over the volcano on 28 January and 1 February. The Level of Concern 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

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

During 3-9 February, HVO reported an active lava surface about 200 m below a vent in the floor of Kilauea’s Halema’uma’u crater. The lava surface occasionally spattered, and both rose and drained through holes in the cavity floor. A plume from the vent drifted mainly SW, dropping small amounts of ash, and occasionally fresh spatter, downwind. Measurements indicated that the sulfur dioxide emission rate at the summit remained elevated; 1,200 and 700 tonnes per day were measured on 4 and 8 February, respectively. The 2003-2007 average rate was 140 tonnes per day.

Lava from beneath the Thanksgiving Eve Breakout (TEB) and rootless shield complex flowed over 3 km SE through a lava tube system before breaking out onto the surface. Thermal anomalies detected by satellite and visual observations revealed active lava flows above and on the pali, and on the coastal plain. By 8 February, pahoehoe lava flows had advanced 700 m from the base of the pali S onto the coastal plain. Incandescence was sometimes seen from a vent low on the S wall of Pu’u ‘O’o crater.

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/

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

KVERT reported that during 29 January-5 February seismic activity from Kliuchevskoi was above background levels and lava continued to flow down the NW flank. Strombolian activity periodically ejected material 300 m above the crater, and phreatic explosions occurred from the front of the lava flow. Satellite imagery revealed a large daily thermal anomaly at the volcano. On 30 and 31 January, gas-and-steam plumes rose to an altitude of 6.2 km (20,300 ft) a.s.l. The Level of Concern Color Code 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

nSAKURA-JIMA Kyushu 31.585°N, 130.657°E; summit elev. 1117 m

Based on information from JMA, the Tokyo VAAC reported that during 3-9 February multiple explosions from Sakura-jima produced plumes that rose to altitudes of 1.5-3 km (5,000-10,000 ft) a.s.l. and drifted SE and N. On 5, 6, and 7 February, pilots reported that ash plumes sometimes drifted SE and S at altitudes of 1.5-3.4 km (5,000-11,000 ft) a.s.l. An eruption on 8 February produced an estimated 1-km-high lava fountain, and an ash plume with abundant lightning. Incandescent material fell onto the flanks.

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: Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html,
nKago-Net http://www.kago-net.com/index.php?itemid=127

nSARYCHEV PEAK Matua Island 48.092°N, 153.20°E; summit elev. 1496 m

SVERT reported that a thermal anomaly on Sarychev Peak was detected by satellite on 3 February.

Geologic Summary. Sarychev Peak, one of the most active volcanoes of the Kuril Islands, occupies the NW end of Matua Island in the central Kuriles. The andesitic central cone was constructed within a 3-3.5 km wide caldera, whose rim is exposed only on the SW side. A dramatic 250-m-wide, very steep-walled crater with a jagged rim caps the volcano. The substantially higher SE rim forms the 1496 m high point of the island. Fresh-looking lava flows descend all sides of Sarychev Peak and often form capes along the coast. Much of the lower-angle outer flanks of the volcano are overlain by pyroclastic-flow deposits. Eruptions have been recorded since the 1760’s and include both quiet lava effusion and violent explosions. The largest historical eruption of Sarychev Peak in 1946 produced pyroclastic flows that reached the sea.

Source: Sakhalin Volcanic Eruption Response Team (SVERT) http://www.imgg.ru/rus/labs_vulcan_hazard.php

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

KVERT reported that during 29 January-5 February seismic activity from Shiveluch was above background levels, possibly indicating ash plumes rising to an altitude of 5.7 km (18,700 ft) a.s.l. Fumarolic activity was observed on 1 February; cloud cover prevented observations on other days. Analyses of satellite imagery revealed a large daily thermal anomaly from the lava dome. The Level of Concern 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

nSOUFRIERE HILLS Montserrat 16.72°N, 62.18°W; summit elev. 915 m

MVO reported that during 29 January-5 February activity from the Soufrière Hills lava dome was variable as the lava dome continued to grow. Cycles of vigorous ash venting, rockfalls, and pyroclastic flows occurred every seven to twelve hours. Pyroclastic flows traveled mostly W down Gages into Spring Ghaut, as far as 3 km, but also occurred in Whites Ghaut to the NE. Rockfall activity was abundant on the N flank. On 4 February, ash fell across NW Montserrat. Observations the next day revealed that the central W part of the lava dome had grown and was 1,070 m a.s.l.

Pyroclastic flows following a Vulcanian explosion on 5 February traveled W, reaching Plymouth and spreading 500 m across the sea. Pyroclastic flows also traveled as far as 2 km NW down Tyers Ghaut and NE down Whites Ghaut. An ash plume rose to an altitude of 6.4 km (21,000 ft) a.s.l. A small Vulcanian explosion on 8 February generated pyroclastic flows that mostly traveled W down Gages Valley. Small pyroclastic surges observed using a thermal camera descended the N flanks. An ash plume rose to an altitude of 4.6 km (15,000 ft) a.s.l. and drifted E and ENE. Ashfall was reported in NW Montserrat and in SW Antigua, 50 km NW. The Hazard Level remained at 4.

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/

nSUWANOSE-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 5-6 and 9 February. Details of possible resulting emissions were not reported.

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

nTUNGURAHUA Ecuador 1.467°S, 78.442°W; summit elev. 5023 m

The IG reported that 14-51 explosions from Tungurahua were detected by the seismic network during 3-9 February. Inclement weather often prevented observations of the volcano; an ash plume was seen rising to an altitude of 7 km (23,000 ft) a.s.l. Ashfall was noted almost daily in areas to the SW, W, and NW, and was particularly heavy towards the end of the reporting period. Roaring noises and sounds resembling “cannon shots” were heard. Explosions sometimes caused windows and structures to vibrate, including large windows at the Tungurahua Observatory (OVT) in Guadalupe, 11 km N. Occasionally at night incandescence emanated from the crater and incandescent blocks rolled down the flanks as far as 1 km. On 3 February lahars descended drainages to the W and SW, carrying tree trunks and blocks up to 1 m in diameter, and causing the road from Riobamba to Baños to close. Strombolian activity from the crater was seen during 6-8 February.

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 bas e. 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.

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

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