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Smithsonian/USGS Weekly Volcanic Activity Report 25-31 May 2011
From: "Kuhn, Sally" <KUHNS@xxxxxx>
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Smithsonian/USGS Weekly Volcanic Activity Report
25-31 May 2011
25-31 May 2011
New Activity/Unrest: | Aso, Kyushu | Dieng Volcanic Complex, Central Java (Indonesia) | Grímsvötn, Northeastern Iceland | Kliuchevskoi, Central Kamchatka (Russia) | Ulawun, New Britain
Ongoing Activity: | Batu Tara, Komba Island (Indonesia) | Karymsky, Eastern Kamchatka (Russia) | Kilauea, Hawaii (USA) | Kizimen, Eastern Kamchatka (Russia) | Popocatépetl, México | Poás, Costa Rica | Sakura-jima, Kyushu | Shiveluch, Central Kamchatka (Russia) | Taal, Luzon | Tungurahua, Ecuador
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
ASO Kyushu 32.881°N, 131.106°E; summit elev. 1592 m
Based on notices from JMA, the Tokyo VAAC reported that during 25, 27-28, and 31 May ash plumes from Aso rose to altitudes of 1.5-1.8 km (5,000-6,000 ft) a.s.l. and drifted NW, N, E, and S.
Geologic Summary. The 24-km-wide Aso caldera was formed during four major explosive eruptions from 300,000 to 80,000 years ago. These produced voluminous pyroclastic flows that covered much of Kyushu. A group of 17 central cones was constructed in the middle of the caldera, one of which, Naka-dake, is one of Japan's most active volcanoes. It was the location of Japan's first documented historical eruption in 553 AD. The Naka-dake complex has remained active throughout the Holocene. Several other cones have been active during the Holocene, including the Kometsuka scoria cone as recently as about 210 AD. Historical eruptions have largely consisted of basaltic to basaltic-andesite ash emission with periodic Strombolian and phreatomagmatic activity. The summit crater of Naka-dake is accessible by toll road and cable car, and is one of Kyushu's most popular tourist destinations.
Source: Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html
DIENG VOLCANIC COMPLEX Central Java (Indonesia) 7.20°S, 109.92°E; summit elev. 2565 m
CVGHM reported that on 29 May gas plumes rose 50 m above Timbang, a cone that is part of the Dieng Volcanic Complex. The gas plumes drifted S through the valley. Observers who visited the cone noted damaged vegetation and dead birds. Seismicity and carbon dioxide gas emissions remained elevated. CVGHM raised the Alert Level to 3 (on a scale of 1-4). According to news articles, about 1,200 people were evacuated from the flanks.
Geologic Summary. The Dieng plateau in the highlands of central Java is renowned both for the variety of its volcanic scenery and as a sacred area housing Java's oldest Hindu temples, dating back to the 9th century AD. The Dieng volcanic complex consists of two or more stratovolcanoes and more than 20 small craters and cones of Pleistocene-to-Holocene age over a 6 x 14 km area. Prahu stratovolcano was truncated by a large Pleistocene caldera, which was subsequently filled by a series of dissected to youthful cones, lava domes, and craters, many containing lakes. Lava flows cover much of the plateau, but have not occurred in historical time, when activity has been restricted to minor phreatic eruptions. Toxic volcanic gas emission has caused fatalities and is a hazard at several craters. The abundant thermal features that dot the plateau and high heat flow make Dieng a major geothermal prospect.
Sources: Center of Volcanology and Geological Hazard Mitigation (CVGHM) http://www.vsi.esdm.go.id/,
Xinhua http://www.philstar.com/Article.aspx?articleId=691979&publicationSubCategoryId=200
Xinhua http://www.philstar.com/Article.aspx?articleId=691979&publicationSubCategoryId=200
GRIMSVOTN Northeastern Iceland 64.42°N, 17.33°W; summit elev. 1725 m
According to scientists from the Institute of Earth Sciences at the University of Iceland and the Icelandic Meteorological Office, explosive activity occurred from four tephra cones surrounded by water in Grímsvötn's crater during the evening of 24 May. Pulsating ash plumes rose a few kilometers above the cones, producing only local fallout of material. Seismic tremor decreased. On 25 May, observers noted steam bursts from the crater. Tephra fallout was noted only in the vicinity of the eruption site. Pilots reported widespread ash in layers 5-7 km W of the volcano and also some ash haze below 3 km (9,800 ft) a.s.l. to the SW. Seismic tremor decreased considerably. On 26 May minor steam explosions continued from the crater. According to news articles, air traffic disruption was reduced to parts of Norway and Sweden. On 28 May tremor rapidly decreased then disappeared, and on 30 May participants on the Iceland Glaciological Society's spring expedition confirmed that the eruption had ended. Satellite imagery and visual observations showed that only small amounts of ice melted during the eruption; no signs of flooding had been detected.
Geologic Summary. Grímsvötn, Iceland's most frequently active volcano in historical time, lies largely beneath the vast Vatnajökull icecap. The caldera lake is covered by a 200-m-thick ice shelf, and only the southern rim of the 6 x 8 km caldera is exposed. The geothermal area in the caldera causes frequent jökulhlaups (glacier outburst floods) when melting raises the water level high enough to lift its ice dam. Long NE-SW-trending fissure systems extend from the central volcano. The most prominent of these is the noted Laki (Skaftar) fissure, which extends to the SW and produced the world's largest known historical lava flow during an eruption in 1783. The 15-cu-km basaltic Laki lavas were erupted over a 7-month period from a 27-km-long fissure system. Extensive crop damage and livestock losses caused a severe famine that resulted in the decimation of one-fifth of the population of Iceland.
Sources: Institute of Earth Sciences http://www.earthice.hi.is/,
Icelandic Meteorological Office http://www.earthice.hi.is/,
Agence France-Presse http://www.nation.co.ke/News/world/-/1068/1169770/-/4duoccz/-/
Icelandic Meteorological Office http://www.earthice.hi.is/,
Agence France-Presse http://www.nation.co.ke/News/world/-/1068/1169770/-/4duoccz/-/
KLIUCHEVSKOI Central Kamchatka (Russia) 56.057°N, 160.638°E; summit elev. 4835 m
Based on video data and ground-based observations, KVERT reported that on 29 May an ash plume from Kliuchevskoi rose to an altitude of 5 km (16,400 ft) a.s.l. and drifted SW. The Aviation Color Code was raised to Orange. No activity was noted on 30 May and the volcano was obscured by clouds the next day. The Aviation Color Code was lowered to Yellow.
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
ULAWUN New Britain 5.05°S, 151.33°E; summit elev. 2334 m
RVO reported that during 23-27 May gray ash plumes rose above Ulawun's summit crater. Fine ash fell in Ubili and Ulamona on the NW flank on 26 May.
Geologic Summary. The symmetrical basaltic to andesitic Ulawun stratovolcano is the highest volcano of the Bismarck arc, and one of Papua New Guinea's most frequently active. Ulawun rises above the N coast of New Britain opposite Bamus volcano. The upper 1,000 m of the 2,334-m-high volcano is unvegetated. A steep-walled valley cuts the NW side of the volcano, and a flank lava-flow complex lies to the S of this valley. Historical eruptions date back to the beginning of the 18th century. Twentieth-century eruptions were mildly explosive until 1967, but after 1970 several larger eruptions produced lava flows and basaltic pyroclastic flows, greatly modifying the summit crater.
Source: Rabaul Volcano Observatory (RVO)
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 during 24-27 May ash plumes from Batu Tara rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted less than 40 km W, NW, and N.
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
KARYMSKY Eastern Kamchatka (Russia) 54.05°N, 159.45°E; summit elev. 1536 m
KVERT reported moderate seismic activity at Karymsky during 20-27 May. Possible ash plumes rose to an altitude of 6.5 km (21,300 ft) a.s.l. on 21 May and to an altitude of 3.5 km (11,500 ft) a.s.l. on the other days. Satellite imagery showed a thermal anomaly during 19-20, 22, and 24 May, and ash plumes that drifted 38 km SW on 22 May. 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
KILAUEA Hawaii (USA) 19.421°N, 155.287°W; summit elev. 1222 m
HVO reported that two lava lakes at Kilauea were active during 25-31 May. The level of the summit lava lake remained mostly stable deep in the vent inset within the E wall of Halema'uma'u Crater. An increase in the lake level covered the vent on the south side wall during 25-28 May. On other days lava from the vent cascaded down into the lake. A gas plume from the vent drifted SW. The (preliminary) sulfur dioxide emission rate from all east rift zone sources was 700 tonnes/day on 26 May; the emission rates were slowly increasing.
Lava from a vent near the W edge of the perched lava lake in the center of Pu'u 'O'o crater floor continued to fill the lake. The lake level fluctuated and occasionally overflowed the edges or flowed through rim breaches, sending lava onto the Pu'u 'O'o crater floor. The rim of the perched lava lake was elevated 10 m higher than the surrounding crater floor, which was 52 m below the E crater rim on 11 May. During 27-29 May lava from a vent at the base of the SW wall produced lava flows that slowly began filling the gap between the crater wall and the perched lake wall.
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 20-27 May seismicity from Kizimen was above background levels. Strong tremor was detected on 12 May; tremor amplitude gradually increased from 18 May to 24 May. Satellite images showed a large bright thermal anomaly daily on the volcano during 21-24 and 26 May. 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
POPOCATEPETL México 19.023°N, 98.622°W; summit elev. 5426 m
CENAPRED reported that on 30 May an ash plume from Popocatépetl rose 800 m above the crater and drifted E.
Geologic Summary. Popocatépetl, whose name is the Aztec word for smoking mountain, towers to 5,426 m 70 km SE of Mexico City and is North America's second-highest volcano. Frequent historical eruptions have been recorded since the beginning of the Spanish colonial era. A small eruption on 21 December 1994 ended five decades of quiescence. Since 1996 small lava domes have incrementally been constructed within the summit crater and destroyed by explosive eruptions. Intermittent small-to-moderate gas-and-ash eruptions have continued, occasionally producing ashfall in neighboring towns and villages.
Source: Centro Nacional de Prevencion de Desastres (CENAPRED) http://www.cenapred.unam.mx/es/
POAS Costa Rica 10.20°N, 84.233°W; summit elev. 2708 m
According to a news article, a team of geologists and volcanologists from the Universidad de Costa Rica (UCR) visited Poás on 25 May and observed 18 phreatic eruptions from Laguna Caliente (the summit lake) in a three-hour period.
Geologic Summary. The broad, well-vegetated edifice of Poás, one of the most active volcanoes of Costa Rica, contains three craters along a N-S line. The frequently visited multi-hued summit crater lakes of the basaltic-to-dacitic volcano, which is one of Costa Rica's most prominent natural landmarks, are easily accessible by vehicle from the nearby capital city of San José. A N-S-trending fissure cutting the 2,708-m-high complex stratovolcano extends to the lower northern flank, where it has produced the Congo stratovolcano and several lake-filled maars. The southernmost of the two summit crater lakes, Botos, is cold and clear and last erupted about 7,500 years ago. The more prominent geothermally heated northern lake, Laguna Caliente, is one of the world's most acidic natural lakes, with a pH of near zero. It has been the site of frequent phreatic and phreatomagmatic eruptions since the first historical eruption was reported in 1828. Poás eruptions often include geyser-like ejection of crater-lake water.
Source: Inside Costa Rica http://www.insidecostarica.com/dailynews/2011/may/27/costarica11052701.htm
SAKURA-JIMA Kyushu 31.585°N, 130.657°E; summit elev. 1117 m
Based on information from JMA, the Tokyo VAAC reported that during 25-30 May explosions from Sakura-jima frequently produced plumes that rose to altitudes of 1.2-2.4 km (4,000-8,000 ft) a.s.l. Plumes drifted N, NW, E, SE, and S. On 27 May, a pilot observed an ash plume that rose to an altitude of 2.7 km (9,000 ft) a.s.l. and drifted E.
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 20-27 May seismic activity at Shiveluch did not exceed background levels. Strong gas-and-steam activity was observed on 21 May; cloud cover prevented ground-based observations on the other days. Satellite imagery showed ash plumes drifting 58 km SW on 20 May and a thermal anomaly over the lava dome during 19-21 and 24 May. The Aviation Color Code remained at Orange.
Based on information from KEMSD, the Tokyo VAAC reported that during 30-31 May eruptions produced plumes that rose to altitudes of 7.6-8.2 km (25,000-27,000 ft) a.s.l. and drifted S. According to news articles, ash plumes caused authorities to reroute a number of international flights in the region.
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,
BNO News http://channel6newsonline.com/2011/05/ash-cloud-forces-russian-authorities-to-reroute-international-flights-2/
Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html,
BNO News http://channel6newsonline.com/2011/05/ash-cloud-forces-russian-authorities-to-reroute-international-flights-2/
TAAL Luzon 14.002°N, 120.993°E; summit elev. 311 m
PHIVOLCS reported that field measurements conducted on 24 May at the E sector inside Taal's Main Crater Lake showed that the water temperature slightly increased from 32.5 to 32.8 degrees Celsius, the pH value became more slightly acidic decreasing from 2.83 to 2.67, and the water level increased by 4 cm. During 25-29 May, between 6 and 10 daily volcanic earthquakes were detected by the seismic network. Some of the earthquakes were felt by nearby residents on the SE part of the island. During 29-30 May, 115 earthquakes were recorded. Twelve of these events were felt at Intensity I-IV by residents of Pira-piraso, Alas-as, and Calauit located in the NE, SW, and SE sectors of Volcano Island, respectively. During 30-31 May there were 31 earthquakes noted. The Alert Level remained at 2 (on a scale of 0-5).
Geologic Summary. Taal volcano is one of the most active volcanoes in the Philippines and has produced some of its most powerful historical eruptions. In contrast to Mayon volcano, Taal is not topographically prominent, but its prehistorical eruptions have greatly changed the topography of SW Luzon. The 15 x 20 km Taal caldera is largely filled by Lake Taal, whose 267 sq km surface lies 700 m below the S caldera rim and only 3 m above sea level. The maximum depth of the lake is 160 m, and several eruptive centers lie submerged beneath the lake. The 5-km-wide Volcano Island in north-central Lake Taal is the location of all historical eruptions. The island is a complex volcano composed of coalescing small stratovolcanoes, tuff rings, and scoria cones that has grown about 25% in area during historical time. Powerful pyroclastic flows and surges from historical eruptions of Taal have caused many fatalities.
Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS) http://www.phivolcs.dost.gov.ph/index.php
TUNGURAHUA Ecuador 1.467°S, 78.442°W; summit elev. 5023 m
The IG reported that during 24-26 May explosions from Tungurahua were detected by the seismic network. On 24 May an ash plume rose to an altitude of 7 km (23,000 ft) a.s.l. Ashfall was reported in areas SW and W. The next day an ash plume drifted W. On 26 May ash plumes were not observed due to cloud cover but ashfall was reported to the SW; cloud cover prevented observations during 27-29 May. Muddy water was observed in multiple drainages during 26-30 May. Lahars on 27 May caused the highway to Baños to close. The highway remained closed during the next two days due to lahar risk.
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 base. 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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