******************************************************************************************** Smithsonian/USGS Weekly Volcanic Activity Report 31 August-6 September 2011 From: "Kuhn, Sally" <KUHNS@xxxxxx> ******************************************************************************************** Smithsonian/USGS Weekly Volcanic Activity Report 31 August-6 September 2011 Sally Kuhn Sennert - Weekly Report Editor kuhns@xxxxxx URL: http://www.volcano.si.edu/reports/usgs/ New Activity/Unrest: | Cleveland, Chuginadak Island | Kilauea, Hawaii (USA) | Kizimen, Eastern Kamchatka (Russia) | Lewotobi, Flores Island (Indonesia) | Popocatépetl, México | Poás, Costa Rica Ongoing Activity: | Karymsky, Eastern Kamchatka (Russia) | Kirishima, Kyushu | Pagan, Mariana Islands | Puyehue-Cordón Caulle, Central Chile | Sakura-jima, Kyushu | 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 CLEVELAND Chuginadak Island 52.825°N, 169.944°W; summit elev. 1730 m On 30 August, AVO reported that satellite observations during the previous two weeks indicated that lava-dome growth at Cleveland had paused. AVO lowered the Volcano Alert Level to Advisory and the Aviation Color Code to Yellow. During 31 August-2 September cloud cover prevented views of the summit crater, but a thermal anomaly at the summit was observed during 3-5 September. Observations on 6 September indicated that the lava dome had resumed growth, reaching 120 m in diameter and filling the floor of the crater. AVO raised the Volcano Alert Level to Watch and the Aviation Color Code to 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/ KILAUEA Hawaii (USA) 19.421°N, 155.287°W; summit elev. 1222 m During 31 August-6 September, HVO reported that the level of the lava-lake surface in the deep pit within Kilauea's Halema'uma'u crater periodically fluctuated but remained mostly stable below the inner ledge 75 m below the crater floor. Periodic measurements indicated that the gas plume from the vent continued to deposit variable amounts of ash and occasionally fresh spatter nearby. At Pu'u 'O'o' crater, lava from sources on the E portion of the crater floor fed a perched lava lake. Lava from a source at the W edge of the crater floor spread N and S along the base of the W crater wall and up to the base of the W, inactive wall of the perched pond. During 2-3 September a new perched pond fed from the W-edge source had formed. 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 26 August-1 September the number and magnitude of volcanic earthquakes at Kizimen continued to increase; about 1,000 earthquakes were detected daily. Satellite images showed a large bright thermal anomaly on the volcano all week and gas-and-steam plumes that drifted 60 km E on 26 and 29 August. Lava on the E flank continued to flow. In addition to strong fumarolic activity, video images from the previous week showed a new long fissure at the top of the volcano. 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 LEWOTOBI Flores Island (Indonesia) 8.542°S, 122.775°E; summit elev. 1703 m CVGHM reported that during 26-31 August seismicity at Lewotobi increased. Plumes of "smoke" rose 15-50 m above the Lewotobi Perampuan crater rim; no other significant changes were visibly apparent. Based on the seismic data, the Alert Level was raised to 2 (on a scale of 1-4) on 31 August. Visitors and residents were advised not to approach the volcano within 1 km of the Lewotobi Perampuan crater. Geologic Summary. The Lewotobi "husband and wife" twin volcano (also known as Lewetobi) in eastern Flores Island is composed of the Lewotobi Lakilaki and Lewotobi Perempuan stratovolcanoes. Their summits are less than 2 km apart along a NW-SE line. The conical 1,584-m-high Lewotobi Lakilaki has been frequently active during the 19th and 20th centuries, while the taller and broader 1,703-m-high Lewotobi Perempuan has erupted only twice in historical time. Small lava domes have grown during the 20th century in the crescentic summit craters of both volcanoes, which are open to the N. A prominent flank cone, Iliwokar, occurs on the E flank of Lewotobi Perampuan. Source: Center of Volcanology and Geological Hazard Mitigation (CVGHM) http://portal.vsi.esdm.go.id/ POPOCATEPETL México 19.023°N, 98.622°W; summit elev. 5426 m CENAPRED reported that on 29 August instances of emissions of gas, steam, and some ash from Popocatépetl increased. The next day an ash plume rose 1 km above the crater and drifted WNW, producing ashfall in San Pedro Nexapa (14 km NW) and Amecameca (19 km NW). CENAPRED noted that recent rain in the area may have contributed to the recent increase in activity. During 30-31 August there were 111 plumes of gas, steam, and some ash detected by the network, in addition to periods of harmonic tremor. Signals from detectors near drainages possibly indicated lahars. During 1-4 September the monitoring network registered 4-12 instances daily of emissions of gas, steam, and some ash. Periods of tremor continued to be detected. 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 On 31 August OVSICORI-UNA reported that since mid-July incandescence was visible during the day on the lava dome of Poás, which had not occurred since 1981, and was the result of changes in activity that had started several months before. OVSICORI-UNA speculated that the changes could be either from recent magma intrusion or a change in the hydrothermal plumbing system and noted the need to further analyze data from seismic, deformation, geochemical, and field measurements. 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: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA) http://www.ovsicori.una.ac.cr/ Ongoing Activity KARYMSKY Eastern Kamchatka (Russia) 54.05°N, 159.45°E; summit elev. 1536 m KVERT reported that during 26 August-1 September moderate seismic activity continued at Karymsky, indicating that possible ash plumes rose to an altitude of 3 km (10,000 ft) a.s.l. Gas-and-steam plumes containing ash drifted 40 km E on 26 and 29 August. A thermal anomaly on the volcano was detected by satellite during 26 and 29-30 August. The Aviation Color Code remained at Orange. Based on information from Yelizovo Airport (UHPP), the Tokyo VAAC reported that on 2 September an ash plume rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted NE. Ash plumes rose to an altitude of 2.1 km (7,000 ft) a.s.l. during 5-6 September and drifted SE and SW. 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 KIRISHIMA Kyushu 31.931°N, 130.864°E; summit elev. 1700 m Based on notifications from JMA, the Tokyo VAAC reported that during 31 August-6 September ash plumes from Kirishima's Shinmoe-dake (Shinmoe peak) rose to altitudes of 1.5-2.1 km (5,000-7,000 ft) a.s.l. and drifted N, S, and SW. Geologic Summary. Kirishima is a large group of more than 20 Quaternary volcanoes located north of Kagoshima Bay. The late-Pleistocene to Holocene volcano group consists of stratovolcanoes, pyroclastic cones, maars, and underlying shield volcanoes located over an area of 20 x 30 km. The larger stratovolcanoes are scattered throughout the field, with the centrally located, 1,700-m-high Karakuni-dake being the highest. Onami-ike and Mi-ike, the two largest maars, are located SW of Karakuni-dake and at its far eastern end, respectively. Holocene eruptions have been concentrated along an E-W line of vents from Mi-ike to Ohachi, and at Shinmoe-dake to the NE. Frequent small-to-moderate explosive eruptions have been recorded since the 8th century. Source: Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html PAGAN Mariana Islands 18.13°N, 145.80°E; summit elev. 570 m A Northern Mariana Islands status report noted that during 26 August-2 September low-level vapor plumes from Pagan, possibly containing minor amounts of ash, were visible in satellite imagery. Reports from people on Pagan Island also indicated intermittent low-level but diffuse ash emissions and trace amounts of ashfall on parts of the island. The Aviation Color Code remained at Yellow and the Volcano Alert Level remained at Advisory. 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. Source: 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/index.php PUYEHUE-CORDON CAULLE Central Chile 40.590°S, 72.117°W; summit elev. 2236 m Based on seismicity during 31 August-5 September, 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. Although cloudy weather mostly prevented satellite and camera observations of the vent, plumes detected in satellite imagery during 31 August-1 September drifted SE and SW. A plume observed by an area camera on 1 September rose 1 km above the crater. On 3 and 5 September plumes observed in satellite imagery drifted 30-80 km SE and E. 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 31 August-6 September explosions from Sakura-jima produced plumes that rose to altitudes of 1.2-3 km (4,000-10,000 ft) a.s.l. and drifted SW, S, and SE. According to a news article, the 660th explosive eruption in 2010 occurred on 3 September. The article also noted that as of 2 September, 607 grams of ash per square meter had fallen in Kagoshima (10 km W), compared to 753 grams for all of 2010, when the volcano had a record-high 896 explosive eruptions. 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, Japan Times http://search.japantimes.co.jp/cgi-bin/nn20110904a9.html SHIVELUCH Central Kamchatka (Russia) 56.653°N, 161.360°E; summit elev. 3283 m KVERT reported that seismic activity at Shiveluch was moderate during 26 August-1 September, and indicated that possible ash plumes rose to an altitude of 8.6 km (28,200 ft) a.s.l. on 28 August. Ground-based observers noted fumarolic activity during 26, 28, and 30-31 August, and an ash plume that rose to an altitude of 6 km (19,700 ft) a.s.l. on 28 August. A thermal anomaly on the volcano was observed in satellite imagery on 29 and 31 August. The Aviation Color Code remained at Orange. Based on information from Yelizovo Airport (UHPP) and KVERT, the Tokyo VAAC reported that on 3 September an ash plume rose to an altitude of 5.8 km (19,000 ft) a.s.l. and drifted NE. Subsequent images that day showed that the ash had dissipated. 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: 202.633.1805 Fax: 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. ==============================================================
