******************************************************************************************** Smithsonian/USGS Weekly Volcanic Activity Report 24-30 August 2011 From: "Kuhn, Sally" <KUHNS@xxxxxx> ******************************************************************************************** Smithsonian/USGS Weekly Volcanic Activity Report 24-30 August 2011 Sally Kuhn Sennert - Weekly Report Editor kuhns@xxxxxx URL: http://www.volcano.si.edu/reports/usgs/ New Activity/Unrest: | Bagana, Bougainville | Etna, Sicily (Italy) | Kilauea, Hawaii (USA) | Papandayan, Western Java (Indonesia) | Ranakah, Flores Island (Indonesia) | Tambora, Sumbawa Island (Indonesia) Ongoing Activity: | Batu Tara, Komba Island (Indonesia) | Karymsky, Eastern Kamchatka (Russia) | Kizimen, Eastern Kamchatka (Russia) | Lokon-Empung, Sulawesi | Popocatépetl, México | 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 BAGANA Bougainville 6.140°S, 155.195°E; summit elev. 1750 m Based on analyses of satellite imagery, the Darwin VAAC reported that on 23 August an ash plume from Bagana rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted 93 km SW. Geologic Summary. Bagana volcano, occupying a remote portion of central Bougainville Island, is one of Melanesia's youngest and most active volcanoes. Bagana is a massive symmetrical lava cone largely constructed by an accumulation of viscous andesitic lava flows. The entire lava cone could have been constructed in about 300 years at its present rate of lava production. Eruptive activity at Bagana is characterized by non-explosive effusion of viscous lava that maintains a small lava dome in the summit crater, although explosive activity occasionally producing pyroclastic flows also occurs. Lava flows form dramatic, freshly preserved tongue-shaped lobes up to 50-m-thick with prominent levees that descend the volcano's flanks on all sides. Source: Darwin Volcanic Ash Advisory Centre (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AU/messages.html ETNA Sicily (Italy) 37.734°N, 15.004°E; summit elev. 3330 m Sezione di Catania - Osservatorio Etneo reported that nine days after the previous episode, the New SE Crater produced its twelfth paroxysmal eruptive episode of 2011 during the early morning of 29 August. The event was preceded by an explosion at 2252 on 27 August, and a series of ash emissions from the New SE Crater almost 15 hours later. Weak Strombolian activity visible during the evening on 28 August intensified during the night. At 0115 on 29 August lava overflowed the rim through a breach in the E crater rim and traveled towards the Valle del Bove. Strombolian activity progressively intensified and two vents within the crater emitted pulsating lava fountains up to 100 m high. The lava fountains again increased in height and a dense plume rose a few kilometers above the summit before drifting toward the SSE. At the same time, a small lava flow issued from the area affected by the collapse of a portion of the cone's ESE flank during the 20 August paroxysm. At 0220 the SE flank of the cone fractured and exposed a line of new eruptive vents down to the base of the cone that produced lava fountains. A broad lava flow fed by the vents descended into the Valle del Bove, somewhat to the S of the lava flow emitted earlier during the episode. The lava fountaining from the vents within the crater turned into ash emission just after 0220, whereas the lowest vent on the new eruptive fracture continued to produce incandescent jets until 0250. Ash emission continued at a diminishing rate until about 0315. Geologic Summary. Mount Etna, towering above Catania, Sicily's second largest city, has one of the world's longest documented records of historical volcanism, dating back to 1500 BC. Historical lava flows cover much of the surface of this massive basaltic stratovolcano, the highest and most voluminous in Italy. Two styles of eruptive activity typically occur at Etna. Persistent explosive eruptions, sometimes with minor lava emissions, take place from one or more of the three prominent summit craters, the Central Crater, NE Crater, and SE Crater. Flank eruptions, typically with higher effusion rates, occur less frequently and originate from fissures that open progressively downward from near the summit. A period of more intense intermittent explosive eruptions from Etna's summit craters began in 1995. The active volcano is monitored by the Instituto Nazionale di Geofisica e Volcanologia (INGV) in Catania. Source: Sezione di Catania - Osservatorio Etneo http://www.ct.ingv.it/ KILAUEA Hawaii (USA) 19.421°N, 155.287°W; summit elev. 1222 m During 24-30 August, 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 below the inner ledge 75 m below the crater floor. At Pu'u 'O'o' crater, lava from sources on the E and S portions of the crater floor fed a lava lake that was formed during 25-26 August. A new source opened at the W edge of the crater floor during 29-30 August, and lava quickly spread N and S along the base of the W crater 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/ PAPANDAYAN Western Java (Indonesia) 7.32°S, 107.73°E; summit elev. 2665 m On 26 August CVGHM reported that Papandayan showed minor to no changes in recent seismicity, deformation, geochemistry, and visual observations; therefore the Alert Level remained at 3 (on a scale of 1-4). Seismicity remained high, but stable, and was dominated by shallow volcanic earthquakes. Deformation measurements showed no change, and water temperatures in multiple fumarolic areas and lakes remained relatively unchanged. Sulfur dioxide gas emissions decreased from 8 tons per day on 12 August to 6 tons per day on 23 August. Carbon dioxide in the soil at a 1 m depth in multiple areas did not increase. Visitors and residents were advised not to venture within 2 km of the active crater. Geologic Summary. Papandayan is a complex stratovolcano with four large summit craters, the youngest of which was breached to the NE by collapse during a brief eruption in 1772 and contains active fumarole fields. The broad 1.1-km-wide, flat-floored Alun-Alun crater truncates the summit of Papandayan, and Gunung Puntang to the N gives the volcano a twin-peaked appearance. Several episodes of collapse have given the volcano an irregular profile and produced debris avalanches that have impacted lowland areas beyond the volcano. Since its first historical eruption in 1772, in which a catastrophic debris avalanche destroyed 40 villages, only two small phreatic eruptions have occurred from vents in the NE-flank fumarole field, Kawah Mas. Source: Center of Volcanology and Geological Hazard Mitigation (CVGHM) http://www.vsi.esdm.go.id/ RANAKAH Flores Island (Indonesia) 8.62°S, 120.52°E; summit elev. 2350 m CVGHM reported that observers of Anak Ranakah, a lava dome that formed in 1987 at the base of the large older lava dome of Ranakah, noted white plumes rising up to 10 m high during January-24 August. Seismicity initially increased in December 2010, but increased again during June-August. Based on visual observations and seismic data analyses, CVGHM raised the Alert Level to 2 (on a scale of 1-4). Geologic Summary. A new lava dome, named Anak Ranakah (Child of Ranakah) was formed in 1987 in an area without previous historical eruptions at the base of the large older lava dome of Gunung Ranakah. An arcuate group of lava domes extending westward from Gunung Ranakah occurs on the outer flanks of the poorly known Poco Leok caldera on western Flores Island. Pocok Mandosawa lava dome, at 2350 m the highest point on the island of Flores, lies west of Anak Ranakah. Source: Center of Volcanology and Geological Hazard Mitigation (CVGHM) http://www.vsi.esdm.go.id/ TAMBORA Sumbawa Island (Indonesia) 8.25°S, 118.00°E; summit elev. 2850 m Based on visual observation and seismic data, CVGHM reported an increase in activity at Tambora during the previous five months. Ground-based observers at an observation post in Tambora village noted dense white plumes rising 50-75 m above the caldera rim during April and June, but no plumes during May or July. In August dense white plumes rose 20 m above the caldera rim. Seismicity started to increase in April and continued to increase through August. On 30 August the Alert Level was raised to 2 (on a scale of 1-4). Geologic Summary. The massive Tambora stratovolcano forms the entire 60-km-wide Sanggar Peninsula on northern Sumbawa Island. The largely trachybasaltic-to-trachyandesitic volcano grew to about 4000 m elevation before forming a caldera more than 43,000 years ago. Late-Pleistocene lava flows largely filled the early caldera, after which activity changed to dominantly explosive eruptions during the early Holocene. Tambora was the source of history's largest explosive eruption, in April 1815. Pyroclastic flows reached the sea on all sides of the peninsula, and heavy tephra fall devastated croplands, causing an estimated 60,000 fatalities. The eruption of an estimated more than 150 cu km of tephra formed a 6-km-wide, 1250-m-deep caldera and produced global climatic effects. Minor lava domes and flows have been extruded on the caldera floor at Tambora during the 19th and 20th centuries. Source: Center of Volcanology and Geological Hazard Mitigation (CVGHM) http://www.vsi.esdm.go.id/ 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 23-30 August ash plumes from Batu Tara rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted 20-90 km N, NW, and 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 KARYMSKY Eastern Kamchatka (Russia) 54.05°N, 159.45°E; summit elev. 1536 m KVERT reported that during 19-26 August moderate seismic activity continued at Karymsky, indicating that possible ash plumes rose to an altitude of 5.2 km (17,000 ft) a.s.l. A thermal anomaly on the volcano was detected by satellite during 21-25 August. Gas-and-steam plumes containing ash drifted 18 and 65 km E on 18 and 24 August, respectively. The Aviation Color Code remained at Orange. Based on information from Yelizovo Airport (UHPP), the Tokyo VAAC reported that on 29 August an ash plume rose to an altitude of 7.3 km (24,000 ft) a.s.l. and drifted E. 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 KIZIMEN Eastern Kamchatka (Russia) 55.130°N, 160.32°E; summit elev. 2376 m KVERT reported that during 19-26 August seismicity from Kizimen was above background levels; volcanic-tremor magnitude gradually increased and several hundred earthquakes were detected the previous week. Video images showed moderate fumarolic activity. A lava flow on the E flank was active. Satellite images showed a large bright thermal anomaly on the volcano all week and gas-and-steam plumes that drifted E on 19 and 22 August. 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, activity from Tompaluan crater, in the saddle between the Lokon-Empung peaks, decreased on 29 August after erupting several times the previous week and specifically 12 times on 28 August. One explosion on 29 August ejected material 250 m above the crater. The article also noted that 222 people remained at temporary refugee camps because their homes were located within 3 kilometers of 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: BNO News http://www.daijiworld.com/news/news_disp.asp?n_id=113965 POPOCATEPETL México 19.023°N, 98.622°W; summit elev. 5426 m CENAPRED reported that, although cloud cover often prevented observations of Popocatépetl during 24-30 August, steam-and-gas emissions were occasionally noted. Based on reports from CENEPRED and the Mexico City MWO, the Washington VAAC reported ash emissions during 28-29 August. 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. Sources: Centro Nacional de Prevencion de Desastres (CENAPRED) http://www.cenapred.unam.mx/es/, Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html PUYEHUE-CORDON CAULLE Central Chile 40.590°S, 72.117°W; summit elev. 2236 m Based on seismicity during 24-25 August, 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. A predominantly white plume observed by an area camera rose 1 km above the crater. The seismic network detected four explosions that caused the plume to turn gray. Ashfall was reported in Temuco. 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 23-30 August 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, W, NW, N, and NE. On 30 August a pilot observed an ash plume that rose to an altitude of 1.2 km (4,000 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 SHIVELUCH Central Kamchatka (Russia) 56.653°N, 161.360°E; summit elev. 3283 m KVERT reported that seismic activity at Shiveluch was moderate during 19-26 August, and indicated that possible ash plumes rose to an altitude of 8.2 km (26,900 ft) a.s.l. on 23 August. A thermal anomaly on the volcano was observed in satellite imagery on 18, 21, and 25 August. The Aviation Color Code remained at Orange. Based on information from KEMSD and analyses of satellite imagery, the Tokyo VAAC reported that on 29 August an eruption produced a plume that rose to an altitude of 6.1 km (20,000 ft) a.s.l. and drifted E. Subsequent images that day showed that continuing ash emissions had later dissipated. According to a news article, international flights were re-routed that day due to ash plumes that reportedly rose to an altitude of 8.6 km (28,000 ft) a.s.l. 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, IOL News http://www.iol.co.za/news/world/ash-forces-air-traffic-reroute-1.1127017?showComments=true +++++++++++++++++++++++++++++++++++++ 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. ==============================================================
