****************************************************************************************** Smithsonian/USGS Weekly Volcanic Activity Report 4-10 May 2011 From: Sally Kuhn Sennert <kuhns@xxxxxx> ****************************************************************************************** Sally Kuhn Sennert - Weekly Report Editor kuhns@xxxxxx URL: http://www.volcano.si.edu/reports/usgs/ New Activity/Unrest: | Etna, Sicily (Italy) | Kizimen, Eastern Kamchatka (Russia) | Planchón-Peteroa, Central Chile-Argentina border | Tungurahua, Ecuador | Ulawun, New Britain Ongoing Activity: | Batu Tara, Komba Island (Indonesia) | Dukono, Halmahera | Karymsky, Eastern Kamchatka (Russia) | Kilauea, Hawaii (USA) | Poás, Costa Rica | Sakura-jima, Kyushu | Santa María, Guatemala | Shiveluch, Central Kamchatka (Russia) | Tengger Caldera, Eastern Java (Indonesia) 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 ETNA Sicily (Italy) 37.734°N, 15.004°E; summit elev. 3330 m Sezione di Catania - Osservatorio Etneo reported that on 8 May mild and discontinuous Strombolian activity resumed at the pit crater located on the E flank of Etna's SE Crater cone. Loud detonations were audible many kilometers away including in Monti Sartorius (NE flank) and in Zafferana Etnea (SW flank). After sunset, Strombolian explosions observed at intervals of 3-10 minutes ejected incandescent bombs up to a few tens of meters above the crater rim. During the night, some explosions ejected bombs well beyond the crater rim, down to the base of the cone that has grown around the crater during the recent events. Strombolian explosions continued without significant variations the next day. 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/ KIZIMEN Eastern Kamchatka (Russia) 55.130°N, 160.32°E; summit elev. 2376 m Following strong explosions at Kizimen on 3 May, KVERT reported that ash fell in Kipelye Springs, 15 km W, and accumulated to a thickness of about 1 cm. A large and hot pyroclastic flow deposit on the NE flank was detected in satellite imagery the next day. Analysis of the satellite images also revealed ash plumes that drifted 280 km S during 3-5 May and 62 km in various directions on 6 May. A daily thermal anomaly was also noted. 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 PLANCHON-PETEROA Central Chile-Argentina border 35.240°S, 70.570°W; summit elev. 4107 m SERNAGEOMIN reported that, based on video camera data, photographs, and observations during an overflight on 4 May, activity at Planchón-Peteroa was relatively stable during 30 April-8 May. Explosions lasting about 30 seconds produced ash plumes that rose at most 1 km above the crater and drifted tens of kilometers E, NE, NNE, NNW and NW. During 4-5 May material fell in Minera Río Teno (about 70 km NW) and Las Leñas, Argentina (45 km ENE). The Alert Level remained at Level 3, Yellow. Based on ODVAS web camera observations, the Buenos Aires VAAC reported that on 9 May gas-and-ash plumes rose to an altitude of 4.3 km (14,000 ft) a.s.l. and rapidly dissipated to the SE. Geologic Summary. Planchón-Peteroa is an elongated complex volcano along the Chile-Argentina border with several overlapping calderas. Activity began in the Pleistocene with construction of the basaltic-andesite to dacitic Volcán Azufre, followed by formation of basaltic and basaltic-andesite Volcán Planchón, 6 km to the N. About 11,500 years ago, much of Azufre and part of Planchón collapsed, forming the massive Río Teno debris avalanche, which reached Chile's Central Valley. Subsequently, Volcán Planchón II was formed. The youngest volcano, andesitic and basaltic-andesite Volcá Peteroa, consists of scattered vents between Azufre and Planchón. Peteroa has been active into historical time and contains a small steaming crater lake. Historical eruptions from the Planchón-Peteroa complex have been dominantly explosive, although lava flows were erupted in 1837 and 1937. Sources: Servicio Nacional de Geología y Minería (SERNAGEOMIN) http://www.sernageomin.cl/, Buenos Aires Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AG/messages.html TUNGURAHUA Ecuador 1.467°S, 78.442°W; summit elev. 5023 m IG reported that, although visual observations of Tungurahua were occasionally limited due to cloud cover, ash plumes were noted during 4-6 May that rose to altitudes of 6-7 km (19,700-23,000 ft) a.s.l. and drifted W. Ashfall was reported in Alao, S of Riobamba (30 km S) on 4 May and in Manzano (8 km SW) on 5 and 7 May. Cloud cover prevented observations during 7-9 May. Roaring was also reported during 4-9 May. An explosion on 10 May produced an ash plume that rose to an altitude of 10 km (32,800 ft) a.s.l. and drifted W and NW. Slight ashfall was reported in areas as far as 23 km NW. 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/ ULAWUN New Britain 5.05°S, 151.33°E; summit elev. 2334 m RVO reported that during 1-9 May diffuse white plumes rose from Ulawun and Real-time Seismic-Amplitude Measurement (RSAM) values ranged between 70 and 100. During 9-10 May RSAM values distinctly increased, fluctuated, and peaked at 1300 units before declining back to 100 units. During this time local residents heard booming. On 10 May grey-to-brown ash plumes were observed. 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 4-7 May ash plumes from Batu Tara rose to altitudes of 0.9-2.1 km (3,000-7,000 ft) a.s.l. and drifted 18-75 km NW, W, and SW. 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 DUKONO Halmahera 1.68°N, 127.88°E; summit elev. 1335 m Based on analyses of satellite imagery, the Darwin VAAC reported that on 10 May ash plumes from Dukono rose to an altitude of 4.3 km (14,000 ft) a.s.l. and drifted 90-110 km NE and E. 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 KARYMSKY Eastern Kamchatka (Russia) 54.05°N, 159.45°E; summit elev. 1536 m KVERT reported moderate seismic activity at Karymsky during 29 April-6 May. Seismic data indicated that possible ash plumes rose to an altitude of 4.9 km (16,000 ft) a.s.l. A thermal anomaly was detected in satellite imagery during 1-4 May. The Aviation Color Code remained at Orange. Based on analyses of satellite imagery and information from KVERT, the Tokyo VAAC reported that on 7 May ash plumes rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted SE. 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, 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 HVO reported that two lava lakes at Kilauea were active during 4-10 May. The level of the summit lava lake fluctuated but remained mostly stable deep in the vent inset within the E wall of Halema'uma'u Crater. On 5 May the lava lake level dropped 10-20 m and lava from a vent well above the south side cascaded down into the lake. A gas plume from the vent drifted SW and deposited very small amounts of ash nearby. At Pu'u 'O'o crater, lava from vents near the W edge of the lake and near the base of the E crater wall continued to fill in a perched lava lake in the center of the crater floor. The lake level fluctuated and occasionally overflowed the edges and filled the entire bottom of Pu'u 'O'o crater floor. The crater had infilled about 70 m since the crater floor collapsed in March. 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/ POAS Costa Rica 10.20°N, 84.233°W; summit elev. 2708 m OVSICORI-UNA reported that during April sporadic phreatic eruptions occurred from the central part of Laguna Caliente, a summit lake of Poás. Gas plumes rose a few meters to several tens of meters above the lake surface. Solid dark material ejected from the lake fell back into it, causing small surges. The temperature of the lava dome was 560 degrees Celsius at accessible areas. Bluish fumarolic plumes rose from the dome; a gas plume rose 1 km and drifted NE, E, and SE. 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/ SAKURA-JIMA Kyushu 31.585°N, 130.657°E; summit elev. 1117 m Based on information from JMA, the Tokyo VAAC reported that during 6-10 May explosions from Sakura-jima produced plumes that rose to altitudes of 1.2-2.4 km (4,000-8,000 ft) a.s.l. Plumes sometimes drifted NW, NE, E, SE, and S. On 4 and 9 May, pilots observed ash plumes that rose to altitudes of 2.1-2.7 km (7,000-9,000 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 Based on analyses of satellite imagery, the Washington VAAC reported that during 5-6 May ash plumes from Santa María's Santiaguito lava dome complex rose to an altitude of 4 km (13,000 ft) a.s.l. and dissipated within about 75 km SW. On 6 May ash plumes also rose to an altitude of 6.7 km (22,000 ft) a.s.l. and dissipated within 10 km NW. Plumes also drifted S and SE. During 5-6 May INSIVUMEH reported that an explosion produced an ash plume that rose 800 m above Caliente cone and drifted W. Ash fell at beach areas and weak avalanches occurred with a lava flow on the E flank. Two areas of incandescence were observed on the S flank of the lava dome. During 8-9 May steam plumes rose 100 m above the Caliente cone crater and a few avalanches descended the SE flank. Explosions during 9-10 May produced ash plumes that rose 1.2 km above the crater and pyroclastic flows from the SW edge of the crater that were deposited in the Río Nima I and Río Nima II drainages. Ash plumes drifted W and block avalanches descended the E, S, and W flanks. 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. Sources: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH) http://www.insivumeh.gob.gt/, Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html SHIVELUCH Central Kamchatka (Russia) 56.653°N, 161.360°E; summit elev. 3283 m KVERT reported that during 29 April-6 May a thermal anomaly on Shiveluch was detected in satellite imagery. According to ground-based observations during 28-29 April ash plumes rose to an altitude of 4.5 km (14,800 ft) a.s.l. On 1 May ash plumes observed in satellite imagery drifted 124 km NE. Seismic data indicated that possible ash plumes rose to an altitude of 6 km (19,700 ft) a.s.l. on 29 April and 2 May. KVERT noted that the Aviation Color Code remained at Orange. Based on analyses of satellite imagery, the Tokyo VAAC reported that on 7 May a possible eruption produced a plume that rose to an altitude of 5.2 km (17,000 ft) a.s.l. and drifted E. Subsequent notices that day stated that 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 TENGGER CALDERA Eastern Java (Indonesia) 7.942°S, 112.95°E; summit elev. 2329 m Based on analyses of satellite imagery, the Darwin VAAC reported that during 9-10 May ash plumes from Tengger Caldera's Bromo cone rose to an altitude of 2.7 km (9,000 ft) a.s.l. and drifted 45-75 km NE and E. Geologic Summary. The 16-km-wide Tengger caldera in eastern Java is located at the northern end of a volcanic massif extending from Semeru volcano. The massive Tengger volcanic complex consists of five overlapping stratovolcanoes, each truncated by a caldera. The most recent is the 9 x 10 km wide Sandsea caldera, which formed incrementally during the late Pleistocene and early Holocene. An overlapping cluster of post-caldera cones was constructed on the floor of the Sandsea caldera within the past several thousand years. The youngest of these is Bromo, one of Java's most frequently visited and most active volcanoes. More than 50 mild-to-moderate explosive eruptions have occurred since 1804. Source: Darwin Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AU/messages.html ============================================================== To unsubscribe from the volcano list, send the message: signoff volcano to: listserv@xxxxxxx, or write to: volcano-request@xxxxxxxx To contribute to the volcano list, send your message to: volcano@xxxxxxxx Please do not send attachments. ==============================================================
