********************************************************** SI/USGS Weekly Volcanic Activity Report 9-15 April 2008 ********************************************************** Sally Kuhn Sennert - Weekly Report Editor kuhns@xxxxxx URL: http://www.volcano.si.edu/reports/usgs/ New Activity/Unrest: | Egon, Flores Island (Indonesia) | Ibu, Halmahera (Indonesia) | Nevado del Huila, Colombia | Papandayan, Western Java (Indonesia) Ongoing Activity: | Batu Tara, Komba Island (Indonesia) | Colima, México | Karymsky, Eastern Kamchatka | Kilauea, Hawaii (USA) | Manam, Northeast of New Guinea (SW Pacific) | Ol Doinyo Lengai, Tanzania | Rabaul, New Britain (SW Pacific) | Sakura-jima, Kyushu (Japan) | Shiveluch, Central Kamchatka (Russia) | Tungurahua, Ecuador | Ubinas, Perú 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 EGON Flores Island (Indonesia) 8.67°S, 122.45°E; summit elev. 1703 m CVGHM reported that white plumes from Egon continued to rise to an altitude of 1.8 km (5,900 ft) a.s.l. during 4-14 April. A peak in seismicity was reached during 6-7 April and then declined significantly during 7-15 April. On 15 April, a phreatic explosion produced an ash plume that rose to an altitude of 5.7 km (18,700 ft) a.s.l. and drifted about 25 km W, reaching the town of Maumere. A team of emergency personnel in the closest village to the explosion reported that about 600 people evacuated. CVGHM raised the Alert Level to 3 (on a scale of 1-4). Geologic Summary. Gunung Egon volcano sits astride the narrow waist of eastern Flores Island. The barren, sparsely vegetated summit region has a 350-m-wide, 200-m-deep crater that sometimes contains a lake. Other small crater lakes occur on the flanks of the 1,703-m-high volcano. A lava dome forms the southern 1,671-m-high summit. Reports of historical eruptive activity are inconclusive. A column of "smoke" was often observed above the summit during 1888-1891 and in 1892. Strong "smoke" emission in 1907 reported by Sapper (1917) was considered by the Catalog of Active Volcanoes of the World (Neumann van Padang, 1951) to be an historical eruption, but Kemmerling (1929) noted that this was likely confused with an eruption on the same date and time from Lewotobi Lakilaki volcano. Source: Center of Volcanology and Geological Hazard Mitigation (CVGHM) http://portal.vsi.esdm.go.id/joomla/ IBU Halmahera (Indonesia) 1.488°N, 127.63°E; summit elev. 1325 m CVGHM reported that white plumes from Ibu rose to an altitude of 1.5 km (5,000 ft) a.s.l. during 17-31 March and were spotted "often." The plume altitudes increased to 1.6 km (5,200 ft) a.s.l. on 31 March. During 4-5 April, seismicity increased in amplitude and plume altitude increased to 1.8-2.0 km (5,900-6,600 ft) a.s.l. On 5 April, the eruption plume was gray and material fell onto the crater. The Alert Level remained at 2 (on a scale of 1-4). The community was not permitted to climb or approach the crater. Geologic Summary. The truncated summit of Gunung Ibu stratovolcano along the NW coast of Halmahera Island has large nested summit craters. The inner crater, 1 km wide and 400 m deep, contained several small crater lakes through much of historical time. The outer crater, 1.2 km wide, is breached on the north side, creating a steep-walled valley. A large parasitic cone is located ENE of the summit. A smaller one to the WSW has fed a lava flow down the western flank. A group of maars is located below the northern and western flanks of the volcano. Only a few eruptions have been recorded from Ibu in historical time, the first a small explosive eruption from the summit crater in 1911. An eruption producing a lava dome that eventually covered much of the floor of the inner summit crater began in December 1998. Source: Center of Volcanology and Geological Hazard Mitigation (CVGHM) http://portal.vsi.esdm.go.id/joomla/ NEVADO DEL HUILA Colombia 2.93°N, 76.03°W; summit elev. 5365 m Seismicity from Nevado del Huila increased during 9-12 April then again on 13 April, prompting INGEOMINAS to raise the Alert Level to Orange (the second highest level on a 4-color scale). During 13-14 April, seismic signals possibly indicated an eruption. According to news articles, authorities ordered about 15,000 people to evacuate. On 14 April at 2325, the Alert Level was raised to Red, the highest level, based on the seismicity. Seismic events decreased in number and intensity in the early evening of 15 April; the Alert Level was lowered to Orange. Weather inhibited visual observations and overflights of the summit. Geologic Summary. Nevado del Huila, the highest active volcano in Colombia, is an elongated N-S-trending volcanic chain mantled by a glacier icecap. The andesitic-dacitic volcano was constructed within a 10-km-wide caldera. Volcanism at Nevado del Huila has produced six volcanic cones whose ages in general migrated from south to north. Two glacier-free lava domes lie at the southern end of the Huila volcanic complex. The first historical eruption from this little known volcano took place in the 16th century. Two persistent steam columns rise from the central peak, and hot springs are also present. Sources: Instituto Colombiano de Geología y Minería (INGEOMINAS) http://www.ingeominas.gov.co//, CNN http://www.cnn.com/2008/WORLD/americas/04/15/volcano.colom/index.html#cnnSTCOther1 PAPANDAYAN Western Java (Indonesia) 7.32°S, 107.73°E; summit elev. 2665 m CVGHM reported that the seismic network recorded one volcanic tremor signal from Papandayan on 15 April. On 16 April, measurements of summit fumaroles revealed an increase in temperature and changes in water chemistry since 7 April. White plumes continued to rise to an altitude of 2.7 km (8,900 ft) a.s.l. and did not change. CVGHM increased the Alert Level to 2 (on a scale of 1-4) and reminded visitors and residents not to venture within 1 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://portal.vsi.esdm.go.id/joomla/ Ongoing Activity BATU TARA Komba Island (Indonesia) 7.792°S, 123.579°E; summit elev. 748 m Based on observations of satellite imagery, the Darwin VAAC reported that a low-level eruption plume from Batu Tara rose to an altitude of 2.4 km (8,000 ft) a.s.l. on 13 April and drifted NW. On 14 April, a steam-and-ash plume visible on satellite imagery again rose to an altitude of about 2.4 km (8,000 ft) a.s.l. and drifted W and NW. 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 http://www.ssd.noaa.gov/VAAC/OTH/AU/messages.html COLIMA México 19.514°N, 103.62°W; summit elev. 3850 m Multiple steam plumes from Colima were observed rising to altitudes of 3.9-4.6 km (12,800-15,100 ft) a.s.l. during 8-15 April. Gray plumes rose to altitudes of 4.5-4.9 km (15,000-16,100 ft) a.s.l. during 10-12 April. Plumes drifted mainly SW, NW, and W. On 14 April incandescent material was propelled about 50 m above the summit. Geologic Summary. The Colima volcanic complex is the most prominent volcanic center of the western Mexican Volcanic Belt. It consists of two southward-younging volcanoes, Nevado de Colima (the 4,320 m high point of the complex) on the N and the historically active Volcán de Colima on the S. Volcán de Colima (also known as Volcán Fuego) is a youthful stratovolcano constructed within a 5-km-wide caldera, breached to the S, that has been the source of large debris avalanches. Major slope failures have occurred repeatedly from both the Nevado and Colima cones, and have produced a thick apron of debris-avalanche deposits on three sides of the complex. Frequent historical eruptions date back to the 16th century. Occasional major explosive eruptions (most recently in 1913) have destroyed the summit and left a deep, steep-sided crater that was slowly refilled and then overtopped by lava dome growth. Source: Gobierno del Estado de Colima http://www.colima-estado.gob.mx/2006/seguridad/indvolcan.php KARYMSKY Eastern Kamchatka 54.05°N, 159.45°E; summit elev. 1536 m KVERT reported that seismic activity at Karymsky was above background levels during 4-11 April. Based on seismic interpretation, weak ash-and-gas explosions or hot avalanches may have occurred daily during the reporting period. Observations of satellite imagery revealed that a thermal anomaly was present in the crater during 4-6 April and an ash plume drifted 70-80 km ESE on 8 April. The Level of Concern Color Code remained at Orange. Geologic Summary. Karymsky, the most active volcano of Kamchatka's eastern volcanic zone, is a symmetrical stratovolcano constructed within a 5-km-wide caldera that formed about 7,600-7,700 radiocarbon years ago. Construction of the Karymsky stratovolcano began about 2,000 years later. The latest eruptive period began about 500 years ago, following a 2,300-year quiescence. Much of the cone is mantled by lava flows less than 200 years old. Historical eruptions have been Vulcanian or Vulcanian-Strombolian with moderate explosive activity and occasional lava flows from the summit crater. Most seismicity preceding Karymsky eruptions has originated beneath Akademia Nauk caldera, which is located immediately S of Karymsky volcano and erupted simultaneously with Karymsky in 1996. Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php KILAUEA Hawaii (USA) 19.421°N, 155.287°W; summit elev. 1222 m Based on observations during helicopter overflights, visual observations from HVO and National Park Service (NPS) crews, and web camera views, HVO reported that during 9-15 April lava flow activity from Kilauea's Thanksgiving Eve Breakout (TEB) and rootless shield complex was mostly concentrated at multiple locations of the Waikupanaha and Ki ocean entries. Occasionally, incandescence from a skylight adjacent to the TEB vents and from breakouts along the lava-tube system was noted. During the reporting period, Kilauea summit earthquakes were located beneath the summit, along the S-flank faults, and along the upper E rift zones. The eruption from the vent in Halema'uma'u Crater continued to produce white ash plumes that drifted mainly SW. During most nights incandescence was seen at the base of the plume. On 10 April, a small explosion from the vent ejected incandescent blocks to the rim of the crater, about 70 m above, and enlarged the vent by 5-10 ms. Seismic tremor was elevated. Sulfur dioxide emission rates from the summit area have been elevated at 2-4 times background values since early January. The emission rate fluctuated between 575 and 890 tonnes per day during 10-14 April, compared to a background rate of 150-200 tonnes per day. At Pu'u 'O'o crater the emission rate was between 1,760 and 2,750 tonnes during 8-13 April. According to news articles, Hawaii Volcanoes National Park was closed during 8-9 April due to elevated levels of sulfur dioxide. 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. Sources: US Geological Survey Hawaiian Volcano Observatory (HVO) http://hvo.wr.usgs.gov/, Associated Press http://www.foxnews.com/wires/2008Apr10/0,4670,KilaueaEruption,00.html MANAM Northeast of New Guinea (SW Pacific) 4.080°S, 145.037°E; summit elev. 1807 m Based on observations of satellite imagery, the Darwin VAAC reported low-level ash-and-steam plumes from Manam during 14-15 April. The plume drifted WNW. Geologic Summary. The 10-km-wide island of Manam, lying 13 km off the northern coast of mainland Papua New Guinea, is one of the country's most active volcanoes. Four large radial valleys extend from the unvegetated summit of the conical 1807-m-high basaltic-andesitic stratovolcano to its lower flanks. These "avalanche valleys," regularly spaced 90 degrees apart, channel lava flows and pyroclastic avalanches that have sometimes reached the coast. Two summit craters are present; both are active, although most historical eruptions have originated from the southern crater, concentrating eruptive products during much of the past century into the SE avalanche valley. Frequent historical eruptions, typically of mild-to-moderate scale, have been recorded at Manam since 1616. Occasional larger eruptions have produced pyroclastic flows and lava flows that reached flat-lying coastal areas and entered the sea, sometimes impacting populated areas. Source: Darwin Volcanic Ash Advisory Centre (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AU/messages.html OL DOINYO LENGAI Tanzania 2.764°S, 35.914°E; summit elev. 2962 m According to Frederick Belton's Ol Doinyo Lengai website, a visitor observed an ash plume during an overflight on 8 April. Geologic Summary. The symmetrical Ol Doinyo Lengai stratovolcano is the only volcano known to have erupted carbonatite tephras and lavas in historical time. The prominent volcano, known as "The Mountain of God," rises abruptly above the broad plain S of Lake Natron. The cone-building stage of the volcano ended about 15,000 years ago and was followed by periodic ejection of natrocarbonatite and nephelinite tephra during the Holocene. Historical eruptions have consisted of smaller tephra eruptions and emission of numerous natrocarbonatitic lava flows on the floor of the summit crater. Petrologists first observed the eruption of carbonatitic lava flows in the 1960s. Subsequent more frequent visits have documented long-term lava effusion in the summit crater that would not have been seen from the foot of the volcano. Source: Frederick Belton's Ol Doinyo Lengai website http://www.mtsu.edu/%7Efbelton/latestnews.html RABAUL New Britain (SW Pacific) 4.271°S, 152.203°E; summit elev. 688 m RVO reported that during 9-13 April ash and steam-and-ash plumes rose to altitudes of 1.7-2.2 km (5,600-7,200 ft) a.s.l. and drifted W and NW. Ashfall was reported in areas downwind, including Rabaul Town (3-5 km NW). Incandescence at night at the summit and intermittent roaring noises were reported. A large explosion on 10 April showered the flanks with lava fragments and produced a shockwave that rattled windows in Rabaul Town. Geologic Summary. The low-lying Rabaul caldera on the tip of the Gazelle Peninsula at the NE end of New Britain forms a broad sheltered harbor. The outer flanks of the 688-m-high asymmetrical pyroclastic shield volcano are formed by thick pyroclastic-flow deposits. The 8 x 14 km caldera is widely breached on the E, where its floor is flooded by Blanche Bay.Two major Holocene caldera-forming eruptions at Rabaul took place as recently as 3,500 and 1,400 years ago. Three small stratovolcanoes lie outside the northern and NE caldera rims. Post-caldera eruptions built basaltic-to-dacitic pyroclastic cones on the caldera floor near the NE and western caldera walls. Several of these, including Vulcan cone, which was formed during a large eruption in 1878, have produced major explosive activity during historical time. A powerful explosive eruption in 1994 occurred simultaneously from Vulcan and Tavurvur volcanoes and forced the temporary abandonment of Rabaul city. Source: Steve Saunders and Harman Patia, Rabaul Volcano Observatory (RVO) SAKURA-JIMA Kyushu (Japan) 31.585°N, 130.657°E; summit elev. 1117 m Based on information from JMA, the Tokyo VAAC reported that explosions from Sakura-jima during 11-15 April produced plumes that rose to altitudes of 2.1-3.4 km (7,000-11,000 ft) a.s.l. and drifted SW, NE, and SE. 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 slightly above background levels and hot avalanches possibly descended the growing lava dome daily during 4-11 April. According to video footage and visual observations, fumarolic activity from the lava dome also occurred every day. Observations of satellite imagery revealed that a thermal anomaly was present in the crater during the reporting period. The Level of Concern Color Code remained at Orange. Geologic Summary. The high, isolated massif of Shiveluch volcano (also spelled Sheveluch) rises above the lowlands NNE of the Kliuchevskaya volcano group and forms one of Kamchatka's largest and most active volcanoes. The currently active Molodoy Shiveluch lava-dome complex was constructed during the Holocene within a large breached caldera formed by collapse of the massive late-Pleistocene Strary Shiveluch volcano. At least 60 large eruptions of Shiveluch have occurred during the Holocene, making it the most vigorous andesitic volcano of the Kuril-Kamchatka arc. Frequent collapses of lava-dome complexes, most recently in 1964, have produced large debris avalanches whose deposits cover much of the floor of the breached caldera. During the 1990s, intermittent explosive eruptions took place from a new lava dome that began growing in 1980. The largest historical eruptions from Shiveluch occurred in 1854 and 1964. Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php TUNGURAHUA Ecuador 1.467°S, 78.442°W; summit elev. 5023 m The IG reported that although visual observations were occasionally limited due to cloud cover, ash and ash-and-steam plumes from Tungurahua were spotted and rose to altitudes of 6-9 km (19,700-30,000 ft) a.s.l. during 9-15 April. Ash plumes drifted NW, W, and SW; ashfall was reported in areas downwind on 9, 11, and 14 April. Roaring noises were reported almost daily. On 9 April, lahars descended S and NW drainages and disrupted the access road to Baños. During the night on 11 April, incandescent material was present at the summit and rolled about 600 m down the flanks. On 12 April, lahars descended NW and SW drainages. On 13 April, a mudflow traveled NW down the Mandur drainage. During 14-15 April, Strombolian activity at the summit was noted. 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/ UBINAS Perú 16.355°S, 70.903°W; summit elev. 5672 m Based on SIGMET advisories, the Buenos Aires VAAC reported that an ash plume from Ubinas rose to altitudes of 5.5-7 km (18,000-23,000 ft) a.s.l. and drifted ENE on 15 April. Geologic Summary. A small, 1.2-km-wide caldera that cuts the top of Ubinas, Peru's most active volcano, gives it a truncated appearance. Ubinas is the northernmost of three young volcanoes located along a regional structural lineament about 50 km behind the main volcanic front of Peru. The upper slopes of the stratovolcano, composed primarily of Pleistocene andesitic lava flows, steepen to nearly 45 degrees. The steep-walled, 150-m-deep summit caldera contains an ash cone with a 500-m-wide funnel-shaped vent that is 200 m deep. Debris-avalanche deposits from the collapse of the SE flank of Ubinas extend 10 km from the volcano. Widespread Plinian pumice-fall deposits from Ubinas include some of Holocene age. Holocene lava flows are visible on the volcano's flanks, but historical activity, documented since the 16th century, has consisted of intermittent minor explosive eruptions. Source: Buenos Aires Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AG/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@xxxxxxxx To contribute to the volcano list, send your message to: volcano@xxxxxxxx Please do not send attachments. ==============================================================
