*********************************************************** SI/USGS Weekly Volcanic Activity Report 19-25 March 2008 *********************************************************** Sally Kuhn Sennert - Weekly Report Editor kuhns@xxxxxx URL: http://www.volcano.si.edu/reports/usgs/ New Activity/Unrest: | Garbuna Group, New Britain (SW Pacific) | Karymsky, Eastern Kamchatka | Kilauea, Hawaii (USA) Ongoing Activity: | Anatahan, Mariana Islands (Central Pacific) | Fuego, Guatemala | Llaima, Central Chile | Rabaul, New Britain (SW Pacific) | Shiveluch, Central Kamchatka (Russia) | Soufrière Hills, Montserrat | Suwanose-jima, Ryukyu Islands (Japan) | Tungurahua, Ecuador The Weekly Volcanic Activity Report is a cooperative project between the Smithsonian's Global Volcanism Program and the US Geological Survey's Volcano Hazards Program. Updated by 2300 UTC every Wednesday, notices of volcanic activity posted on these pages are preliminary and subject to change as events are studied in more detail. This is not a comprehensive list of all of Earth's volcanoes erupting during the week, but rather a summary of activity at volcanoes that meet criteria discussed in detail in the "Criteria and Disclaimers" section. Carefully reviewed, detailed reports on various volcanoes are published monthly in the Bulletin of the Global Volcanism Network. Note: Many news agencies do not archive the articles they post on the Internet, and therefore the links to some sources may not be active. To obtain information about the cited articles that are no longer available on the Internet contact the source. New Activity/Unrest GARBUNA GROUP New Britain (SW Pacific) 5.45°S, 150.03°E; summit elev. 564 m RVO reported that white plumes from two sources at the summit of Garbuna drifted SE during 19-21 March. Ashfall and a strong sulfur odor were reported in Kimbe Town (about 17 km SE) on 19 March. Geologic Summary. The basaltic-to-dacitic Garbuna volcano group consists of three volcanic peaks, Krummel, Garbuna, and Welcker. They are located along a 7-km N-S line above a shield-like foundation at the southern end of the Willaumez Peninsula. The central and lower peaks of the centrally located 564-m-high Garbuna volcano contain a large vegetation-free area that is probably the most extensive thermal field in Papua New Guinea. A prominent lava dome and blocky lava flow in the center of thermal area have resisted destruction by thermal activity, and may be of Holocene age. Krummel volcano at the S end of the group contains a summit crater, breached to the NW. The highest peak of the Garbuna group is 1,005-m-high Welcker volcano, which has fed blocky lava flows that extend to the eastern coast of the peninsula. Source: Herman Patia, Rabaul Volcano Observatory (RVO) KARYMSKY Eastern Kamchatka 54.05°N, 159.45°E; summit elev. 1536 m KVERT reported that seismic activity at Karymsky was slightly above background levels during 13-16 March and at background levels during 17-19 March. Weak ash explosions or avalanches possibly occurred on 15 March when observations of satellite imagery revealed an ash plume drifting 40 km SE. On 16 March, ash deposits 15-20 km in length mantled the snow to the NE and ESE. 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 visual observations from HVO and National Park Service (NPS) crews as well as web camera views, HVO reported that during 19-25 March lava flow activity from Kilauea's Thanksgiving Eve Breakout (TEB) shield was mostly concentrated in and near the Royal Gardens subdivision and at multiple points along the Waikupanaha and Ki ocean entries. Lava flows advanced eastward over an old sea cliff and onto the 1990 lava delta, and were 120 m W of the viewing area on 23 March. Flows through a kipuka produced fires during 18-22 March. During the reporting period, Kilauea summit earthquakes were located beneath the S-half of the caldera, beneath Halema`uma`u Crater, N of Pu'u 'O'o, along the S-flank faults, and along the SW rift zone. At 0258 on 19 March, an explosion from Halema'uma'u Crater scattered debris over an area of about 75 acres (30 hectares), covering a portion of Crater Rim Drive and damaging the overlook. On Crater Rim Drive, the debris was up to 2 cm in diameter and increased in size and thickness towards the overlook. The largest block ejected during the explosion was about 1 cubic meter. Small impact craters from 30-cm-blocks were abundant in the overlook area. The event was the first explosive activity in the crater since 1924. During 19-24 March, seismic tremor levels were elevated above their already high pre-explosion levels and incandescence at the gas vent was intermittent. Small incandescent tephra particles erupted from the vent overnight during 23-24 March and were deposited on the rim of the crater. On 24 March, the gas plume from the vent became ash-laden and rose to an altitude of about 2.8 km (9,200 ft) a.s.l. The plumes drifted SW. Geologists found Pele's hair, Pele's tears, and spatter in the overlook area. The largest spatter was 10 cm in diameter. During 24-25 March, overnight observers reported incandescence at the base of the continuous ash plume. Based on a pilot observation, the Washington VAAC reported that ash plumes rose to an altitude of 2 km (6,500 ft) a.s.l. on 25 March and drifted SW. The eruption was the first to produce lava in Halema'uma'u since 1982. 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 1,200-2,200 tonnes per day during 18-23 March, compared to a background rate of 150-200 tonnes per day. On 23 March, the emission rate was 2,200 tonnes per day at Pu'u 'O'o. Sulfur dioxide concentrations were mostly below detection limits at the Jaggar museum and the Kilauea Visitors Center. 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/, Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html Ongoing Activity ANATAHAN Mariana Islands (Central Pacific) 16.35°N, 145.67°E; summit elev. 790 m The USGS reported that seismicity at Anatahan remained elevated during 19-25 March. Based on observations of satellite imagery, the Washington VAAC reported that diffuse gas-and-ash plumes drifted SW, NE, and E during 19-22 March. The Volcanic Alert Level remained at Watch and the Aviation Color Code remained at Orange. Geologic Summary. The elongate, 9-km-long island of Anatahan in the central Mariana Islands consists of large stratovolcano with a 2.3 x 5 km, E-W-trending compound summit caldera. The larger western caldera is 2.3 x 3 km wide, and its western rim forms the island's 790-m high point. Ponded lava flows overlain by pyroclastic deposits fill the floor of the western caldera, whose SW side is cut by a fresh-looking smaller crater. The 2-km-wide eastern caldera contained a steep-walled inner crater whose floor prior to the 2003 eruption was only 68 m above sea level. Sparseness of vegetation on the most recent lava flows on Anatahan had indicated that they were of Holocene age, but the first historical eruption of Anatahan did not occur until May 2003, when a large explosive eruption took place forming a new crater inside the eastern caldera. Sources: Emergency Management Office of the Commonwealth of the Mariana Islands and the US Geological Survey Hawaiian Volcano Observatory http://volcano.wr.usgs.gov/cnmistatus.php, Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html FUEGO Guatemala 14.473°N, 90.880°W; summit elev. 3763 m INSIVUMEH reported that during 22-25 March more frequent explosions (4-5 per hour) from Fuego produced ash plumes to altitudes of 4.1-4.6 km (13,500-15,100 ft) a.s.l. The plumes drifted 6-8 km S and SE. Most explosions produced degassing and rumbling noises, and shock waves that vibrated windows and ceilings within a 5-8 km radius. Geologic Summary. Volcán Fuego, one of Central America's most active volcanoes, is one of three large stratovolcanoes overlooking Guatemala's former capital, Antigua. The scarp of an older edifice, Meseta, lies between 3,763-m-high Fuego and its twin volcano to the N, Acatenango. Construction of Meseta volcano continued until the late Pleistocene or early Holocene, after which growth of the modern Fuego volcano continued the southward migration of volcanism that began at Acatenango. Frequent vigorous historical eruptions have been recorded at Fuego since the onset of the Spanish era in 1524, and have produced major ashfalls, along with occasional pyroclastic flows and lava flows. The last major explosive eruption from Fuego took place in 1974, producing spectacular pyroclastic flows visible from Antigua. Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH) http://www.insivumeh.gob.gt/ LLAIMA Central Chile 38.692°S, 71.729°W; summit elev. 3125 m SERNAGEOMIN reported that fumarolic activity from the central pyroclastic cone in Llaima's main crater reactivated on 13 March and intensified during 15-17 March. Sulfur dioxide plumes rose to an altitude of 3.6 km (11,800 ft) a.s.l. and drifted E. People from nearby areas reported incandescence in the crater during 19-21 March. Incandescent material propelled from the crater was observed at night during 20-21 March. Geologic Summary. Llaima, one of Chile's largest and most active volcanoes, contains two main historically active craters, one at the summit and the other to the SE. The massive 3,125-m-high, glacier-covered stratovolcano has a volume of 400 cu km. A Holocene edifice built primarily of accumulated lava flows was constructed over an 8-km-wide caldera that formed about 13,200 years ago, following eruption of the 24 cu km Curacautín Ignimbrite. More than 40 scoria cones dot the volcano's flanks. Following the end of an explosive stage about 7,200 years ago, construction of the present edifice began, characterized by Strombolian, hawaiian, and infrequent subplinian eruptions. Frequent moderate explosive eruptions with occasional lava flows have been recorded since the 17th century. Source: Servicio Nacional de Geología y Minería (SERNAGEOMIN) http://www.sernageomin.cl/index.php RABAUL New Britain (SW Pacific) 4.271°S, 152.203°E; summit elev. 688 m RVO reported that ash plumes from Rabaul caldera's Tavurvur cone rose to altitudes of 1.7-3.2 km (5,600-10,500 ft) a.s.l. and drifted in almost all directions during 19-26 March. Ashfall was reported daily in areas downwind, including Rabaul Town (3-5 km NW), Matupit Island (2 km W), and Kokopo (20 km SE). Incandescence at the summit was observed and roaring noises were occasionally heard. An explosion produced lava fragments that showered the flanks on 20 March. Shockwaves rattled windows in Rabaul Town. Another explosion showered the flanks with lava fragments on 22 March. During 25-26 March, ashfall affected flights into Tokua (about 20 km SE of Rabaul). 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: Herman Patia, Rabaul Volcano Observatory (RVO) 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 during 14-21 March. Based on seismic interpretation, ash plumes possibly rose to an altitude of 3.5 km (11,200 ft) a.s.l. on 13 and 17 March. According to video footage and visual observations, an ash plume rose to an altitude of 4 km (12,800 ft) a.s.l. on 17 March and fumarolic activity from the lava dome was observed during 17 and 19-20 March. Observations of satellite imagery revealed that a gas plume drifted 17 km SW on 17 March and 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 SOUFRIERE HILLS Montserrat 16.72°N, 62.18°W; summit elev. 915 m MVO reported that that during 19-25 March the lava dome at Soufrière Hills changed very little, based on visual observations and other measurable parameters. Fumarolic activity was concentrated on the NW and SE flanks where abundant sulfur deposits were noted, and at the head of Gages Valley to the W. The Alert Level remained elevated at 4 (on a scale of 0-5). Geologic Summary. The complex dominantly andesitic Soufrière Hills volcano occupies the southern half of the island of Montserrat. The summit area consists primarily of a series of lava domes emplaced along an ESE-trending zone. English's Crater, a 1-km-wide crater breached widely to the E, was formed during an eruption about 4,000 years ago in which the summit collapsed, producing a large submarine debris avalanche. Block-and-ash flow and surge deposits associated with dome growth predominate in flank deposits at Soufrière Hills. Non-eruptive seismic swarms occurred at 30-year intervals in the 20th century, but with the exception of a 17th-century eruption that produced the Castle Peak lava dome, no historical eruptions were recorded on Montserrat until 1995. Long-term small-to-moderate ash eruptions beginning in that year were later accompanied by lava-dome growth and pyroclastic flows that forced evacuation of the southern half of the island and ultimately destroyed the capital city of Plymouth, causing major social and economic disruption. Source: Montserrat Volcano Observatory (MVO) http://www.mvo.ms/ SUWANOSE-JIMA Ryukyu Islands (Japan) 29.635°N, 129.716°E; summit elev. 799 m Based on information from JMA, the Tokyo VAAC reported that an explosion from Suwanose-jima occurred on 22 March. The altitude and direction of a possible resultant plume were not reported. Geologic Summary. The 8-km-long, spindle-shaped island of Suwanose-jima in the northern Ryukyu Islands consists of an andesitic stratovolcano with two historically active summit craters. Only about 50 persons live on the sparsely populated island. The summit of the volcano is truncated by a large breached crater extending to the sea on the east flank that was formed by edifice collapse. Suwanose-jima, one of Japan's most frequently active volcanoes, was in a state of intermittent Strombolian activity from On-take, the NE summit crater, that began in 1949 and lasted nearly a half century. The largest historical eruption took place in 1813-14, when thick scoria deposits blanketed residential areas, after which the island was uninhabited for about 70 years. The SW crater produced lava flows that reached the western coast in 1813, and lava flows reached the eastern coast of the island in 1884. Source: Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html TUNGURAHUA Ecuador 1.467°S, 78.442°W; summit elev. 5023 m IG reported that although visual observations were limited due to cloud cover, ash-and-steam plumes from Tungurahua were spotted and rose to altitudes of 5.5-8 km (18,000-26,200 ft) a.s.l. during 19-25 March. Ash plumes drifted S, SW, W, NNW, and NNE; ashfall was reported in areas downwind during 19-21 and 23-25 March. Roaring noises were reported on 23 March. During 24-25 March, small explosions were registered by the seismic network. 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/ +++++++++++++++++++++++++++++++++++++ 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. ==============================================================
