************************************************************** SI/USGS Weekly Volcanic Activity Report 12-18 March 2008 ************************************************************** Sally Kuhn Sennert - Weekly Report Editor kuhns@xxxxxx URL: http://www.volcano.si.edu/reports/usgs/ New Activity/Unrest: | Batu Tara, Komba Island (Indonesia) | Garbuna Group, New Britain (SW Pacific) | Karymsky, Eastern Kamchatka | Kilauea, Hawaii (USA) Ongoing Activity: | Anatahan, Mariana Islands (Central Pacific) | Colima, México | Ol Doinyo Lengai, Tanzania | Popocatépetl, México | Rabaul, New Britain (SW Pacific) | Shiveluch, Central Kamchatka (Russia) | Soufrière Hills, Montserrat | 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 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 on 12 March an ash-and-steam plume from Batu Tara rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted SE. 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 GARBUNA GROUP New Britain (SW Pacific) 5.45°S, 150.03°E; summit elev. 564 m RVO reported that renewed eruptive activity from Garbuna started on 11 March and consisted of ash emissions accompanied by occasional booming noises. The resultant ash plumes rose to an altitude less that 1.6 km (5,200 ft) a.s.l. and drifted SW. Fine ashfall was reported in areas downwind. Ash emissions continued during 12-13 March. During 14-15 March, steam-and-ash plumes again rose to an altitude less that 1.6 km (5,200 ft) a.s.l. and drifted SW. Ashfall and a sulfur odor was reported from areas downwind. Occasional booming noises were heard. On 16 March, steam plumes rose to an altitude of 1.6 km (5,200 ft) a.s.l. Observers from KVO (15 km SE) reported that multiple steam plumes rose from numerous vents at the summit. Steam plumes were again noted on 17 and 18 March and a strong sulfur odor was noticed on 18 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 7-14 March. Observations of satellite imagery revealed that a weak thermal anomaly was present in the crater on 9 and 12 March. On 13 March, an ash plume rose to an altitude of 2.5 km (8,200 ft) a.s.l. Ash deposits on the snow about 3-4 km SE of the summit were observed on satellite imagery. The Level of Concern Color Code was raised from Yellow to 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 12-18 March lava flow activity from Kilauea's Thanksgiving Eve Breakout (TEB) shield was concentrated at rootless satellitic shields to the SE, in and near the Royal Gardens subdivision, and at ocean entries. During 12-13 March, lava flows entered the ocean at multiple locations on the Waikupanaha delta and at a new location 100 m E. A breakout from the E margin near the access road split into two lobes, surrounded and destroyed existing structures and covered the access road, and entered a nearby kipuka. On 14 March, lava entered the ocean at two primary Waikupanaha delta locations; the W delta was 600 m wide. An overflight revealed that the Kalalua flow (from the rootless shield complex to the E and SE of the TEB shield) advanced 240 m since 6 March. Lobes from the E-margin lava flows advanced SE into the kipuka and S of the access road, and entered the ocean during 14-15 March. Breakout lava flows were visible inland of the Waikupanaha and new ocean entires, at the base of Royal Gardens, and near the top of the pali. During 15-18 March, lava flows entered the ocean at multiple locations on the Waikupanaha delta and at a new location, 200 m W of the viewing area, named the Ki entry. On 17 March, breakouts and burned vegetation were visible within 1 km of the ocean entries. During the reporting period, Kilauea summit earthquakes were located E of Halema'uma'u crater, along the S-flank faults, and along the SW and lower E rift zones. Sometime during 10-12 March, a new gas vent appeared just above the base of the E wall of Halema'uma'u crater. During 14-18 March, incandescence from the gas vent originated from a spot about 30 m wide within the rubble at the base of the E crater wall. Cracking rocks, possibly due to the heat, were heard by scientists at the Halema'uma'u overlook. On 17 March, the area of incandescence appeared slightly enlarged with a new area higher on the crater wall and to the N. Sulfur dioxide emission rates from the summit area have been elevated at 2-4 times background values since early January. The emission rate abruptly increased on 12 March and fluctuated between 1,600-2,500 tonnes per day during 12-16 March, compared to a background rate of 150-200 tonnes per day. On 16 March, emission rates reached 2,500 tonnes per day, the highest recorded at Kilauea's summit since measurements began in 1979. 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/ Ongoing Activity ANATAHAN Mariana Islands (Central Pacific) 16.35°N, 145.67°E; summit elev. 790 m The USGS reported that elevated seismicity at Anatahan continued during 12-13 March, then dropped to near background levels on 14 and 15 March. Based on observations of satellite imagery, the Washington VAAC reported that an ash plume was spotted around the summit area on 13 March and later that day drifted W and NNE. On 15 March, a possible diffuse ash plume was visible on satellite imagery drifting W. During 16-18 March seismicity remained low but was punctuated by occasional short bursts (typically about a minute in duration) of increased tremor. 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 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 12-18 March. Gray plumes rose to altitudes of 4-4.8 km (13,100-15,700 ft) a.s.l. on 14 and 18 March. Plumes drifted multiple directions. 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 OL DOINYO LENGAI Tanzania 2.764°S, 35.914°E; summit elev. 2962 m Based on a pilot observation, the Toulouse VAAC reported that an ash plume rose to an altitude of 12.2 km (40,000 ft) a.s.l. on 13 March. The plume was not confirmed using satellite imagery. A plume at an altitude of 13.7 km (45,000 ft) a.s.l. was observed on satellite imagery on 16 March. 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: Toulouse Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/FR/messages.html POPOCATEPETL México 19.023°N, 98.622°W; summit elev. 5426 m CENAPRED reported that emissions of steam and gas from Popocatépetl were visible during 12-18 March. The plumes occasionally contained slight amounts of ash. Ash plumes on 17 March rose to altitudes of 7.4-7.9 km (24,300-26,000 ft) a.s.l. and drifted NE. 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/ 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 2.7-3.2 km (8,900-10,500 ft) a.s.l. and drifted N, NW, W, SW, and S during 12-19 March. Ashfall was reported in areas downwind, including Rabaul Town (3-5 km NW) and Matupit Island (2 km W). Incandescence at the summit was observed and roaring noises were occasionally heard. 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 7-14 March. Based on seismic interpretation, ash plumes possibly rose to an altitude of 4.1 km (13,500 ft) a.s.l. on 6 and 7 March. According to video footage and visual observations, fumarolic activity from the lava dome was observed during 6-8 March. 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 SOUFRIERE HILLS Montserrat 16.72°N, 62.18°W; summit elev. 915 m MVO reported that that during 11-18 March the lava dome at Soufrière Hills changed very little, based on visual observations on 12 March and other measurable parameters. The E side of the lava dome continued to erode, with material accumulating in the Tar River Valley. Fumarolic activity was concentrated on the NW and SE flanks 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/ TUNGURAHUA Ecuador 1.467°S, 78.442°W; summit elev. 5023 m IG reported that although visual observations were very limited due to cloud cover, ash-and-steam and ash plumes from Tungurahua were spotted and rose to altitudes of 5.2-7 km (17,100-23,000 ft) a.s.l. during 12-18 March. Ash plumes drifted SW, W, NW, NE, and E; ashfall was reported in areas downwind (SW, W, and NW) on 13, 14, 16, and 18 March. 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 pilot observations, the Buenos Aires VAAC reported that an ash plume from Ubinas rose to altitudes of 5.5-6.1 km (18,000-20,000 ft) a.s.l. and drifted N on 17 March. 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. ==============================================================
