************************************************************ SI/USGS Weekly Volcanic Activity Report 5-11 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) | Kilauea, Hawaii (USA) | Ol Doinyo Lengai, Tanzania Ongoing Activity: | Anatahan, Mariana Islands (Central Pacific) | Karangetang [Api Siau], Sangihe Islands (Indonesia) | 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 11 March, an ash-and-steam plume from Batu Tara rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted 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 KILAUEA Hawaii (USA) 19.421°N, 155.287°W; summit elev. 1222 m Based on visual observations and web camera views when weather permitted, HVO reported that during 5-11 March lava flow activity from Kilauea's Thanksgiving Eve Breakout (TEB) shield was concentrated at rootless satellitic shields to the E and SE, in the Royal Gardens subdivision, and at two ocean entries. A lava flow from the rootless shield complex traveled E towards Kalalua. Earthquakes were located beneath Halema'uma'u crater, along the S-flank faults, beneath the summit, and along the SW rift zones. During 4-6 March, the TEB flow expanded E above and within Royal Gardens, and also split into two 100-m-wide lobes (E and W) about 150 m N of the County access road. According to local sources, at about 2330 local time on 5 March the W lobe entered the ocean at the Waikupanaha entry, named for a nearby pond that was covered by lava in the 1990s. During 7-11 March, incandescence was visible from vents on top of two of the SE satellitic shields. On 8 March, the W lobe continued to build a delta; the E lobe was 470 m from the ocean. A public viewing area with excellent views of the pahoehoe flows opened. On 9 March, the Waikupanaha entry steamed from four points, but small streams of lava were only visible entering the ocean in the evening. The delta was 500 m wide and extended 100-150 m out into the ocean. During 9-10 March, smoke plumes and incandescence from Royal Gardens suggested that active breakouts from the tube system had possibly diminished the amount of lava arriving at the ocean. Diffuse incandescence was observed on the web camera in Pu'u 'O'o crater on 10 and 11 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/ OL DOINYO LENGAI Tanzania 2.764°S, 35.914°E; summit elev. 2962 m Based on pilot reports, MVO reports, and observations of satellite imagery, the Toulouse VAAC reported that ash plumes rose to altitudes of 8.8-10.7 km (29,000-35,000 ft) a.s.l. during 5-6 and 9 March. A cloud at an altitude of 12.2 km (40,000 ft) a.s.l. that possibly contained ash was detected in satellite imagery on 11 March. The cloud drifted S. 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 Ongoing Activity ANATAHAN Mariana Islands (Central Pacific) 16.35°N, 145.67°E; summit elev. 790 m The USGS reported that levels of seismicity at Anatahan were elevated during 5-10 March, but decreased significantly on 11 March. On 5 March, diffuse ash plumes drifted as far as 120 km NW and 95 km SE. During 5-7 March, continuous ash emissions produced plumes that rose to altitudes less than 3 km (10,000 ft) a.s.l. and drifted NE, SW, and W. On 8 and 9 March, a sulfur dioxide plume was detected by the satellite-based Ozone Monitoring Instrument (OMI) and drifted SW and WSW. According to reports from the Washington VAAC, a diffuse ash plume rose to an altitude less than 3 km (10,000 ft) a.s.l. and drifted W on 10 March. 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. Source: 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 KARANGETANG [API SIAU] Sangihe Islands (Indonesia) 2.78°N, 125.40°E; summit elev. 1784 m Based on a pilot observation, the Darwin VAAC reported a possible low-level ash plume on 12 March. Geologic Summary. Karangetang (also known as Api Siau) lies at the northern end of the island of Siau, N of Sulawesi, and contains five summit craters strung along a N-S line. One of Indonesia's most active volcanoes, Karangetang has had more than 40 recorded eruptions since 1675. Twentieth-century eruptions have included frequent explosions, sometimes accompanied by pyroclastic flows and lahars. Source: Darwin Volcanic Ash Advisory Centre (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AU/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 5-11 March. The plumes occasionally contained slight amounts of ash. An explosion on 8 March resulted in ash plumes that rose to an altitude of 6.4 km (21,000 ft) a.s.l. and drifted NE. An ash plume was spotted the next day that rose to the same altitude and also 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 during 4-7 March white plumes rose from Rabaul caldera's Tavurvur cone and incandescence at the summit was noted. Ash was emitted on 6 March. A slight smell of hydrogen-sulfide gas was reported in areas to the S on 5 March. During 8-11 March, ash plumes rose to altitudes of 1.2-1.7 km (3,900-5,600 ft) a.s.l. and drifted NW, W, SW, S, and SE. Ashfall was reported in areas downwind, including Kokopo town (SE) during 8-10 March, and Rabaul town (NW) on 11 March. 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 and Steve Saunders, 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 and small hot avalanches descended the lava dome during 29 February-7 March. Ash plumes were possibly present. According to video footage and visual observations, fumarolic activity was observed during 29 February and 2-6 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 4-11 March the lava dome at Soufrière Hills changed very little, based on visual observations during an overflight on 6 March. The E talus slope continued to erode, with both fresh and older material accumulating in the Tar River Valley. Fumaroles around the lava dome were active, but less vigorous W in the Gages Wall area on 7 March. 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 plumes from Tungurahua were spotted and rose to altitudes of 5.5-8 km (18,000-26,200 ft) a.s.l. during 4-11 March. Incandescence at the summit was observed at night during 4-6 March. Ash plumes drifted W, SW, S, SE, E, and NE; ashfall was reported in areas downwind on 5, 6, and 10 March. Lahars descended drainages to the W and in the Pampas sector to the S on 6 and 8 March. On 8 March, lahars mobilized blocks up to 3 m in diameter. Very active fumaroles near the crater were spotted on 11 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 reports and observations of satellite imagery, the Buenos Aires VAAC reported that an ash plume from Ubinas rose to altitudes of 7 km (23,000 ft) a.s.l. and drifted W and SW on 9 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. ==============================================================
