**************************************************** SI/USGS Weekly Volcanic Activity Report 26 March-1 April 2008 **************************************************** Sally Kuhn Sennert - Weekly Report Editor kuhns@xxxxxx URL: http://www.volcano.si.edu/reports/usgs/ New Activity/Unrest: | Kilauea, Hawaii (USA) | Nevado del Huila, Colombia Ongoing Activity: | Anatahan, Mariana Islands (Central Pacific) | Fuego, Guatemala | Gamkonora, Halmahera (Indonesia) | Karymsky, Eastern Kamchatka | Kerinci, Sumatra (Indonesia) | Rabaul, New Britain (SW Pacific) | Santa María, Guatemala | 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 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 26 March-1 April lava flow activity from Kilauea's Thanksgiving Eve Breakout (TEB) shield was mostly concentrated at multiple points along the Waikupanaha and Ki ocean entries. Incandescence from the TEB vent was noted. During 25-26 March, an active lava flow was spotted SE of Kalalua Cone. Diffuse incandescence was seen on the web camera in Pu'u 'O'o crater. During the reporting period, Kilauea summit earthquakes were located beneath Halema`uma`u Crater, beneath the summit to the W, along the S-flank faults, and along the SW and E rift zones. The eruption from the vent in Halema'uma'u Crater continued to produce brown ash plumes that turned white for periods of time on 27, 28, and 31 March and on 1 April. Analysis of ash from the white plumes revealed that there was more volcanic glass than ash from the brown plumes. The plumes drifted mostly SW. Incandescence was seen at the base of the plume during the night. During 29 March-1 April, incandescent fragments were ejected from the vent. 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 700-1,500 tonnes per day during 26-31 March, compared to a background rate of 150-200 tonnes per day. 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 NEVADO DEL HUILA Colombia 2.93°N, 76.03°W; summit elev. 5365 m INGEOMINAS reported that seismic tremor from Nevado del Huila increased during 18-25 March. Residents reported noises, the odor of sulfur, and small ash plumes. Seismicity increased again on 29 March; INGEOMINAS raised the Alert Level to Orange (on a 4-color scale, Orange is second highest). 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. Source: Instituto Colombiano de Geología y Minería (INGEOMINAS) http://www.ingeominas.gov.co// Ongoing Activity ANATAHAN Mariana Islands (Central Pacific) 16.35°N, 145.67°E; summit elev. 790 m The USGS reported that seismicity at Anatahan decreased during 26-31 March. The Volcanic Alert Level was lowered to Advisory and the Aviation Color Code was lowered to Yellow on 31 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 FUEGO Guatemala 14.473°N, 90.880°W; summit elev. 3763 m Based on observations of satellite imagery, the Washington VAAC reported that multiple ash puffs from Fuego were visible on satellite imagery on 31 March drifting SW and on 1 April. 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: Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html GAMKONORA Halmahera (Indonesia) 1.38°N, 127.53°E; summit elev. 1635 m CVGHM reported that seismic activity from Gamkonora increased on 24 March. The Alert Level remained at 2 (on a scale of 1-4) and visitors were reminded not to approach or climb the crater. Geologic Summary. The shifting of eruption centers on Gamkonora, at 1635 m the highest peak of Halmahera, has produced an elongated series of summit craters along a N-S trending rift. Youthful-looking lava flows originate near the cones of Gunung Alon and Popolojo, south of Gamkonora. Since its first recorded eruption in the 16th century, Gamkonora has typically produced small-to-moderate explosive eruptions. Its largest historical eruption, in 1673, was accompanied by tsunamis that inundated villages. Source: Center of Volcanology and Geological Hazard Mitigation (CVGHM) http://portal.vsi.esdm.go.id/joomla/ 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 23 and 25-26 March, and at background levels during 21-22, 24, and 27-28 March. Based on seismic interpretation, ash plumes possibly rose to an altitude of 3.3 km (10,800 ft) a.s.l. on 22 March. Weak ash explosions or avalanches possibly occurred during 23-26 March. Based on observations of satellite imagery and information from KVERT, the Tokyo VAAC reported that eruption plumes rose to altitudes of 3-7 km (10,000-23,000 ft) a.s.l. during 28-29 March. 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. 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 KERINCI Sumatra (Indonesia) 1.697°S, 101.264°E; summit elev. 3800 m CVGHM reported that seismicity from Kerinci increased during 17-24 March. On 24 March, an ash-and-gas plume rose to an altitude of 4.3 (14,100 ft) a.s.l. The Alert Status remained at 2 (on a scale of 1-4). Residents and visitors were advised not to enter an area within 1 km of the summit. Geologic Summary. The summit of 3800-m-high Kerinci, Indonesia's highest volcano, contains a deep 600-m-wide crater often partially filled by a small crater lake. The massive 13 x 25 km wide volcano towers 2,400-3,300 m above surrounding plains. Kerinci is elongated in a N-S direction and is capped by an unvegetated young summit cone constructed NE of an older crater remnant. One of Sumatra's most active volcanoes, Gunung Kerinci has produced a series of moderate explosive eruptions during the 19th and 20th centuries. Source: Center of Volcanology and Geological Hazard Mitigation (CVGHM) http://portal.vsi.esdm.go.id/joomla/ RABAUL New Britain (SW Pacific) 4.271°S, 152.203°E; summit elev. 688 m During 26 March-1 April, RVO reported that ash and steam-and-ash plumes rose to altitudes of 1.2-2.7 km (3,900-8,900 ft) a.s.l. and drifted SW, W, NW, and N. Incandescent material was propelled above the crater rim and explosive 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 and Steve Saunders, Rabaul Volcano Observatory (RVO) SANTA MARIA Guatemala 14.756°N, 91.552°W; summit elev. 3772 m Based on observations of satellite imagery, the Washington VAAC reported that ash puffs from Santa María's Santiaguito lava dome complex drifted SW on 1 April. 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. Source: 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 seismic activity at Shiveluch was slightly above background levels during 21-28 March and hot avalanches possibly descended the dome during 19-22 March. According to video footage and visual observations, fumarolic activity from the lava dome was observed during 20-24 and 27 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 during 25-31 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, and at the head of Gages Valley to the W where the emissions were bluish. 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 occasionally limited due to cloud cover, ash-and-steam plumes from Tungurahua were spotted and rose to altitudes of 6-8 km (19,700-26,200 ft) a.s.l. during 25 March-1 April. Ash plumes drifted SW, W, and NW and were intermittently produced by explosions; ashfall was reported in areas downwind during 25 and 27-28 March. On 25 March, explosions propelled incandescent blocks from the summit that fell onto the flanks. Explosions also vibrated doors and windows in areas as far as 13 km away on 26 March and produced an ash plume to an altitude of 4 km (13,100 ft) a.s.l. on 27 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 ash plumes from Ubinas rose to altitudes of 3.7-6.7 km (12,000-22,000 ft) a.s.l. on 26 March and 1 April. The plumes drifted SW and NW, respectively. 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. ==============================================================
