************************************************************* SI/USGS Weekly Volcanic Activity Report 3-9 June 2009 ************************************************************* Sally Kuhn Sennert - Weekly Report Editor kuhns@xxxxxx URL: http://www.volcano.si.edu/reports/usgs/ New Activity/Unrest: | Galeras, Colombia | Karangetang [Api Siau], Siau I | Sangeang Api, Lesser Sunda Islands (Indonesia) | Slamet, Central Java (Indonesia) Ongoing Activity: | Batu Tara, Komba Island (Indonesia) | Chaitén, Southern Chile | Dukono, Halmahera | Fuego, Guatemala | Karymsky, Eastern Kamchatka | Kelut, Eastern Java (Indonesia) | Kilauea, Hawaii (USA) | Llaima, Central Chile | Manam, Northeast of New Guinea (SW Pacific) | Pacaya, Guatemala | Popocatépetl, México | Rabaul, New Britain | Redoubt, Southwestern Alaska | Sakura-jima, Kyushu | Santa María, Guatemala | 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 GALERAS Colombia 1.22°N, 77.37°W; summit elev. 4276 m INGEOMINAS reported that an eruption of Galeras on 7 June was preceded by a M 4 earthquake located about 3 km SSE of the crater at a depth of 2 km, and felt by nearby residents. The eruption produced an ash plume that rose to an altitude of 6.8 km (22,300 ft) a.s.l. and drifted NW. Vibrations from an accompanying acoustic wave were detected by residents. Ashfall was reported in areas downwind. The Alert Level was raised to I (Red; "imminent eruption or in progress"). On 8 June, two explosions about 5 minutes apart were heard by people up to 45 km away. The event was preceded by an M 3.9 earthquake located 1 km E at a depth near 2 km. Ashfall was reported in areas to the NW, up to 180 km away. Based on analysis of satellite imagery, the Washington VAAC reported that the ash plume rose to an altitude of 10 km (33,000 ft) a.s.l. and drifted NW. They also reported that a second and larger eruption produced an ash plume that rose to an altitude of 13.7 km (45,000 ft) a.s.l. and drifted SE. On 9 June, INGEOMINAS reported that seismicity and sulfur dioxide output were low, and that clear conditions revealed no emissions. Geologic Summary. Galeras, a stratovolcano with a large breached caldera located immediately W of the city of Pasto, is one of Colombia's most frequently active volcanoes. The dominantly andesitic Galeras volcanic complex has been active for more than 1 million years, and two major caldera collapse eruptions took place during the late Pleistocene. Longterm extensive hydrothermal alteration has affected the volcano. This has contributed to large-scale edifice collapse that has occurred on at least three occasions, producing debris avalanches that swept to the W and left a large horseshoe-shaped caldera inside which the modern cone has been constructed. Major explosive eruptions since the mid Holocene have produced widespread tephra deposits and pyroclastic flows that swept all but the southern flanks. A central cone slightly lower than the caldera rim has been the site of numerous small-to-moderate historical eruptions since the time of the Spanish conquistadors. Sources: Instituto Colombiano de Geología y Minería (INGEOMINAS) http://www.ingeominas.gov.co//, Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html KARANGETANG [API SIAU] Siau I 2.78°N, 125.40°E; summit elev. 1784 m CVGHM reported that during 1-6 June lava flows from Karangetang traveled 50 m E and 600 m SE. Incandescent rocks, from the main craters and ends of the lava flows, traveled as far as 2 km towards multiple river valleys, including the Keting River to the S. On 1 June, white-to-gray-to-brownish plumes rose 700 m above the main crater. Incandescent lava was ejected 500-700 m. On 4 June, tremor amplitude and the number of earthquakes decreased. During 4-6 June, white plumes rose 50-300 m from the main crater. On 7 and 8 June, fog often prevented observations and incandescent rocks were rarely seen. The Alert Level was lowered to 3 (on a scale of 1-4) on 9 June. 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: Center of Volcanology and Geological Hazard Mitigation (CVGHM) http://portal.vsi.esdm.go.id/joomla/ SANGEANG API Lesser Sunda Islands (Indonesia) 8.20°S, 119.07°E; summit elev. 1949 m CVGHM reported that on 4 June the Alert Level for Sangeang Api was raised to 2 (on a scale of 1-4) due to recent increases in the number of earthquakes. White plumes rose 5-25 m during 1 May-3 June. Geologic Summary. Sangeang Api volcano, one of the most active in the Lesser Sunda Islands, forms a small 13-km-wide island off the NE coast of Sumbawa Island. Two large trachybasaltic-to-tranchyandesitic volcanic cones, 1949-m-high Doro Api and 1795-m-high Doro Mantoi, were constructed in the center and on the eastern rim, respectively, of an older, largely obscured caldera. Flank vents occur on the south side of Doro Mantoi and near the northern coast. Intermittent historical eruptions have been recorded since 1512, most of them during in the 20th century. Source: Center of Volcanology and Geological Hazard Mitigation (CVGHM) http://portal.vsi.esdm.go.id/joomla/ SLAMET Central Java (Indonesia) 7.242°S, 109.208°E; summit elev. 3428 m CVGHM reported that during 26 May-4 June activity from Slamet fluctuated, but decreased overall. The number of earthquakes and the temperature of water in areas around the volcano were lower. Inflation and deflation fluctuated within a range of 2 cm. White plumes rose 100-750 high. During 5-7 June, activity was characterized by inflation and an increased number of earthquakes. During that time, white plumes were accompanied by ash emissions that rose 200-800 m from the crater, incandescent material was ejected 50-200 m above the crater, and booming noises were reported. The Alert Level remained at 3 (on a scale of 1-4). Geologic Summary. Slamet, Java's second highest volcano at 3428 m and one of its most active, has a cluster of about three dozen cinder cones on its lower SE-NE flanks and a single cinder cone on the western flank. Slamet is composed of two overlapping edifices, an older basaltic-andesite to andesitic volcano on the west and a younger basaltic to basaltic-andesite one on the east. Gunung Malang II cinder cone on the upper eastern flank on the younger edifice fed a lava flow that extends 6 km to the east. Four craters occur at the summit of Gunung Slamet, with activity migrating to the SW over time. Historical eruptions, recorded since the 18th century, have originated from a 150-m-deep, 450-m-wide, steep-walled crater at the western part of the summit and have consisted of explosive eruptions generally lasting a few days to a few weeks. 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 analysis of satellite imagery, the Darwin VAAC reported that during 3-8 June ash plumes from Batu Tara rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted 40-75 km NW, W, and SW. On 9 June, an ash plume drifted 140 km W. 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 Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AU/messages.html CHAITEN Southern Chile 42.833°S, 72.646°W; summit elev. 1122 m Based on web camera views, SERNAGEOMIN reported that during 27 May-8 June gas-and-ash plumes rose 1.5 km from Chaitén's growing Domo Nuevo 1 and Domo Nuevo 2 lava-dome complex. Collapses originating from unstable slopes generated block-and-ash flows that were sometimes seen from Chaitén town, 10 km SW. Ashfall was occasionally reported in Chaitén town and nearby areas. The Alert Level remained at Red. Based on analysis of satellite imagery, a SIGMET notice, and web camera views, the Buenos Aires VAAC reported that during 5-9 June ash plumes rose to altitudes of 1.5-3.7 km (5,000-12,000 ft) a.s.l. and drifted WSW, SE, ENE, and NE. A thermal anomaly was also seen in satellite imagery on 7 June. Geologic Summary. Chaitén is a small, glacier-free caldera with a Holocene lava dome located 10 km NE of the town of Chaitén on the Gulf of Corcovado. A pyroclastic-surge and pumice deposit considered to originate from the eruption that formed the elliptical 2.5 x 4 km wide summit caldera was dated at about 9400 years ago. A rhyolitic, 962-m-high obsidian lava dome occupies much of the caldera floor. Obsidian cobbles from this dome found in the Blanco River are the source of prehistorical artifacts from archaeological sites along the Pacific coast as far as 400 km away from the volcano to the north and south. The caldera is breached on the SW side by a river that drains to the bay of Chaitén, and the high point on its southern rim reaches 1122 m. Sources: Servicio Nacional de Geología y Minería (SERNAGEOMIN) http://www.sernageomin.cl/, Buenos Aires Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AG/messages.html DUKONO Halmahera 1.68°N, 127.88°E; summit elev. 1335 m Based on analysis of satellite imagery, the Darwin VAAC reported that during 6-8 June ash plumes from Dukono drifted 20-75 km NW and NE. Geologic Summary. Reports from this remote volcano in northernmost Halmahera are rare, but Dukono has been one of Indonesia's most active volcanoes. More-or-less continuous explosive eruptions, sometimes accompanied by lava flows, occurred from 1933 until at least the mid-1990s, when routine observations were curtailed. During a major eruption in 1550, a lava flow filled in the strait between Halmahera and the N-flank cone of Gunung Mamuya. Dukono is a complex volcano presenting a broad, low profile with multiple summit peaks and overlapping craters. Malupang Wariang, 1 km SW of Dukono's summit crater complex, contains a 700 x 570 m crater that has also been active during historical time. Source: Darwin Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AU/messages.html FUEGO Guatemala 14.473°N, 90.880°W; summit elev. 3763 m On 5, 8, and 9 June, INSIVUMEH reported that explosions from Fuego produced ash plumes that rose to altitudes of 4.1-4.7 km (13,500-15,400 ft) a.s.l. and drifted 10 km W, SW, and S. Some explosions were accompanied by rumbling noises and shock waves detected 12-15 km away. Avalanches descended several ravines. Fumarolic plumes rose 150 m and drifted S and SW. 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/ KARYMSKY Eastern Kamchatka 54.05°N, 159.45°E; summit elev. 1536 m Based on information from KEMSD, the Tokyo VAAC reported that on 6 June an eruption from Karymsky produced a plume that rose to an altitude of 3.4 km (11,000 ft) a.s.l. Ash was not identified on satellite imagery. 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: Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html KELUT Eastern Java (Indonesia) 7.93°S, 112.308°E; summit elev. 1731 m On 9 June, CVGHM reported that the Alert Level for Kelut was lowered to 1 (on a scale of 1-4). No changes had been seen; occasional diffuse white plumes rose 50-150 above the crater. CVGHM recommended that people not approach the lava dome due to instability of the area and the presence of potentially high temperatures and poisonous gases. Geologic Summary. The relatively inconcspicuous 1,731-m-high Kelut stratovolcano contains a summit crater lake that has been the source of some of Indonesia's most deadly eruptions. A cluster of summit lava domes cut by numerous craters has given the summit a very irregular profile. More than 30 eruptions have been recorded from Gunung Kelut since 1000 AD. The ejection of water from the crater lake during Kelut's typically short, but violent eruptions has created pyroclastic flows and lahars that have caused widespread fatalities and destruction. After more than 5,000 people were killed during the 1919 eruption, an ambitious engineering project sought to drain the crater lake. This initial effort lowered the lake by more than 50 m, but the 1951 eruption deepened the crater by 70 m, leaving 50 million cubic meters of water after repair of the damaged drainage tunnels. After more than 200 people were killed in the 1966 eruption, a new deeper tunnel was constructed, lowering the lake's volume to only about 1 million cubic meters prior to the 1990 eruption. Source: Center of Volcanology and Geological Hazard Mitigation (CVGHM) http://portal.vsi.esdm.go.id/joomla/ KILAUEA Hawaii (USA) 19.421°N, 155.287°W; summit elev. 1222 m During 3-9 June, HVO reported that lava flowed SE from underneath Kilauea's Thanksgiving Eve Breakout (TEB) and rootless shield complex through a lava tube system, reaching the Waikupanaha ocean entry. The Kupapa'u ocean entry was again active starting on 4 or 5 June. Thermal anomalies detected in satellite images and visual observations revealed active surface flows above and in the abandoned Royal Gardens subdivision, and on the TEB flow field. The vent in Halema'uma'u crater continued to produce a predominantly white plume that drifted mainly SW. Small amounts of tephra, including Pele's hair and fresh spatter, were retrieved from collection bins placed near the plume during the reporting period. A molten lava pool near the base of the cavity, about 100 m below the floor of the crater, produced bright incandescence. Lava was clearly visible in the Halema'uma'u Overlook Vent webcam on 5 June. On 8 and 9 June, sounds resembling rushing gas and rockfalls were heard in the vicinity of the crater. The sulfur dioxide emission rate at the summit remained elevated; measurements were 700 and 800 tonnes per day on 4 and 5 June, respectively. The 2003-2007 average rate was 140 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. Source: US Geological Survey Hawaiian Volcano Observatory (HVO) http://hvo.wr.usgs.gov/ LLAIMA Central Chile 38.692°S, 71.729°W; summit elev. 3125 m SERNAGEOMIN reported that during 5-8 June incandescence from an area in the SW part of Llaima's main crater corresponded to a small active "outcrop of lava." On 6 June, incandescence emanated from a small point along the E-flank fissure. Gas and steam was emitted from an area W of the main crater. The Volcano Alert Level remained at Yellow. 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/ MANAM Northeast of New Guinea (SW Pacific) 4.080°S, 145.037°E; summit elev. 1807 m Based on analysis of satellite imagery, the Darwin VAAC reported that on 8 June an ash plume from Manam rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted about 40 km NW. 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 Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AU/messages.html PACAYA Guatemala 14.381°N, 90.601°W; summit elev. 2552 m On 5, 8, and 9 June, INSIVUMEH reported that fumarolic plumes from Pacaya's MacKenney cone rose 50-200 m and drifted W and SW. During the reporting period, two to four lava flows, each 150-300 m long, were emitted from an area on the lower S flank, SW from the main edifice. Geologic Summary. Eruptions from Pacaya, one of Guatemala's most active volcanoes, are frequently visible from Guatemala City, the nation's capital. Pacaya is a complex volcano constructed on the southern rim of the 14 x 16 km Pleistocene Amatitlan caldera. A cluster of dacitic lava domes occupies the caldera floor. The Pacaya massif includes the Cerro Grande lava dome and a younger volcano to the SW. Collapse of Pacaya volcano about 1,100 years ago produced a debris-avalanche deposit that extends 25 km onto the Pacific coastal plain and left an arcuate somma rim inside which the modern Pacaya volcano (MacKenney cone) grew. During the past several decades, activity at Pacaya has consisted of frequent Strombolian eruptions with intermittent lava flow extrusion on the flanks of MacKenney cone, punctuated by occasional larger explosive eruptions. Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH) http://www.insivumeh.gob.gt/ 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 3-9 June; the plumes contained slight amounts of ash during 8-9 June. 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 4.271°S, 152.203°E; summit elev. 688 m RVO reported that during 29 May-6 June white and occasionally blue plumes from Rabaul caldera's Tavurvur cone rose 1 km above the crater. Incandescence from the summit crater was seen at night. On 5 June, an ash plume drifted NW and caused ashfall in Rabaul town (3-5 km NW) and surrounding areas. 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) REDOUBT Southwestern Alaska 60.485°N, 152.742°W; summit elev. 3108 m AVO reported that during 3-9 June seismicity from Redoubt remained low, but above background levels; small discrete earthquakes and rockfall signals in the summit region were recorded. Growth of the lava dome in the summit crater continued and by 5 June extended 950 m down the N flank. Cloudy conditions often obscured satellite and web camera views; steaming from the summit region was seen periodically. On 3 June, a minor dusting of ash was visible on the NE flank, likely related to rockfall activity. AVO warned that the unstable lava dome could fail with little or no warning, leading to significant ash emissions and possible lahars in the Drift River valley. The Volcanic Alert Level remained at Watch and the Aviation Color Code remained at Orange. Geologic Summary. Redoubt is a 3108-m-high glacier-covered stratovolcano with a breached summit crater in Lake Clark National Park about 170 km SW of Anchorage. Next to Mount Spurr, Redoubt has been the most active Holocene volcano in the upper Cook Inlet. Collapse of the summit of Redoubt 10,500-13,000 years ago produced a major debris avalanche that reached Cook Inlet. Holocene activity has included the emplacement of a large debris avalanche and clay-rich lahars that dammed Lake Crescent on the south side and reached Cook Inlet about 3500 years ago. Eruptions during the past few centuries have affected only the Drift River drainage on the north. Historical eruptions have originated from a vent at the north end of the 1.8-km-wide breached summit crater. The 1989-90 eruption of Redoubt had severe economic impact on the Cook Inlet region and affected air traffic far beyond the volcano. Source: Alaska Volcano Observatory (AVO) http://www.avo.alaska.edu/ SAKURA-JIMA Kyushu 31.585°N, 130.657°E; summit elev. 1117 m Based on information from JMA, the Tokyo VAAC reported that on 7 June an eruption from Sakura-jima produced a plume that rose vertically to an altitude of 3 km (10,000 ft) a.s.l. An eruption on 9 June resulted in a plume that rose to an attitude of 2.4 km (8,000 ft) a.s.l. and drifted N. 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 SANTA MARIA Guatemala 14.756°N, 91.552°W; summit elev. 3772 m INSIVUMEH reported that on 5, 8, and 9 June explosions from Santa María's Santiaguito lava dome complex produced ash plumes that rose to altitudes of 2.8-3.3 km (9,200-10,800 ft) a.s.l. and drifted SW. Gas plumes that were sometimes gray rose 300-600 m above Caliente dome. Avalanches descended the S and W flanks. 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: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH) http://www.insivumeh.gob.gt/ SHIVELUCH Central Kamchatka (Russia) 56.653°N, 161.360°E; summit elev. 3283 m KVERT reported that during 29 May-5 June seismic activity from Shiveluch was above background levels. Based on interpretations of seismic data, diffuse ash plumes were emitted during the reporting period; an ash plume possibly rose to an altitude of 3.8 km (12,500 ft) a.s.l. on 1 June. Video camera images showed steam-and-gas emissions. Analysis of satellite imagery revealed a daily thermal anomaly over the lava dome. The Level of Concern Color Code remained at Orange. Based on analysis of satellite imagery, the Tokyo VAAC reported on 7 June that a possible eruption produced a plume that rose to an altitude of 3.4 km (11,000 ft) a.s.l. and drifted SW. A report a few hours later stated that ash emissions were continuing. 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. Intermittent explosive eruptions began in the 1990s from a new lava dome that began growing in 1980. The largest historical eruptions from Shiveluch occurred in 1854 and 1964. 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 TUNGURAHUA Ecuador 1.467°S, 78.442°W; summit elev. 5023 m The IG reported that during 3-9 June tremor and explosions from Tungurahua were detected by the seismic network. On 3 June, lahars traveled down multiple drainages. A gas-and-ash plume rose 200 m and drifted SW; cloudy conditions prevented visual observations during the rest of the reporting period. Ashfall was detected in areas to the SW and W on 4 June. On 7 June, noises resembling blocks rolling down the flanks, "cannon shots," and roars were reported. The next day, "cannon shot" noises were followed by the vibration of windows in nearby areas. 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 analysis of satellite imagery, the Buenos Aires VAAC reported that on 5 June plumes from Ubinas rose to altitudes of 6.1-6.7 km (20,000-22,000 ft) a.s.l. and drifted W and S. A pilot reported that an ash plume rose to an altitude of 7.9 km (26,000 ft) a.s.l. and drifted SW. On 6 and 9 June, plumes seen on satellite imagery rose to altitudes of 6.1-7.6 km (20,000-25,000 ft) a.s.l. and drifted S and NE, 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 SennertSI/USGS Weekly Volcanic Activity Report EditorGlobal Volcanism Programhttp://www.volcano.si.edu/reports/usgs/Smithsonian Institution, National Museum of Natural History Department of Mineral Sciences, MRC-119Washington, D.C., 20560Phone: 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. ==============================================================
