*********************************************** GVP/USGS Weekly Volcanic Activity Report 9-15 May 2007 http://www.volcano.si.edu/reports/usgs/ *********************************************** New Activity/Unrest: | Bezymianny, Russia Ongoing Activity: | Batu Tara, Indonesia | Bulusan, Philippines | Karymsky, Russia | Kilauea, USA | Kliuchevskoi, Russia | Nevado del Huila, Columbia | Santa María, Guatemala | Shiveluch, Russia | Soufrière Hills, Montserrat | St. Helens, USA | Tungurahua, Ecuador | Ubinas, Perú New Activity/Unrest BEZYMIANNY Kamchatka Peninsula, Russia 55.98°N, 160.59°E; summit elev. 2,882 m ; All times are local (= UTC + 12 hours [or 13 hours late March-late October]) KVERT reported on 11 May that the level of Concern Color Code <http://www.avo.alaska.edu/color_codes.php> for Bezymianny was raised to Orange due to a large thermal anomaly noted on satellite imagery. During 0330-0400 on 12 May, an explosive eruption may have occurred according to seismic data from Kozyrevsk. Ash plumes were visible on satellite imagery drifting multiple directions. Ashfall was reported from the town of Klyuchi, about 47 km NE. A slight amount of the ash originated from Kliuchevskoi, an active volcano directly N of Bezymianny. Hot avalanches were observed and an ash plume rose to an altitude of 4 km (13,100 ft) a.s.l. On 13 May, an elongated thermal anomaly was seen on satellite imagery to the SE of the lava dome. Geologic Summary. Prior to its noted 1955-56 eruption, Bezymianny volcano had been considered extinct. The modern Bezymianny volcano, much smaller in size than its massive neighbors Kamen and Kliuchevskoi, was formed about 4700 years ago over a late-Pleistocene lava-dome complex and an ancestral volcano that was built between about 11,000-7000 years ago. Three periods of intensified activity have occurred during the past 3000 years. The latest period, which was preceded by a 1,000-year quiescence, began with the dramatic 1955-56 eruption. This eruption, similar to that of Mount St. Helens in 1980, produced a large horseshoe-shaped crater that was formed by collapse of the summit and an associated lateral blast. Subsequent episodic but ongoing lava-dome growth, accompanied by intermittent explosive activity and pyroclastic flows, has largely filled the 1956 crater. Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/updates.shtml Bezymianny Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1000-25= Ongoing Activity BATU TARA Lesser Sunda Islands, Indonesia 7.792°S, 123.579°E; summit elev. 748 m Based on satellite imagery and information from CVGHM, the Darwin VAAC reported that during 10-12 May, diffuse ash plumes from Batu Tara rose to an altitude of 1.5 km (5,000 ft) a.s.l. and drifted W. Geologic Summary. The small isolated island of Batu Tara in the Flores Sea about 50 km north of 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 only known historical eruption from Batu Tara, during 1847-52, produced explosions and a lava flow. Source: Darwin Volcanic Ash Advisory Center (VAAC) http://www.bom.gov.au/info/vaac/advisories.shtml Batu Tara Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=0604-26= BULUSAN Luzon, Philippines 12.770°N, 124.05°E; summit elev. 1,565 m PHIVOLCS reported that an explosion from Bulusan on 12 May produced an ash plume that rose to an altitude of 5.6 km (18,400 ft) a.s.l. and drifted WSW and WNW. The activity was accompanied by rumbling sounds and was recorded by the seismic network as an explosion-type earthquake that lasted about 35 minutes. An increase in seismicity was noted during 9-12 May. Ashfall (trace-2 mm thick) was reported in 11 barangays from the municipalities of Irosin and Juban. Geologic Summary. Luzon's southernmost volcano, Bulusan, was constructed within the 11-km-diameter dacitic Irosin caldera, which was formed more than 36,000 years ago. A broad, flat moat is located below the prominent SW caldera rim; the NE rim is buried by the andesitic Bulusan complex. Bulusan is flanked by several other large intracaldera lava domes and cones, including the prominent Mount Jormajan lava dome on the SW flank and Sharp Peak to the NE. The summit of Bulusan volcano is unvegetated and contains a 300-m-wide, 50-m-deep crater. Three small craters are located on the SE flank. Many moderate explosive eruptions have been recorded at Bulusan since the mid-19th century. Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS) http://www.phivolcs.dost.gov.ph/ Bulusan Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=0703-01= KARYMSKY Kamchatka Peninsula, Russia 54.05°N, 159.43°E; summit elev. 1,536 m Seismic activity at Karymsky was above background levels during 4-11 May. No thermal anomalies and ash plumes were seen on satellite imagery. The Level of Concern Color Code remained at Orange <http://www.avo.alaska.edu/color_codes.php>. 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/updates.shtml Karymsky Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1000-13= KILAUEA Hawaii, USA 19.43°N, 155.29°W; summit elev. 1,222 m During 2-8 May, lava from Kilauea continued to flow SE across a lava delta into the ocean at the Kamokuna entry. Incandescence was visible from several vents in the Pu'u 'O'o crater and from breakouts on, above, and at the base of the Pulama pali fault scarp. Earthquake activity was scattered at the S edge of the summit, upper E rift zone between Puhimau and Pauahi craters, and S-flank areas. On 10 May, approximately 6.5 hectares (16 acres) of the East Lae`apuki bench collapsed, starting from the E-side and moving progressively westward. Each section of collapse generated a steam plume, occasionally blackened with rock dust, which rose to about 0.1-0.3 km (200-1,000 ft) a.s.l. The plumes resulted from the explosive interaction between seawater and incandescent rock exposed immediately after each section collapsed. On 11 May, HVO scientists surveyed the collapse and mapped cracks inland of the sea cliff. Rock fragments covered a 1.2 hectare (3 acre) area. 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 by lava flows less than about 1,100 years old; 70% of the volcano's surface is younger than 600 years. The latest Kilauea eruption began in January 1983 along the E rift zone. This long-term ongoing eruption from Pu'u 'O'o-Kupaianaha has produced lava flows that have traveled 11-12 km from the vents to the sea, paving broad areas on the S flank of Kilauea and adding new land beyond the former coastline. Source: US Geological Survey Hawaiian Volcano Observatory http://volcano.wr.usgs.gov/hvostatus.php Kilauea information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1302-01- KLIUCHEVSKOI Kamchatka Peninsula, Russia 56.06°N, 160.64°E; summit elev. 4,835 m KVERT reported that during 4-11 May, seismic activity at Kliuchevskoi continued above background levels and a thermal anomaly in the crater was detected on satellite imagery. Lava flows continued to advance on the NW flank. Phreatic activity and ash plumes from lava-flow fronts were noted. Gas-and-steam plumes containing ash rose to altitudes of 6.7 km (22,000 ft) a.s.l. and drifted N during 4-7 May. Ash plumes were seen on satellite imagery drifting NE, NW, W, and E during the reporting period. Ashfall was reported on 4 May and explosions were heard during 3-6 May in the town of Klyuchi, about 30 km to the NE. Based on information from KEMSD and satellite imagery, the Tokyo VAAC reported that on 11 May ash plumes rose to altitudes of 7.6 km (25,000 ft) a.s.l. and drifted SE and E. On 12 May, the Anchorage VAAC reported that ash plumes were visible on satellite imagery. On 15 May, the Tokyo VAAC reported that an eruption plume was possibly seen on satellite imagery to an altitude of 5.2 km (17,000 ft) a.s.l. drifting N. The Level of Concern Color Code remained at Orange <http://www.avo.alaska.edu/color_codes.php>. Geologic Summary. Kliuchevskoi is Kamchatka's highest and most active volcano. Since its origin about 7,000 years ago, the beautifully symmetrical, 4,835-m- high basaltic stratovolcano has produced frequent moderate-volume explosive and effusive eruptions without major periods of inactivity. More than 100 flank eruptions have occurred during the past 3,000 years, mostly on the NE and SE flanks of the conical volcano between 500 m and 3,600 m elevation. The morphology of its 700-m-wide summit crater has been frequently modified by historical eruptions, which have been recorded since the late-17th century. Historical eruptions have originated primarily from the summit crater, but have also included major explosive and effusive eruptions from flank craters. Sources: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/updates.shtml, Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html, Anchorage Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AK/messages.html Kliuchevskoi Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1000-26= NEVADO DEL HUILA Columbia 2.93°N, 76.03°W; summit elev. 5,365 m Based on satellite imagery, the Washington VAAC reported that on 14 May an ash plume from Nevado del Huila drifted SW and dissipated. INGEOMINAS reported that seismicity was possibly related to an ash emission. 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. 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 Nevado del Huila Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1501-05= SANTA MARÍA Guatemala 14.756°N, 91.552°W; summit elev. 3,772 m Based on satellite imagery, the Washington VAAC reported that ash plumes from Santa María's Santiaguito lava dome complex drifted S on 9 May. INSIVUMEH reported on 10 May that rain caused landslides S down the Nimá Primero river, near the Observatory Vulcanológico de Santiaguito (OVSAN), about 5 km S of the lava dome. Explosions from Caliente dome during 10-11 and 14 May produced gas- and-ash plumes that rose to altitudes of 4.4-5.3 km (14,400-17,400 ft) a.s.l. and drifted SW and E. Ashfall was reported from areas S and SW on 10 May. Avalanches of blocks and ash from the SW edge of Caliente dome were observed on 14 May. 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. Sources: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH) http://www.insivumeh.gob.gt/geofisica/boletin% 20formato.htm, Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html Santa María Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1402-03= SHIVELUCH Kamchatka Peninsula, Russia 56.653°N, 161.360°E; summit elev. 3,283 m KVERT reported that seismic activity at Shiveluch continued above background levels during 4-11 May. Based on seismic interpretation, observation, and video data, ash plumes possibly rose to altitudes of 6-7 km (19,700-23,000 ft) a.s.l. throughout the reporting period. Plumes were seen on satellite imagery drifting E on 5 and 7 May and a thermal anomaly was present during 4-11 May. Gas-and- steam activity was noted during 4-7 May. Visual and video data revealed hot avalanches originating from the lava dome during 4 and 6-7 May. Based on information from the KEMSD, the Tokyo VAAC reported that ash plumes rose to altitude of 5.8-8.2 km (19,000-27,000 ft) a.s.l. during 9-11 May. An ash plume was possibly seen on satellite imagery to an altitude of 4.9 km (16,000 ft) a.s.l. drifting NW on 15 May. The Level of Concern Color Code remained at Orange <http://www.avo.alaska.edu/color_codes.php>. 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 horseshoe-shaped 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. Sources: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/updates.shtml, Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html Shiveluch Information from the Global Volcanism Program http://www.volcano.si.edu/gvp/world/volcano.cfm?vnum=1000-27= SOUFRIÈRE HILLS Montserrat, West Indies 16.72°N, 62.18°W; summit elev. 1,052 m Based on visual observations, MVO reported that during 4-11 May lava-dome growth at Soufrière Hills likely ceased and the overall structure of the dome changed very little. Rockfall activity continued. The Alert Level remained 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 east, was formed during an eruption about 4000 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 http://www.mvo.ms/ Soufrière Hills Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1600-05= ST. HELENS Washington, USA 46.20°N, 122.18°W; summit elev. 2,549 m Data from deformation-monitoring instruments indicated that during 9-15 May lava-dome growth at Mount St. Helens continued. Seismicity persisted at low levels, punctuated by M 1.5-2.5, and occasionally larger, earthquakes. In some instances, clouds inhibited visual observations. Geologic Summary. Prior to 1980, Mount St. Helens formed a conical, youthful volcano sometimes known as the Fuji-san of America. During the 1980 eruption the upper 400 m of the summit was removed by slope failure, leaving a 2 x 3.5 km horseshoe-shaped crater now partially filled by a lava dome. Mount St. Helens was formed during nine eruptive periods beginning about 40-50,000 years ago, and has been the most active volcano in the Cascade Range during the Holocene. The modern edifice was constructed during the last 2,200 years, when the volcano produced basaltic as well as andesitic and dacitic products from summit and flank vents. Historical eruptions in the 19th century originated from the Goat Rocks area on the N flank, and were witnessed by early settlers. Source: US Geological Survey Cascades Volcano Observatory http://vulcan.wr.usgs.gov/Volcanoes/MSH/CurrentActivity/framework.html St. Helens Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1201-05- TUNGURAHUA Ecuador 1.47°S, 78.44°W; summit elev. 5,023 m During 9-12 and 14 May, IG reported that ash plumes were visible from Tungurahua and rose to an altitude of 5.1 km (16,700ft) a.s.l. during 11-12 May. Plumes drifted W and NW. Ashfall was reported on 9 May in areas about 8 km to the SW and W and trace ashfall was reported about 30 km NW in Ambato. Incandescence at the summit was noted that evening. Ashfall was also reported on 10, 11, and 14 May from areas NW, SW, and W; on 11 May, the ashfall was red in color. Lahars and muddy waters that traveled into the Pampas sector and in NW ravines blocked the Baños-Penipe highway during the morning of 10 May. Muddy waters traveled in W ravines on 12 May and SW ravines on 14 May. 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 been restricted to 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 Poltécnica Nacional http://www.igepn.edu.ec/ Tungurahua Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1502-08= UBINAS Perú 16.355°S, 70.903°W; summit elev. 5,672 m Based on pilot reports and satellite imagery, the Buenos Aires VAAC reported that on 12 and 15 May ash plumes from Ubinas rose to altitudes of 5.5-8.2 km (18,000-27,000 ft) a.s.l. and drifted SE and N, 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 Ubinas Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1504-02= +++++++++++++++++++++++++++++++++++++ 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. ==============================================================
