************************************************************ GVP/USGS Weekly Volcanic Activity Report 29 August-4 September 2007 http://www.volcano.si.edu/reports/usgs/ ************************************************************ New Activity/Unrest: | Chikurachki, Russia | Pago, Papua New Guinea | Pavlof, USA Ongoing Activity: | Cleveland, USA | Etna, Italy | Fuego, Guatemala | Karangetang, Indonesia | Karymsky, Russia | Kilauea, USA | Rabaul, Papua New Guinea | Santa María, Guatemala | Shiveluch, Russia | Soufrière Hills, Montserrat | St. Helens, USA | Tungurahua, Ecuador New Activity/Unrest CHIKURACHKI Kuril Islands, Russia 50.325°N, 155.458°E; summit elev. 1,816 m Based on visual observations, KVERT reported that explosions from Chikurachki produced ash plumes during 21-26 August. Ash plumes were visible on satellite imagery drifting NE during 28-30 August. The Level of Concern Color Code remained at Orange <http://www.avo.alaska.edu/color_codes.php>. Based on observations of satellite imagery, the Tokyo VAAC reported that possible eruption plumes rose to an altitude of 3 km (10,000 ft) a.s.l. during 1-3 September. Geologic Summary. Chikurachki, the highest volcano on Paramushir Island in the northern Kuriles, is actually a relatively small cone constructed on a high Pleistocene volcanic edifice. Oxidized scoria deposits covering the upper part of the young cone give it a distinctive red color. Lava flows from 1,816-m-high Chikurachki reached the sea and form capes on the NW coast; several young lava flows also emerge from beneath the scoria blanket on the eastern flank. The more erosionally modified Tatarinov group of six volcanic centers is located immediately to the S of Chikurachki. Tephrochronology gives evidence of only one eruption in historical time from Tatarinov, although its southern cone contains a sulfur-encrusted crater with fumaroles that were active along the margin of a crater lake until 1959. 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 Chikurachki Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=0900-036= PAGO New Britain, Papua New Guinea 5.58°S, 150.52°E; summit elev. 742 m Based on a report from Kimbe Vulcanological Observatory (KVO), RVO reported that people from villages near Pago heard a single booming noise and saw an increase in white vapor emission on 27 August. Seismicity increased during 27-28 August. The second crater of the upper vents ejected lava fragments on 28 August. White vapor emitted from the same crater was seen during an inspection of the area on 29 August. Geologic Summary. Pago is a young post-caldera cone that was constructed within the 5.5 x 7.5 km Witori caldera. Extensive pyroclastic-flow deposits are associated with formation of the caldera about 3,300 years ago. The gently sloping outer flanks of Witori volcano consist primarily of dacitic pyroclastic-flow and air fall deposits produced during a series of five major explosive eruptions from about 5,600 to 1,200 years ago. The Buru caldera, which may have formed around the same time, cuts the SW flank of Witori volcano. The post-caldera cone of Witori, Mount Pago, may have formed less than 350 years ago and has grown to a height above that of the Witori caldera rim. The current lava flow is the 10th of a series of dacitic lava flows from Pago that covers much of the caldera floor. Source: Herman Patia, Rabaul Volcanological Observatory Pago Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=0502-08= PAVLOF Alaska, USA 55.42°N, 161.887°W; summit elev. 2,519 m Seismic activity at Pavlof fluctuated, but generally remained elevated during 29 August-4 September. A strong thermal anomaly was present at the summit on satellite imagery during 29 August-2 September; clouds inhibited observations on 3 and 4 September. Based on pilot reports and observations of satellite imagery, ash plumes rose to altitudes of 2.4-4.9 km (8,000-16,000 ft) a.s.l. during 28-30 August and drifted SSE and SE. On 30 August, National Weather Service observers in Cold Bay (about 60 km SW) reported that a plume rose to an altitude of 6.1 km (20,000 ft) a.s.l. and produced lightning. Based on satellite imagery, AVO reported that steam-and-ash plumes rose to altitudes of 6.1 km (20,000 ft) a.s.l. on 31 August. The Volcanic Alert Level remained at Watch and the Aviation Color Code remained at Orange <http://www.avo.alaska.edu/color_codes.php>. Geologic Summary. The most active volcano of the Aleutian arc, Pavlof is a 2519-m-high Holocene stratovolcano that was constructed along a line of vents extending NE from the Emmons Lake caldera. Pavlof and its twin volcano to the NE, 2142-m-high Pavlof Sister, form a dramatic pair of symmetrical, glacier-covered stratovolcanoes that tower above Pavlof and Volcano bays. A third cone, Little Pavolf, is a smaller volcano on the SW flank of Pavlof volcano, near the rim of Emmons Lake caldera. Unlike Pavlof Sister, Pavlof has been frequently active in historical time, typically producing strombolian to vulcanian explosive eruptions from the summit vents and occasional lava flows. The active vents lie near the summit on the north and east sides. The largest historical eruption of Pavlof took place in 1911, at the end of a 5-year-long eruptive episode; a fissure opened on the northern flank of the volcano, ejecting large blocks and issuing lava flows. Source: Alaska Volcano Observatory http://www.avo.alaska.edu/ Pavlof information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1102-03- Ongoing Activity CLEVELAND Aleutian Islands, USA 52.82°N, 169.95°W; summit elev. 1,730 m Clouds obscured satellite and web camera views of Cleveland volcano during 29 August-4 September. A clear view of the crater on 30 August and 1 September revealed thermal anomalies at the summit. No current seismic information is available because Cleveland does not have a real-time seismic network. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch <http://www.avo.alaska.edu/color_codes.php>. Geologic Summary. The symmetrical Mount Cleveland stratovolcano is situated at the western end of the uninhabited dumbbell-shaped Chuginadak Island in the east-central Aleutians. The 1,730-m-high stratovolcano is the highest of the Islands of Four Mountains group and is one of the most active in the Aleutians. Numerous large lava flows descend its flanks. It is possible that some 18th to 19th century eruptions attributed to Carlisle (a volcano located across the Carlisle Pass Strait to the NW) should be ascribed to Cleveland. In 1944 Cleveland produced the only known fatality from an Aleutian eruption. Recent eruptions from Mt. Cleveland have been characterized by short-lived explosive ash emissions, at times accompanied by lava fountaining and lava flows down the flanks. Source: Alaska Volcano Observatory http://www.avo.alaska.edu/ Cleveland Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1101-24- ETNA Sicily, Italy 37.73°N, 15.00°E; summit elev. 3,315 m Based on information from the Istituto Nazionale di Geofisica e Vulcanologia and observations using satellite imagery, the Toulouse VAAC reported that a diffuse eruption plume from Etna rose to an altitude of 4.6 km (15,000 ft) a.s.l. during 4-5 September and drifted E. According to news reports, a Strombolian eruption on 4 September produced lava flows that descended down the flanks. Ashfall was reported in several villages and the airport in Catania closed through the night. Geologic Summary. Mount Etna, towering above Catania, Sicily's second largest city, has one of the world's longest documented records of historical volcanism, dating back to 1500 BC. Historical lava flows cover much of the surface of this massive basaltic stratovolcano, the highest and most voluminous in Italy. Two styles of eruptive activity typically occur at Etna. Persistent explosive eruptions, sometimes with minor lava emissions, take place from one or more of the three prominent summit craters, the Central Crater, NE Crater, and SE Crater. Flank eruptions, typically with higher effusion rates, occur less frequently and originate from fissures that open progressively downward from near the summit. A period of more intense intermittent explosive eruptions from Etna's summit craters began in 1995. The active volcano is monitored by the Instituto Nazionale di Geofisica e Volcanologia (INGV) in Catania. Sources: Toulouse Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/FR/messages.html, Reuters http://news.yahoo.com/s/nm/20070904/wl_nm/italy_volcano_dc_1 Etna Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=0101-06= FUEGO Guatemala 14.47°N, 90.88°W; summit elev. 3,763 m On 31 August, INSIVUMEH reported that a lahar, 8 m wide and 1.5 m high, descended W down Fuego's Santa Teresa ravine, carrying fine material, tree branches, and blocks. On 3 September, fumarolic plumes rose to an altitude of 4 km (13,000 ft) a.s.l. and drifted W and SW. A 300-m-long lava flow continued to advance W down the Taniluyá River valley. Avalanches in the Ceniza River valley were noted. During 3-4 September, explosions produced ash plumes that rose to an altitude of 4.5 km (14,800 ft) a.s.l. and drifted 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/geofisica/boletin%20formato.htm Fuego Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1402-09= KARANGETANG [Api Siau] Siau Island, Indonesia 2.47°N, 125.29°E; summit elev. 1,784 m The Alert Status of Karangetang was lowered on 30 August from 4 to 3 (on a scale of 1-4). Geologic Summary. Karangetang (also known as Api Siau) lies at the northern end of the island of Siau, N of Sulawesi. The 1,784-m-high stratovolcano contains five summit craters 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/ Karangetang Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=0607-02= KARYMSKY Kamchatka Peninsula, Russia 54.05°N, 159.43°E; summit elev. 1,536 m Seismic activity at Karymsky was above background levels during 24-31 August, with 100-280 shallow earthquakes occurring daily. Based on seismic interpretation, ash plumes may have risen to an altitude of 5.9 km (19,400 ft) a.s.l. Observations of satellite imagery revealed that a thermal anomaly was present in the crater on 24 and 30 August. Ash plumes were also present and drifted SE on 24 August and NE during 28-30 August. The Level of Concern Color Code remained at Orange <http://www.avo.alaska.edu/color_codes.php>. Based on information from KEMSD, satellite imagery, observations in the Petropavlovsk-Kamchatsky Flight Information Region (FIR), and KVERT, the Tokyo VAAC reported that ash plumes rose to altitudes of 4.3-6.1 km (14,000-20,000 ft) a.s.l. during 31 August and 2-3 September. Ash was not identified on satellite imagery on 31 August. 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/updates.shtml, Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html 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 HVO reported that during 29 August-4 September fissure segment D from Kilauea's 21 July fissure eruption continued to feed an advancing 'a'a lava flow that frequently overflowed its channel edges. During 29-30 August, a few small collapses within the Pu'u 'O'o' s crater were detected by seismometers. Incandescence in the crater was visible on the web camera on 31 August. Small earthquakes were located beneath Halema'uma'u crater, the lower SW rift zone, the N and W summit area, and the S flank during the reporting period. 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- RABAUL New Britain Island, Papua New Guinea 4.271°S, 152.203°E; summit elev. 688 m RVO reported that ash plumes from Rabaul caldera's Tavurvur cone decreased in frequency during 30 August-1 September. Ash plumes drifted W and NW on 29 August. On 31 August, an explosion produced an ash plume that rose to an altitude of 3.7 km (12,000 ft) a.s.l. The plume drifted W and resulted in fine ashfall downwind. On 2 September, ash plumes drifted NW and ashfall was reported in Rabaul Town and surrounding areas. The ash emissions were accompanied by roaring noises. Incandescence at the summit was observed during the reporting period. 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 Rabaul Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=0502-14= SANTA MARÍA Guatemala 14.756°N, 91.552°W; summit elev. 3,772 m On 31 August, INSIVUMEH reported that a lahar, 8 m wide and 1.5 m high, descended S down Santa María's Nima I river, carrying fine material, tree branches, and blocks. Explosions from the Santiaguito lava dome complex produced ash plumes that rose to 4.3 km (14,100 ft) a.s.l. and drifted SW. During 3-4 September, explosions produced ash plumes that rose to an altitude of 4.4 km (14,400 ft) a.s.l. and drifted W. A lava flow on the SW flank produced avalanches. 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/geofisica/boletin%20formato.htm 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 was above background levels during 24-31 August. Based on seismic interpretation, avalanches and ash plumes that rose to an altitude of 9 km (29,500 ft) a.s.l. occurred during the reporting period. Based on visual observation and video data, ash plumes rose to an altitude of 4.5 km (14,800 ft) a.s.l. on 25 August. Clouds inhibited observations the other days. Observations of satellite imagery revealed that a thermal anomaly was present in the crater during 24-31 August. The Level of Concern Color Code remained at Orange <http://www.avo.alaska.edu/color_codes.php>. Based on information reported from KEMSD, the Tokyo VAAC reported that an eruption plume rose to an altitude of 5.5 km (18,000 ft) a.s.l. on 2 September. Ash was not identified on satellite imagery. 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 MVO reported that during 28 August-3 September the lava dome at Soufrière Hills changed very little, based on visual observations. Seismic activity was very low and low-level rockfall activity continued. 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 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 29 August-4 September lava-dome growth at Mount St. Helens continued. Seismicity persisted at low levels, punctuated by M 1.5-2.5, and occasionally larger, earthquakes. 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 IG reported that ash plumes from Tungurahua rose to an altitude of 7 km (23,500 ft) a.s.l. on 29 August; clouds inhibited visual observations during 30 August-4 September. Ashfall was reported during 29 August-3 September in areas to the W. On 31 August, lahars were observed in drainages to the NNW and disrupted the road to Baños. Explosions rattled windows in Baños (8 km to the N) and at the Tungurahua Observatory (OVT) in Guadalupe, 11 km N. On 1 September, ashfall was also reported from areas in the SW and NW. Incandescent blocks were propelled from the summit and observed from the OVT. Roars and "cannon shots" were heard during 29 August-1 September and 3 September. On 4 September, incandescence and rolling blocks on the E and N flanks were noted. 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= +++++++++++++++++++++++++++++++++++++ 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. ==============================================================
