**************************************************************** GVP/USGS Weekly Volcanic Activity Report 7-13 November 2007 http://www.volcano.si.edu/reports/usgs/ **************************************************************** New Activity/Unrest: | Bezymianny, Russia | Kelut, Indonesia | Krakatau, Indonesia | Ol Doinyo Lengai, Tanzania | Stromboli, Italy Ongoing Activity: | Chikurachki, Russia | Karymsky, Russia | Kilauea, USA | Shiveluch, Russia | 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 KVERT reported that possibly high-temperature gas-and-steam plumes from Bezymianny along with a thermal anomaly at the summit were visible on satellite imagery on 9 November. A viscous lava flow effused from the summit. During an overflight on the same day, 4-km-long pyroclastic flow deposits from 5 November were observed on the SE flank. Lava flow-front collapses from older lava flows on the SE flank were also evident. The level of Concern Color Code was raised to Orange on 10 November <http://www.avo.alaska.edu/color_codes.php>. 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= KELUT Java, Indonesia 7.93°S, 112.31°E; summit elev. 1,731 m CVGHM reported that on 6 November, temperatures at the surface of Kelut's crater lake measured 75 degrees Celsius and the newly exposed lava dome surface measured 150-210 degrees Celsius. Plumes inhibited clear views of the lava dome. CVGHM lowered the Alert Status of Kelut on 8 November from 4 to 3 (on a scale of 1-4), due to a decrease in seismicity and stability indicated by deformation-monitoring instruments. CVGHM recommended that evacuees could return to their homes, but activity within a 3-km radius was restricted. According on a news article, a volcanologist reported that the lava dome was 250 m in diameter and 120 m above the crater lake surface. On 11 November, a plume rose to an altitude of 3.7 km (12,000 ft) a.s.l. and ashfall was reported in several areas. Geologic Summary. The relatively inconspicuous 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. Sources: Center of Volcanology and Geological Hazard Mitigation (CVGHM) http://portal.vsi.esdm.go.id/joomla/, Agence France-Presse http://www.gulf-times.com/site/topics/article.asp?cu_no=2&item_no=184325&version=1&template_id=45&parent_id=25 Kelut Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=0603-28= KRAKATAU Indonesia 6.10°S, 105.43°E; summit elev. 813 m According to news articles, gas-and-ash plumes from Anak Krakatau continued rise and seismicity was elevated during 9-11 November. Incandescent material was propelled from the summit and fell onto the flanks. Lava flows were also observed traveling down the flanks. Villagers and tourists were advised not go within a 3-km radius of the summit. The Alert Level remained at 3 (on a scale of 1-4). Geologic Summary. The renowned Krakatau volcano lies in the Sunda Strait between Java and Sumatra. Collapse of the ancestral Krakatau edifice, perhaps in 416 AD, resulted in a 7-km-wide caldera. Remnants of this volcano formed Verlaten and Lang Islands; subsequently Rakata, Danan, and Perbuwatan volcanoes were formed, coalescing to create the pre-1883 Krakatau Island. Caldera collapse during the catastrophic 1883 eruption destroyed Danan and Perbuwatan volcanoes, and left only a remnant of Rakata volcano. The post-collapse cone of Anak Krakatau (Child of Krakatau), constructed within the 1883 caldera at a point between the former cones of Danan and Perbuwatan, has been the site of frequent eruptions since 1927. Sources: Center of Volcanology and Geological Hazard Mitigation (CVGHM) http://portal.vsi.esdm.go.id/joomla/, VietNamNet/Xinhuanet http://english.vietnamnet.vn/international/2007/11/754122/, Reuters http://www.deepikaglobal.com/ENG4_sub.asp?ccode=ENG4&newscode=7475 Krakatau Information from the Global Volcanism Program http://www.vsi.esdm.go.id/portal/html/index.php OL DOINYO LENGAI Tanzania, eastern Africa 2.751°S, 35.902°E; summit elev. 2,890 m Based on information from the Tanzania MVO, the Toulouse VAAC reported that Ol Doinyo Lengai erupted on 7 November and remained active. According to Frederick Belton's website, an observer saw a "smoke" plume rise to an altitude of 3.2-3.5 km (10,500-11,500 ft) a.s.l. and drift WSW towards the Gol Mountains on 10 November. Geologic Summary. The symmetrical Ol Doinyo Lengai stratovolcano is the only volcano known to have erupted carbonatite tephras and lavas in historical time. The prominent volcano, known as "The Mountain of God," rises abruptly above the broad plain S of Lake Natron. The cone-building stage of the volcano ended about 15,000 years ago and was followed by periodic ejection of natrocarbonatite and nephelinite tephra during the Holocene. Historical eruptions have consisted of smaller tephra eruptions and emission of numerous natrocarbonatitic lava flows on the floor of the summit crater. Petrologists first observed the eruption of carbonatitic lava flows in the 1960s. Subsequent more frequent visits have documented long-term lava effusion in the summit crater that would not have been seen from the foot of the volcano. Sources: Toulouse Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/FR/messages.html, Frederick Belton's Ol Doinyo Lengai website http://www.mtsu.edu/~fbelton/lengai.html Ol Doinyo Lengai Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=0202-12= STROMBOLI Aeolian Islands, Italy 38.79°N, 15.21°E; summit elev. 926 m Observers reported that on 5 November five active vents at Stromboli were visible at the bottom of the crater terrace, which subsided about 100 m since March 2007. Lava fountains from a vent in the SW crater were sustained for over one minute and spattering was observed from two vents in the central crater. The vents erupted about every five to ten minutes to one hour. Geologic Summary. Spectacular incandescent nighttime explosions at Stromboli volcano have long attracted visitors to the "Lighthouse of the Mediterranean." Stromboli, the NE-most of the Aeolian Islands, has lent its name to the frequent mild explosive activity that has characterized its eruptions throughout historical time. The small, 926-m-high island of Stromboli is the emergent summit of a volcano that grew in two main eruptive cycles, the last of which formed the western portion of the island. The active summit vents are located at the head of the Sciara del Fuoco, a horseshoe-shaped scarp formed as a result of slope failure that extends to below sea level and funnels pyroclastic ejecta and lava flows to the NW. Essentially continuous mild Strombolian explosions, sometimes accompanied by lava flows, have been recorded at Stromboli since Roman times. Source: Stromboli On-line http://www.swisseduc.ch/stromboli/index-en.html Stromboli Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=0101-04= Ongoing Activity CHIKURACHKI Kuril Islands, Russia 50.325°N, 155.458°E; summit elev. 1,816 m KVERT reported that clouds obscured satellite views of Chikurachki during 2-9 November. The Level of Concern Color Code remained at Orange <http://www.avo.alaska.edu/color_codes.php>. 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. Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/updates.shtml Chikurachki Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=0900-036= KARYMSKY Kamchatka Peninsula, Russia 54.05°N, 159.43°E; summit elev. 1,536 m KVERT reported that seismic activity at Karymsky was above background levels during 1-5 November and at background levels during 6-9 November. Based on seismic interpretation, ash explosions occurred and an ash plume may have risen to an altitude of 5 km (16,400 ft) a.s.l. on 2 November. Observations of satellite imagery revealed that a small thermal anomaly was present at the summit on 6 November; cloud cover obscured observations on other days. The Level of Concern Color Code <http://www.avo.alaska.edu/color_codes.php> 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. 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 Based on overflights and web camera views, HVO reported that fissure segment D from Kilauea's 21 July fissure eruption continued to feed an advancing lava flow that frequently overflowed its channel edges during 7-13 November. Lava tubes traveling E and S continued to burn kipukas N and SE of Pu'u Kia'i. Built-up and overturned crust in a lava pond nearest to the vent caused spattering to heights of 8-10 m during 10-11 November. A few small earthquakes were located beneath Halema'uma'u crater and along the S-flank fault during the reporting period. During 11-12 November, several earthquakes were located in an area between the Holei and Hilina palis. 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- 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 2-9 November. Based on seismic interpretation, ash plumes rose to an altitude of 8.5 km (28,000 ft) a.s.l. and small hot avalanches occurred. Visual observations and video footage analysis indicated that ash and gas-and-steam plumes rose to altitudes of 6-8 km (19,700-26,200 ft) a.s.l. during 4-8 November. Clouds obscured views of the volcano on other days. Based on observations of satellite imagery, ash plumes drifted SW on 7 November and a thermal anomaly was present in the crater every day during the reporting period. The Level of Concern Color Code remained at Orange <http://www.avo.alaska.edu/color_codes.php>. Based on information from the KEMSD, the Tokyo VAAC reported that eruption plumes rose to altitudes of 4.9-5.5 km (16,000-18,000 ft) a.s.l. on 11 and 13 November. 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= ST. HELENS Washington, USA 46.20°N, 122.18°W; summit elev. 2,549 m Data from deformation-monitoring instruments indicated that during 7-13 November lava-dome growth at Mount St. Helens continued. Seismicity persisted at low levels, punctuated by M 1.5-2.5, and occasionally larger, earthquakes. Clouds occasionally 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 IG reported that although visual observations were limited due to cloud cover, ash-and-steam and ash plumes from Tungurahua rose to altitudes of 6-9 km (19,700-30,000 ft) a.s.l. during 7-13 November. Plumes mainly drifted W and SW and ashfall was reported from multiple areas downwind, including areas to the N and NW. Roars and "cannon shots" were also reported from several areas. A seismic station recorded a lahar on the SW flank that lasted about 30 minutes on 10 November. The next day, fumarolic activity on the NW edge of the crater rim was noted. Incandescent blocks propelled from the summit landed on the flanks and rolled a few hundred meters during 7-13 November. Incandescent blocks traveled 1 km down the flanks on 12 November. 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 Significant Meteorological Information (SIGMET) advisories and observations of satellite imagery, the Buenos Aires VAAC reported that ash plumes from Ubinas rose to altitudes of 5.5-6.7 km (18,000-22,000 ft) a.s.l. during 11-12 November. Plumes drifted NNE. 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. ==============================================================
