*****************************************************************************************
Smithsonian/USGS Weekly Volcanic Activity Report 7-13 December 2011
From: "Faulk, Elisabeth" <FaulkE@si.edu>
*****************************************************************************************
Smithsonian/USGS Weekly Volcanic Activity Report
7-13 December 2011
Elisabeth Faulk - Weekly Report Editor
faulke@si.edu
URL: http://www.volcano.si.edu/reports/usgs/
New Activity/Unrest: | Galeras, Colombia | Gamalama, Halmahera | Sorikmarapi, Sumatra (Indonesia) | Sundoro, Central Java (Indonesia) | Tungurahua, Ecuador
Ongoing Activity: | Dukono, Halmahera | Fuego, Guatemala | Hierro, Canary Islands (Spain) | Karymsky, Eastern Kamchatka (Russia) | Kilauea, Hawaii (USA) | Kizimen, Eastern Kamchatka (Russia) | Popocatépetl, México | Puyehue-Cordón Caulle, Central Chile | Sakura-jima, Kyushu | Santa María, Guatemala | Shiveluch, Central Kamchatka (Russia)
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 activity continued at Galeras during 7-13 December, with steam rising from the main crater and two craters to the N and SW (Paisita and Chavas, respectively). On 9 and 11 December earthquakes of M 2.3 and 2.5, felt by local residents, occurred near the crater at a depth of 1.5 km. The Alert Level remains at III (Yellow; "changes in the behavior of volcanic activity").
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.
Source: Instituto Colombiano de Geología y Minería (INGEOMINAS) http://www.ingeominas.gov.co/Pasto.aspx
GAMALAMA Halmahera 0.80°N, 127.33°E; summit elev. 1715 m
Based on information from CVGHM, the Darwin VAAC reported that during 7-10 December ash plumes from Gamalama rose to altitudes of 2.1-6.1 km (7,000-20,000 ft) a.s.l. and drifted E and SE. The Alert Level for Gamalama remains at 3 (on a scale from 1-4).
Geologic Summary. Gamalama (Peak of Ternate) is a near-conical stratovolcano that comprises the entire island of Ternate off the western coast of Halmahera and is one of Indonesia's most active volcanoes. The island of Ternate was a major regional center in the Portuguese and Dutch spice trade for several centuries, which contributed to the thorough documentation of Gamalama's historical activity. Three cones, progressively younger to the N, form the summit of Gamalama, which reaches 1,715 m. Several maars and vents define a rift zone, parallel to the Halmahera island arc, that cuts the volcano. Eruptions, recorded frequently since the 16th century, typically originated from the summit craters, although flank eruptions have occurred in 1763, 1770, 1775, and 1962-63.
Source: Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AU/messages.html
SORIKMARAPI Sumatra (Indonesia) 0.686°N, 99.539°E; summit elev. 2145 m
CVGHM reported increased seismicity from Sorik Marapi during 1-12 December and white plumes rose 40-50 m above the summit. CVGHM raised the Alert Level on 12 December from 1 to 2 (on a scale of 1-4) based on seismic data.
Geologic Summary. Sorikmarapi is a forested stratovolcano with a 600-m-wide summit crater containing a crater lake and substantial sulfur deposits. A smaller parasitic crater (Danau Merah) on the upper SE flank also contains a crater lake; these two craters and a series of smaller explosion pits occur along a NW-SE line. Several solfatara fields are located on the eastern flank. Phreatic eruptions have occurred from summit and flank vents during the 19th and 20th centuries.
Source: Center of Volcanology and Geological Hazard Mitigation (CVGHM) http://www.vsi.esdm.go.id/
SUNDORO Central Java (Indonesia) 7.30°S, 109.992°E; summit elev. 3136 m
CVGHM reported increased seismic activity at Sundoro during October -4 December. On 26 November and 2 December smoke was reported from many fumaroles around the summit crater. Based on visual and seismic data, CVGHM raised the Alert Level from 1 to 2 (on a scale of 1-4) on 5 December.
Geologic Summary. Gunung Sundoro, one Java's most symmetrical volcanoes, is separated by a 1400-m-high saddle from Sumbing volcano. Parasitic craters and cones, the largest of which is Kembang, occur on the NW-to-southern flanks, and all fed lava flows. A small lava dome occupies the summit crater of the 3136-m-high volcano, and numerous phreatic explosion vents were formed along radial fissure that cut the dome and extend across the crater rim. Lava flows extend in all directions from the summit crater. Deposits of a large prehistoric debris avalanche are located below the NE flank of Sundoro. Pyroclastic-flow deposits dated at 1720 years before present extend as far as 13 km from the summit. Historical eruptions typically have consisted of mild-to-moderate phreatic explosions, mostly from the summit crater. Flank vents were also active in 1882 and 1903.
Source: Center of Volcanology and Geological Hazard Mitigation (CVGHM) http://www.vsi.esdm.go.id/
TUNGURAHUA Ecuador 1.467°S, 78.442°W; summit elev. 5023 m
IG reported that during 7-8 December activity continued at Tungurahua and roaring noises and sounds resembling "cannon shots" were heard. Ash plumes rose to altitudes of 1.5-4.0 km (4,920-16,400 ft) drifting W and NE on 7 December, and W and SW on 8 December. Ashfall was reported in communities to the W, NE, and SW. On 8 December ashfall was reported in Choglontús (SW), Chacauco, Manzano (8 km SW), Bilbao (8 km W), and Pillate (8 km W). Crater incandescence was observed on 10 December, but activity decreased during 10-11 December.
Based on pilot and satellite observations, the Washington VAAC reported that during 7-8 December ash plumes from Tungurahua rose to altitudes of 7.0-7.9 km (23,000 -26,000 ft) a.s.l. and drifted 18.5-24.0 km S and SW.
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.
Sources: Instituto Geofísico-Escuela Politécnica Nacional (IG) http://www.igepn.edu.ec/ , Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html
Ongoing Activity
DUKONO Halmahera 1.68°N, 127.88°E; summit elev. 1335 m
Based on analyses of satellite imagery, the Darwin VAAC reported that on 13 December an ash plume from Dukono rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted 74 km SW.
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 Centre (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AU/messages.html
FUEGO Guatemala 14.473°N, 90.880°W; summit elev. 3763 m
INSIVUMEH reported that on 9 and 13 December explosions from Fuego produced rumbling sounds and ash plumes that rose 300-600 m above the crater and drifted W, SW, and S. Block avalanches descended the SW flank toward the Ceniza drainage.
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/vulcanologia/boletin%20formato.htm
HIERRO Canary Islands (Spain) 27.73°N, 18.03°W; summit elev. 1500 m
Instituto Geográfico Nacional (IGN) reported that during 7-13 December the submarine eruption continued S of El Hierro Island, with steaming lava fragments sporadically observed floating on the sea. During this period, the mean tremor amplitude oscillated between decreasing and increasing trends during the first days of the week, and since 10 December high-amplitude pulses occurred every 5-10 minutes.
Only seven seismic events were located during this period, most of them offshore to the N of the island at depths of 17-23 km and with a maximum magnitude of 2.0. GPS data analyses showed stability in the horizontal components and trends to deflation in the vertical component.
Geologic Summary. The triangular island of Hierro is the SW-most and least studied of the Canary Islands. The massive Hierro shield volcano is truncated by a large NW-facing escarpment formed as a result of gravitational collapse of El Golfo volcano about 130,000 years ago. The steep-sided 1500-m-high scarp towers above a low lava platform bordering 12-km-wide El Golfo Bay, and three other large submarine landslide deposits occur to the SW and SE. Three prominent rifts oriented NW, NE, and south at 120 degree angles form prominent topographic ridges. The subaerial portion of the volcano consists of flat-lying Quaternary basaltic and trachybasaltic lava flows and tuffs capped by numerous young cinder cones and lava flows. Holocene cones and flows are found both on the outer flanks and in the El Golfo depression. Hierro contains the greatest concentration of young vents in the Canary Islands. Uncertainty surrounds the report of an historical eruption in 1793.
Source: Instituto Geográfico Nacional (IGN) http://www.ign.es/ign/resources/volcanologia/html/informesHIERRO.html
KARYMSKY Eastern Kamchatka (Russia) 54.05°N, 159.45°E; summit elev. 1536 m
KVERT reported that seismic activity continued at a moderate level at Karymsky during 2-9 December and indicated that possible ash plumes rose to an altitude of 3.6 km (11,800 ft) a.s.l. Satellite imagery showed a daily thermal anomaly and ash plumes that drifted 90 km E on 3, 7, and 8 December. The Aviation Color Code remained at Orange. Based on information from KVERT, the Tokyo VAAC reported that on 13 December an ash plume rose to an altitude of 3.0 km (10,000 ft) a.s.l. and drifted E.
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.php , Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html
KILAUEA Hawaii (USA) 19.421°N, 155.287°W; summit elev. 1222 m
During 7-13 December, HVO reported that the lava lake circulated and periodically rose and fell in the deep pit within Kilauea's Halema'uma'u Crater, remaining below the inner ledge (75 m below the crater floor). Almost daily measurements indicated that the gas plume from the vent continued to deposit variable amounts of ash and fresh spatter nearby.
Incandescence was visible along the E and W edges of the Pu'u 'O'o crater floor, along the 21 September fissure on the SE flank of Pu'u 'O'o cone, and from a skylight on the lava tube. Lava continues to erupt into the perched pond formed on 6 December. Pahoehoe flows, fed through lava tubes from the fissure, continued to be active about 6.8 km SE of Pu'u 'O'o based on intermittent views from satellite. Analysis of 10-12 December satellite images suggested that lava had reached the coast and was flowing into the ocean. During 11-12 December incandescence was observed from small spatter cones on the E and S edges of the Pu'u 'O'o crater floor; short lava flows issued from the E edge of the crater floor on 12 December.
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/
KIZIMEN Eastern Kamchatka (Russia) 55.130°N, 160.32°E; summit elev. 2376 m
KVERT reported an increase in seismic activity at Kizimen during 2-9 December and a daily thermal anomaly that was detected in satellite images. A large lava flow on the NE and E flanks continued to effuse. The video camera was down due to technical reasons during the week. The Aviation Color Code remained at Orange.
Geologic Summary. Kizimen is an isolated, conical stratovolcano that is morphologically similar to Mount St. Helens prior to its 1980 eruption. The summit of Kizimen consists of overlapping lava domes, and blocky lava flows descend the flanks of the volcano, which is the westernmost of a volcanic chain north of Kronotsky volcano. The 2,376-m-high Kizimen was formed during four eruptive cycles beginning about 12,000 years ago and lasting 2,000-3,500 years. The largest eruptions took place about 10,000 and 8300-8400 years ago, and three periods of longterm lava-dome growth have occurred. The latest eruptive cycle began about 3,000 years ago with a large explosion and was followed by lava-dome growth lasting intermittently about 1,000 years. An explosive eruption about 1,100 years ago produced a lateral blast and created a 1.0 x 0.7 km wide crater breached to the NE, inside which a small lava dome (the fourth at Kizimen) has grown. A single explosive eruption, during 1927-28, ha
s been recorded in historical time.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/updates.php
POPOCATEPETL México 19.023°N, 98.622°W; summit elev. 5426 m
CENAPRED reported that during 7-13 December steam-and-gas emissions rose from Popocatépetl and occasionally contained small amounts of ash. On 7 December ashfall was reported in San Pedro (13.5 km NW). Crater incandescence was observed during 9-11 December and on 9 December incandescence ballistic fragments were observed on the upper slopes of the cone.
Based on reports from CENEPRED and the Mexico City MWO, the Washington VAAC reported an ash plume that drifted 12.9 km W on 7 December.
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.
Sources: Centro Nacional de Prevencion de Desastres (CENAPRED) http://www.cenapred.unam.mx/cgi-bin/popo/reportes/consulta.cgi , Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html
PUYEHUE-CORDON CAULLE Central Chile 40.590°S, 72.117°W; summit elev. 2236 m
Based on seismicity during 7-13 December, OVDAS-SERNAGEOMIN reported that the eruption from the Cordón Caulle rift zone, part of the Puyehue-Cordón Caulle volcanic complex, continued at a low level. Plumes observed with the web camera during 8-9 December rose 3.0-3.5 km above the crater and plumes were identified in satellite imagery drifting 90 km SE on 8 December and 250 km ENE on 9 December. Cloud cover prevented web camera and satellite observations during 10-13 December, but ashfall was reported to the E during 10-11 December. The Alert Level remained at Red.
Geologic Summary. The Puyehue-Cordón Caulle volcanic complex (PCCVC) is a large NW-SE-trending late-Pleistocene to Holocene basaltic-to-rhyolitic transverse volcanic chain SE of Lago Ranco. The 1799-m-high Pleistocene Cordillera Nevada caldera lies at the NW end, separated from Puyehue stratovolcano at the SE end by the Cordón Caulle fissure complex. The Pleistocene Mencheca volcano with Holocene flank cones lies NE of Puyehue. The basaltic-to-rhyolitic Puyehue volcano is the most geochemically diverse of the PCCVC. The flat-topped, 2236-m-high Puyehue volcano was constructed above a 5-km-wide caldera and is capped by a 2.4-km-wide summit caldera of Holocene age. Lava flows and domes of mostly rhyolitic composition are found on the eastern flank of Puyehue. Historical eruptions originally attributed to Puyehue, including major eruptions in 1921-22 and 1960, are now known to be from the Cordón Caulle rift zone. The Cordón Caulle geothermal area, occupying a 6 x 13 km wide volc
ano-tectonic depression, is the largest active geothermal area of the southern Andes volcanic zone.
Source: Servicio Nacional de Geología y Minería (SERNAGEOMIN) http://www.sernageomin.cl/index.php?option=com_content&task=category§ionid=1&a mp;id=1&Itemid=154
SAKURA-JIMA Kyushu 31.585°N, 130.657°E; summit elev. 1117 m
Based on information from JMA, the Tokyo VAAC reported that during 7-13 December explosions from Sakura-jima produced plumes that rose to altitudes of 1.0-2.7 km (3,000-9,000 ft) a.s.l. and drifted E, SE, S, and NE. Satellite imagery and a pilot report showed ash plumes that rose to an altitude of 2.4 km (8,000 ft) a.s.l and drifted 46 km SW on 9 December and 37 km S on 13 December.
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 9 December plumes from Santa María's Santiaguito lava-dome complex rose 300 m above the crater and drifted SW and explosions generated rumbling noises. On 13 December block avalanche activity increased on the S flank and created pyroclastic flows that were deposited into the San Isidro drainage.
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/vulcanologia/boletin%20formato.htm
SHIVELUCH Central Kamchatka (Russia) 56.653°N, 161.360°E; summit elev. 3283 m
KVERT reported that moderate seismic activity was detected at Shiveluch during 2-9 December, and satellite imagery showed a daily thermal anomaly over the lava dome. Ground-based observers noted that a viscous lava flow continued to effuse in the crater formed during a 2010 eruption. Moderate fumarolic activity at the lava dome was observed during 3-6 December; clouds prevented observations on the other days of the week. The Aviation Color Code remained at Orange.
Geologic Summary. The high, isolated massif of Shiveluch volcano (also spelled Sheveluch) rises above the lowlands NNE of the Kliuchevskaya volcano group and forms one of Kamchatka's largest and most active volcanoes. The currently active Molodoy Shiveluch lava-dome complex was constructed during the Holocene within a large breached caldera formed by collapse of the massive late-Pleistocene Strary Shiveluch volcano. At least 60 large eruptions of Shiveluch have occurred during the Holocene, making it the most vigorous andesitic volcano of the Kuril-Kamchatka arc. Frequent collapses of lava-dome complexes, most recently in 1964, have produced large debris avalanches whose deposits cover much of the floor of the breached caldera. 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.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/updates.php
__._,_.___
No comments:
Post a Comment