Smithsonian/USGS Weekly Volcanic Activity Report 5-11 October 2011
From: "Kuhn, Sally" <KUHNS@xxxxxx>
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Smithsonian/USGS Weekly Volcanic Activity Report
5-11 October 2011
Sally Kuhn Sennert - Weekly Report Editor
URL: http://www.volcano.si.edu/reports/usgs/
New Activity/Unrest: | Gaua, Banks Islands (SW Pacific) | Hierro, Canary Islands (Spain) | Krakatau, Indonesia | Sangay, Ecuador | Shiveluch, Central Kamchatka (Russia) | Tungurahua, Ecuador
Ongoing Activity: | Bagana, Bougainville | Cleveland, Chuginadak Island | Dukono, Halmahera | Etna, Sicily (Italy) | Karymsky, Eastern Kamchatka (Russia) | Kilauea, Hawaii (USA) | Kizimen, Eastern Kamchatka (Russia) | Lokon-Empung, Sulawesi | Marapi, Sumatra (Indonesia) | Puyehue-Cordón Caulle, Central Chile | Sakura-jima, Kyushu
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
GAUA Banks Islands (SW Pacific) 14.27°S, 167.50°E; summit elev. 797 m
Vanuatu Geohazards Observatory reported that the seismic network monitoring Gaua detected volcanic activity in August. Gas plumes were detected by the OMI satellite on 17, 27, and 28 September, and ashfall was reported in the N, E, and W parts of Gaua on 10 October by local authorities. The Alert Level remained at 1 (on a scale of 0-4).
Geologic Summary. The roughly 20-km-diameter Gaua Island, also known as Santa Maria, consists of a basaltic-to-andesitic stratovolcano with an 6 x 9 km wide summit caldera. Small parasitic vents near the caldera rim fed Pleistocene lava flows that reached the coast on several sides of the island; several littoral cones were formed where these lava flows reached the sea. Quiet collapse that formed the roughly 700-m-deep caldera was followed by extensive ash eruptions. Construction of the historically active cone of Mount Garat (Gharat) and other small cinder cones in the SW part of the caldera has left a crescent-shaped caldera lake. The symmetrical, flat-topped Mount Garat cone is topped by three pit craters. The onset of eruptive activity from a vent high on the SE flank of Mount Garat in 1962 ended a long period of dormancy.
Source: Vanuatu Geohazards Observatory http://www.geohazards.gov.vu/
HIERRO Canary Islands (Spain) 27.73°N, 18.03°W; summit elev. 1500 m
Instituto Geográfico Nacional (IGN) reported more than 700 new seismic events were detected at Hierro during 4-11 October, 52 of them were felt by residents. A M 4.3 earthquake was detected on 8 October, located 1.5 km from the SW coast of the island at 14 km depth. Following the event, the trend of the superficial deformation changed, suggesting deflation of the system. During the night of 8 October through the following day, low-magnitude seismic events occurred at depths of less than 2 km. Since 0515 on 10 October volcanic tremor was clearly recorded by all of the seismic stations on the island, with highest amplitudes recorded in the southernmost station. All data suggested a submarine eruption.
On 11 October at about 0700 the amplitude of the tremor increased. During that morning residents on the S of the island reported feeling vibrations. After midday, the Government of the Canary Islands raised the Alert Code to Red for Restinga village (at the southernmost point of Hierro) and evacuated the residents. A maritime exclusion zone extended about 4 nautical miles from Restinga.
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/layout/volcaVolcanologia.do
KRAKATAU Indonesia 6.102°S, 105.423°E; summit elev. 813 m
On 8 October, a news article stated that activity at Anak Krakatau was increasing; the number of seismic events was 5,204 on 6 October, 5,543 on 7 October, and 5,883 on 8 October. The Alert Level remained at 3 (on a scale of 1-4), and visitors and residents were not permitted to approach the volcano within a 2-km radius.
Geologic Summary. 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.
Source: The Jakarta Post http://www.thejakartapost.com/news/2011/10/08/anak-krakatau-volcanic-activity-continues-picking.html
SANGAY Ecuador 2.002°S, 78.341°W; summit elev. 5230 m
Based on information from the Guayaquil MWO and a pilot observation, the Washington VAAC reported that on 11 October an ash plume from Sangay from a possible eruption rose to an altitude of 6.7 km (22,000 ft) a.s.l. and drifted W. Ash was not observed in satellite imagery.
Geologic Summary. The isolated Sangay volcano, located E of the Andean crest, is the southernmost of Ecuador's volcanoes, and its most active. It has been in frequent eruption for the past several centuries. The steep-sided, 5,230-m-high glacier-covered volcano grew within horseshoe-shaped calderas of two previous edifices, which were destroyed by collapse to the E, producing large debris avalanches that reached the Amazonian lowlands. The modern edifice dates back to at least 14,000 years ago. Sangay towers above the tropical jungle on the E side; on the other sides flat plains of ash from the volcano have been sculpted by heavy rains into steep-walled canyons up to 600 m deep. The earliest report of an historical eruption was in 1628. More or less continuous eruptions were reported from 1728 until 1916, and again from 1934 to the present. The more or less constant eruptive activity has caused frequent changes to the morphology of the summit crater complex.
Source: Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html
SHIVELUCH Central Kamchatka (Russia) 56.653°N, 161.360°E; summit elev. 3283 m
KVERT reported that seismic activity at Shiveluch was moderate during 30 September-7 October. Ash plumes rose to altitudes of 6-9 km (19,700-30,000 ft) a.s.l. during 3-5 October, followed by new lava-dome extrusion. Seismicity indicated that possible ash plumes rose to altitudes of 4.5-5 km (14,800-16,400 ft) a.s.l. during 5-6 October; ground-based observers noted that ash plumes rose to an altitude of 5 km (16,400 ft) a.s.l. on those same days. Satellite imagery showed a large and bright thermal anomaly on the lava dome on 5 October and ash plumes that drifted 100 km NE on 6 October. The Aviation Color Code was lowered to Orange.
Based on information from KEMSD, the Tokyo VAAC reported that on 8 October an eruption produced a plume that rose to an altitude of 7 km (23,000 ft) a.s.l. and drifted E. Subsequent satellite images that day showed that ash was present and then had dissipated. An eruption on 10 October produced a plume that rose to an altitude of 7.3 km (24,000 ft) a.s.l.
Geologic Summary. The high, isolated massif of Shiveluch volcano (also spelled Sheveluch) rises above the lowlands NNE of the Kliuchevskaya volcano group and forms one of Kamchatka's largest and most active volcanoes. The currently active Molodoy Shiveluch lava-dome complex was constructed during the Holocene within a large breached caldera formed by collapse of the massive late-Pleistocene Strary Shiveluch volcano. At least 60 large eruptions of Shiveluch have occurred during the Holocene, making it the most vigorous andesitic volcano of the Kuril-Kamchatka arc. Frequent collapses of lava-dome complexes, most recently in 1964, have produced large debris avalanches whose deposits cover much of the floor of the breached caldera. Intermittent explosive eruptions began in the 1990s from a new lava dome that began growing in 1980. The largest historical eruptions from Shiveluch occurred in 1854 and 1964.
Sources: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php,
Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html
TUNGURAHUA Ecuador 1.467°S, 78.442°W; summit elev. 5023 m
Based on information from IG, the Washington VAAC reported that on 7 October an ash plume from Tungurahua rose to an altitude of 6.1 km (20,000 ft) a.s.l. and drifted W. Ash was not observed in satellite imagery.
Geologic Summary. The steep-sided Tungurahua stratovolcano towers more than 3 km above its northern base. It sits ~140 km S of Quito, Ecuador's capital city, and is one of Ecuador's most active volcanoes. Historical eruptions have all originated from the summit crater. They have been accompanied by strong explosions and sometimes by pyroclastic flows and lava flows that reached populated areas at the volcano's base. The last major eruption took place from 1916 to 1918, although minor activity continued until 1925. The latest eruption began in October 1999 and prompted temporary evacuation of the town of Baños on the N side of the volcano.
Source: Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html
Ongoing Activity
BAGANA Bougainville 6.140°S, 155.195°E; summit elev. 1750 m
Based on analyses of satellite imagery, the Darwin VAAC reported that during 8-9 October ash plumes from Bagana rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted 45-55 km E and NW.
Geologic Summary. Bagana volcano, occupying a remote portion of central Bougainville Island, is one of Melanesia's youngest and most active volcanoes. Bagana is a massive symmetrical lava cone largely constructed by an accumulation of viscous andesitic lava flows. The entire lava cone could have been constructed in about 300 years at its present rate of lava production. Eruptive activity at Bagana is characterized by non-explosive effusion of viscous lava that maintains a small lava dome in the summit crater, although explosive activity occasionally producing pyroclastic flows also occurs. Lava flows form dramatic, freshly preserved tongue-shaped lobes up to 50-m-thick with prominent levees that descend the volcano's flanks on all sides.
Source: Darwin Volcanic Ash Advisory Centre (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AU/messages.html
CLEVELAND Chuginadak Island 52.825°N, 169.944°W; summit elev. 1730 m
AVO reported that during 5-6 and 9-11 October cloud cover over Cleveland prevented views of the lava dome in the summit crater. Partly cloudy satellite views during 7-8 October showed elevated surface temperatures at the summit. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange. No current seismic information was available because Cleveland does not have a real-time seismic network.
Geologic Summary. 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 (AVO) http://www.avo.alaska.edu/
DUKONO Halmahera 1.68°N, 127.88°E; summit elev. 1335 m
Based on analyses of satellite imagery, the Darwin VAAC reported that during 5-6 and 8-9 October ash plumes from Dukono rose to altitudes of 2.1-2.4 km (7,000-8,000 ft) a.s.l. and drifted 75-83 km NE and SE.
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
ETNA Sicily (Italy) 37.734°N, 15.004°E; summit elev. 3330 m
Sezione di Catania - Osservatorio Etneo reported that the sixteenth paroxysmal eruptive episode of 2011 took place at the New SE Crater (New SEC) of Etna during the afternoon of 8 October. A rapid increase in volcanic tremor amplitude was detected that morning, and at about 1300 weak and discontinuous Strombolian explosions were recorded by surveillance cameras. Two hours later, lava flowed from a deep notch in the SE rim of the crater.
At around 1545 vigorous Strombolian activity was observed from numerous vents along a short fissure on the SE flank of the cone, which had first been active during the 29 August paroxysm (the twelfth). Weather conditions deteriorated at about 1615, preventing direct observations of the Strombolian activity changing into sustained lava fountaining and ash emissions. However, this change was audible around 1630, and a dense ash-and-vapor plume rapidly rose above the weather clouds and drifted E. At the same time lava flows descended on the W slope of the Valle del Bove. Eruptive vents opened on the NE flank of the cone, approximately along the fracture that first opened during 8 September, and two small lava flows were emitted. The more voluminous lava flow traveled a few hundred meters downslope. The paroxysmal phase lasted a little longer than 20 minutes and ended around 1650. Ash emissions continued until 1945, when the volcanic tremor amplitude returned to levels similar to those preceding the paroxysmal episode, and the lava flow fronts appeared to stagnate. The ash cloud drifted ENE and produced ash- and lapilli-fall in a narrow sector from the Ripe della Naca area and the village of Puntalazzo (13 km E) to the town of Mascali (18 km E).
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.
Source: Sezione di Catania - Osservatorio Etneo http://www.ct.ingv.it/index.php
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 30 September-7 October and indicated that possible ash plumes rose to an altitude of 3.2 km (10,500 ft) a.s.l. Satellite imagery showed a thermal anomaly on the volcano during 4-5 October. The Aviation Color Code 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/index_eng.php
KILAUEA Hawaii (USA) 19.421°N, 155.287°W; summit elev. 1222 m
During 5-11 October, HVO reported that the lava lake circulated and periodically rose and fell in the deep pit within Kilauea's Halema'uma'u crater. Almost daily measurements indicated that the gas plume from the vent continued to deposit variable amounts of ash and occasionally fresh spatter nearby.
At the E rift zone, the fissure that formed on 21 September on the upper E flank of Pu'u 'O'o continued to feed slowly-advancing lava flows to the NE and SE of the fissure. During the beginning of the week, overall activity within and SE of Pu'u 'O'o Crater had slowed; only a few lava patches were visible in webcams. During 7-8 October lava began to flow from a vent at the E end of the crater floor and from an area at the W end the next day. Lava flows from the E-end source stalled on 10 October.
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 that during 30 September-7 October video data showed that a large lava flow on Kizimen's NE flank continued to effuse. Strong fumarolic activity was observed during 29-30 September and 3-6 October. A thermal anomaly on the volcano was detected daily in satellite images but the temperature of the anomaly decreased during the end of the week. During 5-6 October the number of volcanic earthquakes decreased, from 1,300 to 500-700, as well as the magnitudes. 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, has been recorded in historical time.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php
LOKON-EMPUNG Sulawesi 1.358°N, 124.792°E; summit elev. 1580 m
CVGHM reported that on 10 October white and gray plumes rose 100-300 m above Tompaluan crater, in the saddle between the Lokon-Empung peaks. Based on information from CVGHM, the Darwin VAAC reported that on 11 October an ash plume rose to an altitude of 2.1 km (7,000 ft) a.s.l. The Alert Level remained at 3 (on a scale of 1-4).
Geologic Summary. The twin volcanoes Lokon and Empung, rising about 800 m above the plain of Tondano, are among the most active volcanoes of Sulawesi. Lokon, the higher of the two peaks (whose summits are only 2.2 km apart) has a flat, craterless top. The morphologically younger Empung volcano has a 400-m-wide, 150-m-deep crater that erupted last in the 18th century, but all subsequent eruptions have originated from Tompaluan, a 150 x 250 m wide double crater situated in the saddle between the two peaks. Historical eruptions have primarily produced small-to-moderate ash plumes that have occasionally damaged croplands and houses, but lava-dome growth and pyroclastic flows have also occurred.
Sources: Center of Volcanology and Geological Hazard Mitigation (CVGHM) http://www.vsi.esdm.go.id/,
Darwin Volcanic Ash Advisory Centre (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AU/messages.html
MARAPI Sumatra (Indonesia) 0.381°S, 100.473°E; summit elev. 2891 m
Based on a pilot report, the Darwin VAAC reported that on 11 October an ash plume from Marapi rose to an altitude of 3.7 km (12,000 ft) a.s.l. Ash was not identified in satellite imagery.
Geologic Summary. Gunung Marapi, not to be confused with the better known Merapi volcano on Java, is Sumatra's most active volcano. Marapi is a massive complex stratovolcano that rises 2,000 m above the Bukittinggi plain in Sumatra's Padang Highlands. A broad summit contains multiple partially overlapping summit craters constructed within the small 1.4-km-wide Bancah caldera. The summit craters are located along an ENE-WSW line, along which volcanism has migrated to the W. More than 50 eruptions, typically consisting of small-to-moderate explosive activity, have been recorded since the end of the 18th century; no historical lava flows outside the summit craters have been reported.
Source: Darwin Volcanic Ash Advisory Centre (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AU/messages.html
PUYEHUE-CORDON CAULLE Central Chile 40.590°S, 72.117°W; summit elev. 2236 m
Based on seismicity during 5-10 October, 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 visible with an area web camera rose no higher than 4 km above the crater during 5-7 October and were observed in satellite imagery drifting 30-60 km SE, SW, and N. On 9 October a white plume observed with the camera rose 4 km above the crater. Satellite imagery that day showed a widely dispersed ash plume drifting E. On 10 October a plume that was mostly white, but occasionally gray, rose 3.5 km above the crater. 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 volcano-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/
SAKURA-JIMA Kyushu 31.585°N, 130.657°E; summit elev. 1117 m
Based on information from JMA, the Tokyo VAAC reported that during 5-11 October explosions from Sakura-jima produced plumes that rose to altitudes of 1.2-3 km (4,000-10,000 ft) a.s.l. and drifted NW, N, SE, and S. During 6-8 October pilots observed ash plumes that rose to altitudes of 1.8-3.7 km (6,000-12,000 ft) a.s.l.
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
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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: 202.633.1805Fax: 202.357.2476
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