Smithsonian/USGS Weekly Volcanic Activity Report 5-11 February 2014
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Smithsonian/USGS Weekly Volcanic Activity Report
5-11 February 2014
Sally Kuhn Sennert - Weekly Report Editor kuhns@si.edu
URL: http://www.volcano.si.edu/reports/usgs/
New Activity/Unrest: | Asosan, Kyushu | Barren Island, Andaman Islands | Karangetang [Api Siau], Siau | Kelut, Eastern Java (Indonesia) | San Cristóbal, Nicaragua | Shishaldin, Fox Islands | Tungurahua, Ecuador | Ubinas, Perú
Ongoing Activity: | Chirinkotan, Kuril Islands | Chirpoi, Kuril Islands (Russia) | Colima, México border | Dukono, Halmahera | Etna, Sicily (Italy| Karymsky, Eastern Kamchatka (Russia) | Kilauea, Hawaii (USA) | Rabaul, New Britain | Sakurajima, Kyushu | Shiveluch, Central Kamchatka (Russia) | Sinabung, Sumatra (Indonesia)
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
ASOSAN Kyushu 32.881°N, 131.106°E; summit elev. 1592 m
According to a JMA report, volcanologists conducting a field survey of Asosan's Nakadake Crater on 5 February detected decreased sulfur dioxide emissions and fewer volcanic earthquakes. The Alert Level remained at 2 (on a scale of 1-5).
Geologic Summary. The 24-km-wide Aso caldera was formed during four major explosive eruptions from 300,000 to 80,000 years ago. These produced voluminous pyroclastic flows that covered much of Kyushu. A group of 17 central cones was constructed in the middle of the caldera, one of which, Naka-dake, is one of Japan's most active volcanoes. It was the location of Japan's first documented historical eruption in 553 AD. The Naka-dake complex has remained active throughout the Holocene. Several other cones have been active during the Holocene, including the Kometsuka scoria cone as recently as about 210 AD. Historical eruptions have largely consisted of basaltic to basaltic-andesite ash emission with periodic Strombolian and phreatomagmatic activity. The summit crater of Naka-dake is accessible by toll road and cable car, and is one of Kyushu's most popular tourist destinations.
Source: Japan Meteorological Agency (JMA) http://www.jma.go.jp/jma/
BARREN ISLAND Andaman Islands 12.278°N, 93.858°E; summit elev. 354 m
Based on analysis of satellite imagery and wind data, the Darwin VAAC reported that on 6 February an ash plume from Barren Island rose to an altitude of 1.5 km (5,000 ft) a.s.l. and drifted over 35 km SW. A SIGMET report noted that low-level ash plumes were also observed on 9 February.
Geologic Summary. Barren Island, a possession of India in the Andaman Sea about 135 km NE of Port Blair in the Andaman Islands, is the only historically active volcano along the N-S-trending volcanic arc extending between Sumatra and Burma (Myanmar). The 354-m-high island is the emergent summit of volcano that rises from a depth of about 2,250 m. The small, uninhabited 3-km-wide island contains a roughly 2-km-wide caldera with walls 250-350 m high. The caldera, which is open to the sea on the W, was created during a major explosive eruption in the late Pleistocene that produced pyroclastic-flow and -surge deposits. The morphology of a fresh pyroclastic cone that was constructed in the center of the caldera has varied during the course of historical eruptions. Lava flows fill much of the caldera floor and have reached the sea along the western coast during historical eruptions.
Source: Darwin Volcanic Ash Advisory Centre (VAAC) ftp://ftp.bom.gov.au/anon/gen/vaac/
KARANGETANG [API SIAU] Siau I 2.78°N, 125.40°E; summit elev. 1784 m
Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that on 9 February an ash plume from Karangetang rose to an altitude of 4.3 km (14,000 ft) a.s.l. and drifted over 80 km W.
Geologic Summary. Karangetang (also known as Api Siau) lies at the northern end of the island of Siau, N of Sulawesi, and contains five summit craters strung 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: Darwin Volcanic Ash Advisory Centre (VAAC) ftp://ftp.bom.gov.au/anon/gen/vaac/
KELUT Eastern Java (Indonesia) 7.93°S, 112.308°E; summit elev. 1731 m
PVMBG reported that during 3-10 February seismic activity at Kelut was dominated by both shallow and deep volcanic earthquakes; earthquake hypocenters were 3 km below the summit. RSAM values increased on 6 and 9 February. Inflation was detected at one station. Crater lake water temperatures increased since September 2013, particularly during 23 January-9 February. Temperatures decreased slightly on 10 February. Based on increased seismicity, inflation, and higher water temperatures, PVMBG increased the Alert Level to 3 (on a scale of 1-4) on 10 February. Visitors and residents were prohibited from approaching the crater within a 5-km radius.
Geologic Summary. The relatively inconcspicuous 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.
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) also known CVGHM http://www.vsi.esdm.go.id/
SAN CRISTOBAL Nicaragua 12.702°N, 87.004°W; summit elev. 1745 m
INETER reported that a gas emission with small amounts of ash rose from San Cristóbal between 0641 and 0850 on 4 February. Although there was no increase noted, the report stated that seismicity decreased to background levels. By the afternoon sulfur dioxide emission values were 2,000-3,000 tonnes per day, the normal levels, and on 7 February they were 1,000 tonnes per day.
Geologic Summary. The San Cristóbal volcanic complex, consisting of five principal volcanic edifices, forms the NW end of the Marrabios Range. The symmetrical 1,745-m-high youngest cone, San Cristóbal itself (also known as El Viejo), is Nicaragua's highest volcano and is capped by a 500 x 600 m wide crater. El Chonco, with several flank lava domes, is located 4 km to the west of San Cristóbal; it and the eroded Moyotepe volcano, 4 km to the NE of San Cristóbal, are of Pleistocene age. Volcán Casita contains an elongated summit crater and lies immediately E of San Cristóbal; Casita was the site of a catastrophic landslide and lahar in 1998. The Plio-Pleistocene La Pelona caldera is located at the eastern end of the San Cristóbal complex. Historical eruptions from San Cristóbal, consisting of small-to-moderate explosive activity, have been reported since the 16th century. Some other 16th-century eruptions attributed to Casita volcano are uncertain and may pertain to other Marrabios Range volcanoes.
Source: Instituto Nicaragüense de Estudios Territoriales (INETER) http://www.ineter.gob.ni/
SHISHALDIN Fox Islands 54.756°N, 163.97°W; summit elev. 2857 m
AVO reported that elevated surface temperatures in Shishaldin's summit crater were detected in satellite images during 5-6 February. No unusual seismicity was detected by the nearest working station off the flanks of the volcano. A possible ash-poor gas cloud was detected in satellite images beginning at 0645 on 7 February that may have been from a small explosion, too small to be detected by the seismometer but coinciding with a local tiltmeter signal. Satellite image analysis suggested that the short-lived cloud may have risen to an altitude of 7.6 km (25,000 ft) a.s.l. Elevated surface temperatures were not detected after the event, so very little if any hot material was ejected. During 9-11 February elevated surface temperatures were detected in satellite images and a tiltmeter 5.4 km SW of the volcano recorded a small signal. Clear or partly clear web cam images showed no activity. The Aviation Color Code remained at Yellow and the Volcano Alert Level remained at Advisory.
Geologic Summary. The beautifully symmetrical volcano of Shishaldin is the highest and one of the most active volcanoes of the Aleutian Islands. The 2,857-m-high, glacier-covered volcano is the westernmost of three large stratovolcanoes along an E-W line in the eastern half of Unimak Island. Constructed atop an older glacially dissected volcano, Shishaldin is Holocene in age and largely basaltic in composition. Remnants of an older ancestral volcano are exposed on the W and NE sides at 1,500-1,800 m elevation. Shishaldin contains over two dozen pyroclastic cones on its NW flank, which is blanketed by massive aa lava flows. Frequent explosive activity, primarily consisting of Strombolian ash eruptions from the small summit crater, sometimes producing lava flows, have been recorded since the 18th century.
Source: US Geological Survey Alaska Volcano Observatory (AVO) http://www.avo.alaska.edu/
TUNGURAHUA Ecuador 1.467°S, 78.442°W; summit elev. 5023 m
On 6 February, IG reported that since 3 February Tungurahua had produced almost constant emissions of gas, steam, and ash that rose 3-4 km above the crater and drifted N, causing ashfall in Ambato (31 km N), Patate (NW), Latacunga, and parts of Quito (130 km N). During 5-6 February ash plumes drifted E and SE and caused ashfall in Pondoa (8 km N), Vazcún (N), Runtún (6 km NNE), and San Antonio, and to a lesser extent in Rio Verde and Rio Negro. Strombolian activity was observed on 6 February.
Cloud cover often prevented visual observations during 7-11 February; explosions continued to be detected, roaring was periodically heard, and sounds resembling rolling blocks were occasionally reported. On 7 February ash fell in Palictahua. The next day a gas-and-ash plume rose 500 m and drifted W and SW. On 9 February an ash plume rose 4 km and drifted NW and NE. Strombolian activity ejected blocks 1 km away. During 10-11 February explosions vibrated structures, and ashfall was reported in Quero (20 km NW), Mocha (25 km WNW), El Manzano (8 km SW), and Choglontus (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.
Source: Instituto Geofísico-Escuela Politécnica Nacional (IG) http://www.igepn.edu.ec/
UBINAS Perú 16.355°S, 70.903°W; summit elev. 5672 m
IGP's Observatorio Volcanologico de Arequipa (IGP-OVA) reported that on 1 February at 1559 a gas-and-ash plume from Ubinas rose 0.5-2 km above the crater and drifted E and SE. A photo showed ash from the plume falling onto the flanks. The event was accompanied by increased seismicity for several hours. At 2027 on 7 February a large volcano-tectonic earthquake occurred under the volcano at a depth of 9 km. Bluish gas emissions were sporadic during 8-11 February.
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: Instituto Geofísico del Perú (IGP) http://www.igp.gob.pe/
Ongoing Activity
CHIRINKOTAN Kuril Islands 48.980°N, 153.480°E; summit elev. 724 m
SVERT reported that a thermal anomaly over Chirinkotan was observed in satellite images on 8 February, and steam-and-gas emissions were observed on 9 February. Cloud cover obscured views on other days during 4-10 February. The Aviation Color Code remained at Yellow.
Geologic Summary. The small, mostly unvegetated 3-km-wide island of Chirinkotan occupies the far end of an E-W-trending volcanic chain that extends nearly 50 km west of the central part of the main Kuril Islands arc. Chirinkotan is the emergent summit of a volcano that rises 3000 m from the floor of the Kuril Basin. A small 1-km-wide caldera about 300-400 m deep is open to the SE. Lava flows from a cone within the breached crater reached the north shore of the island. Historical eruptions have been recorded at Chirinkotan since the 18th century. Fresh lava flows also descended the SE flank of Chirinkotan during an eruption in the 1880s that was observed by the English fur trader Captain Snow.
Source: Sakhalin Volcanic Eruption Response Team (SVERT) http://www.imgg.ru/?id_d=659
CHIRPOI Kuril Islands (Russia) 46.525°N, 150.875°E; summit elev. 742 m
SVERT reported that a thermal anomaly over Snow, a volcano of Chirpoi, was detected in satellite images during 6 and 8-9 February. Cloud cover obscured views on other days during 4-10 February. The Aviation Color Code remained at Yellow.
Geologic Summary. Chirpoi, a small island lying between the larger islands of Simushir and Urup, contains a half dozen volcanic edifices constructed within an 8-9 km wide, partially submerged caldera. The southern rim of the caldera is exposed on nearby Brat Chirpoev Island. Two volcanoes on Chirpoi Island have been historically active. The symmetrical Cherny volcano, which forms the 691 m high point of the island, erupted twice during the 18th and 19th centuries. The youngest volcano, Snow, originated between 1770 and 1810. It is composed almost entirely of lava flows, many of which have reached the sea on the southern coast. No historical eruptions are known from 742-m-high Brat Chirpoev, but its youthful morphology suggests recent strombolian activity.
Source: Sakhalin Volcanic Eruption Response Team (SVERT) http://www.imgg.ru/en/home.html
COLIMA México 19.514°N, 103.62°W; summit elev. 3850 m
Based on observations of satellite images, the Washington VAAC reported that a small ash cloud from Colima drifted slowly E and then SE on 7 February; the slow drift was indicative of a low altitude. Another small puff of gas with low amounts of ash drifted SE.
Geologic Summary. The Colima volcanic complex is the most prominent volcanic center of the western Mexican Volcanic Belt. It consists of two southward-younging volcanoes, Nevado de Colima (the 4,320 m high point of the complex) on the N and the historically active Volcán de Colima on the S. Volcán de Colima (also known as Volcán Fuego) is a youthful stratovolcano constructed within a 5-km-wide caldera, breached to the S, that has been the source of large debris avalanches. Major slope failures have occurred repeatedly from both the Nevado and Colima cones, and have produced a thick apron of debris-avalanche deposits on three sides of the complex. Frequent historical eruptions date back to the 16th century. Occasional major explosive eruptions (most recently in 1913) have destroyed the summit and left a deep, steep-sided crater that was slowly refilled and then overtopped by lava dome growth.
Source: Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html
DUKONO Halmahera 1.68°N, 127.88°E; summit elev. 1335 m
Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that during 5-6 February ash plumes from Dukono rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted 55 km S and SW. During 9-11 February ash plumes rose to altitudes of 2.1-4.3 km (7,000-14,000 ft) a.s.l. and drifted 40-90 km NW and NE.
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) ftp://ftp.bom.gov.au/anon/gen/vaac/
ETNA Sicily (Italy) 37.734°N, 15.004°E; summit elev. 3330 m
INGV reported that during 4-5 February activity at Etna's New Southeast Crater (NSEC) was characterized by intermittent ash emissions accompanied by jets of incandescent pyroclastic material, and a constant emission of lava from one or two vents at the E base of the NSEC cone. The lava flows reached the base of the W slope of the Valle del Bove. On 6 February ash emissions ceased and small Strombolian explosions ejected incandescent pyroclastic material 100 m above the crater. On 7 February Strombolian explosions ejected material onto the flanks of the cone, and the next day ash puffs were observed. During 9-11 February activity continued to be characterized by Strombolian activity, periodic ash emissions, and advancing lava flows. At 0707 on 11 February a large quantity of reddish brown ash emitted from an area near the vents formed a very dense hot flow which quickly reached the base of the W wall of the Valle del Bove. Reddish brown ash emissions continued after the event.
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 (INGV) http://www.ct.ingv.it/
KARYMSKY Eastern Kamchatka (Russia) 54.05°N, 159.45°E; summit elev. 1536 m
KVERT reported that Vulcanian and Strombolian activity at Karymsky continued during 31 January-7 February. Satellite images detected a bright thermal anomaly on 1 February; cloud cover obscured views of the volcano on the other days. Ash plumes drifted 80 km E during 1-2 February. 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 February HVO reported that the circulating lava lake occasionally rose and fell in the deep pit within Kilauea's Halema'uma'u Crater. The plume from the vent continued to deposit variable amounts of ash, spatter, and Pele's hair onto nearby areas. At Pu'u 'O'o Crater, glow emanated from spatter cones on the N and S portions of the crater floor, and a lava pond was active in the NE spatter cone. The 7.8-km-long Kahauale'a 2 lava flow (based on a satellite image from 2 February), fed by the NE spatter cone, was active with scattered break-out flows 4.8 and 6.9 km NE of Pu'u 'O'o that burned the forest.
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/
RABAUL New Britain 4.271°S, 152.203°E; summit elev. 688 m
RVO reported that Rabaul caldera's Tavurvur cone was quiet during 26 January-11 February. A pale gray/brown plume rose 50-100 m above the vent and dispersed on 12 February.
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: Rabaul Volcano Observatory (RVO)
SAKURAJIMA Kyushu 31.585°N, 130.657°E; summit elev. 1117 m
JMA reported that during 3-7 February five explosions from Sakurajima's Showa Crater ejected tephra as far as 1,300 m. Incandescence from the crater was detected at night. The Alert Level remained at 3 (on a scale of 1-5). The Tokyo VAAC reported explosions during 6, 8-9, and 11 February. On 8 February a pilot observed an ash plume drifting at an altitude of 2.1 km (7,000 ft) a.s.l. Ash plumes rose to an altitude of 1.8 km (6,000 ft) a.s.l. on 9 February and 2.1 (7,000 ft) a.s.l. on 11 February.
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.
Sources: Japan Meteorological Agency (JMA) http://www.jma.go.jp/jma/index.html,
Tokyo Volcanic Ash Advisory Center (VAAC) http://ds.data.jma.go.jp/svd/vaac/data/vaac_list.html
SHIVELUCH Central Kamchatka (Russia) 56.653°N, 161.360°E; summit elev. 3283 m
KVERT reported that during 31 January-7 February a newer lava dome continued to extrude onto the NW part of Shiveluch's older lava dome. Lava-dome extrusion was accompanied by hot avalanches, incandescence, and fumarolic activity. A thermal anomaly was detected in satellite images during 3-4 February. Based on interpretation of seismic data, a large explosion that started at 1245 on 6 February and ended at 0440 on 7 February generated an ash plume that rose to altitudes of 9-10 km (29,500-32,800) a.s.l. A satellite image acquired at 0705 on 7 February showed a large ash cloud (240 x 180 km) over the Sea of Okhotsk 320 km WNW at an altitude of 4-5 km (13,100-16,400) a.s.l. 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/index_eng.php
SINABUNG Sumatra (Indonesia) 3.17°N, 98.392°E; summit elev. 2460 m
Based on reports from PVMBG, BNPB reported on 8 and 9 February that seismicity at Sinabung continued to be dominated by hybrid earthquakes, indicating pressure below the crater and a growing lava dome. Earthquakes associated with avalanches increased. The 9 February report noted that the number of displaced people reached 32,351 (9,991 families) in 42 evacuation centers. Refugees from 17 villages outside the 5-km radius were allowed to return to their homes, starting with four villages during the first phase.
Geologic Summary. Gunung Sinabung is a Pleistocene-to-Holocene stratovolcano with many lava flows on its flanks. The migration of summit vents along a N-S line gives the summit crater complex an elongated form. The youngest crater of this conical, 2460-m-high andesitic-to-dacitic volcano is at the southern end of the four overlapping summit craters. An unconfirmed eruption was noted in 1881, and solfataric activity was seen at the summit and upper flanks of Sinabung in 1912, although no confirmed historical eruptions were recorded prior to 2010.
Source: Badan Nacional Penanggulangan Bencana (BNPB) http://www.bnpb.go.id/
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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: 202.633.1805
Fax: 202.357.2476
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