Smithsonian / USGS Weekly Volcanic Activity Report 4-10 February 2015
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Smithsonian / USGS Weekly Volcanic Activity Report
4-10 February 2015
Sally Kuhn Sennert - Weekly Report Editor (kuhns@xxxxxx)
URL: http://www.volcano.si.edu/reports_weekly.cfm
New Activity/Unrest: Colima, Mexico | Fuego, Guatemala | Karymsky, Eastern Kamchatka (Russia) | Klyuchevskoy, Central Kamchatka (Russia) | Pacaya, Guatemala | Piton de la Fournaise, Reunion Island (France) | Sangay, Ecuador | Soputan, Sulawesi (Indonesia) | Villarrica, Chile
Ongoing Activity: Aira, Kyushu (Japan) | Asosan, Kyushu (Japan) | Bardarbunga, Iceland | Chirinkotan, Kuril Islands (Russia) | Kilauea, Hawaiian Islands (USA) | Sheveluch, Central Kamchatka (Russia) | Shishaldin, Fox Islands (USA) | Sinabung, Indonesia | Zhupanovsky, Eastern 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
Colima | Mexico | 19.514°N, 103.62°W | Summit elev. 3850 m
Based on webcam views, Colima Tower, Mexico City MWO, and Colima Observatory notices, and satellite images, the Washington VAAC reported that on 4 February a small ash puff from Colima drifted E. Later that day an emission rose to an altitude of 7.3 km (24,000 ft) a.s.l. and drifted E, and two additional ash clouds drifted E. On 5 February multiple ash emissions, mostly diffuse, drifted E and NE. One ash plume rose to an altitude of 7.9 km (26,000 ft) a.s.l. and moved ENE.
In a 7 February bulletin, the Unidad Estatal de Protección Civil reported that Colima remained active, although there continued to be a slight decrease in the number and size of lava-block avalanches. Lava flows minimally advanced, and small landslides of lava blocks were observed. Explosions continued but also decreased in intensity. Residents were warned not go within 5 km of the volcano.
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 4320 m high point of the complex) on the north and the 3850-m-high historically active Volcán de Colima at the south. A group of cinder cones of late-Pleistocene age is located on the floor of the Colima graben west and east of the Colima complex. Volcán de Colima (also known as Volcán Fuego) is a youthful stratovolcano constructed within a 5-km-wide caldera, breached to the south, 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.
Sources: Unidad Estatal de Protección Civil www.proteccioncivil.col.gob.mx;
Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html
Fuego | Guatemala | 14.473°N, 90.88°W | Summit elev. 3763 m
INSIVUMEH reported that during 5-6 February explosions at Fuego ejected incandescent tephra 150 m above the crater, causing avalanches in the Taniluya (SSW), Ceniza, and Trinidad (S) drainages. Shock waves rattled nearby structures. Ash plumes rose 550 m above the crater and drifted 11-12 km S and SW. A Strombolian eruption commenced on 7 February; plumes with water vapor and ash rose as high as 1.3 km and drifted 20 km NW. Pyroclastic flows descended multiple drainages. CONRED reported that ash fell in Guatemala City (about 35 km ENE) and flights were diverted to El Salvador. On 8 February, although activity had decreased, the seismic network detected 30 explosions per minute. Explosions sounded like locomotives and generated shock waves detected in areas 15 km S and SW. Lava flows were at most 2 km long in the El Jute (SE) and Trinidad (S) drainages, reaching vegetated areas and causing fires. In a special notice INSIVUMEH stated that activity levels had returned to normal; weak to moderate explosions produced ash plumes that rose 550 m and drifted 8-10 km NW. Morphological changes had occurred on the S flank from pyroclastic flows. Avalanches from the lava flows also descended the southern flanks. Explosions during 9-10 February generated ash plumes that rose 800 m and drifted 11-12 km S and SW.
Geologic Summary. Volcán Fuego, one of Central America's most active volcanoes, is one of three large stratovolcanoes overlooking Guatemala's former capital, Antigua. The scarp of an older edifice, Meseta, lies between 3763-m-high Fuego and its twin volcano to the north, Acatenango. Construction of Meseta dates back to about 230,000 years and continued until the late Pleistocene or early Holocene. Collapse of Meseta may have produced the massive Escuintla debris-avalanche deposit, which extends about 50 km onto the Pacific coastal plain. Growth of the modern Fuego volcano followed, continuing the southward migration of volcanism that began at Acatenango. In contrast to the mostly andesitic Acatenango, eruptions at Fuego have become more mafic with time, and most historical activity has produced basaltic rocks. Frequent vigorous historical eruptions have been recorded since the onset of the Spanish era in 1524, and have produced major ashfalls, along with occasional pyroclastic flows and lava flows.
Sources: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH) http://www.insivumeh.gob.gt/;
Coordinadora Nacional para la Reducción de Desastres (CONRED) http://conred.gob.gt/
Karymsky | Eastern Kamchatka (Russia) | 54.049°N, 159.443°E | Summit elev. 1513 m
KVERT reported that during 30 January-6 February a moderate explosive eruption at Karymsky continued. Satellite images showed a thermal anomaly over the volcano during 30-31 January, and ash plumes that rose 2.5-3 km (8,200-9,800 ft) a.s.l. and drifted 85 km E on 31 January. 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 during the early Holocene. The caldera cuts the south side of the Pleistocene Dvor volcano and is located outside the north margin of the large mid-Pleistocene Polovinka caldera, which contains the smaller Akademia Nauk and Odnoboky calderas. Most seismicity preceding Karymsky eruptions originated beneath Akademia Nauk caldera, located immediately south. The caldera enclosing Karymsky formed about 7600-7700 radiocarbon years ago; construction of the stratovolcano began about 2000 years later. The latest eruptive period began about 500 years ago, following a 2300-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.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php
Klyuchevskoy | Central Kamchatka (Russia) | 56.056°N, 160.642°E | Summit elev. 4754 m
KVERT reported that during 30 January-6 February a Strombolian and Vulcanian eruption at Klyuchevskoy continued. Incandescence at the summit was visible and bombs were ejected 200-300 m above the crater. Explosions generated ash plumes that rose to altitudes of 5-6 km (16,400-19,700 ft) a.s.l.; ashfall was reported in Klyuchi Village (30 km NNE) on 5 February. A lava flow effused onto the E flank. Satellite images showed a daily, big, bright thermal anomaly over the volcano, and ash-and-gas plumes drifting in multiple directions at altitudes of 5.5-6 km (18,000-19,700 ft) a.s.l. During 4-5 February ash plumes drifted about 1,000 km NW and N. The Aviation Color Code remained at Orange.
Geologic Summary. Klyuchevskoy (also spelled Kliuchevskoi) is Kamchatka's highest and most active volcano. Since its origin about 6000 years ago, the beautifully symmetrical, 4835-m-high basaltic stratovolcano has produced frequent moderate-volume explosive and effusive eruptions without major periods of inactivity. It rises above a saddle NE of sharp-peaked Kamen volcano and lies SE of the broad Ushkovsky massif. More than 100 flank eruptions have occurred during the past roughly 3000 years, with most lateral craters and cones occurring along radial fissures between the unconfined NE-to-SE flanks of the conical volcano between 500 m and 3600 m elevation. The morphology of the 700-m-wide summit crater has been frequently modified by historical eruptions, which have been recorded since the late-17th century. Historical eruptions have originated primarily from the summit crater, but have also included numerous major explosive and effusive eruptions from flank craters.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php
Pacaya | Guatemala | 14.381°N, 90.601°W | Summit elev. 2552 m
INSIVUMEH reported that during 5-10 February fumarolic plumes from Pacaya's Mackenney Crater drifted 700-800 m S and SW.
Geologic Summary. Eruptions from Pacaya, one of Guatemala's most active volcanoes, are frequently visible from Guatemala City, the nation's capital. Pacaya is a complex basaltic volcano constructed just outside the southern topographic rim of the 14 x 16 km Pleistocene Amatitlán caldera. A cluster of dacitic lava domes occupies the southern caldera floor. The post-caldera Pacaya massif includes the ancestral Pacaya Viejo and Cerro Grande stratovolcanoes and the currently active Mackenney stratovolcano. Collapse of Pacaya Viejo volcano between 600 and 1500 years ago produced a debris-avalanche deposit that extends 25 km onto the Pacific coastal plain and left an arcuate somma rim inside which the modern Pacaya volcano (Mackenney cone) grew. A subsidiary crater, Cerro Chino, was constructed on the NW somma rim and was last active in the 19th century. During the past several decades, activity at Pacaya has consisted of frequent strombolian eruptions with intermittent lava flow extrusion that has partially filled in the caldera moat and armored the flanks of Mackenney cone, punctuated by occasional larger explosive eruptions that partially destroy the summit of the growing young stratovolcano.
Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH) http://www.insivumeh.gob.gt/
Piton de la Fournaise | Reunion Island (France) | 21.244°S, 55.708°E | Summit elev. 2632 m
OVPDLF reported that 180 earthquakes at Piton de la Fournaise were recorded from 0400 to 0900 on 4 February, including five events greater than M 2. A seismic crisis began at 0910, tremor was recorded at 1050, and an eruption began at 1100. Observers noted that a fissure had opened on the S flank, triggering an Alert Level 2-2 (ongoing eruption) and the restriction of access by the public to the summit area. The fissure was 500 m long, starting from an area located 100 m outside and to the W of Bory Crater. Activity was concentrated on the southernmost part of the fissure. Lava was ejected from the vent about 10 m high and rapidly flowed SSW towards the Rivals Crater, branched, and spread in an area S and SE of the crater. By the late afternoon the farthest-reaching branch had traveled past Cornu Crater. Tremor levels decreased through the day and were relatively low by 1800; on 6 February tremor levels were very low. Small cones had formed over the vents and produced low gas plumes. Inclement weather reduced visibility of the eruption site, although on 8 February observers noted that lava continued to flow from the vents, and another flow traveled further W. On 9 February a vent was weakly active with small explosions and small splashes of lava. Tremor remained stable and low on 10 February.
Geologic Summary. The massive Piton de la Fournaise basaltic shield volcano on the French island of Réunion in the western Indian Ocean is one of the world's most active volcanoes. Much of its more than 530,000-year history overlapped with eruptions of the deeply dissected Piton des Neiges shield volcano to the NW. Three calderas formed at about 250,000, 65,000, and less than 5000 years ago by progressive eastward slumping of the volcano. Numerous pyroclastic cones dot the floor of the calderas and their outer flanks. Most historical eruptions have originated from the summit and flanks of Dolomieu, a 400-m-high lava shield that has grown within the youngest caldera, which is 8 km wide and breached to below sea level on the eastern side. More than 150 eruptions, most of which have produced fluid basaltic lava flows, have occurred since the 17th century. Only six eruptions, in 1708, 1774, 1776, 1800, 1977, and 1986, have originated from fissures on the outer flanks of the caldera. The Piton de la Fournaise Volcano Observatory, one of several operated by the Institut de Physique du Globe de Paris, monitors this very active volcano.
Source: Observatoire Volcanologique du Piton de la Fournaise (OVPDLF) http://ovpf.univ-reunion.fr/
Sangay | Ecuador | 2.005°S, 78.341°W | Summit elev. 5286 m
Based on a pilot observation, the Washington VAAC reported that on 4 February an ash plume from Sangay rose to an altitude of 6.7 km (22,000 ft) a.s.l. Satellite images showed a possible ash plume drifting less than 20 km SW. A thermal anomaly was visible in satellite images the next day, as well as a diffuse plume with possible ash drifting W.
Geologic Summary. The isolated Sangay volcano, located east of the Andean crest, is the southernmost of Ecuador's volcanoes, and its most active. The dominantly andesitic volcano has been in frequent eruption for the past several centuries. The steep-sided, 5230-m-high glacier-covered volcano grew within horseshoe-shaped calderas of two previous edifices, which were destroyed by collapse to the east, producing large debris avalanches that reached the Amazonian lowlands. The modern edifice dates back to at least 14,000 years ago. It towers above the tropical jungle on the east side; on the other sides flat plains of ash have been sculpted by heavy rains into steep-walled canyons up to 600 m deep. The earliest report of a historical eruption was in 1628. More or less continuous eruptions were reported from 1728 until 1916, and again from 1934 to the present. The almost constant 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
Soputan | Sulawesi (Indonesia) | 1.108°N, 124.73°E | Summit elev. 1784 m
Based on satellite images and weather models, the Darwin VAAC reported that on 8 February an ash plume from Soputan rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted 30 km SSE.
Geologic Summary. The small Soputan stratovolcano on the southern rim of the Quaternary Tondano caldera on the northern arm of Sulawesi Island is one of Sulawesi's most active volcanoes. The youthful, largely unvegetated volcano rises to 1784 m and is located SW of Sempu volcano. It was constructed at the southern end of a SSW-NNE trending line of vents. During historical time the locus of eruptions has included both the summit crater and Aeseput, a prominent NE-flank vent that formed in 1906 and was the source of intermittent major lava flows until 1924.
Source: Darwin Volcanic Ash Advisory Centre (VAAC) ftp://ftp.bom.gov.au/anon/gen/vaac/
Villarrica | Chile | 39.42°S, 71.93°W | Summit elev. 2847 m
Projecto Observación Visual Volcán Villarrica (POVI) reported that at night during 4-5 February faint incandescence was detected with a near-infrared camera. On 5 February Strombolian explosions ejected tephra several hundred meters high. On 6 February tephra was ejected about 65 m above the crater rim and two consecutive ash emissions were observed. OVDAS-SERNAGEOMIN reported that the Alert Level for Villarrica was raised to Yellow (the second lowest level on a four-color scale) due to the increased seismicity, indicating a fluctuating lava lake and small explosions. Scientists noted a rise in the lava-lake level during an overflight. POVI reported that on the morning of 7 February bombs were ejected from the crater, some almost 5 m in diameter. Later that day the intensity of the explosions decreased and crater incandescence became irregular.
Geologic Summary. Glacier-clad Villarrica, one of Chile's most active volcanoes, rises above the lake and town of the same name. It is the westernmost of three large stratovolcanoes that trend perpendicular to the Andean chain. A 6-km wide caldera formed during the late Pleistocene. A 2-km-wide caldera that formed about 3500 years ago is located at the base of the presently active, dominantly basaltic to basaltic-andesitic cone at the NW margin of the Pleistocene caldera. More than 30 scoria cones and fissure vents dot Villarrica's flanks. Plinian eruptions and pyroclastic flows that have extended up to 20 km from the volcano have been produced during the Holocene. Lava flows up to 18 km long have issued from summit and flank vents. Historical eruptions, documented since 1558, have consisted largely of mild-to-moderate explosive activity with occasional lava effusion. Glaciers cover 40 sq km of the volcano, and lahars have damaged towns on its flanks.
Sources: Servicio Nacional de Geología y Minería (SERNAGEOMIN) http://www.sernageomin.cl/;
Projecto Observación Visual Volcán Villarrica (POVI) http://www.povi.cl/
Ongoing Activity
Aira | Kyushu (Japan) | 31.593°N, 130.657°E | Summit elev. 1117 m
The Tokyo VAAC reported that during 28 January-3 February plumes from Aira Caldera’s Sakurajima volcano rose to altitudes of 1.5-3.3 km (5,000-11,000 ft) a.s.l. and drifted NE, E, SE, and S. On 1 February pilots observed ash plumes that rose to altitudes of 2.7-3.3 km (9,000-11,000 ft) a.s.l. JMA reported that nine explosions from Showa Crater ejected tephra as far as 1,800 m during 26-30 January. Incandescence from the crater was visible at night, and inflation continued to be detected. An explosion on 30 January caused tephra fall (2 cm in diameter) in Kagoshima Kurokami (3.5 km E). The Alert Level remained at 3 (on a scale of 1-5).
Geologic Summary. The Aira caldera in the northern half of Kagoshima Bay contains the post-caldera Sakurajima volcano, one of Japan's most active. Eruption of the voluminous Ito pyroclastic flow accompanied formation of the 17 x 23 km caldera about 22,000 years ago. The smaller Wakamiko caldera was formed during the early Holocene in the NE corner of the Aira caldera, along with several post-caldera cones. The construction of Sakurajima began about 13,000 years ago on the southern rim of Aira caldera and built an island that was finally joined to the Osumi Peninsula during the major explosive and effusive eruption of 1914. Activity at the Kitadake summit cone ended about 4850 years ago, after which eruptions took place at Minamidake. 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/;
Tokyo Volcanic Ash Advisory Center (VAAC) http://ds.data.jma.go.jp/svd/vaac/data/vaac_list.html
Asosan | Kyushu (Japan) | 32.884°N, 131.104°E | Summit elev. 1592 m
JMA reported that, based on seismicity and infrasound data, the eruption from Asosan’s Nakadake Crater that began on 25 November 2014 continued intermittently during 2-6 February. Incandescent material was sometimes ejected onto the crater rim, and plumes rose 1 km above the crater. High-amplitude tremor continued. The Alert Level remained at 2 (on a scale of 1-5).
Geologic Summary. The 24-km-wide Asosan caldera was formed during four major explosive eruptions from 300,000 to 90,000 years ago. These produced voluminous pyroclastic flows that covered much of Kyushu. The last of these, the Aso-4 eruption, produced more than 600 cu km of airfall tephra and pyroclastic-flow deposits. A group of 17 central cones was constructed in the middle of the caldera, one of which, Nakadake, is one of Japan's most active volcanoes. It was the location of Japan's first documented historical eruption in 553 AD. The Nakadake 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 CE. Historical eruptions have largely consisted of basaltic to basaltic-andesite ash emission with periodic strombolian and phreatomagmatic activity. The summit crater of Nakadake 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/
Bardarbunga | Iceland | 64.63°N, 17.53°W | Summit elev. 2009 m
During 4-10 February, IMO maintained Aviation Colour Code Orange due to continued activity at Bárdarbunga’s Holuhraun eruptive fissure. A 6 February statement noted that although there was a visible reduction in activity during the previous two weeks, seismicity remained strong. Local air pollution from gas emissions persisted and GPS measurements showed that subsidence continued.
Geologic Summary. The large central volcano of Bárdarbunga lies beneath the NW part of the Vatnajökull icecap, NW of Grímsvötn volcano, and contains a subglacial 700-m-deep caldera. Related fissure systems include the Veidivötn and Trollagigar fissures, which extend about 100 km SW to near Torfajökull volcano and 50 km NE to near Askja volcano, respectively. Voluminous fissure eruptions, including one at Thjorsarhraun, which produced the largest known Holocene lava flow on Earth with a volume of more than 21 cu km, have occurred throughout the Holocene into historical time from the Veidivötn fissure system. The last major eruption of Veidivötn, in 1477, also produced a large tephra deposit. The subglacial Loki-Fögrufjöll volcanic system located SW of Bárdarbunga volcano is also part of the Bárdarbunga volcanic system and contains two subglacial ridges extending from the largely subglacial Hamarinn central volcano; the Loki ridge trends to the NE and the Fögrufjöll ridge to the SW. Jökulhlaups (glacier-outburst floods) from eruptions at Bárdarbunga potentially affect drainages in all directions.
Source: Icelandic Met Office http://en.vedur.is/
Chirinkotan | Kuril Islands (Russia) | 48.98°N, 153.48°E | Summit elev. 724 m
SVERT reported that weak steam-and-gas emissions from Chirinkotan were detected in satellite images on 6 and 8 February. Cloud cover obscured views on the other days during 2-9 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
Kilauea | Hawaiian Islands (USA) | 19.421°N, 155.287°W | Summit elev. 1222 m
During 4-10 February HVO reported that Kilauea’s 27 June NE-trending lava flow continued to be active with several small breakouts across the interior and edges of the lobes, upslope of the leading front. The most northern lobe of lava remained about 500 m above Highway 130, near police and fire stations. At Pu'u 'O'o Crater, glow emanated from several outgassing openings in the crater floor. The circulating lava lake occasionally rose and fell in the deep pit within Halema'uma'u Crater. Gas emissions remained elevated. The plume from the vent continued to deposit variable amounts tephra onto nearby areas.
Geologic Summary. Kilauea volcano, which overlaps the east flank of the massive Mauna Loa shield volcano, has been Hawaii's most active volcano during historical time. Eruptions of Kilauea are prominent in Polynesian legends; written documentation extending back to only 1820 records frequent summit and flank lava flow eruptions that were interspersed with periods of long-term lava lake activity that lasted until 1924 at Halemaumau crater, within the summit caldera. The 3 x 5 km caldera was formed in several stages about 1500 years ago and during the 18th century; eruptions have also originated from the lengthy East and SW rift zones, which extend to the sea on both sides of the volcano. About 90% of the surface of the basaltic shield volcano is formed of lava flows less than about 1100 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/
Sheveluch | Central Kamchatka (Russia) | 56.653°N, 161.36°E | Summit elev. 3283 m
KVERT reported that during 30 January-6 February lava-dome extrusion onto Sheveluch’s N flank was accompanied by incandescence, hot block avalanches, and fumarolic activity. Strong explosions on 1 and 4 February generated ash plumes that rose to altitudes of 10 and 6 km (32,800 and 19,700 ft) a.s.l., respectively. Satellite images detected ash plumes drifting NE and N more than 800 km during 1-2 February and 90 km during 4-5 February. A thermal anomaly over the dome was detected daily. The Aviation Color Code remained at Orange.
Geologic Summary. The high, isolated massif of Sheveluch volcano (also spelled Shiveluch) rises above the lowlands NNE of the Kliuchevskaya volcano group. The 1300 cu km volcano is one of Kamchatka's largest and most active volcanic structures. The summit of roughly 65,000-year-old Stary Shiveluch is truncated by a broad 9-km-wide late-Pleistocene caldera breached to the south. Many lava domes dot its outer flanks. The Molodoy Shiveluch lava dome complex was constructed during the Holocene within the large horseshoe-shaped caldera; Holocene lava dome extrusion also took place on the flanks of Stary Shiveluch. At least 60 large eruptions have occurred during the Holocene, making it the most vigorous andesitic volcano of the Kuril-Kamchatka arc. Widespread tephra layers from these eruptions have provided valuable time markers for dating volcanic events in Kamchatka. Frequent collapses of dome complexes, most recently in 1964, have produced debris avalanches whose deposits cover much of the floor of the breached caldera.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php
Shishaldin | Fox Islands (USA) | 54.756°N, 163.97°W | Summit elev. 2857 m
AVO reported that seismicity at Shishaldin continued to be slightly elevated over background levels during 4-10 February. Elevated surface temperatures were observed in satellite images on most days, and minor steam emissions were recorded by the web cam during 6-9 February. Low-level eruptive activity confined to the summit crater likely continued. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.
Geologic Summary. The beautifully symmetrical volcano of Shishaldin is the highest and one of the most active volcanoes of the Aleutian Islands. The 2857-m-high, glacier-covered volcano is the westernmost of three large stratovolcanoes along an E-W line in the eastern half of Unimak Island. The Aleuts named the volcano Sisquk, meaning "mountain which points the way when I am lost." A steady steam plume rises from its small summit crater. Constructed atop an older glacially dissected volcano, it is Holocene in age and largely basaltic in composition. Remnants of an older ancestral volcano are exposed on the west and NE sides at 1500-1800 m elevation. There are 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, but sometimes producing lava flows, has been recorded since the 18th century.
Source: US Geological Survey Alaska Volcano Observatory (AVO) http://www.avo.alaska.edu/
Sinabung | Indonesia | 3.17°N, 98.392°E | Summit elev. 2460 m
Based on satellite images, weather models, and ground observations, the Darwin VAAC reported that on 9 February an ash plume from Sinabung rose to an altitude of 4 km (13,000 ft) a.s.l. and drifted 10-30 km W.
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 in 1912. No confirmed historical eruptions were recorded prior to explosive eruptions during August-September 2010 that produced ash plumes to 5 km above the summit.
Source: Darwin Volcanic Ash Advisory Centre (VAAC) ftp://ftp.bom.gov.au/anon/gen/vaac/
Zhupanovsky | Eastern Kamchatka (Russia) | 53.589°N, 159.15°E | Summit elev. 2899 m
KVERT reported that a moderate eruption at Zhupanovsky continued during 30 January-6 February. Satellite images detected a daily thermal anomaly over the volcano. The Aviation Color Code remained at Orange.
Geologic Summary. The Zhupanovsky volcanic massif consists of four overlapping stratovolcanoes along a WNW-trending ridge. The elongated volcanic complex was constructed within a Pliocene-early Pleistocene caldera whose rim is exposed only on the eastern side. Three of the stratovolcanoes were built during the Pleistocene, the fourth is Holocene in age and was the source of all of Zhupanovsky's historical eruptions. An early Holocene stage of frequent moderate and weak eruptions from 7000 to 5000 years before present (BP) was succeeded by a period of infrequent larger eruptions that produced pyroclastic flows. The last major eruption took place about 800-900 years BP. Historical eruptions have consisted of relatively minor explosions from the third cone.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php
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