Smithsonian / USGS Weekly Volcanic Activity Report 30 December 2015-5 January 2016
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Smithsonian / USGS Weekly Volcanic Activity Report
30 December 2015-5 January 2016
Sally Kuhn Sennert - Weekly Report Editor (kuhns@xxxxxx)
URL: http://www.volcano.si.edu/reports_weekly.cfm
New Activity/Unrest: Etna, Sicily (Italy) | Kanlaon, Philippines | Nevados de Chillán, Chile | Soputan, Sulawesi (Indonesia) | Tengger Caldera, Eastern Java (Indonesia)
Ongoing Activity: Barren Island, Andaman Islands (India) | Chirpoi, Kuril Islands (Russia) | Colima, Mexico | Copahue, Central Chile-Argentina border | Dukono, Halmahera (Indonesia) | Fuego, Guatemala | Karymsky, Eastern Kamchatka (Russia) | Kilauea, Hawaiian Islands (USA) | Momotombo, Nicaragua | Popocatepetl, Mexico | Sheveluch, Central Kamchatka (Russia) | Sinabung, 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
Etna | Sicily (Italy) | 37.734°N, 15.004°E | Summit elev. 3330 m
INGV reported that after intense activity at Etna's Voragine Crater, Bocca Nuova, and the New Southeast Crater (NSEC) during the first 10 days of December, activity shifted to the Northeast Crater (NEC). During 9-10 December Strombolian activity was detected at NEC, with a few ejected incandescence bombs falling onto the outer flank and abundant ash emissions. Activity gradually diminished over a few days. On 13 December ash emissions rose from NSEC and on 18 December the Voragine Crater produced two brief ash emissions. Ash emissions began at 1100 on 28 December from a vent located high on the E flank of the NSEC cone. The emissions ceased in the afternoon; very minor and sporadic explosions continued from the same vent during the following days.
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 BCE. Historical lava flows of basaltic composition cover much of the surface of this massive volcano, whose edifice is the highest and most voluminous in Italy. The Mongibello stratovolcano, truncated by several small calderas, was constructed during the late Pleistocene and Holocene over an older shield volcano. The most prominent morphological feature of Etna is the Valle del Bove, a 5 x 10 km horseshoe-shaped caldera open to the east. 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 (the latter formed in 1978). Flank vents, typically with higher effusion rates, are less frequently active and originate from fissures that open progressively downward from near the summit (usually accompanied by strombolian eruptions at the upper end). Cinder cones are commonly constructed over the vents of lower-flank lava flows. Lava flows extend to the foot of the volcano on all sides and have reached the sea over a broad area on the SE flank.
Source: Sezione di Catania - Osservatorio Etneo (INGV) http://www.ct.ingv.it/
Kanlaon | Philippines | 10.412°N, 123.132°E | Summit elev. 2435 m
PHIVOLCS reported that at around 1230 on 30 Decemeber a low-energy explosion at Kanlaon, observed by residents in barangays Cabagnaan and Sag-ang in La Castellana (16 km SW), produced an ash plume that rose 100 m above the crater and slowly drifted SW. The Alert Level remained at 1 (on a scale of 0-5).
Geologic Summary. Kanlaon volcano (also spelled Canlaon), the most active of the central Philippines, forms the highest point on the island of Negros. The massive 2435-m-high andesitic stratovolcano is dotted with fissure-controlled pyroclastic cones and craters, many of which are filled by lakes. The largest debris avalanche known in the Philippines traveled 33 km to the SW from Kanlaon. The summit of Kanlaon contains a 2-km-wide, elongated northern caldera with a crater lake and a smaller, but higher, historically active vent, Lugud crater, to the south. Historical eruptions from Kanlaon, recorded since 1866, have typically consisted of phreatic explosions of small-to-moderate size that produce minor ashfalls near the volcano.
Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS) http://www.phivolcs.dost.gov.ph/
Nevados de Chillán | Chile | 36.863°S, 71.377°W | Summit elev. 3212 m
Servicio Nacional de Geología and Minería (SERNAGEOMIN) Observatorio Volcanológico de Los Andes del Sur (OVDAS) reported that increasing seismicity at Nevados de Chillán and increased activity of the hydrothermal system prompted an Alert Level increase to Yellow, on a three-color scale. During 1-31 December the seismic network recorded 1,259 seismic events, including 186 volcano-tectonic events with a maximum local M (LM) of 1.8 located 17 km NNW at a depth of 4 km, 1,030 long-period earthquakes with a maximum LM 1.7, 40 short episodes of spasmodic tremor, and three tornillo-type events. The webcam recorded a small white plume rising from the crater on 9 December.
Geologic Summary. The compound volcano of Nevados de Chillán is one of the most active of the Central Andes of Chile. Three late-Pleistocene to Holocene stratovolcanoes were constructed along a NNW-SSE line within three nested Pleistocene calderas, which produced ignimbrite sheets extending more than 100 km into the Central Depression of Chile. The largest stratovolcano, dominantly andesitic, 3212-m-high Cerro Blanco (Volcán Nevado), is located at the NW end of the group, and 3089-m-high Volcán Viejo (Volcán Chillán), which was the main active vent during the 17th-19th centuries, occupies the SE end. The new Volcán Nuevo lava-dome complex formed between 1906 and 1945 between the two volcanoes and grew to exceed Volcán Viejo in altitude. The Volcán Arrau dome complex was constructed SE of Volcán Nuevo between 1973 and 1986, eventually exceeding its height by 20 m.
Source: Servicio Nacional de Geología y Minería (SERNAGEOMIN) http://www.sernageomin.cl/
Soputan | Sulawesi (Indonesia) | 1.112°N, 124.737°E | Summit elev. 1785 m
PVMBG reported that during 28 December- 1 January white plumes rose 100 m above Soputan. Photos taken during 2-3 January showed that the plumes became denser and turned light gray, rising as high as 300 m. Thermal images revealed incandescence in Puncak Crater. Seismicity increased significantly on 4 January. At 1800 PVMBG raised the Alert Level to 3 (on a scale of 1-4). Residents and tourists were advised not to approach the craters within a radius of 4 km, or 6.5 km on the WSW flank. BNPB reported that at 2053 an explosion produced a dense gray ash plume that rose as high as 2 km and drifted SE. Lava flowed down the E flank and roaring was reported. Minor ashfall occurred in Langowan (8 km ENE).
Geologic Summary. The 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 Riendengan-Sempu, which some workers have included with Soputan and Manimporok (3.5 km ESE) as a volcanic complex. 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.
Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://www.vsi.esdm.go.id/;
Badan Nacional Penanggulangan Bencana (BNPB) http://www.bnpb.go.id/
Tengger Caldera | Eastern Java (Indonesia) | 7.942°S, 112.95°E | Summit elev. 2329 m
Based on satellite and webcam images, the Darwin VAAC reported that during 30 December-5 January ash plumes from Tengger Caldera's Bromo cone rose to altitudes of 3.6-4.2 km (12,000-14,000 ft) a.s.l. and drifted 15-110 km in multiple directions.
Geologic Summary. The 16-km-wide Tengger caldera is located at the northern end of a volcanic massif extending from Semeru volcano. The massive volcanic complex dates back to about 820,000 years ago and consists of five overlapping stratovolcanoes, each truncated by a caldera. Lava domes, pyroclastic cones, and a maar occupy the flanks of the massif. The Ngadisari caldera at the NE end of the complex formed about 150,000 years ago and is now drained through the Sapikerep valley. The most recent of the calderas is the 9 x 10 km wide Sandsea caldera at the SW end of the complex, which formed incrementally during the late Pleistocene and early Holocene. An overlapping cluster of post-caldera cones was constructed on the floor of the Sandsea caldera within the past several thousand years. The youngest of these is Bromo, one of Java's most active and most frequently visited volcanoes.
Source: Darwin Volcanic Ash Advisory Centre (VAAC) ftp://ftp.bom.gov.au/anon/gen/vaac/
Ongoing Activity
Barren Island | Andaman Islands (India) | 12.278°N, 93.858°E | Summit elev. 354 m
Based on analysis of satellite imagery and wind data, the Darwin VAAC reported that during 3-4 January an ash plume from Barren Island rose to an altitude of 1.5 km (5,000 ft) a.s.l. and drifted almost 85 km SW.
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 a volcano that rises from a depth of about 2250 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 west, was created during a major explosive eruption in the late Pleistocene that produced pyroclastic-flow and -surge deposits. Historical eruptions have changed the morphology of the pyroclastic cone in the center of the caldera, and lava flows that fill much of the caldera floor have reached the sea along the western coast.
Source: Darwin Volcanic Ash Advisory Centre (VAAC) ftp://ftp.bom.gov.au/anon/gen/vaac/
Chirpoi | Kuril Islands (Russia) | 46.525°N, 150.875°E | Summit elev. 742 m
SVERT reported that satellite images detected a thermal anomaly over Snow, a volcano of Chirpoi, during 28-29 December and 2 January. 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. 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/?id_d=659
Colima | Mexico | 19.514°N, 103.62°W | Summit elev. 3850 m
Based on satellite images, wind data, webcam images, and notices from the Mexico City MWO, the Washington VAAC reported that during 30 December-3 January and 5 January ash plumes from Colima rose to altitudes of 4.6-6.7 km (15,000-22,000 ft) a.s.l. and drifted NW, N, NE, and E.
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.
Source: Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html
Copahue | Central Chile-Argentina border | 37.856°S, 71.183°W | Summit elev. 2953 m
Based on satellite and webcam views, the Buenos Aires VAAC reported that on 30 December diffuse gas and steam plumes possibly containing ash drifted SSE. The next day ash emissions drifted SW.
Geologic Summary. Volcán Copahue is an elongated composite cone constructed along the Chile-Argentina border within the 6.5 x 8.5 km wide Trapa-Trapa caldera that formed between 0.6 and 0.4 million years ago near the NW margin of the 20 x 15 km Pliocene Caviahue (Del Agrio) caldera. The eastern summit crater, part of a 2-km-long, ENE-WSW line of nine craters, contains a briny, acidic 300-m-wide crater lake (also referred to as El Agrio or Del Agrio) and displays intense fumarolic activity. Acidic hot springs occur below the eastern outlet of the crater lake, contributing to the acidity of the Río Agrio, and another geothermal zone is located within Caviahue caldera about 7 km NE of the summit. Infrequent mild-to-moderate explosive eruptions have been recorded at Copahue since the 18th century. Twentieth-century eruptions from the crater lake have ejected pyroclastic rocks and chilled liquid sulfur fragments.
Source: Buenos Aires Volcanic Ash Advisory Center (VAAC) http://www.smn.gov.ar/vaac/buenosaires/productos.php
Dukono | Halmahera (Indonesia) | 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 30 December-5 January ash plumes from Dukono rose to altitudes of 2.1-3.7 km (7,000-12,000 ft) a.s.l. and drifted 55-170 km in multiple directions.
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 north-flank cone of Gunung Mamuya. This complex volcano presents a broad, low profile with multiple summit peaks and overlapping craters. Malupang Wariang, 1 km SW of the 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/
Fuego | Guatemala | 14.473°N, 90.88°W | Summit elev. 3763 m
In a special report, INSIVUMEH reported a significant increase in activity at Fuego on 30 December. A series of pyroclastic flows descended the Las Lajas and El Jute drainages on the SE flank, and a dense ash plume rose 5 km and drifted 20 km W. Ashfall was reported in multiple communities on the flanks, including Panimache I and II (8 km SW), Morelia (9 km SW), and Santa Sofía (12 km SW). In another special report issued on 4 January, INSIVUMEH noted that dense ash plumes rose as high as 7 km and drifted over 40 km W, SW, S, and SE. Some explosions generated shock waves that vibrated nearby houses. Ash fell in Panimache I and II, Morelia, Santa Sofía, El Porvenir (8 km ENE), La Rochelle, and Osuna. Lava fountains rose 400-500 m above the crater and fed 2.5-km-long lava flows in the Santa Teresa (SW), Trinidad (S), and Las Lajas (SE) drainages. Collapses of parts of the cone generated pyroclastic flows that descended the Las Lajas, El Jute, and Trinidad drainages. By the next day activity had decreased; explosions produced ash plumes that rose 550 m and drifted 12 km S, SE, and SW. The lava flows were no longer active.
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.
Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH) http://www.insivumeh.gob.gt/
Karymsky | Eastern Kamchatka (Russia) | 54.049°N, 159.443°E | Summit elev. 1513 m
KVERT reported that moderate explosive activity at Karymsky continued during 25 December-1 January. Satellite images detected an ash cloud, 56 km long and 6 km wide, drifting 145 km ENE on 25 December, and a thermal anomaly during 25, 27-28, and 31 December. 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
Kilauea | Hawaiian Islands (USA) | 19.421°N, 155.287°W | Summit elev. 1222 m
HVO reported that seismicity beneath Kilauea's summit, upper East Rift Zone, and Southwest Rift Zone was at background levels during 30 December-5 January. The lava lake continued to circulate and spatter in the Overlook vent. On 2 January part of the E rim of the Overlook vent collapsed into the lava lake, triggering an explosion that ejected tephra onto the rim of the vent. At 0318 on 4 January another explosion occurred from the collapse of part of the N wall.
Webcams recorded multiple incandescent outgassing vents within Pu'u 'O'o Crater and high on the northeast rim. During 30 December-1 January a few small lava flows erupted from the vents, and on 4 January a small lava flow erupted from a vent on the NE side of the crater floor. The June 27th NE-trending lava flow continued to be active within 6 km NE of Pu'u 'O'o Crater, burning some areas of forest.
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/
Momotombo | Nicaragua | 12.422°N, 86.54°W | Summit elev. 1297 m
INETER reported that during 29-30 December no explosions at Momotombo were detected, though Real-time Seismic-Amplitude Measurements (RSAM) continued to be at moderate-to-high levels. Based on INETER and SINAPRED reports, three gas-and-ash explosions on 2 January, at 1333, 1426, and 1434, excavated the remaining parts of the lava dome which was emplaced about a month ago. An ash plume rose 500 m above the crater, drifted S and SW, and caused ashfall in Puerto Momotombo (9 km WSW). Possible ash plumes from an explosion at 2129 were hidden by darkness. At 0420 on 3 January an explosion ejected lava bombs 2 km away and caused ashfall in La Paz Centro (18 km SW). Lava flows had advanced as far as 2 km down the NE flank.
Geologic Summary. Momotombo is a young, 1297-m-high stratovolcano that rises prominently above the NW shore of Lake Managua, forming one of Nicaragua's most familiar landmarks. Momotombo began growing about 4500 years ago at the SE end of the Marrabios Range and consists of a somma from an older edifice that is surmounted by a symmetrical younger cone with a 150 x 250 m wide summit crater. Young lava flows from Momotombo have flowed down the NW flank into the 4-km-wide Monte Galán caldera. The youthful cone of Momotombito forms a 391-m-high island offshore in Lake Managua. Momotombo has a long record of strombolian eruptions, punctuated by occasional larger explosive activity. The latest eruption, in 1905, produced a lava flow that traveled from the summit to the lower NE base. A small black plume was seen above the crater after an April 10, 1996 earthquake, but later observations noted no significant changes in the crater. A major geothermal field is located on the southern flank of the volcano.
Sources: Sistema Nacional para la Prevención, Mitigación y Atención de Desastres (SINAPRED) http://www.sinapred.gob.ni/;
Instituto Nicaragüense de Estudios Territoriales (INETER) http://www.ineter.gob.ni/
Popocatepetl | Mexico | 19.023°N, 98.622°W | Summit elev. 5426 m
CENAPRED reported that during 29 December-5 January the seismic network at Popocatépetl recorded 4-92 daily emissions; 191 were detected on 3 January. As many as 11 explosions were detected daily and variable nighttime crater incandescence was observed. Explosions on 2 January ejected tephra onto the N flank, and a small steam, gas, and ash plume drifted E on 4 January. A seven-hour period of explosions started at 2246 on 4 January and ended at 0545 on 5 January. Six more explosions occurred in the evening. The Alert Level remained at Yellow, Phase Two.
Geologic Summary. Volcán Popocatépetl, whose name is the Aztec word for smoking mountain, towers to 5426 m 70 km SE of Mexico City to form North America's 2nd-highest volcano. The glacier-clad stratovolcano contains a steep-walled, 400 x 600 m wide crater. The generally symmetrical volcano is modified by the sharp-peaked Ventorrillo on the NW, a remnant of an earlier volcano. At least three previous major cones were destroyed by gravitational failure during the Pleistocene, producing massive debris-avalanche deposits covering broad areas to the south. The modern volcano was constructed south of the late-Pleistocene to Holocene El Fraile cone. Three major plinian eruptions, the most recent of which took place about 800 CE, have occurred from Popocatépetl since the mid Holocene, accompanied by pyroclastic flows and voluminous lahars that swept basins below the volcano. Frequent historical eruptions, first recorded in Aztec codices, have occurred since precolumbian time.
Source: Centro Nacional de Prevencion de Desastres (CENAPRED) http://www.cenapred.unam.mx/es/
Sheveluch | Central Kamchatka (Russia) | 56.653°N, 161.36°E | Summit elev. 3283 m
KVERT reported that during 25 December-1 January lava-dome extrusion onto Sheveluch’s N flank was accompanied by fumarolic activity, dome incandescence, ash explosions, and hot avalanches. A collapse from the W flank of the lava dome produced a hot avalanche, and an ash plume that rose 5.5 km (18,000 ft) a.s.l. and drifted 50 km SE. Satellite images detected a daily and intense thermal anomaly over the dome. 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
Sinabung | Indonesia | 3.17°N, 98.392°E | Summit elev. 2460 m
PVMBG reported that during 21-28 December inclement weather sometimes prevented visual observations of Sinabung and the growing lava dome in the summit crater. As many as 21 hot avalanches and pyroclastic flows traveled 0.7-1.5 km ESE, producing ash plumes that rose 1 km. Ash plumes from explosions rose as high as 3 km and drifted E and SW. Seismicity consisted of avalanche and pyroclastic-flow signals, low-frequency and hybrid events, tremor, tectonic events, and volcanic earthquakes. Seismicity fluctuated at high levels, although it had declined compared to the previous week, and indicated lava-dome growth. The Alert Level remained at 4 (on a scale of 1-4), indicating that people within 7 km of the volcano on the SSE sector, and within 6 km in the ESE sector, should evacuate.
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: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://www.vsi.esdm.go.id/
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