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Smithsonian/USGS Weekly Volcanic Activity Report 19-25 December 2012
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Smithsonian/USGS Weekly Volcanic Activity Report
19-25 December 2012
Sally Kuhn Sennert - Weekly Report Editor
URL: http://www.volcano.si.edu/reports/usgs/
New Activity/Unrest: | Chirpoi, Kuril Islands (Russia) | Copahue, Chile/Argentina | Kilauea, Hawaii (USA) | Kliuchevskoi, Central Kamchatka (Russia) | San Cristóbal, Nicaragua | Tolbachik, Central Kamchatka (Russia) | Tungurahua, Ecuador | White Island, New Zealand
Ongoing Activity: | Karymsky, Eastern Kamchatka (Russia) | Paluweh, Lesser Sunda Islands (Indonesia) | Shiveluch, Central Kamchatka (Russia)
The Weekly Volcanic Activity Report is a cooperative project between the Smithsonian's Global Volcanism Program and the US Geological Survey's Volcano Hazards Program. Updated by 2300 UTC every Wednesday, notices of volcanic activity posted on these pages are preliminary and subject to change as events are studied in more detail. This is not a comprehensive list of all of Earth's volcanoes erupting during the week, but rather a summary of activity at volcanoes that meet criteria discussed in detail in the "Criteria and Disclaimers" section. Carefully reviewed, detailed reports on various volcanoes are published monthly in the Bulletin of the Global Volcanism Network.
Note: Many news agencies do not archive the articles they post on the Internet, and therefore the links to some sources may not be active. To obtain information about the cited articles that are no longer available on the Internet contact the source.
New Activity/Unrest
CHIRPOI Kuril Islands (Russia) 46.525°N, 150.875°E; summit elev. 742 m
SVERT reported that a thermal anomaly was detected over Snow, a volcano of Chirpoi, during 17, 19, and 21-22 December. A steam-and-gas plume was observed on 19 December. Cloud cover prevented observations of the volcano on the other days during 10-17 December.
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
COPAHUE Central Chile 37.85°S, 71.17°W; summit elev. 2997 m
OVDAS-SERNAGEOMIN reported increased seismicity at Copahue on 22 December. Seismicity fluctuated but was high and indicated that emissions from what was thought to be a phreatic eruption varied between white gas and dark ash plumes. The plumes rose 1-1.5 km above the crater and were observed in satellite imagery drifting 400 km SE. The Alert Level was raised to Orange.
Scientists aboard an overflight observed a low plume rising 1.5 km above a vent in Del Agrio Crater, in the same area as the previous eruption in 2000, and drifting SE. The scientists noted that at 1600 the emissions changed from ash to gas. Later that day web cameras showed incandescence from the crater reflecting in the clouds. The Alert Level was raised to Red, and people within a 15-km-radius and along drainages were warned about potential increases in activity or lahars.
On 23 December incandescence from the crater increased with explosions, as high as 450 m. Strombolian activity ejected incandescent blocks, and mostly white plumes turned dark during explosions. The plumes rose 1 km and drifted SE. On 24 December seismicity decreased. The camera recorded crater incandescence which increased to heights of 200 m with explosions. Incandescent blocks were again ejected with Strombolian explosions. Plumes rose 300 m and drifted SE; they were mostly white, but turned dark with ash during explosions. The Alert Level was lowered to Orange. On 25 December seismicity decreased to low values and tremor was not detected. Cloud cover obscured web camera views. Diffuse plumes visible in satellite images drifted 70 km SE.
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: Servicio Nacional de Geología y Minería (SERNAGEOMIN) http://www.sernageomin.cl/
KILAUEA Hawaii (USA) 19.421°N, 155.287°W; summit elev. 1222 m
During 19-25 December HVO reported that on most days the circulating lava lake periodically rose and fell in the deep pit within Kilauea's Halema'uma'u Crater. The gas 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 SE part of the crater floor, from a spatter cone at the NW edge of the floor, and from a circulating lava lake on the NE part of the floor. During 21-24 December a few brief and short lava flows issued from the spatter cones at the S edge of the crater floor. Lava flows were active in a 1-km-wide area that stretched from near the base of the pali to the coast. There were no webcam recordings of any ocean entry plumes or reports suggesting that lava had been entering the ocean since 17 December.
Geologic Summary. Kilauea, one of five coalescing volcanoes that comprise the island of Hawaii, is one of the world's most active volcanoes. Eruptions at Kilauea originate primarily from the summit caldera or along one of the lengthy E and SW rift zones that extend from the caldera to the sea. About 90% of the surface of Kilauea is formed of lava flows less than about 1,100 years old; 70% of the volcano's surface is younger than 600 years. A long-term eruption from the East rift zone that began in 1983 has produced lava flows covering more than 100 sq km, destroying nearly 200 houses and adding new coastline to the island.
Source: US Geological Survey Hawaiian Volcano Observatory (HVO) http://hvo.wr.usgs.gov/
KLIUCHEVSKOI Central Kamchatka (Russia) 56.057°N, 160.638°E; summit elev. 4835 m
KVERT reported that during 14-21 December video footage and satellite imagery showed Strombolian explosions at Kliuchevskoi, along with crater incandescence and gas-and-steam emissions. A thermal anomaly was detected in satellite images on 16 and 18 December; cloud cover obscured views on the other days. The Aviation Color Code remained at Orange.
Geologic Summary. Kliuchevskoi is Kamchatka's highest and most active volcano. Since its origin about 7,000 years ago, the beautifully symmetrical, 4,835-m-high basaltic stratovolcano has produced frequent moderate-volume explosive and effusive eruptions without major periods of inactivity. More than 100 flank eruptions, mostly on the NE and SE flanks of the conical volcano between 500 m and 3,600 m elevation, have occurred during the past 3,000 years. The morphology of its 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 major explosive and effusive events from flank craters.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php
SAN CRISTOBAL Nicaragua 12.702°N, 87.004°W; summit elev. 1745 m
INETER reported that on 25 December at 1800 seismicity at San Cristóbal increased. A series of explosions starting at 2000 produced ash-and-gas plumes that rose 500 m above the crater and drifted SW and likely W. Ash fell near the volcano. Seismicity increased significantly the next day. Explosions continued to generate ash-and-gas plumes that rose 2.5 km above the crater and drifted N, W, and SW as far as the Pacific Ocean (30-40 km SW and W, respectively). Ashfall was reported in areas downwind, including Puerto Morazan, Jiquilillo, Aposentillo, Tonalá, El Viejo, Santa Marta, and the cities of Chinandega, Chichigalpa, Corinth, and Realejo. According to news articles, some families near the volcano self-evacuated.
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.
Sources: Nicaraguan Institute of Territorial Studies (INETER) http://www.ineter.gob.ni/,
TOLBACHIK Central Kamchatka (Russia) 55.830°N, 160.330°E; summit elev. 3682 m
KVERT reported that the S fissure along the W side of Tolbachinsky Dol, a lava plateau on the SW side of Tolbachik, continued to produce very fluid lava flows that traveled 17-20 km during 17-21 December. Strong seismicity was detected. Gas-and-ash plumes drifted in multiple directions, and a fifth cone grew above the fissure. A very large thermal anomaly on the N part of Tolbachinsky Dol was visible in satellite imagery. The Aviation Color Code remained at Orange.
Geologic Summary. The massive Tolbachik basaltic volcano is located at the southern end of the dominantly andesitic Kliuchevskaya volcano group. The Tolbachik massif is composed of two overlapping, but morphologically dissimilar volcanoes. The flat-topped Plosky Tolbachik shield volcano with its nested Holocene Hawaiian-type calderas up to 3 km in diameter is located east of the older and higher sharp-topped Ostry Tolbachik stratovolcano. The summit caldera at Plosky Tolbachik was formed in association with major lava effusion about 6500 years ago and simultaneously with a major southward-directed sector collapse of Ostry Tolbachik volcano. Lengthy rift zones extending NE and SSW of the volcano have erupted voluminous basaltic lava flows during the Holocene, with activity during the past two thousand years being confined to the narrow axial zone of the rifts. The 1975-76 eruption originating from the SSW-flank fissure system and the summit was the largest historical basaltic eruption in Kamchatka.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php
TUNGURAHUA Ecuador 1.467°S, 78.442°W; summit elev. 5023 m
IG reported that during 19-25 activity at Tungurahua remained high. On 19 December there were 60 explosions detected by the seismic network; explosions vibrated structures and were often heard by local residents. Ash plumes rose 2 km above the crater and drifted SW, causing ashfall in communities downwind including Choglontús (SW), Manzano (8 km SW), Palitahua (S), and Puela (8 km SW). The next day 78 explosions were detected, roaring was heard, and windows vibrated. Ash plumes rose 1 km and drifted W and SW. Ashfall was reported in Manzano, Palitahua, Choglontús. A pyroclastic flow, generated after an explosion, traveled 2 km down drainages on the NW flank.
During 21-25 December explosions ejected incandescent blocks that rolled as far as 1 km down the flanks. Gas-and-ash plumes rose less than 2 km above the crater and drifted W and NW. On 22 December ashfall was reported in Pillate and Manzano, and lava fountains 500 m high were observed at night. On 23 December explosions rattled windows. Strombolian explosions ejected incandescent blocks more than 500 m above the crater that rolled 1 km down the W and NW flanks. The next day seismicity decreased and minor ashfall Choglontús in was reported.
Geologic Summary. The steep-sided Tungurahua stratovolcano towers more than 3 km above its northern base. It sits ~140 km S of Quito, Ecuador's capital city, and is one of Ecuador's most active volcanoes. Historical eruptions have all originated from the summit crater. They have been accompanied by strong explosions and sometimes by pyroclastic flows and lava flows that reached populated areas at the volcano's base. The last major eruption took place from 1916 to 1918, although minor activity continued until 1925. The latest eruption began in October 1999 and prompted temporary evacuation of the town of Baños on the N side of the volcano.
Sources: Instituto Geofísico-Escuela Politécnica Nacional (IG) http://www.igepn.edu.ec/
WHITE ISLAND New Zealand 37.52°S, 177.18°E; summit elev. 321 m
On 20 December, GeoNet Data Centre reported that the spiny lava dome at White Island had not changed during the previous 10 days. No changes to the lava dome were noted when scientists compared photos taken on 19 December to previous ones, but several small lakes occupied parts of where a large lake was before August. The highest temperature reading from the lava dome was 187 degrees Celsius, the hot lake to the S was at least 71 degrees and upwelling strongly, and the cool lake on the N side of the dome was 35 degrees. The Alert Level remained at 2 (on a scale of 0-5), and the Aviation Colour Code remained at Orange (second highest on a four-color scale).
Geologic Summary. The uninhabited 2 x 2.4 km White Island, one of New Zealand's most active volcanoes, is the emergent summit of a 16 x 18 km submarine volcano in the Bay of Plenty about 50 km offshore of North Island. The 321-m-high island consists of two overlapping stratovolcanoes; the summit crater appears to be breached to the SE because the shoreline corresponds to the level of several notches in the SE crater wall. Throughout the short historical period beginning in 1826 the volcano has had long periods of continuous hydrothermal activity and steam release, punctuated by small-to-medium eruptions. Its activity also forms a prominent part of Maori legends. The most recent eruptive episode, which began on 7 March 2000, included the largest eruption at White Island in the past 20 years on 27 July.
Source: GeoNet Data Centre http://www.geonet.org.nz/
Ongoing Activity
KARYMSKY Eastern Kamchatka (Russia) 54.05°N, 159.45°E; summit elev. 1536 m
KVERT reported that weak-to-moderate seismic activity at Karymsky was detected during 14-21 December. Seismic data indicated that ash plumes possibly rose to an altitude of 3 km (9,800 ft) a.s.l. during 13-15 December. Volcanologists observed weak gas-and-steam activity on 18 December. Satellite imagery showed a thermal anomaly on the volcano on 20 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 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
PALUWEH Lesser Sunda Islands (Indonesia) 8.32°S, 121.708°E; summit elev. 875 m
Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that during 19 and 21-23 December ash plumes from Paluweh rose to altitudes of 2.4-2.7 km (8,000-9,000 ft) a.s.l. and drifted 55-75 km E, SW,W, and NW.
Geologic Summary. Paluweh volcano, also known as Rokatenda, forms the 8-km-wide island of Paluweh N of the volcanic arc that cuts across Flores Island. Although the volcano rises about 3,000 m above the sea floor, its summit reaches only 875 m above sea level. The broad irregular summit region contains overlapping craters up to 900 m wide and several lava domes. Several flank vents occur along a NW-trending fissure. The largest historical eruption of Paluweh occurred in 1928, when a strong explosive eruption was accompanied by landslide-induced tsunamis and lava-dome emplacement.
Source: Darwin Volcanic Ash Advisory Centre (VAAC) ftp://ftp.bom.gov.au/anon/gen/vaac/
SHIVELUCH Central Kamchatka (Russia) 56.653°N, 161.360°E; summit elev. 3283 m
Based on visual observations and analyses of satellite data, KVERT reported that during 14-21 December a viscous lava flow continued to effuse on the NW flank of Shiveluch's lava dome, accompanied by hot avalanches, incandescence, and fumarolic activity. Satellite imagery showed a daily thermal anomaly on the lava dome. 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
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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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