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SI/USGS Weekly Volcanic Activity Report 27 January-2 February 2010
From: Sally Kuhn Sennert kuhns@xxxxxx
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SI/USGS Weekly Volcanic Activity Report
27 January-2 February 2010
Sally Kuhn Sennert - Weekly Report Editor
kuhns@xxxxxx
URL: http://www.volcano.si.edu/reports/usgs/
New Activity/Unrest: | Nyiragongo, Democratic Republic of Congo | Tungurahua, Ecuador
Ongoing Activity: | Gaua, Banks Islands (SW Pacific) | Karymsky, Eastern Kamchatka | Kilauea, Hawaii (USA) | Kliuchevskoi, Central Kamchatka (Russia) | Nyamuragira, Democratic Republic of Congo | Popocatépetl, México | Sakura-jima, Kyushu | Sangay, Ecuador | Shiveluch, Central Kamchatka (Russia) | Soufrière Hills, Montserrat | Suwanose-jima, Ryukyu Islands (Japan)
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
NYIRAGONGO Democratic Republic of Congo 1.52°S, 29.25°E; summit elev. 3470 m
During 27 January-2 February, the MODIS sensor aboard the Earth Observing System (EOS) satellite continued to frequently detect thermal anomalies from Nyiragongo, likely from lava lake activity. Based on analyses of satellite imagery, the Toulouse VAAC reported that during 30-31 January a diffuse plume drifted 240 km W.
Geologic Summary. One of Africa's most notable volcanoes, Nyiragongo contained an active lava lake in its deep summit crater that drained catastrophically through its outer flanks in 1977. In contrast to the low profile of its neighboring shield volcano, Nyamuragira, Nyiragongo displays the steep slopes of a stratovolcano. Benches in the steep-walled, 1.2-km-wide summit crater mark the levels of former lava lakes, which have been observed since the late 19th century. anks and along a NE-SW zone extending as far as Lake Kivu. Monitoring is done from a small observatory building located in Goma, ~18 km S of the Nyiragongo crater.
Sources: Toulouse Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/FR/messages.html,
Hawai'i Institute of Geophysics and Planetology (HIGP) Moderate Resolution imaging Spectroradiometer (MODIS) Thermal Alert System http://modis.higp.hawaii.edu/
TUNGURAHUA Ecuador 1.467°S, 78.442°W; summit elev. 5023 m
The IG reported that during 26 January-2 February explosions from Tungurahua were detected by the seismic network. Inclement weather occasionally prevented observations of the volcano; ash plumes were seen rising to altitudes no higher than 8 km (26,200 ft) a.s.l. Ashfall was noted almost daily in areas to the SW, W, and NW. Roaring noises and sounds resembling "cannon shots" were reported. During 26 and 28-30 January lava fountains were seen and sometimes ejected incandescent blocks that fell onto and rolled down the flanks. On 31 January, a lahar descended the Chontapamba drainage to the W.
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 bas e. 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/
Ongoing Activity
GAUA Banks Islands (SW Pacific) 14.27°S, 167.50°E; summit elev. 797 m
On 29 January, the Vanuatu Geohazards Observatory reported significant changes in Gaua's activity over the previous two weeks. They noted that since 16 January more gas was emitted and multiple explosions produced denser and darker ash plumes. During 22-29 January, the water level in the river to the E that Lake Letas feeds rose 10 cm. Gas-and-ash plumes rose 3 km and drifted S and W. On 24 January nearby villagers reported seeing ejected material from Strombolian activity. The Wellington VAAC reported that on 27 January an ash cloud was seen on satellite imagery. Strong explosions were seen and heard from East Gaua on 29 January. According to the VAAC, the Vanuatu Geohazards Observatory reported that gas-and-ash plumes rose to altitudes of 3 km (10,000 ft) a.s.l. and drifted S and W that same day.
Geologic Summary. The roughly 20-km-diameter Gaua Island, also known as Santa Maria, consists of a basaltic-to-andesitic stratovolcano with an 6 x 9 km wide summit caldera. Small parasitic vents near the caldera rim fed Pleistocene lava flows that reached the coast on several sides of the island; several littoral cones were formed where these lava flows reached the sea. Quiet collapse that formed the roughly 700-m-deep caldera was followed by extensive ash eruptions. Construction of the historically active cone of Mount Garat (Gharat) and other small cinder cones in the SW part of the caldera has left a crescent-shaped caldera lake. The symmetrical, flat-topped Mount Garat cone is topped by three pit craters. The onset of eruptive activity from a vent high on the SE flank of Mount Garat in 1962 ended a long period of dormancy.
Sources: Vanuatu Geohazards Observatory http://www.geohazards.gov.vu/,
Wellington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/NZ/messages.html
KARYMSKY Eastern Kamchatka 54.05°N, 159.45°E; summit elev. 1536 m
KVERT reported that during 22-29 January seismic activity from Karymsky was above background levels and possibly indicated weak ash explosions. Analyses of satellite imagery revealed a thermal anomaly over the volcano during 21-25 and 27 January. The Level of Concern 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 27 January-2 February, HVO reported an active lava surface about 200 m below a vent in the floor of Kilauea's Halema'uma'u crater. The lava surface occasionally spattered, and both rose and drained through a hole in the cavity floor. A plume from the vent drifted N, NW, and W, dropping small amounts of ash, and occasionally fresh spatter, downwind. Measurements indicated that the sulfur dioxide emission rate at the summit remained elevated; 400 and 1,000 tonnes per day were measured on 28 January and 1 February, respectively. The 2003-2007 average rate was 140 tonnes per day.
Lava from beneath the Thanksgiving Eve Breakout (TEB) and rootless shield complex flowed over 3 km SE through a lava tube system before breaking out onto the surface. Thermal anomalies detected by satellite and visual observations revealed active lava flows on top of and on the pali; lava burned forest on the W side of the TEB flows. Incandescence was seen from a vent low on the S wall of Pu'u 'O'o crater.
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 22-29 January seismic activity from Kliuchevskoi was above background levels and lava continued to flow down the NW flank. Strombolian activity periodically ejected material 200 m above the crater, and phreatic explosions occurred from the front of the lava flow. Satellite imagery revealed a large daily thermal anomaly at the volcano. Ashfall was reported in Klyuchi, about 30 km to the NE, on 22 January. The Level of Concern 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
NYAMURAGIRA Democratic Republic of Congo 1.408°S, 29.20°E; summit elev. 3058 m
During 27 January-2 February, the MODIS sensor aboard the Earth Observing System (EOS) satellite frequently detected thermal anomalies from Nyamuragira. The Toulouse VAAC reported that a diffuse ash plume was seen on satellite imagery on 29 January.
Geologic Summary. Africa's most active volcano, Nyamuragira (Also spelled Nyamulagira) is a massive basaltic shield volcano N of Lake Kivu and NW of Nyiragongo volcano. Lava flows from Nyamuragira cover 1,500 sq km of the East African Rift. The 3058-m-high summit is truncated by a small 2 x 2.3 km summit caldera that has walls up to about 100 m high. About 40 historical eruptions have occurred since the mid-19th century within the summit caldera and from numerous fissures and cinder cones on the volcano's flanks. A lava lake in the summit crater, active since at least 1921, drained in 1938. Twentieth-century flank lava flows extend more than 30 km from the summit, reaching as far as Lake Kivu.
Sources: Toulouse Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/FR/messages.html,
Hawai'i Institute of Geophysics and Planetology (HIGP) Moderate Resolution imaging Spectroradiometer (MODIS) Thermal Alert System http://modis.higp.hawaii.edu/
POPOCATEPETL México 19.023°N, 98.622°W; summit elev. 5426 m
CENAPRED reported that during 27-31 January and 1 February emissions of steam and gas from Popocatépetl contained minor amounts of ash.
Geologic Summary. Popocatépetl, whose name is the Aztec word for smoking mountain, towers to 5,426 m 70 km SE of Mexico City and is North America's second-highest volcano. Frequent historical eruptions have been recorded since the beginning of the Spanish colonial era. A small eruption on 21 December 1994 ended five decades of quiescence. Since 1996 small lava domes have incrementally been constructed within the summit crater and destroyed by explosive eruptions. Intermittent small-to-moderate gas-and-ash eruptions have continued, occasionally producing ashfall in neighboring towns and villages.
Source: Centro Nacional de Prevencion de Desastres (CENAPRED) http://www.cenapred.unam.mx/es/
SAKURA-JIMA Kyushu 31.585°N, 130.657°E; summit elev. 1117 m
Based on information from JMA, the Tokyo VAAC reported that during 27 January-2 February multiple explosions from Sakura-jima produced plumes that rose to altitudes of 1.8-2.4 km (6,000-8,000 ft) a.s.l. and drifted SE, E, and NE. During 27-29 January and 1-2 February, pilots reported that ash plumes sometimes drifted SE and S at altitudes of 1.2-3 km (4,000-10,000 ft) a.s.l.
Geologic Summary. Sakura-jima, one of Japan's most active volcanoes, is a post-caldera cone of the Aira caldera at the northern half of Kagoshima Bay. Eruption of the voluminous Ito pyroclastic flow was associated with the formation of the 17 x 23-km-wide Aira caldera about 22,000 years ago. The construction of Sakura-jima began about 13,000 years ago and built an island that was finally joined to the Osumi Peninsula during the major explosive and effusive eruption of 1914. Activity at the Kita-dake summit cone ended about 4,850 years ago, after which eruptions took place at Minami-dake. Frequent historical eruptions, recorded since the 8th century, have deposited ash on Kagoshima, one of Kyushu's largest cities, located across Kagoshima Bay only 8 km from the summit. The largest historical eruption took place during 1471-76.
Source: Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html
SANGAY Ecuador 2.002°S, 78.341°W; summit elev. 5230 m
Based on pilot observations, the Washington VAAC reported that on 2 February an ash plume from Sangay rose to an altitude of 8.2 km (27,000 ft) a.s.l. Ash was not identified in satellite imagery, although weather clouds were present in the area.
Geologic Summary. The isolated Sangay volcano, located E of the Andean crest, is the southernmost of Ecuador's volcanoes, and its most active. It has been in frequent eruption for the past several centuries. The steep-sided, 5,230-m-high glacier-covered volcano grew within horseshoe-shaped calderas of two previous edifices, which were destroyed by collapse to the E, producing large debris avalanches that reached the Amazonian lowlands. The modern edifice dates back to at least 14,000 years ago. Sangay towers above the tropical jungle on the E side; on the other sides flat plains of ash from the volcano have been sculpted by heavy rains into steep-walled canyons up to 600 m deep. The earliest report of an historical eruption was in 1628. More or less continuous eruptions were reported from 1728 until 1916, and again from 1934 to the present. The more or less constant eruptive activity has caused frequent changes to the morphology of the summit crater complex.
Source: Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html
SHIVELUCH Central Kamchatka (Russia) 56.653°N, 161.360°E; summit elev. 3283 m
KVERT reported that during 22-29 January seismic activity from Shiveluch was above background levels, possibly indicating ash plumes rising to an altitude of 4.6 km (15,100 ft) a.s.l. Fumarolic activity was occasionally observed. Analyses of satellite imagery revealed a large daily thermal anomaly from the lava dome. The Level of Concern Color Code remained at Orange. Based on information from KEMSD, the Tokyo VAAC reported that during 29-30 January eruptions produced plumes that rose to altitudes of 4.9-5.8 km (16,000-19,000 ft) a.s.l.
Geologic Summary. The high, isolated massif of Shiveluch volcano (also spelled Sheveluch) rises above the lowlands NNE of the Kliuchevskaya volcano group and forms one of Kamchatka's largest and most active volcanoes. The currently active Molodoy Shiveluch lava-dome complex was constructed during the Holocene within a large breached caldera formed by collapse of the massive late-Pleistocene Strary Shiveluch volcano. At least 60 large eruptions of Shiveluch have occurred during the Holocene, making it the most vigorous andesitic volcano of the Kuril-Kamchatka arc. Frequent collapses of lava-dome complexes, most recently in 1964, have produced large debris avalanches whose deposits cover much of the floor of the breached caldera. Intermittent explosive eruptions began in the 1990s from a new lava dome that began growing in 1980. The largest historical eruptions from Shiveluch occurred in 1854 and 1964.
Sources: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php,
Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html
SOUFRIERE HILLS Montserrat 16.72°N, 62.18°W; summit elev. 915 m
MVO reported that during 22-29 January activity from the Soufrière Hills lava dome was variable as the lava dome continued to grow. Cycles of vigorous ash venting, rockfalls, and pyroclastic flows occurred every five to seven hours. Pyroclastic flows traveled down multiple valleys, including Whites Ghaut to the NE, and W down Gages into Spring Ghaut. The increasing number of pyroclastic flows that traveled E down the Tar River Valley, frequently reaching the sea, were attributed to new lava-dome growth in the SE part of the lava dome. Ash fell across most of Montserrat on 23 January. Vigorous steaming from hot pyroclastic flows emplaced in the Belham Valley on 8 January was caused by heavy rains on 25 January. Small steam explosions generated steam plumes that sometimes contained ash. The Hazard Level remained at 4.
Geologic Summary. The complex dominantly andesitic Soufrière Hills volcano occupies the southern half of the island of Montserrat. The summit area consists primarily of a series of lava domes emplaced along an ESE-trending zone. English's Crater, a 1-km-wide crater breached widely to the E, was formed during an eruption about 4,000 years ago in which the summit collapsed, producing a large submarine debris avalanche. Block-and-ash flow and surge deposits associated with dome growth predominate in flank deposits at Soufrière Hills. Non-eruptive seismic swarms occurred at 30-year intervals in the 20th century, but with the exception of a 17th-century eruption that produced the Castle Peak lava dome, no historical eruptions were recorded on Montserrat until 1995. Long-term small-to-moderate ash eruptions beginning in that year were later accompanied by lava-dome growth and pyroclastic flows that forced evacuation of the southern half of the island and ultimately destroyed the capital city of Plymouth, causing major social and economic disruption.
Source: Montserrat Volcano Observatory (MVO) http://www.mvo.ms/
SUWANOSE-JIMA Ryukyu Islands (Japan) 29.635°N, 129.716°E; summit elev. 799 m
Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima during 27 January-2 February. On 27 January, plumes rose to altitudes of 1.2-1.5 km (4,000-5,000 ft) a.s.l. and drifted W. Plumes rose to an altitude of 1.8 km (6,000 ft) a.s.l. on 29 January.
Geologic Summary. The 8-km-long, spindle-shaped island of Suwanose-jima in the northern Ryukyu Islands consists of an andesitic stratovolcano with two historically active summit craters. Only about 50 persons live on the sparsely populated island. The summit of the volcano is truncated by a large breached crater extending to the sea on the east flank that was formed by edifice collapse. Suwanose-jima, one of Japan's most frequently active volcanoes, was in a state of intermittent Strombolian activity from On-take, the NE summit crater, that began in 1949 and lasted nearly a half century. The largest historical eruption took place in 1813-14, when thick scoria deposits blanketed residential areas, after which the island was uninhabited for about 70 years. The SW crater produced lava flows that reached the western coast in 1813, and lava flows reached the eastern coast of the island in 1884.
Source: Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html
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