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SI/USGS Weekly Volcanic Activity Report 7-13 July 2010
From: "Sally Kuhn Sennert " <KUHNS@xxxxxx>
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SI/USGS Weekly Volcanic Activity Report
7-13 July 2010
Sally Kuhn Sennert - Weekly Report Editor
kuhns@xxxxxx
URL: http://www.volcano.si.edu/reports/usgs/
New Activity/Unrest: | Soufrière Hills, Montserrat | Stromboli, Aeolian Islands (Italy)
Ongoing Activity: | Bagana, Bougainville | Dukono, Halmahera | Karymsky, Eastern Kamchatka (Russia) | Kilauea, Hawaii (USA) | Kirishima, Kyushu | Kliuchevskoi, Central Kamchatka (Russia) | Pacaya, Guatemala | Sakura-jima, Kyushu | Shiveluch, Central Kamchatka (Russia) | Tungurahua, Ecuador | Ulawun, New Britain
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
SOUFRIERE HILLS Montserrat 16.72°N, 62.18°W; summit elev. 915 m
MVO reported that small swarms of volcano-tectonic earthquakes from Soufrière Hills on 23 and 25 June were coincident with ash venting beginning on 25 June. Ash venting diminished on 28 June. A second period of ash venting took place on 2 July and was preceded by two volcano-tectonic and two long-period earthquakes. An emission of ash, with accompanying rumbling noises, formed a plume that drifted WNW and caused ashfall in uninhabited areas of Gages, Plymouth, and the Foxes Bay region. During 2-9 July, roaring was often heard. The Hazard Level remained at 3.
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/
STROMBOLI Aeolian Islands (Italy) 38.789°N, 15.213°E; summit elev. 924 m
INGV-CT reported that two major explosions from Stromboli were detected by the seismic network. These explosions occurred from the SW crater area on 25 June and from the NE crater area on 30 June. Poor weather conditions prevented visual observations using the web camera monitoring system. The event on 30 June was stronger, with several explosions occurring in a short time. Fallout from incandescent blocks triggered vegetation fires.
Geologic Summary. Spectacular incandescent nighttime explosions at Stromboli volcano have long attracted visitors to the "Lighthouse of the Mediterranean."Stromboli, the NE-most of the Aeolian Islands, has lent its name to the frequent mild explosive activity that has characterized its eruptions throughout historical time. The small, 926-m-high island of Stromboli is the emergent summit of a volcano that grew in two main eruptive cycles, the last of which formed the western portion of the island. The active summit vents are located at the head of the Sciara del Fuoco, a horseshoe-shaped scarp formed as a result of slope failure that extends to below sea level and funnels pyroclastic ejecta and lava flows to the NW. Essentially continuous mild Strombolian explosions, sometimes accompanied by lava flows, have been recorded at Stromboli since Roman times.
Source: Istituto Nazionale di Geofisica e Vulcanologia Sezione di Catania (INGV-CT) http://www.ct.ingv.it/
Ongoing Activity
BAGANA Bougainville 6.140°S, 155.195°E; summit elev. 1750 m
Based on analyses of satellite imagery, the Darwin VAAC reported that an ash plume from Bagana rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted 75-150 km SW during 10-11 July.
Geologic Summary. Bagana volcano, occupying a remote portion of central Bougainville Island, is one of Melanesia's youngest and most active volcanoes. Bagana is a massive symmetrical lava cone largely constructed by an accumulation of viscous andesitic lava flows. The entire lava cone could have been constructed in about 300 years at its present rate of lava production. Eruptive activity at Bagana is characterized by non-explosive effusion of viscous lava that maintains a small lava dome in the summit crater, although explosive activity occasionally producing pyroclastic flows also occurs. Lava flows form dramatic, freshly preserved tongue-shaped lobes up to 50-m-thick with prominent levees that descend the volcano's flanks on all sides.
Source: Darwin Volcanic Ash Advisory Centre (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AU/messages.html
DUKONO Halmahera 1.68°N, 127.88°E; summit elev. 1335 m
Based on analyses of satellite imagery, the Darwin VAAC reported that during 7 and 9-10 July ash plumes from Dukono rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted 35-75 km NW and N.
Geologic Summary. Reports from this remote volcano in northernmost Halmahera are rare, but Dukono has been one of Indonesia's most active volcanoes. More-or-less continuous explosive eruptions, sometimes accompanied by lava flows, occurred from 1933 until at least the mid-1990s, when routine observations were curtailed. During a major eruption in 1550, a lava flow filled in the strait between Halmahera and the N-flank cone of Gunung Mamuya. Dukono is a complex volcano presenting a broad, low profile with multiple summit peaks and overlapping craters. Malupang Wariang, 1 km SW of Dukono's summit crater complex, contains a 700 x 570 m crater that has also been active during historical time.
Source: Darwin Volcanic Ash Advisory Centre (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AU/messages.html
KARYMSKY Eastern Kamchatka (Russia) 54.05°N, 159.45°E; summit elev. 1536 m
KVERT reported that during 2-9 July seismic activity from Karymsky was above background levels and suggested that possible ash plumes rose to an altitude of 2 km (6,500 ft) a.s.l. A thermal anomaly was detected in satellite imagery on most days; cloud cover occasionally prevented views of the volcano. On 7 July ash plumes drifted 20 km S. Based on information from the Yelizovo Airport (UHPP), the Tokyo VAAC reported that on 13 July an ash plume rose to an altitude of 2.7 km (9,000 ft) a.s.l. and drifted W. The Aviation Color Code level 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.
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
KILAUEA Hawaii (USA) 19.421°N, 155.287°W; summit elev. 1222 m
During 7-13 July HVO reported that activity at Kilauea continued from the summit and the east rift zone. At the summit, the level of a lava-pool surface in the deep pit within the floor of Halema'uma'u crater remained mostly stable; glow from the vent was also visible at night. A plume from the vent mainly drifted SW, dropping small amounts of tephra downwind. At the east rift zone, lava flows that broke out of the TEB lava-tube system built up a number of rootless shields between 580 and 395 m elevation. Thermal anomalies detected in satellite images and visual observations showed that minor lava flows originating from the shields traveled as far down as 60 m elevation near the base of the pali on 11 July.
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/
KIRISHIMA Kyushu 31.931°N, 130.864°E; summit elev. 1700 m
Based on reports from JMA, the Tokyo VAAC reported that an eruption from the Kirishima volcanic complex on 10 July produced a plume that rose to an altitude of 1.8 km (6,000 ft) a.s.l.
Geologic Summary. Kirishima is a large group of more than 20 Quaternary volcanoes located north of Kagoshima Bay. The late-Pleistocene to Holocene volcano group consists of stratovolcanoes, pyroclastic cones, maars, and underlying shield volcanoes located over an area of 20 x 30 km. The larger stratovolcanoes are scattered throughout the field, with the centrally located, 1,700-m-high Karakuni-dake being the highest. Onami-ike and Mi-ike, the two largest maars, are located SW of Karakuni-dake and at its far eastern end, respectively. Holocene eruptions have been concentrated along an E-W line of vents from Mi-ike to Ohachi, and at Shinmoe-dake to the NE. Frequent small-to-moderate explosive eruptions have been recorded since the 8th century.
Source: Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html
KLIUCHEVSKOI Central Kamchatka (Russia) 56.057°N, 160.638°E; summit elev. 4835 m
KVERT reported that during 2-9 July seismic activity from Kliuchevskoi was above background levels. Satellite imagery analysis showed a large daily thermal anomaly over the volcano and a gas-and-steam plume that drifted 76 km S on 2 July. Ash plumes occasionally rose to an altitude of 5.3 km (17,400 ft) a.s.l., and gas-and-steam activity was seen during 2-4 July. According to a news article, lava flowed from a fissure during 8-9 July. The Aviation Color Code level 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.
Sources: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php,
Itar-Tass http://www.itar-tass.com/eng/level2.html?NewsID=15304958&PageNum=0
PACAYA Guatemala 14.381°N, 90.601°W; summit elev. 2552 m
On 7 and 9 July, INSIVUMEH reported that white plumes rose from Pacaya's MacKenney cone and drifted N. Small explosions were detected by the seismic network on 7 July. According to a CONRED notice, INSIVUMEH reported that an explosion on 13 July generated an ash plume that rose 300 m above the crater and drifted SW. Ash and tephra fell in nearby areas, and 150 people were evacuated.
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 volcano constructed on the southern rim of the 14 x 16 km Pleistocene Amatitlan caldera. A cluster of dacitic lava domes occupies the caldera floor. The Pacaya massif includes the Cerro Grande lava dome and a younger volcano to the SW. Collapse of Pacaya volcano about 1,100 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. During the past several decades, activity at Pacaya has consisted of frequent Strombolian eruptions with intermittent lava flow extrusion on the flanks of MacKenney cone, punctuated by occasional larger explosive eruptions.
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/
SAKURA-JIMA Kyushu 31.585°N, 130.657°E; summit elev. 1117 m
Based on pilot observations, the Tokyo VAAC reported that on 7 and 9 July ash plumes from Sakura-jima rose to altitudes of 1.8-2.7 km (6,000-9,000 ft) a.s.l. and drifted SE and NE. The VAAC also noted that the JMA reported explosions during 11-13 July.
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
SHIVELUCH Central Kamchatka (Russia) 56.653°N, 161.360°E; summit elev. 3283 m
KVERT reported that during 2-9 July seismic activity from Shiveluch was above background levels and suggested that on most days possible ash plumes rose to an altitude of 7 km (22,900 ft) a.s.l. On 5 July ash plumes from hot avalanches rose to an altitude of 4 km (13,100 ft) a.s.l. and strong fumarolic activity was noted. Ashfall was observed around the volcano. Satellite imagery showed a large daily thermal anomaly over the lava dome and an ash plume that drifted 20 km S on 7 July. Tokyo VAAC reported that satellite imagery analyses indicated a possible eruption on 10 July. The Aviation Color Code level 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.
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
TUNGURAHUA Ecuador 1.467°S, 78.442°W; summit elev. 5023 m
Observations of Tungurahua's summit area during 7-13 July were often not possible due to inclement weather. On 7 July steam-and-ash plumes rose to an altitude of 6 km (19,700 ft) a.s.l. and drifted WSW. The next day explosions were accompanied by acoustic waves. A steam plume rose to an altitude of 8 km (26,200 ft) a.s.l. and drifted NW. Ashfall was reported in Cusúa about 8 km downwind. Incandescence from the crater was seen during both nights. Ash-and-steam plumes were seen on 9 July. Ashfall was reported in a few areas 8 km SW and W. On 10 and 12 July plumes with low ash content drifted W. Ashfall was reported 7-8 km to the W and NNW on 12 July. Incandescent blocks descended the flanks at night to 500 m below the crater on 9 and 12 July.
Geologic Summary. The steep-sided Tungurahua stratovolcano towers more than 3 km above its northern base. It sits ~140 km S of Quito, Ecuador's capital city, and is one of Ecuador's most active volcanoes. Historical eruptions have all originated from the summit crater. They have been accompanied by strong explosions and sometimes by pyroclastic flows and lava flows that reached populated areas at the volcano's base. The last major eruption took place from 1916 to 1918, although minor activity continued until 1925. The latest eruption began in October 1999 and prompted temporary evacuation of the town of Baños on the N side of the volcano.
Source: Instituto Geofísico-Escuela Politécnica Nacional (IG) http://www.igepn.edu.ec/
ULAWUN New Britain 5.05°S, 151.33°E; summit elev. 2334 m
RVO reported that white-to-gray plumes rose less than 500 m from Ulawun during 27 June-9 July, and fine ash fell in areas to the SW, W, and NW. Occasional roaring noises were heard on 28 June and during 5-6 July. A slight increase in seismicity (above moderate levels) indicated by overlapping tremors and Real-time Seismic-Amplitude Measurement (RSAM) values was noted during 5-8 July.
Geologic Summary. The symmetrical basaltic to andesitic Ulawun stratovolcano is the highest volcano of the Bismarck arc, and one of Papua New Guinea's most frequently active. Ulawun rises above the N coast of New Britain opposite Bamus volcano. The upper 1,000 m of the 2,334-m-high volcano is unvegetated. A steep-walled valley cuts the NW side of the volcano, and a flank lava-flow complex lies to the S of this valley. Historical eruptions date back to the beginning of the 18th century. Twentieth-century eruptions were mildly explosive until 1967, but after 1970 several larger eruptions produced lava flows and basaltic pyroclastic flows, greatly modifying the summit crater.
Source: Rabaul Volcano Observatory (RVO)
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