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SI/USGS Weekly Volcanic Activity Report 16-22 June 2010 Sally Kuhn Sennert - Weekly Report Editor kuhns@xxxxxx URL: http://www.volcano.si.edu/reports/usgs/ New Activity/Unrest: | Etna, Sicily (Italy) | Gorely,
Southern Kamchatka (Russia) | Ioto [Iwo-jima], Volcano Islands (Japan) | Nevado
del Huila, Colombia | Pacaya, Guatemala | Tiatia, Kunashir Island | Tungurahua,
Ecuador | Ulawun, New Britain Ongoing Activity: | Batu Tara, Komba Island (Indonesia) |
Dukono, Halmahera | Gaua, Banks Islands (SW Pacific) | Karymsky, Eastern
Kamchatka (Russia) | Kilauea, Hawaii (USA) | Kliuchevskoi, Central Kamchatka
(Russia) | Sakura-jima, Kyushu | Shiveluch, Central Kamchatka (Russia) |
Soufrière Hills, Montserrat 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-CT reported a series of landslides on 19 June from the
NW rim of the pit crater located on the lower E side of Etna's Southeast
Crater. The collapses generated small ash clouds that drifted NE, and changed
the pit crater’s morphology. Data from a thermal camera showed thermal
anomalies over 180 degrees Celsius indicating that the landslide material was
hot. Fumarolic activity was seen in the landslide area during an inspection the
day before. 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 BC. Historical lava flows cover
much of the surface of this massive basaltic stratovolcano, the highest and
most voluminous in Italy. 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. Flank eruptions, typically with higher
effusion rates, occur less frequently and originate from fissures that open
progressively downward from near the summit. A period of more intense
intermittent explosive eruptions from Etna's summit craters began in 1995. The
active volcano is monitored by the Instituto Nazionale di Geofisica e
Volcanologia (INGV) in Catania. Source: Istituto Nazionale di Geofisica e Vulcanologia
Sezione di Catania (INGV-CT) http://www.ct.ingv.it/ GORELY Southern Kamchatka (Russia) 52.558°N, 158.03°E;
summit elev. 1829 m KVERT reported that during 6 and 12-13 June strong
steam-and-gas activity from Gorely was noted, and during 11-18 June seismic
activity was above background levels. A small increase in the size and temperature
of a thermal anomaly over the volcano began on 15 June and was detected through
18 June. The Level of Concern Color Code remained at Green. Geologic Summary. Gorely volcano, one of the most active in
southern Kamchatka, consists of five small overlapping stratovolcanoes
constructed along a WNW-ESE line within a large 9 x 13.5 km late-Pleistocene
caldera. The massive Gorely complex contains 11 summit and 30 flank craters.
During the early Holocene, activity was characterized by frequent mild eruptions
with occasional larger explosions and lava flows that filled in the caldera.
Quiescent periods became longer between 6,000 and 2,000 years ago, after which
the activity was mainly explosive. About 600-650 years ago intermittent strong
explosions and lava flow effusion accompanied frequent mild eruptions.
Historical eruptions have consisted of vulcanian and phreatic explosions of
moderate volume. Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
http://www.kscnet.ru/ivs/kvert/index_eng.php IOTO [IWO-JIMA] Volcano Islands (Japan) 24.754°N, 141.290°E;
summit elev. 161 m Based on a pilot observation, the Tokyo VAAC reported that
an ash plume from Ioto (Iwo-jima) drifted more than 35 km N. Geologic Summary. Ioto (also known as Iwo-jima) in the
central Volcano Islands portion of the Izu-Marianas arc lies within a 9-km-wide
submarine caldera. Ioto, Iwo-jima, and Io-jima are among many transliterations
of the name, which means "Sulfur Island;" the volcano is also known
as Ogasawara Io-jima to distinguish it from several other "Sulfur
Island" volcanoes in Japan. The triangular, low-elevation, 8-km-long
island narrows toward its SW tip and has produced trachyandesitic and trachytic
rocks that are more alkalic than those of other Izu-Marianas arc volcanoes. The
island has undergone dramatic uplift for at least the past 700 years
accompanying resurgent doming of the caldera. A shoreline landed upon by
Captain Cook's surveying crew in 1779 is now 40 m above sea level. The
Moto-yama plateau on the NE half of the island consists of submarine tuffs
overlain by coral deposits and forms the island's high point. Many fumaroles
are oriented along a NE-SW zone cutting through Moto-yama. Numerous historical
phreatic eruptions, many from vents on the west and NW sides of the island,
have accompanied the remarkable uplift. Source: Tokyo Volcanic Ash Advisory Center (VAAC)
http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html NEVADO DEL HUILA Colombia 2.93°N, 76.03°W; summit elev. 5364
m INGEOMINAS reported that during 9-15 June sulfur dioxide
plumes from Nevado del Huila were detected by multiple sources. A distinct
change in seismicity was noted on 13 June and was characterized by an increased
intensity and a greater number of hybrid earthquakes. These earthquakes were
shallow events beneath Pico Central. The Alert Level was raised to II (Orange;
"probable eruption in term of days or weeks"). On 16 June two
episodes of tremor possibly indicated ash emissions; this was unconfirmed.
However, sulfur dioxide plumes were again detected. During 20-21 June small
white pulsating fumarolic plumes drifted W. Geologic Summary. Nevado del Huila, the highest active
volcano in Colombia, is an elongated N-S-trending volcanic chain mantled by a
glacier icecap. The andesitic-dacitic volcano was constructed within a
10-km-wide caldera. Volcanism at Nevado del Huila has produced six volcanic
cones whose ages in general migrated from south to north. Two glacier-free lava
domes lie at the southern end of the Huila volcanic complex. The first
historical eruption from this little known volcano took place in the 16th
century. Two persistent steam columns rise from the central peak, and hot
springs are also present. Source: Instituto Colombiano de Geología y Minería
(INGEOMINAS) http://www.ingeominas.gov.co// PACAYA Guatemala 14.381°N, 90.601°W; summit elev. 2552 m INSIVUMEH reported that during 16-22 June Pacaya's MacKenney
cone emitted white-and-blue fumarolic plumes that rose 50-400 m high. Ash
emissions were occasionally observed. INSIVUMEH also noted that the lava flows
on the SE flank were advancing more slowly and exhibited fewer areas of
incandescence. 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. Source: Instituto Nacional de Sismologia, Vulcanologia,
Meteorologia, e Hidrologia (INSIVUMEH) http://www.insivumeh.gob.gt/ TIATIA Kunashir Island 44.351°N, 146.256°E; summit elev.
1819 m SVERT reported that a thermal anomaly from Tiatia, a volcano
on NE Kunashir Island, was detected by satellite on 19 June. Tiatia does not
have a seismic network; satellite image observations are the primary tool for
monitoring many of the Kuril Islands volcanoes. Geologic Summary. Tiatia volcano, one of the most impressive
of the Kuril Islands, consists of a beautifully symmetrical cone that rises
above the broad rim of an erosionally furrowed, 2.1 x 2.4 km wide caldera. The
1819-m-high Tiatia (also known as Chacha-dake) occupies the NE tip of Kunashir
Island and morphologically resembles Mount Vesuvius. The pristine-looking
conical central cone, mostly formed by basaltic to basaltic-andesite
strombolian eruptions, rises 400 m above the floor of the caldera and contains
a 400 x 250 m wide crater with two explosion vents separated by a linear
septum. Fresh lava flows cover much of the SW caldera floor and have overflowed
the rim, extending to the foot of the older somma, which formed during the late
Pleistocene or early Holocene. A lava flow from a flank cone on the northern
caldera rim reached the Sea of Okhotsk. A major explosive eruption in 1973 was
the first since Tiatia's initial historical eruption in 1812. Source: Sakhalin Volcanic Eruption Response Team (SVERT)
http://www.imgg.ru/rus/labs_vulcan_hazard.php TUNGURAHUA Ecuador 1.467°S, 78.442°W; summit elev. 5023 m Although storm clouds occasionally prevented observations of
Tungurahua's summit area during 16-18 June, steam-and-ash plumes were seen that
rose to altitudes of 5.5-7 km (18,000-23,000 ft) a.s.l. Daily reports of
ashfall came from multiple areas about 8 km W and SW, but ash was noted as far
away as 15 km SW on 17 June. Ashfall in Cahuají (8 km SW) covered pastureland,
preventing animals from grazing. Roaring noises were occasionally reported.
During 17-18 June, incandescence from the crater was seen at night. An
explosion was followed by roaring noises, sounds resembling blocks rolling down
the flanks, and incandescence. On 19 June steam-and-ash plumes rose 500 m above the crater
and large windows vibrated after noises were heard. The next day snow covered
parts of the E and S flanks. Steam-and-gas plumes rose 500 m and drifted SSW,
E, and NW during 20-21 June. Lahars in drainages to the SW carried blocks up to
50 cm in diameter. On 21 June ashfall was reported in areas 8 km 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 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 during 16-17 June white and gray plumes
from Ulawun rose 1 km high. Fine ash fell on the SW, W, and NW flanks. Low rumbling
noises were heard from the S and SE flanks, and weak fluctuating incandescence
was observed for a brief period of time. On 18 and 19 June, white-to-gray
plumes rose from the crater, and roaring noises were reported from the NW
flank. Seismicity increased to a high level and was dominated by volcanic
tremor. During 19-20 June continuing white and gray emissions produced plumes
that rose 1 km. Fine ashfall was seen on the NW and SW flanks. Fluctuating
incandescence was seen from the S and SE flanks and occasional low roaring
noises were noted. Seismicity declined to moderate levels on 20 June. 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) Ongoing Activity BATU TARA Komba Island (Indonesia) 7.792°S, 123.579°E;
summit elev. 748 m Based on analyses of satellite imagery, the Darwin VAAC
reported that during 19-20 June ash plumes from Batu Tara rose to an altitude
of 3 km (10,000 ft) a.s.l. and drifted more than 35 km NW. Geologic Summary. The small isolated island of Batu Tara in
the Flores Sea about 50 km north of Lembata (formerly Lomblen) Island contains
a scarp on the eastern side similar to the Sciara del Fuoco of Italy's
Stromboli volcano. Vegetation covers the flanks of Batu Tara to within 50 m of
the 748-m-high summit. Batu Tara lies north of the main volcanic arc and is
noted for its potassic leucite-bearing basanitic and tephritic rocks. The first
historical eruption from Batu Tara, during 1847-52, produced explosions and a
lava flow. 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 18-20 June ash plumes from Dukono rose to an altitude of
2.4 km (8,000 ft) a.s.l. and drifted 120 km W. 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 GAUA Banks Islands (SW Pacific) 14.27°S, 167.50°E; summit
elev. 797 m Based on information from the Vanuatu Geohazards
Observatory, the Wellington VAAC reported that during 16-19 June ash plumes
from Gaua rose to an altitude of 3 km (10,000 ft) a.s.l. On 19 June the plume
drifted more than 90 km W. 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. Source: Wellington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/UK/messages.html KARYMSKY Eastern Kamchatka (Russia) 54.05°N, 159.45°E;
summit elev. 1536 m KVERT reported that during 11-18 June seismic activity from
Karymsky was above background levels. Seismic data suggested that possible ash
plumes rose to an altitude of 5.2 km (17,000 ft) a.s.l. during 10-12 June and
to an altitude of 3.9 km (12,800 ft) a.s.l. on 16 June. Satellite imagery
analysis revealed ash plumes that drifted about 195 km E on 10 and 11 June and
a thermal anomaly over the volcano on 11, 15, and 16 June. Small ash clouds
drifted 22 km E on 17 June. 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. 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 16-22 June 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 inset 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, and occasionally
fresh spatter, 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 520 m
elevation. Satellite images showed thermal anomalies from minor lava flows
originating from the shields. The Pu'u 'O'o web camera views of a lava pond on
the crater floor, that was an estimated 300 x 150 m in dimension, were often
obscured by fumes. One small lava flow was seen on the crater floor on 18 June.
Scientists saw a new gas vent on the E wall of the crater during an overflight
on 21 June that had generated incandescence during the previous few days. 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 11-18 June seismic activity from
Kliuchevskoi was above background levels and Strombolian activity was observed.
Ashfall was reported in Klyuchi, 30 km NNE on 11 June. Ash plumes occasionally
rose to an altitude of 5.5 km (18,000 ft) a.s.l. during 13-16 June. Satellite
imagery analysis revealed a large daily thermal anomaly from the volcano and
ash plumes that drifted 40 km SE on 13 and 15 June. 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. Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
http://www.kscnet.ru/ivs/kvert/index_eng.php SAKURA-JIMA Kyushu 31.585°N, 130.657°E; summit elev. 1117 m Based on information from JMA, the Tokyo VAAC reported that
during 16-22 June explosions from Sakura-jima sometimes produced plumes. Those
plumes, along with ash plumes occasionally seen by pilots, rose to altitudes of
1.2-3 km (4,000-10,000 ft) a.s.l. According to a news article, the JMA noted
that two eruptions on 20 June brought the total number of eruptions in 2010 to
550, setting a new annual record. The total number of eruptions in 2009, the
previous high at Sakura-jima, was 548. 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. Sources: Tokyo Volcanic Ash Advisory Center (VAAC)
http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html, Japan Times
http://search.japantimes.co.jp/rss/nn20100621a6.html SHIVELUCH Central Kamchatka (Russia) 56.653°N, 161.360°E;
summit elev. 3283 m KVERT reported that during 11-18 June seismic activity from
Shiveluch was above background levels and suggested that possible ash plumes
rose to an altitude of 4.9 km (16,100 ft) a.s.l. Strong fumarolic activity and
hot avalanches were seen on most days. Satellite imagery showed a large daily
thermal anomaly over the lava dome, and a small anomaly near the lava dome on
15 June. 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. Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
http://www.kscnet.ru/ivs/kvert/index_eng.php SOUFRIERE HILLS Montserrat 16.72°N, 62.18°W; summit elev.
915 m MVO reported that pyroclastic flows from the Soufrière Hills
lava dome occurred during 11-18 June. One of the largest pyroclastic flows
traveled W down Gages Valley; others originated from within the collapse scar.
A thermal camera showed several hot areas on the lava dome, likely exposed from
rockfall and pyroclastic flow activity. On 28 June a small lahar descended the
Belham Valley, to the NW. 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/ +++++++++++++++++++++++++++++++++++++ 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 To contribute to the volcano list, send your message to: volcano@xxxxxxxx Please do not send attachments. ============================================================== |
