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GVP/USGS Weekly Volcanic Activity Report
7-13 February 2007
http://www.volcano.si.edu/reports/usgs/
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New Activity/Unrest: | Concepción, Nicaragua
Ongoing Activity: | Barren Island, India | Karymsky, Russia | Kilauea,
USA | Sakura-jima, Japan | Sangay, Ecuador | Santa María, Guatemala |
Semeru, Indonesia | Shiveluch, Russia | Soufrière Hills, Montserrat |
St. Helens, USA | Suwanose-jima, Japan | Tungurahua, Ecuador
New Activity/Unrest
CONCEPCIÓN Nicaragua 11.538°N, 85.622°W; summit elev. 1,700 m
INETER reported that explosions in the crater of Concepción produced
ash-and-gas plumes that traveled down the WSW flanks on 9 February.
Explosions continued on 10 February and produced minor ash-and-gas
plumes. No seismicity was registered.
Geologic Summary. Volcán Concepción is one of Nicaragua's highest
volcanoes and is also one of its most active. The symmetrical volcano
forms the NW half of the dumbbell-shaped island of Ometepe in Lake
Nicaragua. Concepción is connected to neighboring Madera volcano by a
narrow isthmus. N-S-trending fractures cutting across the volcano are
associated with spatter cones, cinder cones, and maars located on the
middle N flank and on the lower S flank down to Lake Nicaragua.
Concepción has had frequent moderate explosive eruptions in the past
century, most of which have originated from a small summit crater.
Source: Instituto Nicaragüense de Estudios Territoriales (INETER)
http://www.ineter.gob.ni/
Concepción Information from the Global Volcanism Program
http://www.volcano.si.edu/world/volcano.cfm?vnum=1404-12=
Ongoing Activity
BARREN ISLAND Andaman Islands, Indian Ocean, India 12.29°N, 93.88°E;
summit elev. 354 m
Based on satellite imagery, the Darwin VAAC reported that an ash plume
from Barren Island reached an altitude of 3 km (10,000 ft) a.s.l. and
drifted SW on 8 February.
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 2,250
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 W, was created during a major explosive eruption in the late
Pleistocene that produced pyroclastic-flow and -surge deposits. The
morphology of a fresh pyroclastic cone that was constructed in the
center of the caldera has varied during the course of historical
eruptions. Lava flows fill much of the caldera floor and have reached
the sea along the western coast during eruptions in the 19th century and
more recently in 1991 and 1995.
Source: Darwin Volcanic Ash Advisory Centre
http://www.ssd.noaa.gov/VAAC/OTH/AU/messages.html
Barren Island Information from the Global Volcanism Program
http://www.volcano.si.edu/world/volcano.cfm?vnum=0600-01=
KARYMSKY Kamchatka Peninsula, Russia 54.05°N, 159.43°E; summit elev. 1,536 m
Seismic activity at Karymsky was above background levels during 2-9
February, with 80-400 shallow earthquakes occurring daily. Ash plumes
may have reached altitudes of 4 km (13,000 ft) a.s.l. during the
reporting period. The Level of Concern Color Code remained at Orange
<http://www.avo.alaska.edu/color_codes.php>.
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
http://www.kscnet.ru/ivs/kvert/updates.shtml
Karymsky Information from the Global Volcanism Program
http://www.volcano.si.edu/world/volcano.cfm?vnum=1000-13=
KILAUEA Hawaii, USA 19.43°N, 155.29°W; summit elev. 1,222 m
During 7-13 February, lava from Kilauea continued to flow from lava
deltas into the ocean at the East Lae'apuki, Kamokuna, and East
Ka'ili'ili entries. Incandescence was seen from the Campout and PKK
flows on the pali and from several vents in Pu'u 'O'o's crater. Tremor
near Pu'u 'O'o continued at low levels.
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 by
lava flows less than about 1,100 years old; 70% of the volcano's surface
is younger than 600 years. The latest Kilauea eruption began in January
1983 along the E rift zone. This long-term ongoing eruption from Pu`u
`O`o-Kupaianaha has produced lava flows that have traveled 11-12 km from
the vents to the sea, paving broad areas on the S flank of Kilauea and
adding new land beyond the former coastline.
Source: US Geological Survey Hawaiian Volcano Observatory
http://volcano.wr.usgs.gov/hvostatus.php
Kilauea information from the Global Volcanism Program
http://www.volcano.si.edu/world/volcano.cfm?vnum=1302-01-
SAKURA-JIMA Kyushu, Japan 31.58°N, 130.67°E; summit elev. 1,117 m
Based on information from Japan Meteorological Agency (JMA), the Tokyo
VAAC reported an explosion from Sakura-jima on 10 February. The altitude
and direction of a resultant plume were not reported. On 13 February, an
explosion produced a plume that rose to an altitude of 2.1 km (7,000 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
http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html
Sakura-jima Information from the Global Volcanism Program
http://www.volcano.si.edu/gvp/world/volcano.cfm?vnum=0802-08=
SANGAY Ecuador 2.03°S, 78.34°W; summit elev. 5,188 m
Based on information from Guayaquil MWO, IG, pilot reports, and
satellite imagery, the Washington VAAC reported that eruptions from
Sangay during 6-10 and 13 February produced ash plumes that drifted SW,
NW, N, and W. Plumes reached altitudes of 9 km (30,000 ft) a.s.l. on 6
February and 6.1 km (20,000 ft) a.s.l. on 9 February. A hotspot was seen
on satellite imagery at the summit during 7-9 and 13 February.
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
http://www.ssd.noaa.gov/VAAC/messages.html
Sangay Information from the Global Volcanism Program
http://www.volcano.si.edu/world/volcano.cfm?vnum=1502-09=
SANTA MARÍA Guatemala 14.756°N, 91.552°W; summit elev. 3,772 m
Based on satellite imagery, the Washington VAAC reported that diffuse
plumes from Santa María's Santiaguito lava dome complex drifted SW and S
in a fan shape on 8 February. A hot spot was detected on satellite imagery.
Geologic Summary. Symmetrical, forest-covered Santa María volcano is one
of a chain of large stratovolcanoes that rises dramatically above the
Pacific coastal plain of Guatemala. The stratovolcano has a
sharp-topped, conical profile that is cut on the SW flank by a large,
1-km-wide crater, which formed during a catastrophic eruption in 1902
and extends from just below the summit to the lower flank. The renowned
Plinian eruption of 1902 followed a long repose period and devastated
much of SW Guatemala. The large dacitic Santiaguito lava-dome complex
has been growing at the base of the 1902 crater since 1922. Compound
dome growth at Santiaguito has occurred episodically from four
westward-younging vents, accompanied by almost continuous minor
explosions and periodic lava extrusion, larger explosions, pyroclastic
flows, and lahars.
Source: Washington Volcanic Ash Advisory Center
http://www.ssd.noaa.gov/VAAC/messages.html
Santa María Information from the Global Volcanism Program
http://www.volcano.si.edu/world/volcano.cfm?vnum=1402-03=
SEMERU Java, Indonesia 8.11°S, 112.92°E; summit elev. 3,676 m
Based on a news report, eruption plumes from Semeru drifted E on 10 and
11 February. Ashfall was reported from areas including the town of
Lumajang, about 35 km E.
Geologic Summary. Semeru is the highest volcano on Java and one of its
most active. The symmetrical stratovolcano rises abruptly to 3,676 m
above coastal plains to the S and lies at the southern end of a volcanic
massif extending N to the Tengger caldera. Semeru has been in almost
continuous eruption since 1967. Frequent small-to-moderate Vulcanian
eruptions have accompanied intermittent lava dome extrusion, and
periodic pyroclastic flows and lahars have damaged villages below the
volcano. A major secondary lahar on 14 May 1981 caused more than 250
deaths and damaged 16 villages.
Source: Agence France-Presse
http://www.nationmultimedia.com/worldhotnews/read.php?newsid=30026618
Semeru Information from the Global Volcanism Program
http://www.volcano.si.edu/world/volcano.cfm?vnum=0603-30=
SHIVELUCH Kamchatka Peninsula, Russia 56.653°N, 161.360°E; summit elev.
3,283 m
Activity at Shiveluch continued above background levels during 2-9
February, with over 200 shallow earthquakes occurring daily. Based on
seismic interpretation, observation, and video data, gas-and-ash plumes
rose 4.0-5.5 km (13,100-18,000 ft) a.s.l. throughout the reporting
period. Plumes drifted NE and NW. A large thermal anomaly was visible on
satellite imagery. The Tokyo VAAC reported ash plumes to an altitude of
5.2-5.5 km (17,000-18,000 ft) a.s.l. on 10 and 13 February that were
visible on satellite imagery. The Level of Concern Color Code remained
at Orange <http://www.avo.alaska.edu/color_codes.php>.
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 horseshoe-shaped 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. During the 1990s,
intermittent explosive eruptions took place 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
http://www.kscnet.ru/ivs/kvert/updates.shtml,
Tokyo Volcanic Ash Advisory Center
http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html
Shiveluch Information from the Global Volcanism Program
http://www.volcano.si.edu/gvp/world/volcano.cfm?vnum=1000-27=
SOUFRIÈRE HILLS Montserrat, West Indies 16.72°N, 62.18°W; summit elev.
1,052 m
During 7-13 February, growth of the Soufrière Hills lava dome continued
on the W side. A small lobe was observed on 7 February growing to the
SW. On 8 February, three pyroclastic flows traveled a maximum distance
of a few kilometers E down the Tar River Valley. At least one of the
pyroclastic flows was the result of a small collapse from the S or SW
part of the dome. Small pyroclastic flows traveled NW down Tyres Ghaut
on 9 February and down the northern flanks onto Farrell's Plain on 12
and 13 February. Based on satellite imagery, information from MVO, and
pilot reports, the Washington VAAC reported that ash-and-gas and steam
plumes drifted predominantly NW during 10-13 February. Plumes reached a
maximum altitude of 2.7 km (9,000 ft) a.s.l. on 13 February.
Based on a news article on 13 February, the lava-dome volume was
approximately 250 million cubic meters, surpassing the previous record
size of 240 million cubic meters in 2003.
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 east, was formed during an eruption about 4000 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.
Sources: Montserrat Volcano Observatory http://www.mvo.ms/,
Washington Volcanic Ash Advisory Center
http://www.ssd.noaa.gov/VAAC/messages.html,
Caribbean Net News
http://www.caribbeannetnews.com/cgi-script/csArticles/articles/000059/005927.htm
Soufrière Hills Information from the Global Volcanism Program
http://www.volcano.si.edu/world/volcano.cfm?vnum=1600-05=
ST. HELENS Washington, USA 46.20°N, 122.18°W; summit elev. 2,549 m
Seismicity from the growing lava dome at Mount St. Helens was low during
7-13 February. Crater views were obscured by clouds.
Geologic Summary. Prior to 1980, Mount St. Helens formed a conical,
youthful volcano sometimes known as the Fuji-san of America. During the
1980 eruption the upper 400 m of the summit was removed by slope
failure, leaving a 2 x 3.5 km horseshoe-shaped crater now partially
filled by a lava dome. Mount St. Helens was formed during nine eruptive
periods beginning about 40-50,000 years ago, and has been the most
active volcano in the Cascade Range during the Holocene. The modern
edifice was constructed during the last 2,200 years, when the volcano
produced basaltic as well as andesitic and dacitic products from summit
and flank vents. Historical eruptions in the 19th century originated
from the Goat Rocks area on the N flank, and were witnessed by early
settlers.
Source: US Geological Survey Cascades Volcano Observatory
http://vulcan.wr.usgs.gov/Volcanoes/MSH/CurrentActivity/framework.html
St. Helens Information from the Global Volcanism Program
http://www.volcano.si.edu/world/volcano.cfm?vnum=1201-05-
SUWANOSE-JIMA Ryukyu Islands, Japan 29.53°N, 129.72°E; summit elev. 799 m
Based on information from JMA and satellite imagery, the Tokyo VAAC
reported that an explosion from Suwanose-jima produced an eruption plume
during 7 February. The altitude and direction of the plume were not
reported.
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 E 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 around 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
http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html
Suwanose-jima Information from the Global Volcanism Program
http://www.volcano.si.edu/world/volcano.cfm?vnum=0802-03=
TUNGURAHUA Ecuador 1.47°S, 78.44°W; summit elev. 5,023 m
During 7-13 February, visual observations of Tungurahua were limited due
to inclement weather. During 12-13 February, seismicity increased and
fumarolic activity was observed from the N and NE flanks. ON 13
February, a plume with moderate ash content rose to an altitude of 7 km
(23,000 ft) a.s.l. and drifted NW.
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 been restricted to 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 Poltécnica Nacional
http://www.igepn.edu.ec/
Tungurahua Information from the Global Volcanism Program
http://www.volcano.si.edu/world/volcano.cfm?vnum=1502-08=
**+++++++++++++++++++++++++++++++++++++**
**Sally Kuhn Sennert**
**SI/USGS Weekly Volcanic Activity Report Editor**
**Global Volcanism Program**
Smithsonian Institution
National Museum of Natural History MRC-119
Department of Mineral Sciences
Washington, D.C., 20560
http://www.volcano.si.edu/reports/usgs/index.cfm
Phone: 202.633.1805
Fax: 202.357.2476
<http://www.volcano.si.edu/reports/usgs/>++++++++++++++++++++++++++++++++++++++++++
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