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GVP/USGS Weekly Volcanic Activity Report
28 February-6 March 2007
http://www.volcano.si.edu/reports/usgs/
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New Activity/Unrest: | Chikurachki, Russia | Nevado del Huila, Columbia
| Stromboli, Italy | Tungurahua, Ecuador
Ongoing Activity: | Barren Island, India | Kilauea, USA | Rabaul, Papua
New Guinea | Sangay, Ecuador | Santa María, Guatemala | Soufrière Hills,
Montserrat | St. Helens, USA | Suwanose-jima, Japan
New Activity/Unrest
CHIKURACHKI Kurile Islands, Russia 50.325°N, 155.458°E; summit elev. 1,816 m
On 4 March, weak ash explosions from Chikurachki were reported by
residents of Podgorny village (Paramushir Island), about 20 km SSE. On 5
March, observers reported a continuous ash column to an altitude of 3.4
km (11,000 ft) a.s.l.
Geologic Summary. Chikurachki, the highest volcano on Paramushir Island
in the northern Kuriles, is actually a relatively small cone constructed
on a high Pleistocene volcanic edifice. Oxidized scoria deposits
covering the upper part of the young cone give it a distinctive red
color. Lava flows from 1,816-m-high Chikurachki reached the sea and form
capes on the NW coast; several young lava flows also emerge from beneath
the scoria blanket on the eastern flank. The more erosionally modified
Tatarinov group of six volcanic centers is located immediately to the S
of Chikurachki. Tephrochronology gives evidence of only one eruption in
historical time from Tatarinov, although its southern cone contains a
sulfur-encrusted crater with fumaroles that were active along the margin
of a crater lake until 1959.
Source: Alaska Volcano Observatory http://www.avo.alaska.edu/
Chikurachki Information from the Global Volcanism Program
http://www.volcano.si.edu/world/volcano.cfm?vnum=0900-36=
NEVADO DEL HUILA Columbia 2.93°N, 76.03°W; summit elev. 5,365 m
The Washington VAAC reported that satellite imagery confirmed an
eruption from Nevado del Huila on 19 February. The ash cloud rose to an
altitude of 6.1 km (20,000 ft) a.s.l. and drifted W. Later the same day,
a pilot reported an ash cloud to the same height and direction. During
2-3 March, INGEOMINAS reported that volcanic tremor was accompanied by
gas-and-ash emissions that drifted NW. Fumaroles emitted from a N-S
trending fissure.
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.
Sources: Instituto Colombiano de Geología y Minería (INGEOMINAS)
http://www.ingeominas.gov.co/,
Washington Volcanic Ash Advisory Center (VAAC)
http://www.ssd.noaa.gov/VAAC/messages.html
Nevado del Huila Information from the Global Volcanism Program
http://www.volcano.si.edu/world/volcano.cfm?vnum=1501-05=
STROMBOLI Aeolian Islands, Italy 38.79°N, 15.21°E; summit elev. 926 m
INGV-CT reported that the eruption at Stromboli that started on 27
February continued during 7 March. Lava from a fissure on the NE flank
of Crater 1 (the NE crater) flowed down the Sciara del Fuoco and formed
two branches that reached the sea, resulting in steam plumes and a
modified coastline. Explosive activity from the summit craters ceased
when the lava flowed from the fissure, but gas puffing accompanied by
small landslides inside the craters started again after 3 March.
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 http://www.ct.ingv.it/
Stromboli Information from the Global Volcanism Program
http://www.volcano.si.edu/world/volcano.cfm?vnum=0101-04=
TUNGURAHUA Ecuador 1.47°S, 78.44°W; summit elev. 5,023 m
IG reported that noises produced by material rolling down the flanks of
Tungurahua, roars, and "cannon shots" were heard during 28 February-6
March. Visual observations were limited due to cloud cover. Based on
pilot reports, the Washington VAAC reported on 28 February that an ash
plume rose to an altitude of 7.6 km (25,000 ft) a.s.l. and drifted W. On
1 and 2 March, gas-and-ash plumes rose to altitudes of 7-10 km
(23,000-32,800 ft) a.s.l. and also drifted W. Incandescent material was
ejected above the summit and rolled down the N and NW flanks. During 4-5
March, ash plumes rose to altitudes of 10-12 km (32,800-39,400 ft)
a.s.l. and drifted W and NW. During 4-6 March, explosions rattled
windows in Guadalupe, about 11 km N, and Baños, about 8 km N. Ashfall
was reported from areas to the SW during the reporting period.
According to news articles, authorities conducted a voluntary evacuation
of about 100 families on 5 March due to increased activity at Tungurahua.
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.
Sources: Instituto Geofísico-Escuela Poltécnica Nacional
http://www.igepn.edu.ec/,
Washington Volcanic Ash Advisory Center (VAAC)
http://www.ssd.noaa.gov/VAAC/messages.html,
Associated Press
http://www.cbsnews.com/stories/2007/03/06/ap/tech/main2538921.shtml
Tungurahua Information from the Global Volcanism Program
http://www.volcano.si.edu/world/volcano.cfm?vnum=1502-08=
Ongoing Activity
BARREN ISLAND Andaman Islands, Indian Ocean, India 12.29°N, 93.88°E;
summit elev. 354 m
Based on pilot reports, the Darwin VAAC reported that a diffuse ash
plume from Barren Island reached an altitude of 2.1 km (7,000 ft) a.s.l.
and drifted S on 3 March.
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=
KILAUEA Hawaii, USA 19.43°N, 155.29°W; summit elev. 1,222 m
During 28 February-6 March, 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 intermittently visible from
several breakouts on the pali and from several vents in Pu'u 'O'o's
crater. Tremor at Kilauea's summit 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-
RABAUL New Britain Island, Papua New Guinea 4.271°S, 152.203°E; summit
elev. 688 m
RVO reported that during 28 February-6 March, Rabaul caldera's Tavurvur
cone emitted white vapor plumes containing a small amount of ash that
rose to 1.2-1.7 km (3,900-5,600 ft) a.s.l. and drifted ENE and E. Loud
roaring noises occasionally accompanied emissions. During 3-6 March,
multiple explosions occurred. Larger explosions produced shockwaves that
rattled windows in Rabaul town and surrounding areas on 3 and 5 March.
The flanks were showered with lava fragments. On 4 and 6 March, ash
plumes rose to a maximum altitude of 2.7 km (8,900 ft) a.s.l. and
drifted E and SE. Ashfall was reported from areas downwind during the
reporting period.
Geologic Summary. The low-lying Rabaul caldera on the tip of the Gazelle
Peninsula at the NE end of New Britain forms a broad sheltered harbor.
The outer flanks of the 688-m-high asymmetrical pyroclastic shield
volcano are formed by thick pyroclastic-flow deposits. The 8 x 14 km
caldera is widely breached on the E, where its floor is flooded by
Blanche Bay. Two major Holocene caldera-forming eruptions at Rabaul took
place as recently as 3,500 and 1,400 years ago. Three small
stratovolcanoes lie outside the northern and NE caldera rims.
Post-caldera eruptions built basaltic-to-dacitic pyroclastic cones on
the caldera floor near the NE and western caldera walls. Several of
these, including Vulcan cone, which was formed during a large eruption
in 1878, have produced major explosive activity during historical time.
A powerful explosive eruption in 1994 occurred simultaneously from
Vulcan and Tavurvur volcanoes and forced the temporary abandonment of
Rabaul city.
Source: Herman Patia, Rabaul Volcano Observatory
Rabaul Information from the Global Volcanism Program
http://www.volcano.si.edu/world/volcano.cfm?vnum=0502-14=
SANGAY Ecuador 2.03°S, 78.34°W; summit elev. 5,188 m
Based on information from the Guayaquil MWO and satellite imagery, the
Washington VAAC reported that an eruption from Sangay on 28 February
produced an ash plume that rose to an altitude of 7.6 km (25,000 ft)
a.s.l. On 2 March, a diffuse plume and a weak hotspot were seen on
satellite imagery. On 5 March, a pilot reported that an ash plume rose
to between 5.2-6.1 km (17,000-20,000 ft) a.s.l. and drifted W.
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 a diffuse
ash plume from Santa María's Santiaguito lava dome complex drifted SW on
5 March. A diffuse plume and a hotspot were seen on satellite imagery on
6 March.
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 (VAAC)
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=
SOUFRIÈRE HILLS Montserrat, West Indies 16.72°N, 62.18°W; summit elev.
1,052 m
During 28 February-2 March, lava-dome growth at Soufrière Hills
continued and was concentrated on the E and N sides. Ash venting and
roaring noises originated from the W side of the dome, above Gages Wall.
On 2 March, two small pyroclastic flows traveled down Tyres Ghaut to the
NW.
Based on satellite data and pilot reports the Washington VAAC reported
continuous ash emissions during 28 February-4 March. Resultant plumes
rose to altitudes of 2.1 km (7,000 ft) a.s.l. and drifted mainly W. A
thermal anomaly was detected in the crater on satellite imagery. On 6
March, an ash plume rose to altitudes between 1.8-2.7 km (6,000-9,000
ft) a.s.l. and drifted W and NW.
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 (VAAC)
http://www.ssd.noaa.gov/VAAC/messages.html
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
Data from deformation-monitoring instruments showed that during 28
February-6 March the lava dome at Mount St. Helens continued to grow.
Crater views were mostly 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, the Tokyo VAAC reported that on 2 March
an eruption plume from Suwanose-jima rose to an altitude of 1.2 km
(4,000 ft) a.s.l. and drifted W.
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 (VAAC)
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=
**+++++++++++++++++++++++++++++++++++++**
**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/
Phone: 202.633.1805
Fax: 202.357.2476
<http://www.volcano.si.edu/reports/usgs/>++++++++++++++++++++++++++++++++++++++++++
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