*********************************************************
GVP/USGS Weekly Volcanic Activity Report
29 November-5 December 2006
http://www.volcano.si.edu/reports/usgs/
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New Activity/Unrest: | Mayon, Philippines | Nyamuragira, D.R. of Congo |
Shiveluch, Russia
Ongoing Activity: | Bagana, Papua New Guinea | Colima, México | Dukono,
Indonesia | Etna, Italy | Karymsky, Russia | Kilauea, USA | Rabaul,
Papua New Guinea | Sangay, Ecuador | Soufrière Hills, Montserrat | St.
Helens, USA | Tungurahua, Ecuador | Ubinas, Perú | Ulawun, Papua New Guinea
New Activity/Unrest
MAYON southeastern Luzon, Philippines 13.257°N, 123.685°E; summit elev.
2,462 m
A typhoon that struck the Philippines on 30 November mobilized material
from the flanks of Mayon that resulted in significant lahars. Several
villages around the flanks were buried by up to 1.5 m (5 ft) of debris.
Depending on the news source, the death toll ranges from about 325 to
400 and about 300 to 400 people are still missing.
Geologic Summary. The beautifully symmetrical Mayon volcano, which rises
to 2,462 m above the Albay Gulf, is the Philippines' most active
volcano. The structurally simple volcano has steep upper slopes that
average 35-40° and is capped by a small summit crater. The historical
eruptions of this basaltic-andesitic volcano date back to 1616 and range
from Strombolian to basaltic Plinian. Eruptions occur predominately from
the central conduit and have also produced lava flows that travel far
down the flanks. Pyroclastic flows and mudflows have commonly swept down
many of the approximately 40 ravines that radiate from the summit and
have often devastated populated lowland areas. Mayon’s most violent
eruption, in 1814, killed more than 1,200 people and devastated several
towns. Eruptions that began in February 2000 led PHIVOLCS to recommend
on 23 February the evacuation of people within a radius of 7 km from the
summit in the SE and within a 6 km radius for the rest of the volcano.
Sources: Associated Press
http://www.cnn.com/2006/WORLD/asiapcf/12/04/philippines.typhoon.ap/index.html?section=cnn_latest,
Associated Press
http://news.yahoo.com/s/ap/20061203/ap_on_re_as/asia_storm_40
Mayon Information from the Global Volcanism Program
http://www.volcano.si.edu/world/volcano.cfm?vnum=0703-03=
NYAMURAGIRA Democratic Republic of the Congo 1.408°S, 29.20°E; summit
elev. 3,058 m
Based on satellite imagery, the Toulouse VAAC reported that during 29
November-2 December emissions from Nyamuragira produced ash plumes to
altitudes of 3-6.1 km (10,000-20,000 ft) a.s.l. The plumes drifted W and
NW. By mid-morning on 2 December, ash plumes were no longer visible.
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 3,058-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.
Source: Toulouse Volcanic Ash Advisory Center
http://www.ssd.noaa.gov/VAAC/OTH/FR/messages.html
Nyamuragira Information from the Global Volcanism Program
http://www.volcano.si.edu/world/volcano.cfm?vnum=0203-02=
SHIVELUCH Kamchatka Peninsula, Russia 56.653°N, 161.360°E; summit elev.
3,283 m; All times are local (= UTC + 12 hours [or 13 hours in March-June])
KVERT reported that a strong seismic event from Shiveluch was recorded
on 4 December at 2100. Prior to the event, seismicity was at background
levels and weak fumarolic activity was observed. According to video data
from 5 December, explosions produced plumes that rose to an altitude of
4 km (13,100 ft) a.s.l. and drifted NW. Strong explosions from the lava
dome were possible and avalanches to a distance of 3-5 km down the SW
flank were noted. The Level of Concern Color Code was raised from Yellow
to 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.
Source: Kamchatkan Volcanic Eruption Response Team
http://www.kscnet.ru/ivs/kvert/updates.shtml
Shiveluch Information from the Global Volcanism Program
http://www.volcano.si.edu/gvp/world/volcano.cfm?vnum=1000-27=
Ongoing Activity
BAGANA Bougainville Island, Papua New Guinea 6.14°S, 155.19°E; summit
elev. 1,750 m
Based on satellite imagery, the Darwin VAAC reported that an ash plume
from Bagana rose to an altitude of 3 km (10,000 ft) a.s.l. on 5 December.
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
http://www.ssd.noaa.gov/VAAC/OTH/AU/messages.html
Bagana Information from the Global Volcanism Program
http://www.volcano.si.edu/world/volcano.cfm?vnum=0505-02=
COLIMA Western México 19.514°N, 103.62°W; summit elev. 3,850 m
Based on reports from the Mexico City MWO and satellite imagery, the
Washington VAAC reported that an ash plume from Colima on 30 November
reached an altitude of 6.7 km (22,000 ft) a.s.l. and drifted SE and NE.
Geologic Summary. The Colima volcanic complex is the most prominent
volcanic center of the western Mexican Volcanic Belt. It consists of two
southward-younging volcanoes, Nevado de Colima (the 4,320 m high point
of the complex) on the N and the historically active Volcán de Colima on
the S. Volcán de Colima (also known as Volcán Fuego) is a youthful
stratovolcano constructed within a 5-km-wide caldera, breached to the S,
that has been the source of large debris avalanches. Major slope
failures have occurred repeatedly from both the Nevado and Colima cones,
and have produced a thick apron of debris-avalanche deposits on three
sides of the complex. Frequent historical eruptions date back to the
16th century. Occasional major explosive eruptions (most recently in
1913) have destroyed the summit and left a deep, steep-sided crater that
was slowly refilled and then overtopped by lava dome growth.
Source: Washington Volcanic Ash Advisory Center
http://www.ssd.noaa.gov/VAAC/messages.html
Colima Information from the Global Volcanism Program
http://www.volcano.si.edu/world/volcano.cfm?vnum=1401-04=
DUKONO Halmahera, Indonesia 1.70°N, 127.87°E; summit elev. 1,185 m
According to the Darwin VAAC, a diffuse ash plume from Dukono that was
visible on satellite imagery on 5 December rose to an altitude of 3 km
(10,000 ft) a.s.l. and drifted ENE.
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 since 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
http://www.bom.gov.au/info/vaac/advisories.shtml
Dukono Information from the Global Volcanism Program
http://www.volcano.si.edu/world/volcano.cfm?vnum=0608-01=
ETNA Sicily, Italy 37.73°N, 15.00°E; summit elev. 3,315 m
Based on a pilot report and satellite imagery, the Toulouse VAAC
reported that an ash plume from Etna was visible during 4-5 December.
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: Toulouse Volcanic Ash Advisory Center
http://www.ssd.noaa.gov/VAAC/OTH/FR/messages.html
Etna Information from the Global Volcanism Program
http://www.volcano.si.edu/world/volcano.cfm?vnum=0101-06=
KARYMSKY Kamchatka Peninsula, Russia 54.05°N, 159.43°E; summit elev. 1,536 m
Seismic data from Karymsky was unavailable during 29 November-5
December. A large thermal anomaly in the crater was detected on 26, 27,
and 29 November. On 29 November ash plumes drifted NE. Based on pilot
reports and satellite imagery, the Tokyo VAAC reported that during 1-2
December, ash plumes rose to 7 km (23,000 ft) a.s.l. and drifted N and
E. 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.
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
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 29 November-5 December, lava from Kilauea continued to flow off
of a lava delta into the ocean at the East Lae'apuki and East Ka'ili'ili
entries. On 30 November and 5 December, incandescence was visible on the
Pulama pali. Incandescence was intermittently visible from the East Pond
and January vents, South Wall complex, and Drainhole and Beehive vents
in Pu'u 'O'o's crater. The intensity of the incandescence was strongest
at the E (East Pond) and diminished towards the W (Beehive).
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 26-27 November Rabaul emitted weak gray ash
clouds that drifted NW to W. Ashfall was reported from areas downwind.
During 28 November-1 December, the emissions were forceful and plumes
rose to 900 m (3,000 ft) a.s.l. and drifted E. On 2 December, emissions
of white vapor and gray ash clouds produced plumes to 2.7 km (8,900 ft)
a.s.l. that drifted ENE. During 3-6 December, ash plumes rose to
altitudes of 1.2-2.7 km (3,900-8,900 ft) a.s.l. and drifted in multiple
directions. Ashfall was again reported from areas downwind. Seismicity
continued at low levels and deformation rates were low.
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 pilot reports and satellite imagery, the Washington VAAC
reported that an eruption from Sangay on 2 December produced an ash
plume that rose to an altitude of 8.5 km (28,000 ft) a.s.l. and drifted SW.
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=
SOUFRIÈRE HILLS Montserrat, West Indies 16.72°N, 62.18°W; summit elev.
1,052 m
During 24 November-1 December, lava-dome growth at Soufrière Hills
continued and was concentrated on the NE part of the edifice. The two
cracks in the curved back of the shear E-facing lobe on the summit have
propagated downward and divided the lobe into three blocks. Rockfalls
and small pyroclastic flows traveled down the sector between the SE and
NE flanks and are also affecting the N part of the dome at the back of
the lobe. Pyroclastic flows reached the upper region of Tuitts Ghaut on
27 November.
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.
Source: Montserrat Volcano Observatory http://www.mvo.ms/
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 29
November-5 December the lava dome at Mount St. Helens continued to grow
and produce small rockfalls.
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-
TUNGURAHUA Ecuador 1.47°S, 78.44°W; summit elev. 5,023 m
IG reported that during 29 November-5 December, emissions from
Tungurahua produced ash-and-steam plumes that reached altitudes of 6-7
km (19,700-23,000 ft) a.s.l. and drifted predominantly W and N.
Observations on 3 December were hindered due to inclement weather.
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=
UBINAS Perú 16.355°S, 70.903°W; summit elev. 5,672 m
Based on pilot reports, the Buenos Aires VAAC reported continuous
emissions from Ubinas on 2 December. Ash plumes rose to 5.5 km (18,000
ft) a.s.l. and drifted N.
Geologic Summary. A small, 1.2-km-wide caldera that cuts the top of
Ubinas, Peru's most active volcano, gives it a truncated appearance.
Ubinas is the northernmost of three young volcanoes located along a
regional structural lineament about 50 km behind the main volcanic front
of Peru. The upper slopes of the stratovolcano, composed primarily of
Pleistocene andesitic lava flows, steepen to nearly 45 degrees. The
steep-walled, 150-m-deep summit caldera contains an ash cone with a
500-m-wide funnel-shaped vent that is 200 m deep. Debris-avalanche
deposits from the collapse of the SE flank of Ubinas extend 10 km from
the volcano. Widespread plinian pumice-fall deposits from Ubinas include
some of Holocene age. Holocene lava flows are visible on the volcano's
flanks, but historical activity, documented since the 16th century, has
consisted of intermittent minor explosive eruptions.
Source: Buenos Aires Volcanic Ash Advisory Center
http://www.ssd.noaa.gov/VAAC/OTH/AG/messages.html
Ubinas Information from the Global Volcanism Program
http://www.volcano.si.edu/world/volcano.cfm?vnum=1504-02
ULAWUN New Britain Island, Papua New Guinea 5.04°S, 151.34°E; summit
elev. 2,334 m
Based on satellite imagery, the Darwin VAAC reported a diffuse
ash-and-steam plume from Ulawun on 29 November and an ash plume on 4
December. The altitudes and drift directions were not reported.
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: Darwin Volcanic Ash Advisory Centre
http://www.ssd.noaa.gov/VAAC/OTH/AU/messages.html
Ulawun Information from the Global Volcanism Program
http://www.volcano.si.edu/world/volcano.cfm?vnum=0502-12=
**+++++++++++++++++++++++++++++++++++++**
**Sally Kuhn Sennert**
**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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