*******************************************************
GVP/USGS Weekly Volcanic Activity Report
14-20 February 2007
http://www.volcano.si.edu/reports/usgs/
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New Activity/Unrest: | Kliuchevskoi, Russia | Nevado del Huila, Columbia
| Piton de la Fournaise, Reunion Island | Telica, Nicaragua | White
Island, New Zealand
Ongoing Activity: | Karangetang, Indonesia | Karymsky, Russia | Kilauea,
USA | Manam, Papua New Guinea | Popocatépetl, México | Rabaul, Papua New
Guinea | Sakura-jima, Japan | Santa María, Guatemala | Shiveluch, Russia
| Soufrière Hills, Montserrat | St. Helens, USA | Suwanose-jima, Japan |
Ubinas, Perú
New Activity/Unrest
KLIUCHEVSKOI Kamchatka Peninsula, Russia 56.06°N, 160.64°E; summit elev.
4,835 m
Increased summit activity at Kliuchevskoi on 15 February led KVERT to
raise the Concern Color Code from Yellow to Orange
<http://www.avo.alaska.edu/avo4/updates/color_code.html>. Ash explosions
and incandescence at the summit were observed. Strombolian explosions
expelled bombs about 300 m above the crater. Based on video data and
observations, gas-and-steam plumes with small amounts of ash rose to
altitudes of 5.3 km (17,400 ft) a.s.l. and drifted SW. A thermal anomaly
at the summit was seen on satellite imagery.
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 have occurred during the
past 3,000 years, mostly on the NE and SE flanks of the conical volcano
between 500 m and 3,600 m elevation. 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 eruptions from flank craters.
Source: Kamchatkan Volcanic Eruption Response Team
http://www.kscnet.ru/ivs/kvert/updates.shtml
Kliuchevskoi Information from the Global Volcanism Program
http://www.volcano.si.edu/world/volcano.cfm?vnum=1000-26=
NEVADO DEL HUILA Columbia 2.93°N, 76.03°W; summit elev. 5,365 m
INGEOMINAS reported increased seismic activity and two explosions from
Nevado del Huila on 19 February. An ash plume rose to an altitude of
approximately 6 km (19,700 ft) a.s.l. During aerial observations on 20
February, ash deposits were seen on the W sector of a summit glacier and
dispersed to the NW. Fumarolic plumes originating from several points
along a fissure rose to 7 km (23,000 ft) a.s.l. Small mudflows from a
glacier traveled down a gorge. Based on news reports, small avalanches
prompted officials to order evacuations from towns bordering rivers.
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: Center of Volcanology and Geological Hazard Mitigation (CVGHM)
http://portal.vsi.esdm.go.id/joomla/,
Reuters
http://www.nzherald.co.nz/section/2/story.cfm?c_id=2&objectid=10424841
Nevado del Huila Information from the Global Volcanism Program
http://www.volcano.si.edu/world/volcano.cfm?vnum=1501-05=
PITON DE LA FOURNAISE Réunion Island, Indian Ocean 21.23°S, 55.71°E;
summit elev. 2,631 m; All times are local (= UTC + 4 hours)
OVPDLF reported that on 18 February a small "seismic crisis" at Piton de
la Fournaise began at 1611 and lasted only a few minutes. About 20
minutes later, based on seismic interpretation, an eruption at the
summit began and ended the next day at 0155. A crack across Dolomieu
crater was seen during an aerial observation on 18 February.
Geologic Summary. The massive Piton de la Fournaise shield volcano on
the island of Réunion is one of the world's most active volcanoes. Most
historical eruptions have originated from the summit and flanks of
Dolomieu, a 400-m-high lava shield that has grown within the youngest of
three large calderas. This latter caldera is 8 km wide and is breached
to below sea level on the eastern side. More than 150 eruptions, most of
which have produced fluid basaltic lava flows within the caldera, have
been documented since the 17th century.
Source: Observatoire Volcanologique du Piton de la Fournaise (OVPDLF)
http://ovpf.univ-reunion.fr/
Piton de la Fournaise Information from the Global Volcanism Program
http://www.volcano.si.edu/world/volcano.cfm?vnum=0303-02=
TELICA Nicaragua 12.602°N, 86.845°W; summit elev. 1061 m
The Washington VAAC reported that continuous emissions of ash from
Telica were visible on a web-camera on 15 February. A resultant plume
rose to an altitude of 1.5 km (5,000 ft) a.s.l. Based on satellite
imagery, the plume drifted SW and a hotspot was present at the summit.
Geologic Summary. Telica, one of Nicaragua's most active volcanoes, has
erupted frequently since the beginning of the Spanish era. The Telica
volcano group consists of several interlocking cones and vents with a
general NW alignment. Sixteenth-century eruptions were reported at
symmetrical Santa Clara volcano at the SW end of the Telica group.
However, its eroded and breached crater has been covered by forests
throughout historical time, and these eruptions may have originated from
Telica, whose upper slopes in contrast are unvegetated. The steep-sided
cone of 1061-m-high Telica is truncated by a 700-m-wide double crater;
the southern crater, the source of recent eruptions, is 120 m deep. El
Liston, immediately SE of Telica, has several nested craters. The
fumaroles and boiling mudpots of Hervideros de San Jacinto, SE of
Telica, form a prominent geothermal area frequented by tourists, and
geothermal exploration has occurred nearby.
Source: Washington Volcanic Ash Advisory Center (VAAC)
http://www.ssd.noaa.gov/VAAC/messages.html
Telica Information from the Global Volcanism Program
http://www.volcano.si.edu/gvp/world/volcano.cfm?vnum=1404-04=
WHITE ISLAND Bay of Plenty, New Zealand 37.52°S, 177.78°E; summit elev.
321 m
Recent visits to White Island’s Crater Lake, including one on 13
February, have confirmed a continual rise in lake temperature since
August 2006 from a normal range of 48-50ºC. In January 2007, the
temperature reached over 60ºC. The last temperature measurement was
74ºC, the highest ever recorded in the lake. The increased heat flow
caused accelerated evaporation, and the lake level has dropped over 6 m.
Steam plumes have been observed over the island. A deformation survey of
the crater floor showed no significant changes from recent months.
Geologic Summary. The uninhabited 2 x 2.4 km White Island, one of New
Zealand's most active volcanoes, is the emergent summit of a 16 x 18 km
submarine volcano in the Bay of Plenty about 50 km offshore of North
Island. The 321-m-high island consists of two overlapping
stratovolcanoes; the summit crater appears to be breached to the SE
because the shoreline corresponds to the level of several notches in the
SE crater wall. Throughout the short historical period beginning in 1826
the volcano has had long periods of continuous hydrothermal activity and
steam release, punctuated by small-to-medium eruptions. Its activity
also forms a prominent part of Maori legends. The most recent eruptive
episode, which began on 7 March 2000, included the largest eruption at
White Island in the past 20 years on 27 July.
Source: GeoNet Data Centre
http://data.geonet.org.nz/geonews/sab/2007/02/alert-bulletin-white-island-volcano-15.html
White Island Information from the Global Volcanism Program
http://www.volcano.si.edu/world/volcano.cfm?vnum=0401-04=
Ongoing Activity
KARANGETANG [Api Siau] Siau Island, Indonesia 2.47°N, 125.29°E; summit
elev. 1,784 m
On 14 February, the Alert Level at Karangetang was lowered to 2 (scale
of 1-4). Seismicity had decreased in intensity and frequency since 18
November 2006. Lava flows and incandescent avalanches were not observed
after 25 January 2007.
Geologic Summary. Karangetang (also known as Api Siau) lies at the
northern end of the island of Siau, N of Sulawesi. The 1,784-m-high
stratovolcano contains five summit craters along a N-S line. One of
Indonesia's most active volcanoes, Karangetang has had more than 40
recorded eruptions since 1675. Twentieth-century eruptions have included
frequent explosions, sometimes accompanied by pyroclastic flows and lahars.
Source: Center of Volcanology and Geological Hazard Mitigation (CVGHM)
http://portal.vsi.esdm.go.id/joomla/
Karangetang Information from the Global Volcanism Program
http://www.volcano.si.edu/world/volcano.cfm?vnum=0607-02=
KARYMSKY Kamchatka Peninsula, Russia 54.05°N, 159.43°E; summit elev. 1,536 m
Seismic activity at Karymsky was above background levels during 9-16
February, with 50-200 shallow earthquakes occurring daily. Minor
explosions may have occurred and a thermal anomaly in the crater was
detected on satellite imagery. 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 14-20 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 intermittently visible from
several breakouts on the pali and from several vents in Pu'u 'O'o's
crater. On 15 February, breakout surface lava from the Campout flow
produced seven lava falls over the seacliff behind the East Lae'apuki
bench. Lava continued to flow over the seacliff in this area for the
rest of the reporting period. 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-
MANAM offshore New Guinea, Papua New Guinea 4.10°S, 145.06°E; summit
elev. 1,807 m
Based on satellite imagery and information from Rabaul Volcano
Observatory, the Darwin VAAC reported that diffuse plumes from Manam
drifted WSW on 15 February.
Geologic Summary. The 10-km-wide island of Manam is one of Papua New
Guinea's most active volcanoes. Four large radial valleys extend from
the unvegetated summit of the conical 1,807-m-high stratovolcano to its
lower flanks. These "avalanche valleys," regularly spaced 90 degrees
apart, channel lava flows and pyroclastic avalanches that have sometimes
reached the coast. Five satellitic centers are located near the island's
shoreline. Two summit craters are present; both are active, although
most historical eruptions have originated from the southern crater,
concentrating eruptive products during the past century into the SE
avalanche valley. Frequent historical eruptions have been recorded since
1616.
Source: Darwin Volcanic Ash Advisory Centre (VAAC)
http://www.ssd.noaa.gov/VAAC/OTH/AU/messages.html
Manam Information from the Global Volcanism Program
http://www.volcano.si.edu/world/volcano.cfm?vnum=0501-02=
POPOCATÉPETL México 19.02°N, 98.62°W; summit elev. 5,426 m
According to the Washington VAAC, a puff with little ash content emitted
from Popocatépetl was reported from the MWO and visible from the camera
operated by CENEPRED on 14 February. A very diffuse plume was seen
drifting to the E on satellite imagery. Base on an aerial photograph
taken on 24 January, CENEPRED reported that the lava-dome dimensions
have slightly increased since 24 November 2006.
Geologic Summary. Popocatépetl, whose name is the Aztec word for smoking
mountain, towers to 5,426 m 70 km SE of Mexico City and is North
America's second-highest volcano. Frequent historical eruptions have
been recorded since the beginning of the Spanish colonial era. A small
eruption on 21 December 1994 ended five decades of quiescence. Since
1996 small lava domes have incrementally been constructed within the
summit crater and destroyed by explosive eruptions. Intermittent
small-to-moderate gas-and-ash eruptions have continued, occasionally
producing ashfall in neighboring towns and villages.
Sources: Centro Nacional de Prevencion de Desastres (CENEPRED)
http://www.cenapred.unam.mx/cgi-bin/popo/reportes/ultrep.cgi,
Washington Volcanic Ash Advisory Center (VAAC)
http://www.ssd.noaa.gov/VAAC/messages.html
Popocatépetl Information from the Global Volcanism Program
http://www.volcano.si.edu/world/volcano.cfm?vnum=1401-09=
RABAUL New Britain Island, Papua New Guinea 4.271°S, 152.203°E; summit
elev. 688 m
Based on satellite imagery and RVO, the Darwin VAAC reported that
diffuse plumes from Rabaul rose to altitudes of 2.1 km (7,000 ft) a.s.l.
and drifted ESE.
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: Darwin Volcanic Ash Advisory Centre (VAAC)
http://www.ssd.noaa.gov/VAAC/OTH/AU/messages.html
Rabaul Information from the Global Volcanism Program
http://www.volcano.si.edu/world/volcano.cfm?vnum=0502-14=
SAKURA-JIMA Kyushu, Japan 31.58°N, 130.67°E; summit elev. 1,117 m
Based on satellite imagery and pilot reports, the Tokyo VAAC reported
that an ash plume from Sakura-jima reached an altitude of 1.5 km (5,000
ft) a.s.l. on 15 February.
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
Sakura-jima Information from the Global Volcanism Program
http://www.volcano.si.edu/gvp/world/volcano.cfm?vnum=0802-08=
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 NE on 15
February. INSIVUMEH reported that avalanches descended the SW flank to
the base of Caliente Dome and explosions produced diffuse ash plumes
that drifted SW on 15 February. Explosions on 19 February produced ash
plumes and ashfall to areas SW. According to the Washington VAAC diffuse
plumes were visible 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.
Sources: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e
Hidrologia (INSIVUMEH)
http://www.insivumeh.gob.gt/geofisica/boletin%20formato.htm,
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=
SHIVELUCH Kamchatka Peninsula, Russia 56.653°N, 161.360°E; summit elev.
3,283 m
Activity at Shiveluch continued above background levels during 9-16
February, with over 180 volcanic earthquakes and tremor occurring daily.
Based on seismic interpretation, observation, and video data,
gas-and-ash plumes rose to altitudes of 5.5-6 km (18,000-19,700 ft)
a.s.l. throughout the reporting period. Plumes drifted W and SW. A large
thermal anomaly was visible on satellite imagery. The Tokyo VAAC
reported eruption plumes to altitudes of 5.2-6.1 km (17,000-20,000 ft)
a.s.l. on 15 and 19 February based on information from KEMSD, KVERT, and
satellite imagery. Plumes drifted NW on 19 February. 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 (VAAC)
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 9-16 February, seismic activity at Soufrière Hills was slightly
elevated as compared to previous weeks. The lava-dome volume was
estimated at 200 million cubic meters based on recent measurements from
LIDAR data. Previous measurements over-estimated the lava-dome volume
due to the perceived location of the dome and the lack of data from
inside the crater. The height of the dome was about 1060 m a.s.l. During
17-18 February, rockfalls and small pyroclastic flows traveled W down
Gages Valley and E down Tar River Valley. Incandescence was seen from
the E and N sides of the dome. Rockfalls continued on 19 and 20 February.
Based on satellite data and information from the MVO, the Washington
VAAC reported continuous emissions during 14-20 February. Resultant
plumes rose to altitudes of km (5,000-8,000 ft) a.s.l. and drifted
mainly NW, W, and S. A thermal anomaly in the crater was detected on
satellite imagery.
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 14-20
February the lava dome at Mount St. Helens continued to grow. Seismicity
continued at low levels, punctuated by M 1.5-2.5 and occasionally larger
earthquakes. Inclement weather inhibited observations.
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 eruption plumes
during 19-20 February. The altitude and direction of the plumes 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 (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=
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 during 18-20 February. Ash plumes rose to 5.5-7 km
(18,000-23,000 ft) a.s.l. and drifted E and SW.
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 (VAAC)
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
*++++++++++++++++++++++++++++++++++
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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