***************************************
GVP/USGS Weekly Volcanic Activity Report
8-14 November 2006
http://www.volcano.si.edu/reports/usgs/index.cfm
***************************************
New Activity/Unrest: | Home Reef, Tonga
Ongoing Activity: | Barren Island, India | Etna, Italy | Karymsky,
Russia | Kilauea, USA | Manam, Papua New Guinea | Rabaul, Papua New
Guinea | Santa María, Guatemala | Soufrière Hills, Montserrat | St.
Helens, USA | Suwanose-jima, Japan | Tungurahua, Ecuador | Ubinas, Perú
| Ulawun, Papua New
New Activity/Unrest
HOME REEF Tonga Islands, Tonga 18.992°S, 174.775°W; summit elev. -2 m
Pumice rafts originally reported to have been from Metis Shoal are now
confirmed to have originated from an island-building eruption of the
submarine Home Reef volcano. On 12 August, possibly four days after the
beginning of the eruption, a sailor spotted the new island after
encountering pumice rafts the previous day. The encounter was written in
an on-line journal that described the island as four-peaked. A central
crater produced steam plumes and occasional bursts of tephra.
Data from the Ozone Monitoring Instrument (OMI) on NASA’s Aura satellite
showed that sulfur dioxide emissions from the Home Reef area began on 8
August, peaked during 8-9 August, and ceased on 15 August. Based on
ASTER satellite imagery from 4 October, the island was an estimated 1 km
long with an area of 0.23 square km. The temperature of a small lake on
the island was 64.7ºC. The island area was estimated as 0.15 square km,
based on ASTER imagery from 12 October.
Geologic Summary. Home Reef, a submarine volcano midway between Metis
Shoal and Late Island in the central Tonga islands, was first reported
active in the mid-19th century, when an ephemeral island formed. An
eruption in 1984 produced a 12-km-high eruption plume, copious amounts
of floating pumice, and an ephemeral island 500 x 1500 m wide, with
cliffs 30-50 m high that enclosed a water-filled crater.
Sources: Fredrik Fransson
http://yacht-maiken.blogspot.com/2006/08/whales-and-volcanoes.html,
Simon Carn,
Alain Bernard http://www.ulb.ac.be/sciences/cvl/homereef/homereef.html
Home Reef Information from the Global Volcanism Program
http://www.volcano.si.edu/world/volcano.cfm?vnum=0403-08=
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 diffuse plumes
from Barren Island on 8 November reached altitudes of 3 km (10,000 ft)
a.s.l. and drifted SW and W.
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 Center
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=
ETNA Sicily, Italy 37.73°N, 15.00°E; summit elev. 3,315 m
An English-language report on Etna’s activity during 31 August-5
November that was recently prepared and distributed by scientists from
the Instituto Nazionale di Geofisica e Volcanologia (INGV) is summarized
this week.
Strombolian activity and lava flows from SE Crater that began on 31
August continued until 15 September. During 22-27 September, 3-6
October, and 10-11 October, new but similar eruptive episodes with
Strombolian explosions produced lava flows.
On 12 October, a short fissure opened on the ESE flank at the base of SE
Crater. Lava spread in the upper Valle del Bove and advanced a few
hundred meters downslope. On 17 October, mild spattering led to the
growth of three hornitos on the fissure. Vigorous Strombolian activity
from a vent in the SE Crater and large explosions occurred on 20
October. Lava flowed less than 1 km SE and a new cone grew at the summit.
On 23 October, vigorous Strombolian activity and lava fountaining from
SE Crater marked a new eruptive episode. Lava flowed down the ESE flank
and the summit cone rapidly grew. The explosive activity ceased the next
day and was followed by ash emissions. Field observations revealed that
a 50 m wide collapse pit opened on the SE flank and the new cone at the
summit of the SE Crater had collapsed.
On 25 October ash emissions and weak Strombolian activity were observed
from the summit of the SE Crater. Lava flows were emitted from fissures
on the SSE flank and the S base of the central summit cone. On 27
October, ash emissions were followed by lava flows from the SSE flank
fissure. Ash emissions on 29 and 30 October produced ashfall in
inhabited areas including Catania, 27 km S of the summit cone. Lava
continued to flow from the 25 October fissure and from the 12 October
fissure at least until 5 November, when field observers reported
actively flowing lava in the uppermost portions of the flow fields.
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 http://www.ct.ingv.it/
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 were not available during 4-10 November,
except on 2, 3, and 7 November, when seismicity was elevated above
background levels. Explosions produced ash plumes that may have reached
altitudes of 3 km (9,800 ft) a.s.l. Based on satellite imagery, plumes
drifted NE on 2 November and SE during 6 and 7 November. A thermal
anomaly in the crater was detected on 2-3 and 5-7 November. 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 8-14 November, 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.
During 7-9 November, a break-out flow was visible about halfway down
Paluma pali. Incandescence was intermittently visible from the East Pond
and January vents, South Wall complex, and Drainhole vent in Pu'u 'O'o's
crater. Summit inflation S of Halema'uma'u caldera continued. Tremor at
Pu'u 'O'o remained at a typical moderate level.
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
RVO reported that during 1-13 November white vapor plumes from Manam
were emitted from South Crater and from Main Crater. Incandescence was
noted from both craters during 8-10 November and from Main Crater on 12
November. Based on satellite imagery, the Darwin VAAC reported that on
13 November a diffuse plume drifted W.
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.
Sources: Herman Patia and Steve Saunders, Rabaul Volcano Observatory,
Darwin Volcanic Ash Advisory Center
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=
RABAUL New Britain Island, Papua New Guinea 4.271°S, 152.203°E; summit
elev. 688 m
RVO reported that during 25 October-1 November, Rabaul emitted thick
white vapor and sub-continuous gray ash clouds. Fine ashfall was
reported from areas N and NW, including Rabaul town. On 28 October, a
large explosion produced an ash cloud that reached an altitude of 2 km
(6,600 ft) a.s.l. and drifted NW. Fine ashfall was reported from areas
downwind and lava fragments fell onto the flanks. Only continuous,
thick, white vapor clouds were emitted during 1-7 November. Two
explosive events occurred on 2 November. Ash plumes from the first
explosion reached altitudes of 1.5 km (4,900 ft) a.s.l. Plumes from both
explosions drifted N. During 3-10 November, occasional small-to-moderate
ash emissions produced plumes that drifted SE, away from populated
areas. During 11-13 November, thick white vapor and occasional gray ash
clouds drifted SE, S, W, NW, and N. Fine ashfall was reported downwind
on 11 November.
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 and Steve Saunders, Rabaul Volcano Observatory
Rabaul Information from the Global Volcanism Program
http://www.volcano.si.edu/world/volcano.cfm?vnum=0502-14=
SANTA MARÍA Guatemala 14.756°N, 91.552°W; summit elev. 3,772 m
According to the Washington VAAC, minor emissions from Santa María's
Santiaguito lava-dome complex were visible on satellite imagery on 14
November. The small ash clouds drifted WSW.
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=
SOUFRIÈRE HILLS Montserrat, West Indies 16.72°N, 62.18°W; summit elev.
1,052 m
During 3-10 November, lava-dome growth at Soufrière Hills continued and
was concentrated on the E part of the edifice. Rockfalls and small
pyroclastic flows originating from a large active lobe on the NE sector
of the dome traveled down the SW and NE flanks. High-temperature
rockfalls from the NNE sector were deposited on a ridge between Tuitt’s
and White’s Ghauts. Sulfur dioxide measurements were higher than
previous weeks, but still within the long-term average range.
Based on information from the MVO, satellite imagery, and pilot reports,
the Washington VAAC reported continuous ash-and-gas emissions during
8-14 November. Resulting plumes drifted mainly W and S. A hotspot was
detected on satellite imagery during 9-13 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.
Sources: Montserrat Volcano Observatory http://www.mvo.ms/,
Washington Volcanic Ash Advisory Center
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 8-14
November the lava dome at Mount St. Helens continued to grow. Inclement
weather prohibited visual observations during most of the reporting period.
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 9
November an eruption plume from Suwanose-jima reached an altitude of 1.5
km (5,000 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
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
IG reported that during 7-12 November, emissions from Tungurahua
produced ash plumes that reached altitudes of 6-9 km (19,700-29,500 ft)
a.s.l. and drifted predominantly NE, NW, and W. On 7 November, a
voluminous lahar traveled down gorges to the W and reached as far as the
Chambo River, about 7 km from the summit. On 8 November, blocks expelled
from the summit rolled down the flanks and ash fall was reported from
areas including Casúa (7 km NW) and Baños (8 km NE). On 10, 11, and 13
November, ash fall was reported from areas including Penipe (8 km SW).
During 12-13 November, lahars traveled down W and NW drainages and the
Vazcún River swelled with muddy water.
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 and satellite imagery, the Buenos Aires VAAC
reported continuous emissions from Ubinas during 9-11 and 13 November.
Ash plumes rose to 5.5-7.3 km (18,000-24,000 ft) a.s.l. and drifted S,
SW, NW, and NE.
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.bom.gov.au/products/Volc_ash_recent.shtml
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 that on 12 November
a diffuse plume from Ulawun reached an altitude of 4.6 km (15,000 ft)
a.s.l. and drifted NW.
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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