*************************************************************
GVP/USGS Weekly Volcanic Activity Report
4-10 July 2007
http://www.volcano.si.edu/reports/usgs/
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New Activity/Unrest: | Gamkonora, Indonesia | Kilauea, USA |
Kliuchevskoi, Russia
Ongoing Activity: | Concepción, Nicaragua | Etna, Italy | Karymsky,
Russia | Langila, Papua New Guinea | Nyiragongo, D.R. of Congo | Salak,
Indonesia | Sangay, Ecuador | Shiveluch, Russia | Soufrière Hills,
Montserrat | St. Helens, USA | Tungurahua, Ecuador | Ubinas, Perú
New Activity/Unrest
GAMKONORA Halmahera, Indonesia 1.38°N, 127.53°E; summit elev. 5,364 m
On 8 July, a phreatic eruption from Gamkonora produced an ash plume that
rose to an altitude of 1.8 km (5,900 ft) a.s.l. The plume drifted N and
ashfall was reported from villages as far as 7 km downwind. The Alert
Level was raised to 2 (on a scale of 1-4). On 9 July, seismic activity
increased and eruption plumes rose to altitudes of 2.1-2.6 km
(7,000-8,500 ft) a.s.l. The Alert Level was raised to 3. Later that day,
ash plumes rose to an altitude of 5.6 km (18,400 ft) a.s.l. and the
Alert Level was raised to 4. During 9-10 July, incandescent material was
propelled 5-50 m above the crater. On 10 July, booming noises were
followed by ash plumes that rose to 4.1 km (13,500 ft) a.s.l. About
8,400 people evacuated from villages within an 8 km radius of the volcano.
Geologic Summary. The shifting of eruption centers on Gamkonora, at 1635
m the highest peak of Halmahera, has produced an elongated series of
summit craters along a N-S trending rift. Youthful-looking lava flows
originate near the cones of Gunung Alon and Popolojo, south of
Gamkonora. Since its first recorded eruption in the 16th century,
Gamkonora has typically produced small-to-moderate explosive eruptions.
Its largest historical eruption, in 1673, was accompanied by tsunamis
that inundated villages.
Source: Center of Volcanology and Geological Hazard Mitigation (CVGHM)
http://portal.vsi.esdm.go.id/joomla/
Gamkonora information from the Global Volcanism Program
http://www.volcano.si.edu/world/volcano.cfm?vnum=0608-04=
KILAUEA Hawaii, USA 19.43°N, 155.29°W; summit elev. 1,222 m
On 2 July, HVO scientists confirmed new lava flows at the bottom of
Kilauea's Pu'u 'O'o crater and raised the Volcanic Alert Level from
Advisory to Watch and Aviation Color Code from Yellow to Orange
<http://www.avo.alaska.edu/color_codes.php>. During 3-10 July, the lava
lake grew and was active. On 6 July, two vents that fed the growing lava
lake were identified: the W vent near the former Beehive location and
the E vent near the former East Pond location. On 8 July, a small area
of crust in the lava lake intermittently fumed.
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-
KLIUCHEVSKOI Kamchatka Peninsula, Russia 56.06°N, 160.64°E; summit elev.
4,835 m
KVERT reported that seismic activity at Kliuchevskoi had decreased, but
remained above background levels during 29 June-6 July. Based on seismic
interpretation, ash plumes possibly rose to altitudes of 6-7 km
(19,700-23,000 ft) a.s.l. On 4 July, the Level of Concern Color Code was
lowered from Red to Orange <http://www.avo.alaska.edu/color_codes.php>.
During 2-5 July, ash plumes rose to estimated altitudes of 5-6 km
(16,400-20,000 ft) a.s.l. based on atmospheric profiles. Plumes were
visible on satellite imagery drifting NNW, W, and SE.
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 (KVERT)
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=
Ongoing Activity
CONCEPCIÓN Nicaragua 11.538°N, 85.622°W; summit elev. 1,700 m
INETER reported that explosions in the crater of Concepción on 10 July
produced ash-and-gas plumes that drifted NW. Ashfall was reported from
areas downwind.
Geologic Summary. Volcán Concepción is one of Nicaragua's highest
volcanoes and is also one of its most active. The symmetrical volcano
forms the NW half of the dumbbell-shaped island of Ometepe in Lake
Nicaragua. Concepción is connected to neighboring Madera volcano by a
narrow isthmus. N-S-trending fractures cutting across the volcano are
associated with spatter cones, cinder cones, and maars located on the
middle N flank and on the lower S flank down to Lake Nicaragua.
Concepción has had frequent moderate explosive eruptions in the past
century, most of which have originated from a small summit crater.
Source: Instituto Nicaragüense de Estudios Territoriales (INETER)
http://www.ineter.gob.ni/
Concepción Information from the Global Volcanism Program
http://www.volcano.si.edu/world/volcano.cfm?vnum=1404-12=
ETNA Sicily, Italy 37.73°N, 15.00°E; summit elev. 3,315 m
The Toulouse VAAC reported that minor activity from Etna was detected on
satellite imagery on 7 July.
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 (VAAC)
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
During 29 June-6 July, seismic activity at Karymsky was above background
levels. The seismic data indicated that ash plumes may have risen to
altitudes of 2.7 and 4.6 km (8,900 and 15,100 ft) a.s.l. on 1 and 4
July, respectively. A thermal anomaly in the crater was visible on
satellite imagery on 30 June and 1 July. The Level of Concern Color Code
remained at Orange <http://www.avo.alaska.edu/color_codes.php>.
Based on information from KEMSD, the Tokyo VAAC reported that an
eruption plume rose to an altitude of 2.4 km (8,000 ft) a.s.l. on 8
July. Ash was not identified on satellite imagery.
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 (KVERT)
http://www.kscnet.ru/ivs/kvert/updates.shtml,
Tokyo Volcanic Ash Advisory Center (VAAC)
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=
LANGILA New Britain Island, Papua New Guinea 5.53°S, 148.42°E; summit
elev. 1,330 m
RVO reported that emission of ash plumes from Langila's Crater 2
continued during 10 June-3 July and were occasionally forceful. Ash
plumes rose to altitudes of 2.3-3.3 km (7,500-10,800 ft) a.s.l. and
drifted N and NW. Crater 3 was quiet.
Geologic Summary. Langila, one of the most active volcanoes of New
Britain, consists of a group of four small overlapping composite cones
on the lower eastern flank of the extinct Talawe volcano. Talawe is the
highest volcano in the Cape Gloucester area of NW New Britain. A
rectangular, 2.5-km-long crater is breached widely to the SE; Langila
volcano was constructed NE of the breached crater of Talawe. An
extensive lava field reaches the coast on the N and NE sides of Langila.
Frequent mild-to-moderate explosive eruptions, sometimes accompanied by
lava flows, have been recorded since the 19th century from three active
craters at the summit of Langila. The youngest and smallest crater (no.
3 crater) was formed in 1960 and has a diameter of 150 m.
Source: Herman Patia, Rabaul Volcano Observatory
Langila Information from the Global Volcanism Program
http://www.volcano.si.edu/world/volcano.cfm?vnum=0502-01=
NYIRAGONGO Democratic Republic of the Congo 1.52°S, 29.25°E; summit
elev. 3,469 m
According to news articles, a tourist climbed over the rim of Nyiragongo
on 6 July to photograph the lava lake and died after slipping and
falling about 100 m. Intense heat and gas from the active lava lake made
the recovery mission difficult.
Geologic Summary. One of Africa's most notable volcanoes, Nyiragongo
contained an active lava lake in its deep summit crater that drained
catastrophically through its outer flanks in 1977. In contrast to the
low profile of its neighboring shield volcano, Nyamuragira, Nyiragongo
displays the steep slopes of a stratovolcano. Benches in the
steep-walled, 1.2-km-wide summit crater mark the levels of former lava
lakes, which have been observed since the late 19th century. About 100
parasitic cones are located on the volcano's flanks and along a NE-SW
zone extending as far as Lake Kivu. Monitoring is done from a small
observatory building located in Goma, ~18 km S of the Nyiragongo crater.
Extremely fluid, fast-moving lava flows draining from the summit lava
lake in 1977 caused many fatalities, as did lava flows inundating
portions of the city of Goma in January 2002.
Sources: Agence France-Presse
http://travel.iafrica.com/bulletinboard/189702.htm,
Reuters http://africa.reuters.com/top/news/usnBAN731642.html
Nyiragongo Information from the Global Volcanism Program
http://www.volcano.si.edu/world/volcano.cfm?vnum=0203-03=
SALAK Java, Indonesia 6.72°S, 106.73°E; summit elev. 2,211 m
According to news articles, sulfur gas poisoning from one of Salak’s
fume-filled craters was suspected in the deaths of six teenagers on 7
July. Several more poisoned students were taken to a nearby hospital for
treatment. The students were part of a group camping on the volcano for
the weekend.
Geologic Summary. Salak volcano was constructed at the NE end of an
eroded volcanic range. Satellitic cones occur on the SW flank and at the
northern foot of the forested volcano. Two large breached craters
truncate the summit of Gunung Salak. One crater is breached to the NE
and the westernmost crater was the source of a debris-avalanche deposit
that extends 10 km WNW of the summit. Historical eruptions from Gunung
Salak have been restricted to phreatic explosions from craters in a
prominent solfataric area at 1400 m on the western flank. Salak volcano
has been the site of extensive geothermal exploration.
Sources: Deutsche Presse-Agentur
http://news.monstersandcritics.com/asiapacific/news/article_1327631.php/Six_Indonesian_teenagers_killed_by_poisonous_fumes,
Reuters http://uk.reuters.com/article/worldNews/idUKJAK28979320070709
Salak Information from the Global Volcanism Program
http://www.volcano.si.edu/gvp/world/volcano.cfm?vnum=0603-05=
SANGAY Ecuador 2.03°S, 78.34°W; summit elev. 5,188 m
Based on pilot observations, the Washington VAAC reported that an ash
plume from Sangay rose to an altitude between 5.2-7.9 km (17,000-26,000
ft) a.s.l. and drifted W on 3 July.
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 (VAAC)
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=
SHIVELUCH Kamchatka Peninsula, Russia 56.653°N, 161.360°E; summit elev.
3,283 m
KVERT reported that seismic activity at Shiveluch continued above
background levels during 29 June-6 July. Based on seismic
interpretation, ash plumes rose to an altitude of 6.5 km (21,300 ft)
a.s.l. during the reporting period. A large thermal anomaly was detected
in the crater on satellite imagery all days. The Level of Concern Color
Code remained at Orange <http://www.avo.alaska.edu/color_codes.php>.
Based on information from KEMSD, the Tokyo VAAC reported that an
eruption plume rose to 4.6 km (15,000 ft) a.s.l. during 27-28 June. Ash
was not identified on satellite imagery.
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 (KVERT)
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
MVO reported that during 29 June-10 July the lava dome at Soufrière
Hills changed very little based on visual observations, and seismic
activity was very low. Low-level rockfall activity continued, however,
and predominantly affected the Tar River Valley to the E. Heavy rainfall
generated lahars in E drainages during 4-6 July. The Alert Level
remained at 4 (on a scale of 0-5).
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 indicated that during 4-10
July lava-dome growth at Mount St. Helens continued. Seismicity
persisted at low levels, punctuated by M 1.5-2.5, and occasionally
larger, earthquakes. In some instances, clouds inhibited visual
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-
TUNGURAHUA Ecuador 1.47°S, 78.44°W; summit elev. 5,023 m
During 3-10 July, IG reported that ash plumes from Tungurahua rose to
altitudes of 6-7.5 km (19,700-24,600 ft) a.s.l. and drifted mainly SW
and W. Ashfall was reported from areas downwind during 4 and 6-9 July.
Incandescence was visible at the crater on 4 and 9 July and noises were
reported during 4-5, 7, and 10 July. On 8 July, incandescence was again
seen at the summit and blocks rolled 500 m down the flanks. On 9 July,
two explosions were accompanied by “cannon shots” that vibrated windows
at the Tungurahua Observatory (OVT) in Guadalupe, 11 km N. Strombolian
activity was observed and blocks rolled 1 km down the flanks. On 10
July, a lahar occurred in a W drainage.
Based on pilot reports, information from IG, and satellite imagery, the
Washington VAAC reported that during 9-10 July, ash plumes rose to
altitudes of 4.9-7 km (16,000-23,000 ft) a.s.l. and drifted W.
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
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 a Significant Meteorological Information (SIGMET) advisory, the
Buenos Aires VAAC reported that an ash plume from Ubinas rose to an
altitude between 5.5-6.1 km (18,000-20,000 ft) a.s.l. and drifted S on 4
July. Ash was not identified on satellite imagery.
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**
http://www.volcano.si.edu/reports/usgs/
Smithsonian Institution, National Museum of Natural History
Department of Mineral Sciences, MRC-119
Washington, D.C., 20560
Phone: 202.633.1805
Fax: 202.357.2476
+++++++++++++++++++++++++++++++++++++++++++
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