Thursday, September 30, 2010

[ Volcano ] SI/USGS Weekly Volcanic Activity Report 22-28 September 2010

SI/USGS Weekly Volcanic Activity Report 22-28 September 2010

SI/USGS Weekly Volcanic Activity Report

22-28 September 2010

Sally Kuhn Sennert - Weekly Report Editor


New Activity/Unrest: | Karangetang [Api Siau], Siau I | Kliuchevskoi,
Central Kamchatka (Russia) | Merapi, Central Java (Indonesia) | Piton de la
Fournaise, Reunion Island | Planchón-Peteroa, Central Chile-Argentina border
| Sinabung, Sumatra (Indonesia)

Ongoing Activity: | Cleveland, Chuginadak Island | Dukono, Halmahera |
Karymsky, Eastern Kamchatka (Russia) | Kilauea, Hawaii (USA) | Reventador,
Ecuador | Sakura-jima, Kyushu | Shiveluch, Central Kamchatka (Russia) |
Soufrière Hills, Montserrat | Suwanose-jima, Ryukyu Islands (Japan)

The Weekly Volcanic Activity Report is a cooperative project between the
Smithsonian's Global Volcanism Program and the US Geological Survey's
Volcano Hazards Program. Updated by 2300 UTC every Wednesday, notices of
volcanic activity posted on these pages are preliminary and subject to
change as events are studied in more detail. This is not a comprehensive
list of all of Earth's volcanoes erupting during the week, but rather a
summary of activity at volcanoes that meet criteria discussed in detail in
the "Criteria and Disclaimers" section. Carefully reviewed, detailed reports
on various volcanoes are published monthly in the Bulletin of the Global
Volcanism Network.

Note: Many news agencies do not archive the articles they post on the
Internet, and therefore the links to some sources may not be active. To
obtain information about the cited articles that are no longer available on
the Internet contact the source.

New Activity/Unrest

KARANGETANG [API SIAU] Siau I 2.78°N, 125.40°E; summit elev. 1784 m

CVGHM reported that during 1-7 September lava seen from the observation post
(5 km SSW) traveled 75 m down Karangetang's flanks. Avalanches traveled as
far as 1.5 km down the Batang (S), Batu Awang (E), and Nanitu drainages.
Incandescent material was ejected 350 m above the crater. During 8-21
September lava traveled 500 m down the flanks. Avalanches originating from
the end of the lava flow traveled as far as 2 km down the Batang, Kahetang
(E), and Nanitu drainages. During 18-20 September material was ejected
300-500 m above the crater. Ashfall was reported in areas to the NW. On 21
and 22 September incandescent material traveled down multiple drainages.
Strombolian activity was observed on 22 September; material ejected 50 m
high fell back down around the crater. That same day the Alert level was
raised to 3 (on a scale of 1-4).

Geologic Summary. Karangetang (also known as Api Siau) lies at the northern
end of the island of Siau, N of Sulawesi, and contains five summit craters
strung 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)

KLIUCHEVSKOI Central Kamchatka (Russia) 56.057°N, 160.638°E; summit elev.
4835 m

KVERT reported that during 17-24 September seismic activity from
Kliuchevskoi was above background levels and lava from the summit crater
flowed down the SW flank. Satellite imagery analyses showed a large and
intense daily thermal anomaly over the volcano. Strombolian activity was
observed during 17 and 20-21 September, and ash plumes were seen rising to
altitudes of 6.5-7 km (21,300-23,000 ft) a.s.l. on 20 and 21 September.
Satellite imagery showed ash plumes drifting about 60 km W on 19 September
and about 240 km E on 20 and 21 September. The Aviation Color Code level
remained at Orange.

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, mostly on the NE and SE flanks of
the conical volcano between 500 m and 3,600 m elevation, have occurred
during the past 3,000 years. 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 events from flank craters.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

MERAPI Central Java (Indonesia) 7.542°S, 110.442°E; summit elev. 2968 m

CVGHM reported that a pattern of increasing seismicity from Merapi began in
to emerge in early September. Observers at Babadan (7 km W) and Kaliurang (8
km S) heard an avalanche on 12 September. On 13 September white plumes rose
800 m above the crater. Inflation, detected since March, increased from
background levels of 0.1 to 0.3 mm per day to a rate of 11 mm per day on 16
September. On 19 September earthquakes continued to be numerous, and the
next day CVGHM raised the Alert Level to 2 (on a scale of 1-4).

Geologic Summary. Merapi, one of Indonesia's most active volcanoes, lies in
one of the world's most densely populated areas and dominates the landscape
immediately N of the major city of Yogyakarta. The steep-sided modern Merapi
edifice, its upper part unvegetated due to frequent eruptive activity, was
constructed to the SW of an arcuate scarp cutting the eroded older
Batulawang volcano. Pyroclastic flows and lahars accompanying growth and
collapse of the steep-sided active summit lava dome have devastated
cultivated and inhabited lands on the volcano's western-to-southern flanks
and caused many fatalities during historical time. The volcano is the object
of extensive monitoring efforts by the Merapi Volcano Observatory (MVO).

Source: Center of Volcanology and Geological Hazard Mitigation (CVGHM)

PITON DE LA FOURNAISE Reunion Island 21.231°S, 55.713°E; summit elev. 2632 m

Starting on 14 August and continuing through 10 September, OVPDLF recorded a
slow but steady increase in the number and magnitude of earthquakes from
Piton de la Fournaise. Inflation of the summit area began in late August. A
report on 13 September noted localized deformation W of Dolomieu crater and
a small number of landslides in the crater. On 20 September a significant
increase in earthquakes was recorded, although the average magnitude was
low. The earthquakes were located at the base of Piton de la Fournaise, W
and S of Dolomieu crater. A seismic crisis on 24 September was characterized
by several tens of earthquakes located beneath Dolomieu crater, and occurred
in conjunction with 3 cm of inflation. The Alert level was raised to 1
("Probable or Imminent Eruption").

Geologic Summary. 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 a 400-m-high lava
shield, Dolomieu, that has grown within the youngest of three large
calderas. This depression 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. The volcano is monitored by the Piton de la Fournaise Volcano
Observatory, one of several operated by the Institut de Physique du Globe de

Source: Observatoire Volcanologique du Piton de la Fournaise (OVPDLF)

PLANCHON-PETEROA Central Chile-Argentina border 35.240°S, 70.570°W; summit
elev. 4107 m

Based on analyses of satellite imagery, the Buenos Aires VAAC reported that
on 26 September an ash plume from Planchón-Peteroa rose to an altitude of
4.3 km (14,000 ft) a.s.l. and drifted SSE.

Geologic Summary. Planchón-Peteroa is an elongated complex volcano along the
Chile-Argentina border with several overlapping calderas. Activity began in
the Pleistocene with construction of the basaltic-andesite to dacitic Volcán
Azufre, followed by formation of basaltic and basaltic-andesite Volcán
Planchón, 6 km to the N. About 11,500 years ago, much of Azufre and part of
Planchón collapsed, forming the massive Río Teno debris avalanche, which
reached Chile's Central Valley. Subsequently, Volcán Planchón II was formed.
The youngest volcano, andesitic and basaltic-andesite Volcá Peteroa,
consists of scattered vents between Azufre and Planchón. Peteroa has been
active into historical time and contains a small steaming crater lake.
Historical eruptions from the Planchón-Peteroa complex have been dominantly
explosive, although lava flows were erupted in 1837 and 1937.

Source: Buenos Aires Volcanic Ash Advisory Center (VAAC)

SINABUNG Sumatra (Indonesia) 3.17°N, 98.392°E; summit elev. 2460 m

CVGHM reported that on 22 September a white plume from Sinabung rose as high
as 100 m above the crater. On 23 September the Alert Level was lowered to 3
(on a scale of 1-4).

Geologic Summary. Gunung Sinabung is a Pleistocene-to-Holocene stratovolcano
with many lava flows on its flanks. The migration of summit vents along a
N-S line gives the summit crater complex an elongated form. The youngest
crater of this conical, 2460-m-high andesitic-to-dacitic volcano is at the
southern end of the four overlapping summit craters. An unconfirmed eruption
was noted in 1881, and solfataric activity was seen at the summit and upper
flanks of Sinabung in 1912, although no confirmed historical eruptions were
recorded prior to 2010.

Source: Center of Volcanology and Geological Hazard Mitigation (CVGHM)

Ongoing Activity

CLEVELAND Chuginadak Island 52.825°N, 169.944°W; summit elev. 1730 m

AVO reported that during 25-26 September a weak thermal anomaly from
Cleveland was detected in satellite imagery. Cloud cover prevented views of
the volcano during 22-24 and 27-28 September. The Volcano Alert Level
remained at Advisory and the Aviation Color Code remained at Yellow. No
current seismic information was available because Cleveland does not have a
real-time seismic network.

Geologic Summary. Symmetrical Mount Cleveland stratovolcano is situated at
the western end of the uninhabited dumbbell-shaped Chuginadak Island in the
east-central Aleutians. The 1,730-m-high stratovolcano is the highest of the
Islands of Four Mountains group and is one of the most active in the
Aleutians. Numerous large lava flows descend its flanks. It is possible that
some 18th to 19th century eruptions attributed to Carlisle (a volcano
located across the Carlisle Pass Strait to the NW) should be ascribed to
Cleveland. In 1944 Cleveland produced the only known fatality from an
Aleutian eruption. Recent eruptions from Mt. Cleveland have been
characterized by short-lived explosive ash emissions, at times accompanied
by lava fountaining and lava flows down the flanks.

Source: Alaska Volcano Observatory (AVO)

DUKONO Halmahera 1.68°N, 127.88°E; summit elev. 1335 m

Based on analyses of satellite imagery, the Darwin VAAC reported that during
21-25 September ash plumes from Dukono rose to an altitude of 2.4 km (8,000
ft) a.s.l. and drifted 35-95 km W.

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 from 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 (VAAC)

KARYMSKY Eastern Kamchatka (Russia) 54.05°N, 159.45°E; summit elev. 1536 m

KVERT reported that seismic activity from Karymsky was above background
levels during 16-20 September and suggested possible ash explosions.
Seismicity was at background levels on 21 and 22 September. Cloud cover
prevented satellite image views. The Aviation Color Code level remained at

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 (KVERT)

KILAUEA Hawaii (USA) 19.421°N, 155.287°W; summit elev. 1222 m

During 22-28 September HVO reported that activity at Kilauea continued from
the summit caldera and the east rift zone. At the summit caldera, the level
of the lava-pool surface in the deep pit within Halema'uma'u crater remained
mostly stable around 160 m below the crater floor; periodically the lava
rose 15-35 m above that level. Glow from the vent was also visible at night.
A plume from the vent drifted SW and deposited ash nearby. At the east rift
zone, lava that flowed through the TEB lava-tube system mainly fed the
Puhi-o-Kalaikini ocean entry. Weak thermal anomalies detected in satellite
imagery suggested little to no lava flow activity on the pali or the coastal
plain. On 26 September lava broke out of the lava-tube system W of the end
of Highway 130 and produced a flow E toward Kalapana Gardens. The next day
lava, flowing at a slower rate, filled in low areas S of the Hawaii County
lava viewing area.

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 of lava flows less than about 1,100
years old; 70% of the volcano's surface is younger than 600 years. A
long-term eruption from the East rift zone that began in 1983 has produced
lava flows covering more than 100 sq km, destroying nearly 200 houses and
adding new coastline to the island.

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)

REVENTADOR Ecuador 0.077°S, 77.656°W; summit elev. 3562 m

The IG reported that on 28 September three seismic events from Reventador
were recorded. Cloud cover prevented observations during the first event.
During the second period of increased seismicity, observers noted that a
steam plume with a small amount of ash rose 400-500 m above the crater and
drifted N. The third episode was accompanied by a steam-and-ash plume that
rose 2 km above the crater and drifted NW. Ash fell on Reventador.

Geologic Summary. Reventador is the most frequently active of a chain of
Ecuadorian volcanoes in the Cordillera Real, well E of the principal
volcanic axis. It is a forested stratovolcano that rises above the remote
jungles of the western Amazon basin. A 3-km-wide caldera breached to the E
was formed by edifice collapse and is partially filled by a young,
unvegetated stratovolcano that rises about 1,300 m above the caldera floor.
Reventador has been the source of numerous lava flows as well as explosive
eruptions that were visible from Quito in historical time. Frequent lahars
in this region of heavy rainfall have constructed a debris plain on the
eastern floor of the caldera.

Source: Instituto Geofísico-Escuela Politécnica Nacional (IG)

SAKURA-JIMA Kyushu 31.585°N, 130.657°E; summit elev. 1117 m

Based on a pilot observation, the Tokyo VAAC reported that on 22 September
an ash plume rose to an altitude of 1.8 km (6,000 ft) a.s.l. and drifted SE.

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)

SHIVELUCH Central Kamchatka (Russia) 56.653°N, 161.360°E; summit elev. 3283

KVERT reported that during 17-24 September seismic activity from Shiveluch
was above background levels and suggested that possible ash plumes rose to
an altitude of 3.5 km (11,500 ft) a.s.l. Satellite imagery analysis showed a
thermal anomaly on the volcano. Gas-and-ash plumes were observed on 21
September, and satellite imagery showed ash plumes drifting 16 km SE the
same day. The Aviation Color Code level remained at Orange.

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 breached 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.
Intermittent explosive eruptions began in the 1990s 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 (KVERT)

SOUFRIERE HILLS Montserrat 16.72°N, 62.18°W; summit elev. 915 m

MVO reported that during 17-24 September activity from the Soufrière Hills
lava dome was at a low level. Heavy rains caused lahars during 19-20
September in the Belham valley to the NW. One pyroclastic flow traveled 1.5
km E down the Tar River valley on 21 September. The Hazard Level remained at

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 E, was
formed during an eruption about 4,000 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 (MVO)

SUWANOSE-JIMA Ryukyu Islands (Japan) 29.635°N, 129.716°E; summit elev. 799 m

Based on information from JMA, the Tokyo VAAC reported explosions from
Suwanose-jima during 22, 25, and 27-28 September. A pilot observed an ash
plume on 22 September that rose to an altitude of 2.1 km (7,000 ft) a.s.l.
and drifted SE. JMA noted that plumes on 25 September rose to an altitude of
1.5 km (5,000 ft) a.s.l. and drifted E.

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 east 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 about 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)


[ Volcano ]

Yahoo! Groups Links

<*> To visit your group on the web, go to:

<*> Your email settings:
Individual Email | Traditional

<*> To change settings online go to:
(Yahoo! ID required)

<*> To change settings via email:

<*> To unsubscribe from this group, send an email to:

<*> Your use of Yahoo! Groups is subject to:

No comments:

Post a Comment