VOLCANO: Smithsonian/USGS Weekly Volcanic Activity Report 4-10 May 2011

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Smithsonian/USGS Weekly Volcanic Activity Report 4-10 May 2011
From: Sally Kuhn Sennert <kuhns@xxxxxx>

Sally Kuhn Sennert - Weekly Report Editor
URL: http://www.volcano.si.edu/reports/usgs/

New Activity/Unrest: | Etna, Sicily (Italy) | Kizimen, Eastern
Kamchatka (Russia) | Planchón-Peteroa, Central Chile-Argentina border
| Tungurahua, Ecuador | Ulawun, New Britain

Ongoing Activity: | Batu Tara, Komba Island (Indonesia) | Dukono,
Halmahera | Karymsky, Eastern Kamchatka (Russia) | Kilauea, Hawaii
(USA) | Poás, Costa Rica | Sakura-jima, Kyushu | Santa María,
Guatemala | Shiveluch, Central Kamchatka (Russia) | Tengger Caldera,
Eastern Java (Indonesia)

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

ETNA Sicily (Italy) 37.734°N, 15.004°E; summit elev. 3330 m

Sezione di Catania - Osservatorio Etneo reported that on 8 May mild
and discontinuous Strombolian activity resumed at the pit crater
located on the E flank of Etna's SE Crater cone. Loud detonations were
audible many kilometers away including in Monti Sartorius (NE flank)
and in Zafferana Etnea (SW flank). After sunset, Strombolian
explosions observed at intervals of 3-10 minutes ejected incandescent
bombs up to a few tens of meters above the crater rim. During the
night, some explosions ejected bombs well beyond the crater rim, down
to the base of the cone that has grown around the crater during the
recent events. Strombolian explosions continued without significant
variations the next day.

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: Sezione di Catania - Osservatorio Etneo http://www.ct.ingv.it/

KIZIMEN Eastern Kamchatka (Russia) 55.130°N, 160.32°E; summit elev. 2376 m

Following strong explosions at Kizimen on 3 May, KVERT reported that
ash fell in Kipelye Springs, 15 km W, and accumulated to a thickness
of about 1 cm. A large and hot pyroclastic flow deposit on the NE
flank was detected in satellite imagery the next day. Analysis of the
satellite images also revealed ash plumes that drifted 280 km S during
3-5 May and 62 km in various directions on 6 May. A daily thermal
anomaly was also noted. The Aviation Color Code remained at Orange.

Geologic Summary. Kizimen is an isolated, conical stratovolcano that
is morphologically similar to Mount St. Helens prior to its 1980
eruption. The summit of Kizimen consists of overlapping lava domes,
and blocky lava flows descend the flanks of the volcano, which is the
westernmost of a volcanic chain north of Kronotsky volcano. The
2,376-m-high Kizimen was formed during four eruptive cycles beginning
about 12,000 years ago and lasting 2,000-3,500 years. The largest
eruptions took place about 10,000 and 8300-8400 years ago, and three
periods of longterm lava-dome growth have occurred. The latest
eruptive cycle began about 3,000 years ago with a large explosion and
was followed by lava-dome growth lasting intermittently about 1,000
years. An explosive eruption about 1,100 years ago produced a lateral
blast and created a 1.0 x 0.7 km wide crater breached to the NE,
inside which a small lava dome (the fourth at Kizimen) has grown. A
single explosive eruption, during 1927-28, has been recorded in
historical time.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

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

SERNAGEOMIN reported that, based on video camera data, photographs,
and observations during an overflight on 4 May, activity at
Planchón-Peteroa was relatively stable during 30 April-8 May.
Explosions lasting about 30 seconds produced ash plumes that rose at
most 1 km above the crater and drifted tens of kilometers E, NE, NNE,
NNW and NW. During 4-5 May material fell in Minera Río Teno (about 70
km NW) and Las Leñas, Argentina (45 km ENE).  The Alert Level remained
at Level 3, Yellow. Based on ODVAS web camera observations, the Buenos
Aires VAAC reported that on 9 May gas-and-ash plumes rose to an
altitude of 4.3 km (14,000 ft) a.s.l. and rapidly dissipated to the

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

Sources: Servicio Nacional de Geología y Minería (SERNAGEOMIN)
Buenos Aires Volcanic Ash Advisory Center (VAAC)

TUNGURAHUA Ecuador 1.467°S, 78.442°W; summit elev. 5023 m

IG reported that, although visual observations of Tungurahua were
occasionally limited due to cloud cover, ash plumes were noted during
4-6 May that rose to altitudes of 6-7 km (19,700-23,000 ft) a.s.l. and
drifted W.  Ashfall was reported in Alao, S of Riobamba (30 km S) on 4
May and in Manzano (8 km SW) on 5 and 7 May. Cloud cover prevented
observations during 7-9 May. Roaring was also reported during 4-9 May.
An explosion on 10 May produced an ash plume that rose to an altitude
of 10 km (32,800 ft) a.s.l. and drifted W and NW. Slight ashfall was
reported in areas as far as 23 km NW.

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 all originated from 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 Politécnica Nacional (IG)

ULAWUN New Britain 5.05°S, 151.33°E; summit elev. 2334 m

RVO reported that during 1-9 May diffuse white plumes rose from Ulawun
and Real-time Seismic-Amplitude Measurement (RSAM) values ranged
between 70 and 100. During 9-10 May RSAM values distinctly increased,
fluctuated, and peaked at 1300 units before declining back to 100
units. During this time local residents heard booming. On 10 May
grey-to-brown ash plumes were observed.

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: Rabaul Volcano Observatory (RVO)

Ongoing Activity

BATU TARA Komba Island (Indonesia) 7.792°S, 123.579°E; summit elev. 748 m

Based on analyses of satellite imagery, the Darwin VAAC reported that
during 4-7 May ash plumes from Batu Tara rose to altitudes of 0.9-2.1
km (3,000-7,000 ft) a.s.l. and drifted 18-75 km NW, W, and SW.

Geologic Summary. The small isolated island of Batu Tara in the Flores
Sea about 50 km north of Lembata (formerly Lomblen) Island contains a
scarp on the eastern side similar to the Sciara del Fuoco of Italy's
Stromboli volcano. Vegetation covers the flanks of Batu Tara to within
50 m of the 748-m-high summit. Batu Tara lies north of the main
volcanic arc and is noted for its potassic leucite-bearing basanitic
and tephritic rocks. The first historical eruption from Batu Tara,
during 1847-52, produced explosions and a lava flow.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)

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

Based on analyses of satellite imagery, the Darwin VAAC reported that
on 10 May ash plumes from Dukono rose to an altitude of 4.3 km (14,000
ft) a.s.l. and drifted 90-110 km NE and E.

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 moderate seismic activity at Karymsky during 29 April-6
May. Seismic data indicated that possible ash plumes rose to an
altitude of 4.9 km (16,000 ft) a.s.l. A thermal anomaly was detected
in satellite imagery during 1-4 May. The Aviation Color Code remained
at Orange. Based on analyses of satellite imagery and information from
KVERT, the Tokyo VAAC reported that on 7 May ash plumes rose to an
altitude of 3 km (10,000 ft) a.s.l. and drifted SE.

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)
Tokyo Volcanic Ash Advisory Center (VAAC)

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

HVO reported that two lava lakes at Kilauea were active during 4-10
May. The level of the summit lava lake fluctuated but remained mostly
stable deep in the vent inset within the E wall of Halema'uma'u
Crater. On 5 May the lava lake level dropped 10-20 m and lava from a
vent well above the south side cascaded down into the lake. A gas
plume from the vent drifted SW and deposited very small amounts of ash
nearby. At Pu'u 'O'o crater, lava from vents near the W edge of the
lake and near the base of the E crater wall continued to fill in a
perched lava lake in the center of the crater floor. The lake level
fluctuated and occasionally overflowed the edges and filled the entire
bottom of Pu'u 'O'o crater floor. The crater had infilled about 70 m
since the crater floor collapsed in March.

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)

POAS Costa Rica 10.20°N, 84.233°W; summit elev. 2708 m

OVSICORI-UNA reported that during April sporadic phreatic eruptions
occurred from the central part of Laguna Caliente, a summit lake of
Poás. Gas plumes rose a few meters to several tens of meters above the
lake surface. Solid dark material ejected from the lake fell back into
it, causing small surges. The temperature of the lava dome was 560
degrees Celsius at accessible areas. Bluish fumarolic plumes rose from
the dome; a gas plume rose 1 km and drifted NE, E, and SE.

Geologic Summary. The broad, well-vegetated edifice of Poás, one of
the most active volcanoes of Costa Rica, contains three craters along
a N-S line. The frequently visited multi-hued summit crater lakes of
the basaltic-to-dacitic volcano, which is one of Costa Rica's most
prominent natural landmarks, are easily accessible by vehicle from the
nearby capital city of San José. A N-S-trending fissure cutting the
2,708-m-high complex stratovolcano extends to the lower northern
flank, where it has produced the Congo stratovolcano and several
lake-filled maars. The southernmost of the two summit crater lakes,
Botos, is cold and clear and last erupted about 7,500 years ago. The
more prominent geothermally heated northern lake, Laguna Caliente, is
one of the world's most acidic natural lakes, with a pH of near zero.
It has been the site of frequent phreatic and phreatomagmatic
eruptions since the first historical eruption was reported in 1828.
Poás eruptions often include geyser-like ejection of crater-lake

Source: Observatorio Vulcanologico y Sismologico de Costa
Rica-Universidad Nacional (OVSICORI-UNA)

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

Based on information from JMA, the Tokyo VAAC reported that during
6-10 May explosions from Sakura-jima produced plumes that rose to
altitudes of 1.2-2.4 km (4,000-8,000 ft) a.s.l. Plumes sometimes
drifted NW, NE, E, SE, and S. On 4 and 9 May, pilots observed ash
plumes that rose to altitudes of 2.1-2.7 km (7,000-9,000 ft) a.s.l.

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)

SANTA MARIA Guatemala 14.756°N, 91.552°W; summit elev. 3772 m

Based on analyses of satellite imagery, the Washington VAAC reported
that during 5-6 May ash plumes from Santa María's Santiaguito lava
dome complex rose to an altitude of 4 km (13,000 ft) a.s.l. and
dissipated within about 75 km SW.  On 6 May ash plumes also rose to an
altitude of 6.7 km (22,000 ft) a.s.l. and dissipated within 10 km NW.
Plumes also drifted S and SE. During 5-6 May INSIVUMEH reported that
an explosion produced an ash plume that rose 800 m above Caliente cone
and drifted W. Ash fell at beach areas and weak avalanches occurred
with a lava flow on the E flank. Two areas of incandescence were
observed on the S flank of the lava dome. During 8-9 May steam plumes
rose 100 m above the Caliente cone crater and a few avalanches
descended the SE flank. Explosions during 9-10 May produced ash plumes
that rose 1.2 km above the crater and pyroclastic flows from the SW
edge of the crater that were deposited in the Río Nima I and Río Nima
II drainages. Ash plumes drifted W and block avalanches descended the
E, S, and W flanks.

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/,
Washington Volcanic Ash Advisory Center (VAAC)

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

KVERT reported that during 29 April-6 May a thermal anomaly on
Shiveluch was detected in satellite imagery. According to ground-based
observations during 28-29 April ash plumes rose to an altitude of 4.5
km (14,800 ft) a.s.l. On 1 May ash plumes observed in satellite
imagery drifted 124 km NE. Seismic data indicated that possible ash
plumes rose to an altitude of 6 km (19,700 ft) a.s.l. on 29 April and
2 May. KVERT noted that the Aviation Color Code remained at Orange.
Based on analyses of satellite imagery, the Tokyo VAAC reported that
on 7 May a possible eruption produced a plume that rose to an altitude
of 5.2 km (17,000 ft) a.s.l. and drifted E. Subsequent notices that
day stated that ash had dissipated.

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.

Sources: Kamchatkan Volcanic Eruption Response Team (KVERT)
Tokyo Volcanic Ash Advisory Center (VAAC)

TENGGER CALDERA Eastern Java (Indonesia) 7.942°S, 112.95°E; summit elev. 2329 m

Based on analyses of satellite imagery, the Darwin VAAC reported that
during 9-10 May ash plumes from Tengger Caldera's Bromo cone rose to
an altitude of 2.7 km (9,000 ft) a.s.l. and drifted 45-75 km NE and E.

Geologic Summary. The 16-km-wide Tengger caldera in eastern Java is
located at the northern end of a volcanic massif extending from Semeru
volcano. The massive Tengger volcanic complex consists of five
overlapping stratovolcanoes, each truncated by a caldera. The most
recent is the 9 x 10 km wide Sandsea caldera, which formed
incrementally during the late Pleistocene and early Holocene. An
overlapping cluster of post-caldera cones was constructed on the floor
of the Sandsea caldera within the past several thousand years. The
youngest of these is Bromo, one of Java's most frequently visited and
most active volcanoes. More than 50 mild-to-moderate explosive
eruptions have occurred since 1804.

Source: Darwin Volcanic Ash Advisory Center (VAAC)


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