author: [redacted]

subject: Re: New Volcanos Erupting This Week: 2 / Total Active: 15

text:
SI / USGS Weekly Volcanic Activity Report

                                20 January-26 January 2010

New Activity/Unrest:

| Soufrière Hills, Montserrat
| Tungurahua, Ecuador

Ongoing Activity:

| Barren Island, Andaman Is
| Batu Tara, Komba Island (Indonesia)
| Chaitén, Southern Chile
| Fuego, Guatemala
| Gaua, Banks Islands (SW Pacific)
| Karymsky, Eastern Kamchatka
| Kilauea, Hawaii (USA)
| Kliuchevskoi, Central Kamchatka (Russia)
| Llaima, Central Chile
| Sakura-jima, Kyushu
| Santa María, Guatemala
| Shiveluch, Central Kamchatka (Russia)
| Suwanose-jima, Ryukyu Islands (Japan)

This page is updated on Wednesdays, please
see the GVP Home Page for news of the
latest significant activity.

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
volcanos 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

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

MVO reported that during 15-22 January activity from the Soufrière
Hills lava dome was variable as dome growth continued. Cycles of
vigorous ash venting, rockfalls, and pyroclastic flows occurred every
six to eight hours. Light ashfall occasionally occurred in NW
Montserrat. On 18 January, a small lava-dome collapse from the W side
of the volcano generated a large pyroclastic flow that traveled 4 km
down Gages Valley into Spring Ghaut, and into Aymer's Ghaut, reaching
the sea at Kinsale to the S of Plymouth. Ash clouds associated with
the pyroclastic flows rose to an altitude of 3 km (10,000 ft) a.s.l.
Several houses in Kinsale seen from a helicopter on 22 January had
been buried or were burning. The Hazard Level remained at 4.

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.

Map

Source: Montserrat Volcano Observatory (MVO)

Soufrière Hills Information from the Global Volcanism Program

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

The IG reported that during 20-26 January explosions from Tungurahua
were detected by the seismic network. Inclement weather often
prevented observations of the volcano; occasionally ash plumes were
seen rising to altitudes of 5.3-8 km (17,400-26,200 ft) a.s.l. Ashfall
was noted almost daily in areas to the SW and sometimes to the W and
NW. Roaring noises, sounds resembling "cannon shots," and vibrating
windows were reported. During 20-23 January lava fountains and
explosions ejected incandescent blocks that fell onto and rolled down
the flanks. Blocks were also seen rolling down the flanks on 24 and 25
January. On 26 January, an explosion generated an ash plume that rose
to an altitude of 9 km (30,000 ft) a.s.l. Ashfall was reported in
areas to the NW, W, and WSW.

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.

Map

Source: Instituto Geofísico-Escuela Politécnica Nacional (IG)

Tungurahua Information from the Global Volcanism Program

Ongoing Activity

BARREN ISLAND Andaman Is 12.278°N, 93.858°E; summit elev. 354 m

Based on a pilot observation, the Darwin VAAC reported that on 23
January an ash plume from Barren Island rose to an altitude of 3 km
(10,000 ft) a.s.l. Ash was not identified in satellite imagery.

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 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 historical
eruptions.

Map

Source: Darwin Volcanic Ash Advisory Centre (VAAC)

Barren Island Information from the Global Volcanism Program

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
on 23 January an ash plume from Batu Tara rose to an altitude of 1.5
km (5,000 ft) a.s.l. and drifted 25 km E.

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.

Map

Source: Darwin Volcanic Ash Advisory Centre (VAAC)

Batu Tara Information from the Global Volcanism Program

CHAITEN Southern Chile 42.833°S, 72.646°W; summit elev. 1122 m

SERNAGEOMIN reported that during 5-19 January Chaitén's lava-dome
complex continued to grow, although possibly at rates lower than
during previous weeks. The magnitude and number of hybrid earthquakes
decreased. The Alert Level remained at Red.

Geologic Summary. Chaitén is a small, glacier-free caldera with a
Holocene lava dome located 10 km NE of the town of Chaitén on the Gulf
of Corcovado. A pyroclastic-surge and pumice deposit considered to
originate from the eruption that formed the elliptical 2.5 x 4 km wide
summit caldera was dated at about 9400 years ago. A rhyolitic, 962-m-
high obsidian lava dome occupies much of the caldera floor. Obsidian
cobbles from this dome found in the Blanco River are the source of
prehistorical artifacts from archaeological sites along the Pacific
coast as far as 400 km away from the volcano to the north and south.
The caldera is breached on the SW side by a river that drains to the
bay of Chaitén, and the high point on its southern rim reaches 1122 m.

Map

Source: Servicio Nacional de Geología y Minería (SERNAGEOMIN)

Chaitén Information from the Global Volcanism Program

FUEGO Guatemala 14.473°N, 90.880°W; summit elev. 3763 m

On 22 January, INSIVUMEH reported that explosions from Fuego produced
gray plumes that rose to altitudes of 4.4-4.8 km (14,400-15,700 ft)
a.s.l. and drifted 5-12 km SW. Incandescent material was ejected to
heights of 75 m and avalanches descended the flanks. Based on analyses
of satellite imagery, the Washington VAAC reported that on 25 January
a dense ash cloud drifted 15 km NW. The next day an ash cloud drifted
11 km W.

Geologic Summary. Volcán Fuego, one of Central America's most active
volcanoes, is one of three large stratovolcanoes overlooking
Guatemala's former capital, Antigua. The scarp of an older edifice,
Meseta, lies between 3,763-m-high Fuego and its twin volcano to the N,
Acatenango. Construction of Meseta volcano continued until the late
Pleistocene or early Holocene, after which growth of the modern Fuego
volcano continued the southward migration of volcanism that began at
Acatenango. Frequent vigorous historical eruptions have been recorded
at Fuego since the onset of the Spanish era in 1524, and have produced
major ashfalls, along with occasional pyroclastic flows and lava
flows. The last major explosive eruption from Fuego took place in
1974, producing spectacular pyroclastic flows visible from Antigua.

Map

Sources: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia,
e Hidrologia (INSIVUMEH), Washington Volcanic Ash Advisory Center
(VAAC)

Fuego Information from the Global Volcanism Program

GAUA Banks Islands (SW Pacific) 14.27°S, 167.50°E; summit elev. 797 m

Based on analyses of satellite imagery and pilot observations, the
Wellington VAAC reported that on 21 January an ash plume from Gaua
rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted S. An ash
cloud was seen in satellite imagery on 26 January.

Geologic Summary. The roughly 20-km-diameter Gaua Island, also known
as Santa Maria, consists of a basaltic-to-andesitic stratovolcano with
an 6 x 9 km wide summit caldera. Small parasitic vents near the
caldera rim fed Pleistocene lava flows that reached the coast on
several sides of the island; several littoral cones were formed where
these lava flows reached the sea. Quiet collapse that formed the
roughly 700-m-deep caldera was followed by extensive ash eruptions.
Construction of the historically active cone of Mount Garat (Gharat)
and other small cinder cones in the SW part of the caldera has left a
crescent-shaped caldera lake. The symmetrical, flat-topped Mount Garat
cone is topped by three pit craters. The onset of eruptive activity
from a vent high on the SE flank of Mount Garat in 1962 ended a long
period of dormancy.

Map

Source: Wellington Volcanic Ash Advisory Center (VAAC)

Gaua Information from the Global Volcanism Program

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

KVERT reported that during 15-22 January seismic activity from
Karymsky was above background levels, possibly indicating that ash
plumes rose to an altitude of 3 km (10,000 ft) a.s.l. Analyses of
satellite imagery revealed a daily thermal anomaly over the volcano.
The Level of Concern Color Code remained at Orange.

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.

Map

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

Karymsky Information from the Global Volcanism Program

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

During 20-26 January, HVO reported an active lava surface about 200 m
below a vent in the floor of Kilauea's Halema'uma'u crater. The lava
surface occasionally spattered, and both rose and drained through a
hole in the cavity floor. A plume from the vent drifted multiple
directions, dropping small amounts of ash, and occasionally fresh
spatter, downwind. Lava from beneath the Thanksgiving Eve Breakout
(TEB) and rootless shield complex flowed SE through a lava tube
system. Thermal anomalies detected by satellite and visual
observations revealed active lava flows on top of the pali from lava-
tube breakouts.

During an overflight of Pu'u 'O'o crater on 19 January scientists saw
a recent but inactive lava flow across the bottom of the crater. On 22
January a small part of the crater rim collapsed in front of the web
camera, revealing an incandescent vent at the base of the E wall.
During 23-26 January, incandescence was seen from the vent, as well as
from high on the E wall, the crater floor, and low on the S wall.

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.

Map

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)

Kilauea Information from the Global Volcanism Program

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

KVERT reported that during 15-22 January seismic activity from
Kliuchevskoi was above background levels and lava continued to flow
down the NW flank. Strombolian activity periodically ejected material
300 m above the crater. Phreatic explosions from the front of the lava
flow ejected material that rose to altitudes of 4.5-8 km
(14,800-26,200 ft) a.s.l. Satellite imagery also revealed a large
daily thermal anomaly at the volcano. The Level of Concern Color Code
remained at Orange. Based on information from the Yelizovo Airport
(UHPP) and analyses of satellite imagery, the Tokyo VAAC reported that
during 22-23 January ash plumes rose to altitudes of 7-10.1 km
(23,000-33,000 ft) a.s.l. and drifted NE.

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.

Map

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

Kliuchevskoi Information from the Global Volcanism Program

LLAIMA Central Chile 38.692°S, 71.729°W; summit elev. 3125 m

On 22 January, SERNAGEOMIN reported that seismicity from Llaima had
decreased during the previous few weeks to background levels. The
Alert Level was lowered to Green, (Level 2) on a three-color scale.

Geologic Summary. Llaima, one of Chile's largest and most active
volcanoes, contains two main historically active craters, one at the
summit and the other to the SE. The massive 3,125-m-high, glacier-
covered stratovolcano has a volume of 400 cu km. A Holocene edifice
built primarily of accumulated lava flows was constructed over an 8-km-
wide caldera that formed about 13,200 years ago, following eruption of
the 24 cu km Curacautín Ignimbrite. More than 40 scoria cones dot the
volcano's flanks. Following the end of an explosive stage about 7,200
years ago, construction of the present edifice began, characterized by
Strombolian, Hawaiian, and infrequent subplinian eruptions. Frequent
moderate explosive eruptions with occasional lava flows have been
recorded since the 17th century.

Map

Source: Servicio Nacional de Geología y Minería (SERNAGEOMIN)

Llaima Information from the Global Volcanism Program

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

During 26 December 2009-9 January 2010, a visitor to Sakura-jima
observed and photographed Strombolian and Vulcanian explosions from
Showa crater. Based on information from JMA, the Tokyo VAAC reported
that during 20-26 January multiple explosions often produced plumes
that rose to altitudes of 1.2-2.4 km (4,000-8,000 ft) a.s.l. and
drifted NE, E, SE, and S. On 23 January, a pilot reported that an ash
plume drifted SE at an altitude of 1.8 km (6,000 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.

Map

Sources: Tokyo Volcanic Ash Advisory Center (VAAC), Richard Roscoe,
Photo Volcanica

Sakura-jima Information from the Global Volcanism Program

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

INSIVUMEH reported that on 21 January ashfall was reported in areas
near Santa María's Santiaguito lava dome complex. The next day an
explosion produced an ash plume that rose to an altitude of 3.2 km
(10,500 ft) a.s.l. and drifted SW. The Washington VAAC reported that
an ash plume seen on satellite imagery drifted less than 10 km.

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.

Map

Sources: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia,
e Hidrologia (INSIVUMEH), Washington Volcanic Ash Advisory Center
(VAAC)

Santa María Information from the Global Volcanism Program

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

KVERT reported that during 15-22 January seismic activity from
Shiveluch was above background levels, possibly indicating ash plumes
rising to an altitude of 4.7 km (15,400 ft) a.s.l. Analyses of
satellite imagery revealed a large daily thermal anomaly from the lava
dome. The Level of Concern Color Code remained at Orange. Based on
information from KEMSD, the Tokyo VAAC reported that during 23-24 and
26 January eruptions produced plumes that rose to altitudes of 3-4.6
km (10,000-15,000 ft) a.s.l.

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.

Map

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

Shiveluch Information from the Global Volcanism Program

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

During 29-30 December 2009, a visitor to Suwanose-jima observed and
photographed multiple Strombolian explosions and ash eruptions from On-
take (Otake) crater. Based on information from JMA, the Tokyo VAAC
reported explosions during 22-26 January. On 24 and 26 January, plumes
rose to altitudes of 1.2-1.5 km (4,000-5,000 ft) a.s.l.

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.

Map

Sources: Tokyo Volcanic Ash Advisory Center (VAAC), Richard Roscoe,
Photo Volcanica

Suwanose-jima Information from the Global Volcanism Program

Additional Reports of Volcanic Activity by Country

The following websites have frequently updated activity reports on
volcanoes in addition to those that meet the criteria for inclusion in
the Weekly Volcanic Activity Report. The websites are organized by
country and are maintained by various agencies.

Ecuador, Indonesia, Japan, New Zealand, United States and Russia

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

Global Volcanism Program — Department of Mineral Sciences
National Museum of Natural History — Smithsonian Institution


subject: Re: New Volcanos Erupting This Week: 4Total Active: 12

text:
SI / USGS Weekly VolcanicActivityReport

                                            1 March- 6 April 2010

                               4 new + 8 Ongoing = 12 Actives

     Weekly Report Editor Sally Kuhn Sennert -

                               http://www.volcano.si.edu/reports/usgs/

         NewActivity/Unrest:

| Eyjafjöll, Southern Iceland
| Karymsky, Eastern Kamchatka
| Kirishima, Kyushu
| Redoubt, Southwestern Alaska

         Ongoing Activity:

| Batu Tara, Komba Island (Indonesia)
| Dukono, Halmahera
| Kilauea, Hawaii (USA)
| Kliuchevskoi, Central Kamchatka (Russia)
| Sakura-jima, Kyushu
| Shiveluch, Central Kamchatka (Russia)
| Soufrière Hills, Montserrat
| Suwanose-jima, Ryukyu Islands (Japan)

            This page is updated on Wednesdays, please
            see the GVP Home Page for news of the
            latest significantactivity.

            The Weekly VolcanicActivityReport is a
            cooperative project between the Smithsonian's
            Global Volcanism Program and the US
            Geological Survey'sVolcanoHazards Program.

           Updated by 2300 UTC every Wednesday,
            notices of volcanicactivityposted 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
            volcanoseruptingduring theweek, but rather a
            summary ofactivity 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.

                              NewActivity/Unrest

EYJAFJOLL Southern Iceland 63.63°N, 19.62°W; summit elev. 1666 m

The Icelandic Met Office reported that around 1900 on 31 March a new
fissure at Eyjafjöll opened NE of the first fissure that began
erupting on 20 March. Activity from the second fissure was not
preceded by detectable seismicity. According to a news article, the
fissure was about 300 m long, and about 200 m away from the first
fissure. At the time of reporting by the Icelandic Met Office on 5
April, lava fountains had remained active from both fissures. Lava
mostly accumulated near the new vent but some lava flows had entered
the Hruná and Hvanná gullies. News outlets reported that two people
had died during the journey back from seeing the eruption. The police
estimated that 25,000 people had visited the site since the eruption
began.

Geologic Summary. Eyjafjöll (also known as Eyjafjallajökull) is
located immediately west of Katla volcano. Eyjafjöll consists of an E-
W-trending, elongated ice-covered basaltic-andesite stratovolcano with
a 2.5-km-wide summit caldera. Fissure-fed lava flows occur on both the
eastern and western flanks of the volcano, but are more prominent on
the western side. Although the 1666-m-high volcano has erupted during
historical time, it has been less active than other volcanoes of
Iceland's eastern volcanic zone, and relatively few Holocene lava
flows are known. The sole historical eruption of Eyjafjöll, prior to
an eruption in 2010, produced intermediate-to-silicic tephra from the
central caldera during December 1821 to January 1823.

Map

Sources: Icelandic Met Office, Morgunbladid News, Iceland Review,
Iceland Review

Eyjafjöll Information from the Global Volcanism Program

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

KVERT reported that during 26 March-2 April seismic activity from
Karymsky was above background levels, possibly indicating ash plumes
rising to an altitude of 4.1 km (13,500 ft) a.s.l. Satellite imagery
revealed an intense daily thermal anomaly from the volcano, and ash
plumes that drifted about 250 km generally E during 28-29 and 31
March. The Aviation Color Code level was raised to Orange.

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.

Map

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

Karymsky Information from the Global Volcanism Program

KIRISHIMA Kyushu 31.931°N, 130.864°E; summit elev. 1700 m

An eruption from Shinmoe-dake (Shinmoe peak), a stratovolcano of the
Kirishima volcano group, on 30 March prompted JMA to raise the Alert
Level from 1 to 2 (on a scale of 1-5). Ash blanketed the ground to the
W of the crater.

Geologic Summary. Kirishima is a large group of more than 20
Quaternary volcanoes located north of Kagoshima Bay. The late-
Pleistocene to Holocene volcano group consists of stratovolcanoes,
pyroclastic cones, maars, and underlying shield volcanoes located over
an area of 20 x 30 km. The larger stratovolcanoes are scattered
throughout the field, with the centrally located, 1,700-m-high
Karakuni-dake being the highest. Onami-ike and Mi-ike, the two largest
maars, are located SW of Karakuni-dake and at its far eastern end,
respectively. Holocene eruptions have been concentrated along an E-W
line of vents from Mi-ike to Ohachi, and at Shinmoe-dake to the NE.
Frequent small-to-moderate explosive eruptions have been recorded
since the 8th century.

Map

Source: Japan Meteorological Agency (JMA)

Kirishima Information from the Global Volcanism Program

REDOUBT Southwestern Alaska 60.485°N, 152.742°W; summit elev. 3108 m

AVO reported that a series of small repetitive earthquakes in the
vicinity of Redoubt's summit were detected on 5 April. The Volcano
Alert Level was raised to Advisory and the Aviation Color Code was
raised to Yellow.

Geologic Summary. Redoubt is a 3108-m-high glacier-covered
stratovolcano with a breached summit crater in Lake Clark National
Park about 170 km SW of Anchorage. Next to Mount Spurr, Redoubt has
been the most active Holocene volcano in the upper Cook Inlet.
Collapse of the summit of Redoubt 10,500-13,000 years ago produced a
major debris avalanche that reached Cook Inlet. Holocene activity has
included the emplacement of a large debris avalanche and clay-rich
lahars that dammed Lake Crescent on the south side and reached Cook
Inlet about 3500 years ago. Eruptions during the past few centuries
have affected only the Drift River drainage on the north. Historical
eruptions have originated from a vent at the north end of the 1.8-km-
wide breached summit crater. The 1989-90 eruption of Redoubt had
severe economic impact on the Cook Inlet region and affected air
traffic far beyond the volcano.

Map

Source: Alaska Volcano Observatory (AVO)

Redoubt Information from the Global Volcanism Program

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
on 5 April an ash plume from Batu Tara rose to an altitude of 2.1 km
(7,000 ft) a.s.l. and drifted more than 35 km N.

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.

Map

Source: Darwin Volcanic Ash Advisory Centre (VAAC)

Batu Tara Information from the Global Volcanism Program

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

The Darwin VAAC reported that on 2 April an ash plume from Dukono was
seen on satellite imagery drifting 55 km S at an altitude of 2.4 km
(8,000 ft) a.s.l.

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.

Map

Source: Darwin Volcanic Ash Advisory Centre (VAAC)

Dukono Information from the Global Volcanism Program

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

During 31 March-6 April, HVO reported incandescence from a 60-m-wide
active lava surface about 200 m below a vent in the floor of Kilauea's
Halema'uma'u crater. The lava surface circulated and both rose and
drained through a pit in the cavity floor; a few times the level
fluctuated between 235 and 260 m below the surface. Plumes from the
vent drifted mainly SW, dropping small amounts of ash downwind. The
sulfur dioxide emission rate at the summit on 31 March was 1,400
tonnes per day, the highest recorded in 2010. The rate on 1 and 2
April was 1,000 and 650 tonnes per day, respectively.

Lava from beneath the Thanksgiving Eve Breakout (TEB) and rootless
shield complex flowed SE through the upper portion of a lava tube
system and broke out onto the surface. Lava flows advanced E, and then
SE down Pulama pali.

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.

Map

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)

Kilauea Information from the Global Volcanism Program

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

KVERT reported that during 26 March-2 April seismic activity from
Kliuchevskoi was above background levels, and gas-and-steam plumes
containing small amounts of ash were sometimes seen rising to an
altitude of 5.3 km (17,400 ft) a.s.l. Strombolian activity ejected
material 300 m above the crater and lava continued to flow down the
flanks. Satellite imagery revealed a large daily thermal anomaly from
the volcano, and gas-and-steam plumes that drifted about 70 km E on 30
March. 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.

Map

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

Kliuchevskoi Information from the Global Volcanism Program

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

The Tokyo VAAC reported that during 31 March-6 April explosions from
Sakura-jima sometimes produced plumes identified on satellite imagery.
Those plumes, along with ash plumes occasionally seen by pilots, rose
to altitudes of 1.5-3 km (5,000-10,000 ft) a.s.l. and drifted SW, SE,
E, and NE.

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.

Map

Source: Tokyo Volcanic Ash Advisory Center (VAAC)

Sakura-jima Information from the Global Volcanism Program

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

KVERT reported that during 26 March-2 April seismic activity from
Shiveluch was above background levels, possibly indicating ash plumes
rising to an altitude of 4.7 km (15,400 ft) a.s.l. Hot avalanches from
the lava dome were seen at night. Satellite imagery revealed a large
daily thermal anomaly from the lava dome, and ash plumes that drifted
about 40 km SE on 29 March. Based on information from KVERT, the Tokyo
VAAC reported that on 5 April an ash plume rose to an altitude of 3 km
(10,000 ft) a.s.l. and drifted SE. 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.

Map

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

Shiveluch Information from the Global Volcanism Program

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

MVO reported that during 26 March-2 April activity from the Soufrière
Hills lava dome was at a low level. Rockfalls and pyroclastic flows
occurred sporadically on the W and S flanks. The Hazard Level remained
at 3.

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.

Map

Source: Montserrat Volcano Observatory (MVO)

Soufrière Hills Information from the Global Volcanism Program

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

Based on information from JMA, the Tokyo VAAC reported an explosion
from Suwanose-jima on 2 April. Details of possible resulting 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 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.

Map

Source: Tokyo Volcanic Ash Advisory Center (VAAC)

Suwanose-jima Information from the Global Volcanism Program

Additional Reports of Volcanic Activity by Country

The following websites have frequently updated activity reports on
volcanoes in addition to those that meet the criteria for inclusion in
the Weekly Volcanic Activity Report. The websites are organized by
country and are maintained by various agencies.

Ecuador, Indonesia, Japan, New Zealand, United States and Russia

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

Global Volcanism Program — Department of Mineral Sciences
National Museum of Natural History — Smithsonian Institution


author: Androcles

text:
<[email]> wrote in message
news:[email]...

                     SI / USGS Weekly Volcanic Activity Report

                                20 January-26 January 2010

New Activity/Unrest:

| Soufriï¿½re Hills, Montserrat
| Tungurahua, Ecuador

Ongoing Activity:

| Barren Island, Andaman Is
| Batu Tara, Komba Island (Indonesia)
| Chaitï¿½n, Southern Chile
| Fuego, Guatemala
| Gaua, Banks Islands (SW Pacific)
| Karymsky, Eastern Kamchatka
| Kilauea, Hawaii (USA)
| Kliuchevskoi, Central Kamchatka (Russia)
| Llaima, Central Chile
| Sakura-jima, Kyushu
| Santa Marï¿½a, Guatemala
| Shiveluch, Central Kamchatka (Russia)
| Suwanose-jima, Ryukyu Islands (Japan)

This page is updated on Wednesdays, please
see the GVP Home Page for news of the
latest significant activity.

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
volcanos 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

SOUFRIERE HILLS Montserrat 16.72ï¿½N, 62.18ï¿½W; summit elev. 915 m

MVO reported that during 15-22 January activity from the Soufriï¿½re
Hills lava dome was variable as dome growth continued. Cycles of
vigorous ash venting, rockfalls, and pyroclastic flows occurred every
six to eight hours. Light ashfall occasionally occurred in NW
Montserrat. On 18 January, a small lava-dome collapse from the W side
of the volcano generated a large pyroclastic flow that traveled 4 km
down Gages Valley into Spring Ghaut, and into Aymer's Ghaut, reaching
the sea at Kinsale to the S of Plymouth. Ash clouds associated with
the pyroclastic flows rose to an altitude of 3 km (10,000 ft) a.s.l.
Several houses in Kinsale seen from a helicopter on 22 January had
been buried or were burning. The Hazard Level remained at 4.

Geologic Summary. The complex dominantly andesitic Soufriï¿½re 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 Soufriï¿½re 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.

Map

Source: Montserrat Volcano Observatory (MVO)

Soufriï¿½re Hills Information from the Global Volcanism Program

TUNGURAHUA Ecuador 1.467ï¿½S, 78.442ï¿½W; summit elev. 5023 m

The IG reported that during 20-26 January explosions from Tungurahua
were detected by the seismic network. Inclement weather often
prevented observations of the volcano; occasionally ash plumes were
seen rising to altitudes of 5.3-8 km (17,400-26,200 ft) a.s.l. Ashfall
was noted almost daily in areas to the SW and sometimes to the W and
NW. Roaring noises, sounds resembling "cannon shots," and vibrating
windows were reported. During 20-23 January lava fountains and
explosions ejected incandescent blocks that fell onto and rolled down
the flanks. Blocks were also seen rolling down the flanks on 24 and 25
January. On 26 January, an explosion generated an ash plume that rose
to an altitude of 9 km (30,000 ft) a.s.l. Ashfall was reported in
areas to the NW, W, and WSW.

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
Baï¿½os on the N side of the volcano.

Map

Source: Instituto Geofï¿½sico-Escuela Politï¿½cnica Nacional (IG)

Tungurahua Information from the Global Volcanism Program

Ongoing Activity

BARREN ISLAND Andaman Is 12.278ï¿½N, 93.858ï¿½E; summit elev. 354 m

Based on a pilot observation, the Darwin VAAC reported that on 23
January an ash plume from Barren Island rose to an altitude of 3 km
(10,000 ft) a.s.l. Ash was not identified in satellite imagery.

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 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 historical
eruptions.

Map

Source: Darwin Volcanic Ash Advisory Centre (VAAC)

Barren Island Information from the Global Volcanism Program

BATU TARA Komba Island (Indonesia) 7.792ï¿½S, 123.579ï¿½E; summit elev.
748 m

Based on analyses of satellite imagery, the Darwin VAAC reported that
on 23 January an ash plume from Batu Tara rose to an altitude of 1.5
km (5,000 ft) a.s.l. and drifted 25 km E.

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.

Map

Source: Darwin Volcanic Ash Advisory Centre (VAAC)

Batu Tara Information from the Global Volcanism Program

CHAITEN Southern Chile 42.833ï¿½S, 72.646ï¿½W; summit elev. 1122 m

SERNAGEOMIN reported that during 5-19 January Chaitï¿½n's lava-dome
complex continued to grow, although possibly at rates lower than
during previous weeks. The magnitude and number of hybrid earthquakes
decreased. The Alert Level remained at Red.

Geologic Summary. Chaitï¿½n is a small, glacier-free caldera with a
Holocene lava dome located 10 km NE of the town of Chaitï¿½n on the Gulf
of Corcovado. A pyroclastic-surge and pumice deposit considered to
originate from the eruption that formed the elliptical 2.5 x 4 km wide
summit caldera was dated at about 9400 years ago. A rhyolitic, 962-m-
high obsidian lava dome occupies much of the caldera floor. Obsidian
cobbles from this dome found in the Blanco River are the source of
prehistorical artifacts from archaeological sites along the Pacific
coast as far as 400 km away from the volcano to the north and south.
The caldera is breached on the SW side by a river that drains to the
bay of Chaitï¿½n, and the high point on its southern rim reaches 1122 m.

Map

Source: Servicio Nacional de Geologï¿½a y Minerï¿½a (SERNAGEOMIN)

Chaitï¿½n Information from the Global Volcanism Program

FUEGO Guatemala 14.473ï¿½N, 90.880ï¿½W; summit elev. 3763 m

On 22 January, INSIVUMEH reported that explosions from Fuego produced
gray plumes that rose to altitudes of 4.4-4.8 km (14,400-15,700 ft)
a.s.l. and drifted 5-12 km SW. Incandescent material was ejected to
heights of 75 m and avalanches descended the flanks. Based on analyses
of satellite imagery, the Washington VAAC reported that on 25 January
a dense ash cloud drifted 15 km NW. The next day an ash cloud drifted
11 km W.

Geologic Summary. Volcï¿½n Fuego, one of Central America's most active
volcanoes, is one of three large stratovolcanoes overlooking
Guatemala's former capital, Antigua. The scarp of an older edifice,
Meseta, lies between 3,763-m-high Fuego and its twin volcano to the N,
Acatenango. Construction of Meseta volcano continued until the late
Pleistocene or early Holocene, after which growth of the modern Fuego
volcano continued the southward migration of volcanism that began at
Acatenango. Frequent vigorous historical eruptions have been recorded
at Fuego since the onset of the Spanish era in 1524, and have produced
major ashfalls, along with occasional pyroclastic flows and lava
flows. The last major explosive eruption from Fuego took place in
1974, producing spectacular pyroclastic flows visible from Antigua.

Map

Sources: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia,
e Hidrologia (INSIVUMEH), Washington Volcanic Ash Advisory Center
(VAAC)

Fuego Information from the Global Volcanism Program

GAUA Banks Islands (SW Pacific) 14.27ï¿½S, 167.50ï¿½E; summit elev. 797 m

Based on analyses of satellite imagery and pilot observations, the
Wellington VAAC reported that on 21 January an ash plume from Gaua
rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted S. An ash
cloud was seen in satellite imagery on 26 January.

Geologic Summary. The roughly 20-km-diameter Gaua Island, also known
as Santa Maria, consists of a basaltic-to-andesitic stratovolcano with
an 6 x 9 km wide summit caldera. Small parasitic vents near the
caldera rim fed Pleistocene lava flows that reached the coast on
several sides of the island; several littoral cones were formed where
these lava flows reached the sea. Quiet collapse that formed the
roughly 700-m-deep caldera was followed by extensive ash eruptions.
Construction of the historically active cone of Mount Garat (Gharat)
and other small cinder cones in the SW part of the caldera has left a
crescent-shaped caldera lake. The symmetrical, flat-topped Mount Garat
cone is topped by three pit craters. The onset of eruptive activity
from a vent high on the SE flank of Mount Garat in 1962 ended a long
period of dormancy.

Map

Source: Wellington Volcanic Ash Advisory Center (VAAC)

Gaua Information from the Global Volcanism Program

KARYMSKY Eastern Kamchatka 54.05ï¿½N, 159.45ï¿½E; summit elev. 1536 m

KVERT reported that during 15-22 January seismic activity from
Karymsky was above background levels, possibly indicating that ash
plumes rose to an altitude of 3 km (10,000 ft) a.s.l. Analyses of
satellite imagery revealed a daily thermal anomaly over the volcano.
The Level of Concern Color Code remained at Orange.

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.

Map

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

Karymsky Information from the Global Volcanism Program

KILAUEA Hawaii (USA) 19.421ï¿½N, 155.287ï¿½W; summit elev. 1222 m

During 20-26 January, HVO reported an active lava surface about 200 m
below a vent in the floor of Kilauea's Halema'uma'u crater. The lava
surface occasionally spattered, and both rose and drained through a
hole in the cavity floor. A plume from the vent drifted multiple
directions, dropping small amounts of ash, and occasionally fresh
spatter, downwind. Lava from beneath the Thanksgiving Eve Breakout
(TEB) and rootless shield complex flowed SE through a lava tube
system. Thermal anomalies detected by satellite and visual
observations revealed active lava flows on top of the pali from lava-
tube breakouts.

During an overflight of Pu'u 'O'o crater on 19 January scientists saw
a recent but inactive lava flow across the bottom of the crater. On 22
January a small part of the crater rim collapsed in front of the web
camera, revealing an incandescent vent at the base of the E wall.
During 23-26 January, incandescence was seen from the vent, as well as
from high on the E wall, the crater floor, and low on the S wall.

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.

Map

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)

Kilauea Information from the Global Volcanism Program

KLIUCHEVSKOI Central Kamchatka (Russia) 56.057ï¿½N, 160.638ï¿½E; summit
elev. 4835 m

KVERT reported that during 15-22 January seismic activity from
Kliuchevskoi was above background levels and lava continued to flow
down the NW flank. Strombolian activity periodically ejected material
300 m above the crater. Phreatic explosions from the front of the lava
flow ejected material that rose to altitudes of 4.5-8 km
(14,800-26,200 ft) a.s.l. Satellite imagery also revealed a large
daily thermal anomaly at the volcano. The Level of Concern Color Code
remained at Orange. Based on information from the Yelizovo Airport
(UHPP) and analyses of satellite imagery, the Tokyo VAAC reported that
during 22-23 January ash plumes rose to altitudes of 7-10.1 km
(23,000-33,000 ft) a.s.l. and drifted NE.

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.

Map

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

Kliuchevskoi Information from the Global Volcanism Program

LLAIMA Central Chile 38.692ï¿½S, 71.729ï¿½W; summit elev. 3125 m

On 22 January, SERNAGEOMIN reported that seismicity from Llaima had
decreased during the previous few weeks to background levels. The
Alert Level was lowered to Green, (Level 2) on a three-color scale.

Geologic Summary. Llaima, one of Chile's largest and most active
volcanoes, contains two main historically active craters, one at the
summit and the other to the SE. The massive 3,125-m-high, glacier-
covered stratovolcano has a volume of 400 cu km. A Holocene edifice
built primarily of accumulated lava flows was constructed over an 8-km-
wide caldera that formed about 13,200 years ago, following eruption of
the 24 cu km Curacautï¿½n Ignimbrite. More than 40 scoria cones dot the
volcano's flanks. Following the end of an explosive stage about 7,200
years ago, construction of the present edifice began, characterized by
Strombolian, Hawaiian, and infrequent subplinian eruptions. Frequent
moderate explosive eruptions with occasional lava flows have been
recorded since the 17th century.

Map

Source: Servicio Nacional de Geologï¿½a y Minerï¿½a (SERNAGEOMIN)

Llaima Information from the Global Volcanism Program

SAKURA-JIMA Kyushu 31.585ï¿½N, 130.657ï¿½E; summit elev. 1117 m

During 26 December 2009-9 January 2010, a visitor to Sakura-jima
observed and photographed Strombolian and Vulcanian explosions from
Showa crater. Based on information from JMA, the Tokyo VAAC reported
that during 20-26 January multiple explosions often produced plumes
that rose to altitudes of 1.2-2.4 km (4,000-8,000 ft) a.s.l. and
drifted NE, E, SE, and S. On 23 January, a pilot reported that an ash
plume drifted SE at an altitude of 1.8 km (6,000 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.

Map

Sources: Tokyo Volcanic Ash Advisory Center (VAAC), Richard Roscoe,
Photo Volcanica

Sakura-jima Information from the Global Volcanism Program

SANTA MARIA Guatemala 14.756ï¿½N, 91.552ï¿½W; summit elev. 3772 m

INSIVUMEH reported that on 21 January ashfall was reported in areas
near Santa Marï¿½a's Santiaguito lava dome complex. The next day an
explosion produced an ash plume that rose to an altitude of 3.2 km
(10,500 ft) a.s.l. and drifted SW. The Washington VAAC reported that
an ash plume seen on satellite imagery drifted less than 10 km.

Geologic Summary. Symmetrical, forest-covered Santa Marï¿½a 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.

Map

Sources: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia,
e Hidrologia (INSIVUMEH), Washington Volcanic Ash Advisory Center
(VAAC)

Santa Marï¿½a Information from the Global Volcanism Program

SHIVELUCH Central Kamchatka (Russia) 56.653ï¿½N, 161.360ï¿½E; summit elev.
3283 m

KVERT reported that during 15-22 January seismic activity from
Shiveluch was above background levels, possibly indicating ash plumes
rising to an altitude of 4.7 km (15,400 ft) a.s.l. Analyses of
satellite imagery revealed a large daily thermal anomaly from the lava
dome. The Level of Concern Color Code remained at Orange. Based on
information from KEMSD, the Tokyo VAAC reported that during 23-24 and
26 January eruptions produced plumes that rose to altitudes of 3-4.6
km (10,000-15,000 ft) a.s.l.

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.

Map

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

Shiveluch Information from the Global Volcanism Program

SUWANOSE-JIMA Ryukyu Islands (Japan) 29.635ï¿½N, 129.716ï¿½E; summit elev.
799 m

During 29-30 December 2009, a visitor to Suwanose-jima observed and
photographed multiple Strombolian explosions and ash eruptions from On-
take (Otake) crater. Based on information from JMA, the Tokyo VAAC
reported explosions during 22-26 January. On 24 and 26 January, plumes
rose to altitudes of 1.2-1.5 km (4,000-5,000 ft) a.s.l.

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.

Map

Sources: Tokyo Volcanic Ash Advisory Center (VAAC), Richard Roscoe,
Photo Volcanica

Suwanose-jima Information from the Global Volcanism Program

Additional Reports of Volcanic Activity by Country

The following websites have frequently updated activity reports on
volcanoes in addition to those that meet the criteria for inclusion in
the Weekly Volcanic Activity Report. The websites are organized by
country and are maintained by various agencies.

Ecuador, Indonesia, Japan, New Zealand, United States and Russia

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

Global Volcanism Program ï¿½ Department of Mineral Sciences
National Museum of Natural History ï¿½ Smithsonian Institution

=============================================
Whoopee, an amanuensis.


subject: Re: New Volcanos Erupting This Week: 5 - Total Active: 19

text:
SI / USGS
                                   Weekly Volcanic Activity Report

                                            21 July - 27 July 2010
                                      5 New+ 14 Ongoing =  19 active

             New Activity/Unrest:

| Ebeko, Paramushir Island
| Gorely, Southern Kamchatka (Russia)
| Kilauea, Hawaii (USA)
| Miyake-jima, Izu Islands (Japan)
| Rabaul, New Britain

          Ongoing Activity:

| Batu Tara, Komba Island (Indonesia)
| Chaitén, Southern Chile
| Dukono, Halmahera
| Karymsky, Eastern Kamchatka (Russia)
| Kliuchevskoi, Central Kamchatka (Russia)
| Pacaya, Guatemala
| Sakura-jima, Kyushu
| Sangay, Ecuador
| Shiveluch, Central Kamchatka (Russia)
| Soufrière Hills, Montserrat
| Suwanose-jima, Ryukyu Islands (Japan)
| Tungurahua, Ecuador
| Turrialba, Costa Rica
| Ulawun, New Britain

                          Weekly Report Editor Sally Kuhn Sennert -

                           http://www.volcano.si.edu/reports/

                           http://www.volcano.si.edu/reports/usgs

               This page is updated on Wednesdays, please
               see the GVP Home Page for news of the
               latest significant activity.

               The Weekly VolcanicActivityReport is a
               cooperative project between the Smithsonian's
               Global Volcanism Program and the US
               Geological Survey'sVolcanoHazards Program.

               Updated by 2300 UTC every Wednesday,
               notices of volcanicactivityposted 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
               Earths volcanos erupting during theweek, 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 variousvolcanosare
               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

New Activity/Unrest

EBEKO Paramushir Island 50.68°N, 156.02°E; summit elev. 1156 m

On 23 July, KVERT reported that the Aviation Color Code level for
Ebeko was lowered to Green. Visual observations and satellite data
indicated no activity from the volcano during 16-23 July.

Geologic Summary. The flat-topped summit of the central cone of Ebeko
volcano, one of the most active in the Kuril Islands, occupies the
northern end of Paramushir Island. Three summit craters located along
a SSW-NNE line form Ebeko volcano proper, at the northern end of a
complex of five volcanic cones. The eastern part of the southern
crater of Ebeko contains strong solfataras and a large boiling spring.
The central crater of Ebeko is filled by a lake about 20 m deep whose
shores are lined with steaming solfataras; the northern crater lies
across a narrow, low barrier from the central crater and contains a
small, cold crescentic lake. Historical activity, recorded since the
late-18th century, has been restricted to small-to-moderate explosive
eruptions from the summit craters. Intense fumarolic activity occurs
in the summit craters of Ebeko, on the outer flanks of the cone, and
in lateral explosion craters.

Map

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

Ebeko Information from the Global Volcanism Program

GORELY Southern Kamchatka (Russia) 52.558°N, 158.03°E; summit elev.
1829 m

KVERT reported that during 16-23 July seismic activity from Gorely was
above background levels and volcanic tremor continued to be detected.
Gas-and-steam activity was noted daily and many new small fumarolic
vents were seen in the active crater. The temperature of a daily
thermal anomaly detected over the volcano in satellite imagery
gradually increased from 29 to 46 degrees Celsius during 17-21 July.
The Aviation Color Code level remained at Yellow.

Geologic Summary. Gorely volcano, one of the most active in southern
Kamchatka, consists of five small overlapping stratovolcanoes
constructed along a WNW-ESE line within a large 9 x 13.5 km late-
Pleistocene caldera. The massive Gorely complex contains 11 summit and
30 flank craters. During the early Holocene, activity was
characterized by frequent mild eruptions with occasional larger
explosions and lava flows that filled in the caldera. Quiescent
periods became longer between 6,000 and 2,000 years ago, after which
the activity was mainly explosive. About 600-650 years ago
intermittent strong explosions and lava flow effusion accompanied
frequent mild eruptions. Historical eruptions have consisted of
vulcanian and phreatic explosions of moderate volume.

Map

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

Gorely Information from the Global Volcanism Program

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

During 21-27 July HVO reported that activity at Kilauea continued from
the summit and the east rift zone. At the summit, the level of a lava-
pool surface in the deep pit within the floor of Halema'uma'u crater
remained mostly stable; glow from the vent was also visible at night.
A plume from the vent mainly drifted SW.

At the east rift zone, lava flows that broke out of the TEB lava-tube
system advanced E and NE along coastal highway 137 beginning on 17
July and expanded S, filling in the area between the highway and the N-
facing scarp of the Hakuma horst. On 24 July, lava flowed N and by the
next morning had destroyed a home in Kalapana Gardens. Advancing lava
flowed over an area of the horst and on 25 July reached the ocean. On
26 July, lava caused small brush fires and methane explosions in a
kipuka on the W edge of the Kalapana subdivision. By 1200 on 27 July,
a second lava flow 500 m E of the ocean entry had advanced over the
horst and was about 20 m from the ocean. At Pu'u 'O'o crater,
intermittent incandescence from lava flows on the N crater floor was
visible starting on 24 July.

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.

Map

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)

Kilauea Information from the Global Volcanism Program

MIYAKE-JIMA Izu Islands (Japan) 34.079°N, 139.529°E; summit elev. 815
m

Based on information from JMA, the Tokyo VAAC reported that an
eruption from Miyake-jima on 21 July produced a plume that rose to an
altitude of 1.2 km (4,000 ft) a.s.l. and drifted E.

Geologic Summary. The circular, 8-km-wide island of Miyake-jima forms
a low-angle stratovolcano that rises about 1100 m from the sea floor
in the northern Izu Islands about 200 km SSW of Tokyo. Parasitic
craters and vents, including maars near the coast and radially
oriented fissure vents, dot the flanks of the volcano. Frequent
historical eruptions have occurred since 1085 AD at vents ranging from
the summit to below sea level, causing much damage on this small
populated island. After a three-century-long hiatus ending in 1469,
activity has been dominated by flank fissure eruptions sometimes
accompanied by minor summit eruptions. A 1.6-km-wide summit caldera
was slowly formed by subsidence during an eruption in 2000; by October
of that year the crater floor had dropped to only 230 m above sea
level.

Map

Source: Tokyo Volcanic Ash Advisory Center (VAAC)

Miyake-jima Information from the Global Volcanism Program

RABAUL New Britain 4.271°S, 152.203°E; summit elev. 688 m

RVO reported an eruption from Rabaul caldera's Tavurvur cone on 23
July, after increased seismicity likely beneath Tavurvur cone was
detected the previous day. The eruption was preceded by a few small
hybrid earthquakes at 1034 followed by small low-frequency earthquakes
and later continuous volcanic tremor. Diffuse white plumes were
initially emitted at 1320, and then pink-gray fumes with low ash
content were seen. A strong odor of hydrogen sulfide was noted, and a
diffuse cloud rose 1 km and drifted NW. Billowing gray clouds a few
hours later (at 1600) indicated a higher ash content and increased
activity. They were also accompanied by roaring and rumbling noises.
Discrete explosions commenced at 1730. Ashfall was reported in areas
to the NW and NNW.

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.

Map

Source: Rabaul Volcano Observatory (RVO)

Rabaul Information from the Global Volcanism Program

          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
on 21 July an ash plume from Batu Tara drifted 55 km NW at an altitude
of 1.5 km (5,000 ft) a.s.l.

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.

Map

Source: Darwin Volcanic Ash Advisory Centre (VAAC)

Batu Tara Information from the Global Volcanism Program

CHAITEN Southern Chile 42.833°S, 72.646°W; summit elev. 1122 m

Based on analyses of satellite imagery, the Buenos Aires VAAC reported
that an ash plume from Chaitén's lava-dome complex drifted 70 km SSE
on 24 July. Meteorological cloud cover in subsequent images prevented
further detection of the plume.

Geologic Summary. Chaitén is a small, glacier-free caldera with a
Holocene lava dome located 10 km NE of the town of Chaitén on the Gulf
of Corcovado. A pyroclastic-surge and pumice deposit considered to
originate from the eruption that formed the elliptical 2.5 x 4 km wide
summit caldera was dated at about 9400 years ago. A rhyolitic, 962-m-
high obsidian lava dome occupies much of the caldera floor. Obsidian
cobbles from this dome found in the Blanco River are the source of
prehistorical artifacts from archaeological sites along the Pacific
coast as far as 400 km away from the volcano to the north and south.
The caldera is breached on the SW side by a river that drains to the
bay of Chaitén, and the high point on its southern rim reaches 1122 m.

Map

Source: Buenos Aires Volcanic Ash Advisory Center (VAAC)

Chaitén Information from the Global Volcanism Program

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

Based on analyses of satellite imagery, the Darwin VAAC reported that
on 24 July an ash plume from Dukono rose to an altitude of 3 km
(10,000 ft) a.s.l. and drifted over 110 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.

Map

Source: Darwin Volcanic Ash Advisory Centre (VAAC)

Dukono Information from the Global Volcanism Program

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

KVERT reported that during 16-23 July seismic activity from Karymsky
was above background levels and suggested that possible ash plumes
rose to an altitude of 3 km (9,800 ft) a.s.l. A daily thermal anomaly
was detected in satellite imagery. Imagery also showed ash plumes that
drifted 58 km SW on 19 July and 85 km SE on 21 July. The Aviation
Color Code level remained at Orange.

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.

Map

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

Karymsky Information from the Global Volcanism Program

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

KVERT reported that during 16-23 July seismic activity from
Kliuchevskoi was above background levels and Strombolian activity was
seen. Gas-and-steam activity was noted with ash plumes periodically
rising to an altitude of 6.3 km (20,700 ft) a.s.l. Effusive lava flows
descended the SSW flank. Satellite imagery analysis showed a large
daily thermal anomaly from the volcano and ash plumes that drifted
about 55-160 km SW, SE, and NE. 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.

Map

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

Kliuchevskoi Information from the Global Volcanism Program

PACAYA Guatemala 14.381°N, 90.601°W; summit elev. 2552 m

INSIVUMEH reported that on 20 July Strombolian explosions from
Pacaya's MacKenney cone ejected ash that fell in neighboring areas.
During 20-21 July there were 90 explosions recorded by the seismic
network. Based on information from INSIVUMEH, the Washington VAAC
reported that on 22 July a plume rose to an altitude of 4.6 km (15,000
ft) a.s.l. and drifted N. A weak thermal anomaly was seen in
subsequent images. The next day, ash plumes drifted N at an altitude
of 4.1 km (13,500 ft) a.s.l. and produced ashfall in areas within 10
km. On 25 July, INSIVUMEH noted that Strombolian explosions ejected
tephra 100 m above the crater, and generated ash plumes that rose 300
m above the crater and drifted 10 km SW. Ejected blocks fell onto the
flanks.

Geologic Summary. Eruptions from Pacaya, one of Guatemala's most
active volcanoes, are frequently visible from Guatemala City, the
nation's capital. Pacaya is a complex volcano constructed on the
southern rim of the 14 x 16 km Pleistocene Amatitlan caldera. A
cluster of dacitic lava domes occupies the caldera floor. The Pacaya
massif includes the Cerro Grande lava dome and a younger volcano to
the SW. Collapse of Pacaya volcano about 1,100 years ago produced a
debris-avalanche deposit that extends 25 km onto the Pacific coastal
plain and left an arcuate somma rim inside which the modern Pacaya
volcano (MacKenney cone) grew. During the past several decades,
activity at Pacaya has consisted of frequent Strombolian eruptions
with intermittent lava flow extrusion on the flanks of MacKenney cone,
punctuated by occasional larger explosive eruptions.

Map

Sources: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia,
e Hidrologia (INSIVUMEH), Washington Volcanic Ash Advisory Center
(VAAC)

Pacaya Information from the Global Volcanism Program

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

Based on information from JMA, the Tokyo VAAC reported that during
21-27 July explosions from Sakura-jima produced plumes. Those plumes,
along with ash plumes occasionally seen by pilots, rose to altitudes
of 1.2-4.6 km (4,000-15,000 ft) a.s.l. Most plumes rose vertically
while others drifted N and NW.

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.

Map

Source: Tokyo Volcanic Ash Advisory Center (VAAC)

Sakura-jima Information from the Global Volcanism Program

SANGAY Ecuador 2.002°S, 78.341°W; summit elev. 5230 m

Based on pilot observations and analyses of satellite imagery, the
Washington VAAC reported that on 21 July an ash cloud from Sangay
drifted W. During 22-23 July, diffuse plumes drifted 65-115 km W.
Occasional thermal anomalies were detected by satellite imagery on 21
and 23 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.

Map

Source: Washington Volcanic Ash Advisory Center (VAAC)

Sangay Information from the Global Volcanism Program

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

KVERT reported that during 16-23 July seismic activity from Shiveluch
was above background levels, possibly indicating weak ash explosions
from the lava dome. According to visual observations, gas-and-steam
plumes rose daily to an altitude of 3.7 km (12,100 ft) a.s.l. and ash
plumes rose to an altitude of 5.5 km (18,000 ft) a.s.l. on 20 and 21
July. Satellite imagery showed a large daily thermal anomaly over the
lava dome and ash plumes that drifted 50 km NE on 21 July. 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.

Map

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

Shiveluch Information from the Global Volcanism Program

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

MVO reported that activity at Soufrière Hills was low during 16-23
July and inclement weather prevented clear observations of the lava
dome. Heavy rains generated a few lahars in the Belham valley to the
NW. The largest occurred on 20 July and lasted about 40 minutes. The
Hazard Level remained at 3.

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.

Map

Source: Montserrat Volcano Observatory (MVO)

Soufrière Hills Information from the Global Volcanism Program

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

Based on information from JMA, the Tokyo VAAC reported that explosions
from Suwanose-jima produced plumes that rose to an altitude of 1.5 km
(5,000 ft) a.s.l. on 23 July and to an altitude of 2.4 km (8,000 ft)
a.s.l. on 26 July. Plumes drifted NW and W, respectively.

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.

Map

Source: Tokyo Volcanic Ash Advisory Center (VAAC)

Suwanose-jima Information from the Global Volcanism Program

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

Observations of Tungurahua's summit area during 21-27 July were
sometimes not possible due to inclement weather. Ash plumes seen
during 21-23 July rose to altitudes of 6-9 km (19,700-29,500 ft)
a.s.l. and drifted W and NW. Ashfall was reported in areas within 10
km NW, W, and SW during 22-24 July. Steam plumes were seen rising 200
m above the crater on 25 July and an explosion was heard on 26 July.
On 27 July a series of explosions was detected by the seismic network.
Roaring noises were followed by vibrating windows in areas to the N
and NW. Slight ashfall was noted in areas to the SW and W, and 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.

Map

Source: Instituto Geofísico-Escuela Politécnica Nacional (IG)

Tungurahua Information from the Global Volcanism Program

TURRIALBA Costa Rica 10.025°N, 83.767°W; summit elev. 3340 m

Based on web camera views of Turrialba, the Washington VAAC reported
that on 24 July a plume of steam, gas, and ash drifted W. Over the
next three hours the plume became more diffuse and steam-rich.

Geologic Summary. Turrialba, the easternmost of Costa Rica's Holocene
volcanoes, is a large vegetated basaltic-to-dacitic stratovolcano
located across a broad saddle NE of Irazú volcano overlooking the city
of Cartago. The massive 3340-m-high Turrialba is exceeded in height
only by Irazú, covers an area of 500 sq km, and is one of Costa Rica's
most voluminous volcanoes. Three well-defined craters occur at the
upper SW end of a broad 800 x 2200 m wide summit depression that is
breached to the NE. Most activity at Turrialba originated from the
summit vent complex, but two pyroclastic cones are located on the SW
flank. Five major explosive eruptions have occurred at Turrialba
during the past 3500 years. Turrialba has been quiescent since a
series of explosive eruptions during the 19th century that were
sometimes accompanied by pyroclastic flows. Fumarolic activity
continues at the central and SW summit craters.

Map

Source: Washington Volcanic Ash Advisory Center (VAAC)

Turrialba Information from the Global Volcanism Program

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

RVO reported that diffuse gray plumes rose 200-500 m above Ulawun
during 16-21 July. Volcanic tremors continued, but overall seismicity
declined slightly. Real-time Seismic-Amplitude Measurement (RSAM)
values remained at a moderate level.

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.

Map

Source: Rabaul Volcano Observatory (RVO)

Ulawun Information from the Global Volcanism Program

Additional Reports of Volcanic Activity by Country

The following websites have frequently updated activity reports on
volcanoes in addition to those that meet the criteria for inclusion in
the Weekly Volcanic Activity Report. The websites are organized by
country and are maintained by various agencies.

Ecuador, Indonesia, Japan, New Zealand, United States and Russia

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

Global Volcanism Program — Department of Mineral Sciences
National Museum of Natural History — Smithsonian Institution