VOLCANO: Smithsonian/USGS Weekly Volcanic Activity Report 4-10 January 2012

[Jean-François Smekens <jsmekens@xxxxxxx>]

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Smithsonian/USGS Weekly Volcanic Activity Report 4-10 January 2012
From: "Faulk, Elisabeth" <FaulkE@xxxxxx>
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Smithsonian/USGS Weekly Volcanic Activity Report

4-10 January 2012


Elisabeth Faulk - Weekly Report Editor faulke@xxxxxx


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





New Activity/Unrest: | Etna, Sicily (Italy) | Galeras, Colombia | 
Lewotolo, Lomblen Island (Indonesia) | Láscar, Northern Chile | 
Nyamuragira, Democratic Republic of Congo | Reventador, Ecuador | 
Sangay, Ecuador | Tungurahua, Ecuador | Zubair Group, Yemen


Ongoing Activity: | Fuego, Guatemala | Hierro, Canary Islands (Spain) | 
Karymsky, Eastern Kamchatka (Russia) | Kilauea, Hawaii (USA) | Kizimen, 
Eastern Kamchatka (Russia) | Popocatépetl, México | Puyehue-Cordón 
Caulle, Central Chile | Sakura-jima, Kyushu | Santa María, Guatemala | 
Shiveluch, Central Kamchatka (Russia)


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 volcanoes erupting during the week, but rather a
 summary of activity at volcanoes that meet criteria discussed in detail
 in the "Criteria and Disclaimers" section. Carefully reviewed, detailed
 reports on various volcanoes are published monthly in the Bulletin of 
the Global Volcanism Network.

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




New Activity/Unrest


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


Sezione di Catania - Osservatorio Etneo reported that on the night of 4 
January the New SE Crater (New SEC) of Etna entered another paroxysmal 
eruption episode after about 50 days of quiescence. Several hours of 
Strombolian activity were observed on the SE and NE slopes starting at 
2230 on 4 January. This activity continued into the early morning of 5 
January when (around 0200) a small lava flow spread out into several 
branches at the SE base of the cone. Strombolian activity increased 
around 0400, generating lava fountains, from several vents within the 
crater that rose 100-150 m above the crater.

Significant ashfall and pyroclastic material fell onto the flanks at 
0450 on 5 January. Around 0515 lava fountains generated a continuous 
eruption of ash-and-gas plumes that rose to an altitude of 2.1-2.4 km 
(7,000-8,000 ft) a.s.l. Small pyroclastic flows went a few hundred 
meters and lahars traveled down the NE, E, and S flanks of the cone. 
Around 0600 active vents along the N edge of the New SEC produced 
intermittent lava fountains. The most intense phase of the eruption 
occurred around 0620 when a strong explosion opened a vent on the top 
side of the SE cone, removed a portion of the SE crater rim, and 
generated ash plumes. The N slope of New SEC showed gravitational 
movement due to the amount of deposited pyroclastic material. Around 
0630 activity started to diminish and ceased abruptly at 0730, but was 
followed by passive ash emissions that lasted until 0830.

Geologic Summary. Mount Etna, towering above Catania, Sicily's second 
largest city, has one of the world's longest documented records of 
historical volcanism, dating back to 1500 BC. Historical lava flows 
cover much of the surface of this massive basaltic stratovolcano, the 
highest and most voluminous in Italy. Two styles of eruptive activity 
typically occur at Etna. Persistent explosive eruptions, sometimes with 
minor lava emissions, take place from one or more of the three prominent
 summit craters, the Central Crater, NE Crater, and SE Crater. Flank 
eruptions, typically with higher effusion rates, occur less frequently 
and originate from fissures that open progressively downward from near 
the summit. A period of more intense intermittent explosive eruptions 
from Etna's summit craters began in 1995. The active volcano is 
monitored by the Instituto Nazionale di Geofisica e Volcanologia (INGV) 
in Catania.

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




GALERAS Colombia 1.22°N, 77.37°W; summit elev. 4276 m


INGEOMINAS reported that low-level activity continued at Galeras during 
4-10 January, with steam rising from the main crater and two craters to 
the N and SW (Paisita and Chavas, respectively). The Alert Level 
remained at III (Yellow; "changes in the behavior of volcanic 
activity").

Geologic Summary. Galeras, a stratovolcano with a large breached caldera
 located immediately W of the city of Pasto, is one of Colombia's most 
frequently active volcanoes. The dominantly andesitic Galeras volcanic 
complex has been active for more than 1 million years, and two major 
caldera collapse eruptions took place during the late Pleistocene. 
Longterm extensive hydrothermal alteration has affected the volcano. 
This has contributed to large-scale edifice collapse that has occurred 
on at least three occasions, producing debris avalanches that swept to 
the W and left a large horseshoe-shaped caldera inside which the modern 
cone has been constructed. Major explosive eruptions since the mid 
Holocene have produced widespread tephra deposits and pyroclastic flows 
that swept all but the southern flanks. A central cone slightly lower 
than the caldera rim has been the site of numerous small-to-moderate 
historical eruptions since the time of the Spanish conquistadors.

Source: Instituto Colombiano de Geología y Minería (INGEOMINAS) http://www.ingeominas.gov.co/Pasto.aspx




LEWOTOLO Lomblen Island (Indonesia) 8.272°S, 123.505°E; summit elev. 1423 m


According to news articles, 500 people have evacuated their homes on 6 
January because of increased activity at Lewotolo. Black smoke rose from
 the crater and rumbling sounds were reported. On 2 January CVGHM raised
 the Alert Level from 2 to 3 (on a scale of 1-4).

Geologic Summary. Anchoring the eastern end of an elongated peninsula 
that is connected to Lomblen Island by a narrow isthmus and extends 
northward into the Flores Sea, Lewotolo rises to 1,423 m. Lewotolo is a 
symmetrical stratovolcano as viewed from the N and E. A small cone with a
 130-m-wide crater constructed at the SE side of a larger crater forms 
the volcano's high point. Many lava flows have reached the coastline. 
Historical eruptions, recorded since 1660, have consisted of explosive 
activity from the summit crater.

Sources: The Jakarta Globe http://www.thejakartaglobe.com/home/hundreds-evacuate-in-ntt-as-mt-lewotolok-activity-rises/489538, BNO News http://channel6newsonline.com/2012/01/hundreds-evacuate-as-activity-rises-at-indonesias-mount-lewotolok/




LASCAR Northern Chile 23.37°S, 67.73°W; summit elev. 5592 m


OVDAS-SERNAGEOMIN reported increased seismicity at Láscar on 5 January 
and raised the Alert Level from Green to Yellow. On 8 January ONEMI 
authorities warned residents about the new Alert Level status and 
restricted residents from going within a 20-km radius of the volcano.

Geologic Summary. Lascar is the most active volcano of the northern 
Chilean Andes. The andesitic-to-dacitic stratovolcano contains six 
overlapping summit craters and lies 5 km W of an older, higher 
stratovolcano, Volcán Aguas Calientes. Lascar consists of two major 
edifices; activity began at the eastern volcano and then shifted to the 
western cone. The largest eruption of Lascar took place about 26,500 
years ago, and following the eruption of the Tumbres scoria flow about 
9,000 years ago, activity shifted back to the eastern edifice, where 
three overlapping craters were formed. Frequent small-to-moderate 
explosive eruptions have been recorded from Lascar in historical time 
since the mid-19th century, along with periodic larger eruptions that 
produced ashfall hundreds of kilometers away from the volcano. The 
largest historical eruption of Lascar took place in 1993 and produced 
pyroclastic flows that extended up to 8.5 km NW of the summit.


Sources: Servicio Nacional de Geología y Minería (SERNAGEOMIN) http://www.sernageomin.cl/, Oficina Nacional de Emergencia Ministerio del Interior (ONEMI) http://www.onemi.cl/




NYAMURAGIRA Democratic Republic of Congo 1.408°S, 29.20°E; summit elev. 3058 m


Satellite imagery acquired on 3 January from the Advanced Land Imager 
(ALI) on NASA's EO-1 satellite showed an active lava flow to the NE of 
the central vent over the fissure located 11-12 km ENE of Nyamuragira's 
main crater. A sulfur dioxide-rich plume was also detected.

Geologic Summary. Africa's most active volcano, Nyamuragira (Also 
spelled Nyamulagira) is a massive basaltic shield volcano N of Lake Kivu
 and NW of Nyiragongo volcano. Lava flows from Nyamuragira cover 1,500 
sq km of the East African Rift. The 3058-m-high summit is truncated by a
 small 2 x 2.3 km summit caldera that has walls up to about 100 m high. 
About 40 historical eruptions have occurred since the mid-19th century 
within the summit caldera and from numerous fissures and cinder cones on
 the volcano's flanks. A lava lake in the summit crater, active since at
 least 1921, drained in 1938. Twentieth-century flank lava flows extend 
more than 30 km from the summit, reaching as far as Lake Kivu.

Source: NASA Earth Observatory http://earthobservatory.nasa.gov/




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


IG reported that staff conducting fieldwork at Reventador during 6-7 
January observed constant emissions of gas-and-steam rising about 300 m 
above the crater and drifting WNW. The emissions originated from a 
growing lava dome that was a few tens of meters above the crater rim and
 almost filled the base.

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

Source: Instituto Geofísico-Escuela Politécnica Nacional (IG) http://www.igepn.edu.ec/




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


Based on information from Guayaquil MWO and a pilot report, a possible 
ash plume from Sangay was reported on 8 January. Ash was not detected in
 partly-cloudy satellite imagery.

Geologic Summary. The isolated Sangay volcano, located E of the Andean 
crest, is the southernmost of Ecuador's volcanoes, and its most active. 
It has been in frequent eruption for the past several centuries. The 
steep-sided, 5,230-m-high glacier-covered volcano grew within 
horseshoe-shaped calderas of two previous edifices, which were destroyed
 by collapse to the E, producing large debris avalanches that reached 
the Amazonian lowlands. The modern edifice dates back to at least 14,000
 years ago. Sangay towers above the tropical jungle on the E side; on 
the other sides flat plains of ash from the volcano have been sculpted 
by heavy rains into steep-walled canyons up to 600 m deep. The earliest 
report of an historical eruption was in 1628. More or less continuous 
eruptions were reported from 1728 until 1916, and again from 1934 to the
 present. The more or less constant eruptive activity has caused 
frequent changes to the morphology of the summit crater complex.

Source: Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html




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


IG reported a decrease in activity from Tungurahua during 4-10 January. 
On 4 January steam plumes rose as high as 500 m above the crater and 
drifted W. Additional steam plumes observed on 8 January also drifted W.

Geologic Summary. The steep-sided Tungurahua stratovolcano towers more 
than 3 km above its northern base. It sits ~140 km S of Quito, Ecuador's
 capital city, and is one of Ecuador's most active volcanoes. Historical
 eruptions have all originated from the summit crater. They have been 
accompanied by strong explosions and sometimes by pyroclastic flows and 
lava flows that reached populated areas at the volcano's base. The last 
major eruption took place from 1916 to 1918, although minor activity 
continued until 1925. The latest eruption began in October 1999 and 
prompted temporary evacuation of the town of Baños on the N side of the 
volcano.

Source: Instituto Geofísico-Escuela Politécnica Nacional (IG) http://www.igepn.edu.ec/




ZUBAIR GROUP Yemen 15.05°N, 42.18°E; summit elev. 191 m


A satellite image acquired on 7 January showed the newly-formed island 
in the northern part of the Zubair Group. The island had grown to about 
530 x 710 m, and a gas-and-steam plume containing ash rose from a 
distinct cone.

Geologic Summary. The 5-km-long Jebel Zubair Island is the largest of a 
group of 10 small islands and submerged shoals that rise from a shallow 
platform in the Red Sea rift. The platform and eruptive vents forming 
the islands and shoals are oriented NNW-SSE, parallel to the rift. An 
early explosive phase was followed by a brief period of marine erosion, 
and then by renewed explosive activity accompanied by the extrusion of 
basaltic pahoehoe lava flows. This latest phase of activity occurred on 
the morphologically youngest islands of Zubair, Centre Peak, Saba, and 
Haycock. Historical explosive activity was reported from Saddle Island 
in the 19th century. Spatter cones and pyroclastic cones were erupted 
along fissures that form the low spine of Zubair Island.

Source: NASA Earth Observatory http://earthobservatory.nasa.gov/





Ongoing Activity




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


INSIVUMEH reported that on 6 and 10 January weak explosions from Fuego 
generated ash plumes that rose 300-600 m above the crater and drifted 10
 km WNW and 15 km SW, respectively. Rumbling noises were detected 
several kilometers away. Incandescence emanated from the crater at night
 and avalanches descended the S, SW, and SE flanks. Based on information
 from satellite observations and INSIVUMEH, the Washington VAAC reported
 that an ash plume drifted SE and later dispersed on 3 January.

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.

Sources: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH) http://www.insivumeh.gob.gt/geofisica/vulcanologia/boletin%20formato.htm, Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html




HIERRO Canary Islands (Spain) 27.73°N, 18.03°W; summit elev. 1500 m


Instituto Geográfico Nacional (IGN) reported that during 4-10 January, 
the submarine eruption continued S of El Hierro Island. The mean 
amplitude of the tremor slightly increased during the week. During this 
period, large floating lava fragments were observed close to the vent 
area and generating steam. The production of these fragments was 
especially intense during 6-8 January.

Nineteen seismic events were located during this period, most of them 
were grouped in the central part of the island, extending offshore to 
the S, at depths between 10 and 18 km, with a maximum magnitude of 2.0. 
GPS data analyses showed little deformation, with a trend to subsidence 
in the stations at the S of the island.

Geologic Summary. The triangular island of Hierro is the SW-most and 
least studied of the Canary Islands. The massive Hierro shield volcano 
is truncated by a large NW-facing escarpment formed as a result of 
gravitational collapse of El Golfo volcano about 130,000 years ago. The 
steep-sided 1500-m-high scarp towers above a low lava platform bordering
 12-km-wide El Golfo Bay, and three other large submarine landslide 
deposits occur to the SW and SE. Three prominent rifts oriented NW, NE, 
and south at 120 degree angles form prominent topographic ridges. The 
subaerial portion of the volcano consists of flat-lying Quaternary 
basaltic and trachybasaltic lava flows and tuffs capped by numerous 
young cinder cones and lava flows. Holocene cones and flows are found 
both on the outer flanks and in the El Golfo depression. Hierro contains
 the greatest concentration of young vents in the Canary Islands. 
Uncertainty surrounds the report of an historical eruption in 1793.

Source: Instituto Geográfico Nacional (IGN) http://www.01.ign.es/ign/layout/volcaVolcanologia.do




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


KVERT reported that seismic activity continued at a moderate level at 
Karymsky during 30 December-6 January and indicated that possible ash 
plumes rose to an altitude of 4.5 km (14,800 ft) a.s.l. Satellite 
imagery showed a thermal anomaly on the volcano all week. An ash cloud 
10 km long and 2 km wide drifted 56 km SSE on 1 January. The Aviation 
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.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/current/krm/index.html




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


During 4-10 January, HVO reported that the lava lake circulated and 
periodically rose and fell in the deep pit within Kilauea's Halema'uma'u
 Crater, remaining below the inner ledge (75 m below the crater floor). 
Almost daily measurements indicated that the gas plume from the vent 
continued to deposit variable amounts of ash and fresh spatter nearby.

Incandescence was visible along the 21 September 2011 fissure on the SE 
flank of the Pu'u 'O'o cone during 4-5 January and from small spatter 
cones on the E, S, and W edges of the Pu'u 'O'o crater floor during 4-10
 January. A web camera showed no activity on the flow field during 4-10 
January; however clouds may have prevented views. On 6 January activity 
increased within a small pit that formed on the E edge of the crater 
during the previous week. The pit filled with lava and overflowed 
generating a small lava flow to the N within the crater. Activity 
continued within the pit during 7-8 January with short lava flows N and 
W. On 8 January thermal anomalies seen in satellite imagery were about 
2-4 km SW of Pu'u 'O'o cone and observers on an overflight reported 
surface flows in the same area. On 9 January satellite imagery showed a 
weaker thermal anomaly.

Geologic Summary. Kilauea, one of five coalescing volcanoes that 
comprise the island of Hawaii, is one of the world's most active 
volcanoes. Eruptions at Kilauea originate primarily from the summit 
caldera or along one of the lengthy E and SW rift zones that extend from
 the caldera to the sea. About 90% of the surface of Kilauea is formed 
of lava flows less than about 1,100 years old; 70% of the volcano's 
surface is younger than 600 years. A long-term eruption from the East 
rift zone that began in 1983 has produced lava flows covering more than 
100 sq km, destroying nearly 200 houses and adding new coastline to the 
island.

Source: US Geological Survey Hawaiian Volcano Observatory (HVO) http://hvo.wr.usgs.gov/




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


KVERT reported moderate seismic activity at Kizimen during 30 December-6
 January and a large thermal anomaly that was detected daily in 
satellite images. Video and satellite observations indicated both 
continued effusion of a large lava flow on the E flank and hot 
avalanches. Video data also showed strong gas-and-steam activity. The 
Aviation Color Code remained at Orange.

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

Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/current/kzm/index.html




POPOCATEPETL México 19.023°N, 98.622°W; summit elev. 5426 m


CENAPRED reported that during 4-10 January steam-and-gas emissions rose 
from Popocatépetl; the plumes contained small amounts of ash during 4-5 
January and 8-10 January. On 5 January two explosions generated 
incandescence in the crater.

Geologic Summary. Popocatépetl, whose name is the Aztec word for smoking
 mountain, towers to 5,426 m 70 km SE of Mexico City and is North 
America's second-highest volcano. Frequent historical eruptions have 
been recorded since the beginning of the Spanish colonial era. A small 
eruption on 21 December 1994 ended five decades of quiescence. Since 
1996 small lava domes have incrementally been constructed within the 
summit crater and destroyed by explosive eruptions. Intermittent 
small-to-moderate gas-and-ash eruptions have continued, occasionally 
producing ashfall in neighboring towns and villages.

Source: Centro Nacional de Prevencion de Desastres (CENAPRED) http://www.cenapred.unam.mx/cgi-bin/popo/reportes/consulta.cgi




PUYEHUE-CORDON CAULLE Central Chile 40.590°S, 72.117°W; summit elev. 2236 m


Based on seismicity during 6-8 January OVDAS-SERNAGEOMIN reported that 
the eruption from the Cordón Caulle rift zone, part of the 
Puyehue-Cordón Caulle volcanic complex, continued at a low level. Plumes
 observed with a web camera rose 2 km above the crater on 6 January. 
Satellite images showed ash plumes drifting 50 km S on 6 January and 
300-450 km SE during 8-9 January. Clouds prevented views on the other 
days. The Alert Level remained at Red.

Geologic Summary. The Puyehue-Cordón Caulle volcanic complex (PCCVC) is a
 large NW-SE-trending late-Pleistocene to Holocene basaltic-to-rhyolitic
 transverse volcanic chain SE of Lago Ranco. The 1799-m-high Pleistocene
 Cordillera Nevada caldera lies at the NW end, separated from Puyehue 
stratovolcano at the SE end by the Cordón Caulle fissure complex. The 
Pleistocene Mencheca volcano with Holocene flank cones lies NE of 
Puyehue. The basaltic-to-rhyolitic Puyehue volcano is the most 
geochemically diverse of the PCCVC. The flat-topped, 2236-m-high Puyehue
 volcano was constructed above a 5-km-wide caldera and is capped by a 
2.4-km-wide summit caldera of Holocene age. Lava flows and domes of 
mostly rhyolitic composition are found on the eastern flank of Puyehue. 
Historical eruptions originally attributed to Puyehue, including major 
eruptions in 1921-22 and 1960, are now known to be from the Cordón 
Caulle rift zone. The Cordón Caulle geothermal area, occupying a 6 x 13 
km wide volc
 ano-tectonic depression, is the largest active geothermal area of the southern Andes volcanic zone.

Source: Servicio Nacional de Geología y Minería (SERNAGEOMIN) http://www.sernageomin.cl/




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


Based on information from JMA, the Tokyo VAAC reported that during 4-10 
January explosions from Sakura-jima produced plumes that rose to 
altitudes of 1.5-2.7 km (5,000-9,000 ft) a.s.l. and drifted NE, E, SE, 
and S. On 7 January an ash plume rose to an altitude 2.7 km (9,000 ft) 
a.s.l. and drifted SE, then later dissipated.

Geologic Summary. Sakura-jima, one of Japan's most active volcanoes, is a
 post-caldera cone of the Aira caldera at the northern half of Kagoshima
 Bay. Eruption of the voluminous Ito pyroclastic flow was associated 
with the formation of the 17 x 23-km-wide Aira caldera about 22,000 
years ago. The construction of Sakura-jima began about 13,000 years ago 
and built an island that was finally joined to the Osumi Peninsula 
during the major explosive and effusive eruption of 1914. Activity at 
the Kita-dake summit cone ended about 4,850 years ago, after which 
eruptions took place at Minami-dake. Frequent historical eruptions, 
recorded since the 8th century, have deposited ash on Kagoshima, one of 
Kyushu's largest cities, located across Kagoshima Bay only 8 km from the
 summit. The largest historical eruption took place during 1471-76.

Source: Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html




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


INSIVUMEH reported that on 6 and 10 January explosions Santa María's 
Santiaguito lava-dome complex generated ash plumes that rose 600 m above
 the complex and drifted N and W, respectively. Crater incandescence was
 observed at night and active lava flows on the SE and SW flanks 
generated block avalanches. Based on analyses of satellite imagery, the 
Washington VAAC reported that an ash plume drifted 18.5 km E of the 
Mexico border.

Geologic Summary. Symmetrical, forest-covered Santa María volcano is one
 of a chain of large stratovolcanoes that rises dramatically above the 
Pacific coastal plain of Guatemala. The stratovolcano has a 
sharp-topped, conical profile that is cut on the SW flank by a large, 
1-km-wide crater, which formed during a catastrophic eruption in 1902 
and extends from just below the summit to the lower flank. The renowned 
Plinian eruption of 1902 followed a long repose period and devastated 
much of SW Guatemala. The large dacitic Santiaguito lava-dome complex 
has been growing at the base of the 1902 crater since 1922. Compound 
dome growth at Santiaguito has occurred episodically from four 
westward-younging vents, accompanied by almost continuous minor 
explosions and periodic lava extrusion, larger explosions, pyroclastic 
flows, and lahars.

Sources: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH) http://www.insivumeh.gob.gt/geofisica/vulcanologia/boletin%20formato.htm, Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html




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


KVERT reported that moderate seismic activity was detected at Shiveluch 
during 30 December-6 January. Satellite imagery showed a daily thermal 
anomaly over the lava dome. Ground-based observers noted that a viscous 
lava flow continued to effuse in the crater that was formed during a 
2010 eruption. Moderate fumarolic activity at the lava dome was observed
 during 30-31 December and on 2 and 4 January; clouds prevented 
observations on the other days of the week. The Aviation Color Code 
remained at Orange.

Geologic Summary. The high, isolated massif of Shiveluch volcano (also 
spelled Sheveluch) rises above the lowlands NNE of the Kliuchevskaya 
volcano group and forms one of Kamchatka's largest and most active 
volcanoes. The currently active Molodoy Shiveluch lava-dome complex was 
constructed during the Holocene within a large breached caldera formed 
by collapse of the massive late-Pleistocene Strary Shiveluch volcano. At
 least 60 large eruptions of Shiveluch have occurred during the 
Holocene, making it the most vigorous andesitic volcano of the 
Kuril-Kamchatka arc. Frequent collapses of lava-dome complexes, most 
recently in 1964, have produced large debris avalanches whose deposits 
cover much of the floor of the breached caldera. Intermittent explosive 
eruptions began in the 1990s from a new lava dome that began growing in 
1980. The largest historical eruptions from Shiveluch occurred in 1854 
and 1964.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/current/shv/index.html

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