Smithsonian/USGS Weekly Volcanic Activity Report 16-22 November 2011
From: "Kuhn, Sally" <KUHNS@si.edu>
*****************************************************************************************
Smithsonian/USGS Weekly Volcanic Activity Report
16-22 November 2011
Sally Kuhn Sennert - Weekly Report Editor
URL: http://www.volcano.si.edu/reports/usgs/
New Activity/Unrest: | Hierro, Canary Islands (Spain) | Nyamuragira, Democratic
Republic of Congo | Nyiragongo, Democratic Republic of Congo
Ongoing Activity: | Cerro Hudson, Southern Chile | Karymsky, Eastern Kamchatka
(Russia) | Kilauea, Hawaii (USA) | Kizimen, Eastern Kamchatka (Russia) |
Popocat?petl, M?xico | Puyehue-Cord?n Caulle, Central Chile | Sakura-jima,
Kyushu | Sangay, Ecuador | Shiveluch, Central Kamchatka (Russia)
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
HIERRO Canary Islands (Spain) 27.73?N, 18.03?W; summit elev. 1500 m
Instituto Geogr?fico Nacional (IGN) reported that during 16-22 November the
submarine eruption continued S of El Hierro Island. During this period, the
amplitude of the tremor showed two rapid changes, a decrease in amplitude at
2200 on 17 November and an increase at 1710 on 19 November. Seismic amplitudes
decreased between late 20 November and mid-day on 21 November, and then
remained stable at values similar to those noted during 19-25 October.
Superficial activity over the emission center was rare, characterized by
alternating days without seawater discoloration and days where there was minor
gas and tephra content in the water and persistent discoloration.
During the period, 200 seismic events were located, most of them offshore to the
N of the island at depths of 16-23 km and a maximum magnitude of 3.7. Seventeen
of these events were felt by residents at a maximum intensity value of III
using EMS-98 (European Macroseismic Scale). GPS data analyses showed little
deformation in the horizontal components, while in the vertical component
stations located in the N of the island showed uplift and the rest showed
subsidence.
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 Geogr?fico Nacional (IGN)
http://www.01.ign.es/ign/layout/volcaVolcanologia.do
NYAMURAGIRA Democratic Republic of Congo 1.408?S, 29.20?E; summit elev. 3058 m
On 18 November, Virunga National Park reported that lava flows from the eruption
along a fissure 11-12 km ENE of Nyamuragira's main crater had possibly stalled.
An observer aboard an overflight a few days before noted that the lava did not
appear to have moved any further N. A photo taken from the Rumangabo
headquarters (7.5 km NE of the eruption site) on 16 November showed a tall
cinder cone with lava fountains rising above the rim.
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.
Sources Virunga National Park http://gorillacd.org/
NYIRAGONGO Democratic Republic of Congo 1.52?S, 29.25?E; summit elev. 3470 m
According to NASA's Earth Observatory, a satellite image of Nyiragongo acquired
on 15 November showed heat coming from the active lava lake in the summit
crater.
Geologic Summary. One of Africa's most notable volcanoes, Nyiragongo contained
an active lava lake in its deep summit crater that drained catastrophically
through its outer flanks in 1977. In contrast to the low profile of its
neighboring shield volcano, Nyamuragira, Nyiragongo displays the steep slopes
of a stratovolcano. Benches in the steep-walled, 1.2-km-wide summit crater mark
the levels of former lava lakes, which have been observed since the late 19th
century. About 100 parasitic cones are located on the volcano's flanks and
along a NE-SW zone extending as far as Lake Kivu. Monitoring is done from a
small observatory building located in Goma, ~18 km S of the Nyiragongo crater.
Source: NASA Earth Observatory http://earthobservatory.nasa.gov/
Ongoing Activity
CERRO HUDSON Southern Chile 45.90?S, 72.97?W; summit elev. 1905 m
OVDAS-SERNAGEOMIN reported that satellite imagery and an area web camera showed
no plumes rising from Cerro Hudson during 7-15 November. Seismic activity
decreased significantly, reaching a low level characterized by no more than
four earthquakes per hour and the absence of tremor. The Alert Level remained
at Yellow, Level 4.
Geologic Summary. The ice-filled, 10-km-wide caldera of the remote Cerro Hudson
volcano was not recognized until its first 20th-century eruption in 1971. Cerro
Hudson is the southernmost volcano in the Chilean Andes related to subduction of
the Nazca plate beneath the South American plate. The massive, 1905-m-high Cerro
Hudson covers an area of 300 sq km. The compound caldera is drained through a
breach on its NW rim, which has been the source of mudflows down the R?o de Los
Huemeles. Two cinder cones occur north of the volcano and others occupy the SW
and SE flanks. Hudson has been the source of several major Holocene explosive
eruptions. An eruption about 6700 years ago was one of the largest known in the
southern Andes during the Holocene; another eruption about 3600 years ago also
produced more than 10 cu km of tephra. An eruption in 1991 was Chile's second
largest of the 20th century and formed a new 800-m-wide crater in the SW part
of the caldera.
Source: Servicio Nacional de Geolog?a y Miner?a (SERNAGEOMIN)
http://www.sernageomin.cl/
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 11-18 November, and indicated that possible ash plumes rose to an
altitude of 3.9 km (12,800 ft) a.s.l. Satellite imagery showed ash plumes that
drifted 172 km E on 11 November and a thermal anomaly on the volcano during
11-12 November. 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/index_eng.php
KILAUEA Hawaii (USA) 19.421?N, 155.287?W; summit elev. 1222 m
During 16-22 November, 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 from the E and W edges of the Pu'u 'O'o crater floor, and from the 21
September fissure on the SE flank of Pu'u 'O'o cone. Pahoehoe flows, fed
through lava tubes from the fissure, continued to be active about 5 km SE of
Pu'u 'O'o based on intermittent views from satellite. Incandescence from a
skylight on the lava tube was also observed. During 18-19 November the vent on
the E edge of the crater produced lava flows that partially filled the
depression left by the flank fissure eruption in September. There were also two
brief and small lava-flow effusions from the W edge vent. Intermittent lava
flows continued from the E vent during 20-22 November.
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 10-18 November and a
thermal anomaly that was detected on 11-14 and 17 November in satellite images.
Video observations showed gas-and-steam activity during 10 and 13-14 November. A
large lava flow on the NE and E flanks continued to effuse, and the crater was
incandescent at night during 13-14 November. The Aviation Color Code remained
at Orange.
Geologic Summary. Kizimen is an isolated, conical stratovolcano that is
morphologically similar to Mount St. Helens prior to its 1980 eruption. The
summit of Kizimen consists of overlapping lava domes, and blocky lava flows
descend the flanks of the volcano, which is the westernmost of a volcanic chain
north of Kronotsky volcano. The 2,376-m-high Kizimen was formed during four
eruptive cycles beginning about 12,000 years ago and lasting 2,000-3,500 years.
The largest eruptions took place about 10,000 and 8300-8400 years ago, and three
periods of longterm lava-dome growth have occurred. The latest eruptive cycle
began about 3,000 years ago with a large explosion and was followed by
lava-dome growth lasting intermittently about 1,000 years. An explosive
eruption about 1,100 years ago produced a lateral blast and created a 1.0 x 0.7
km wide crater breached to the NE, inside which a small lava dome (the fourth at
Kizimen) has grown. A single explosive eruption, during 1927-28, has been
recorded in historical time.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
http://www.kscnet.ru/ivs/kvert/index_eng.php
POPOCATEPETL M?xico 19.023?N, 98.622?W; summit elev. 5426 m
During 16-20 November CENAPRED reported steam-and-gas emissions from
Popocat?petl. A series of emissions was detected on 18 November; clouds
prevented ground observations and no ashfall was reported. Based on information
from the Mexico City MWO however, the Washington VAAC reported that an ash plume
rose to an altitude of 7.6 km (25,000 ft) a.s.l. and drifted SW that same day.
Satellite imagery showed another ash plume drifting E at an approximate
altitude of 9.1 km (30,000 ft) a.s.l. CENAPRED noted that at 1201 on 20
November an explosion produced an ash plume that rose approximately 2 km above
the crater and drifted N. The explosion was heard in Amecameca (19 km NW).
Steam-and-gas plumes rose from the crater during 21-22 November.
Geologic Summary. Popocat?petl, 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.
Sources: Centro Nacional de Prevencion de Desastres (CENAPRED)
http://www.cenapred.unam.mx/es/
Washington Volcanic Ash Advisory Center (VAAC)
http://www.ssd.noaa.gov/VAAC/messages.html
PUYEHUE-CORDON CAULLE Central Chile 40.590?S, 72.117?W; summit elev. 2236 m
Based on seismicity during 16-20 November, OVDAS-SERNAGEOMIN reported that the
eruption from the Cord?n Caulle rift zone, part of the Puyehue-Cord?n Caulle
volcanic complex, continued at a low level. Cloud cover prevented web camera
views on 16 November, but satellite imagery showed an ash plume drifting 100 km
SW and sparse ashfall to the E. During 18-20 November plumes observed with the
web camera rose 2.5-3 km above the crater. Satellite imagery showed ash clouds
drifting E and SE on 18 November and an ash plume drifting 250 km SE on 19
November. During the night on 20 November the crater was incandescent. Cloud
cover prevented observations on 21 November. The Alert Level remained at Red.
According to a news article, flights in Uruguay and Argentina were disrupted or
cancelled on 22 November due to the presence of ash.
Geologic Summary. The Puyehue-Cord?n 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 Cord?n 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 Cord?n Caulle rift
zone. The Cord?n Caulle geothermal area, occupying a 6 x 13 km wide
volcano-tectonic depression, is the largest active geothermal area of the
southern Andes volcanic zone.
Sources: Servicio Nacional de Geolog?a y Miner?a (SERNAGEOMIN)
http://www.sernageomin.cl/,
Agence France-Presse
http://www.interaksyon.com/article/17953/volcanic-ash-disrupts-air-travel-in-uruguay-argen
tina
SAKURA-JIMA Kyushu 31.585?N, 130.657?E; summit elev. 1117 m
Based on information from JMA, the Tokyo VAAC reported that during 16-17 and
19-22 November explosions from Sakura-jima produced plumes that rose to
altitudes of 1.8-3 km (6,000-10,000 ft) a.s.l. and drifted S, SE, E, and N.
Satellite imagery on 16 and 21 November showed ash emissions that later
dissipated. On 19 November a pilot reported an ash plume at an altitude of 3 km
(10,000 ft) a.s.l.
Geologic Summary. Sakura-jima, one of Japan's most active volcanoes, is a
post-caldera cone of the Aira caldera at the northern half of Kagoshima Bay.
Eruption of the voluminous Ito pyroclastic flow was associated with the
formation of the 17 x 23-km-wide Aira caldera about 22,000 years ago. The
construction of Sakura-jima began about 13,000 years ago and built an island
that was finally joined to the Osumi Peninsula during the major explosive and
effusive eruption of 1914. Activity at the Kita-dake summit cone ended about
4,850 years ago, after which eruptions took place at Minami-dake. Frequent
historical eruptions, recorded since the 8th century, have deposited ash on
Kagoshima, one of Kyushu's largest cities, located across Kagoshima Bay only 8
km from the summit. The largest historical eruption took place during 1471-76.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html
SANGAY Ecuador 2.002?S, 78.341?W; summit elev. 5230 m
The Washington VAAC reported that on 20 November an ash plume from a possible
eruption at Sangay was observed by a pilot and drifted at an altitude of 5.9 km
(19,500 ft) a.s.l. 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
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
11-18 November, and indicated that possible ash plumes rose to a maximum
altitude of 4.5 km (14,800 ft) a.s.l. Ground-based observers noted that a
viscous lava flow continued to effuse in the crater formed during a 2010
eruption. Strong fumarolic activity at the lava dome was observed during 13-14
November; cloud cover prevented observations on the other days. Satellite
imagery showed a thermal anomaly over the lava dome during 11-14 and 17
November and gas-and-steam plumes containing ash drifted 100 km E on 14
November. 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/index_eng.php
+++++++++++++++++++++++++++++++++++++
Sally Kuhn Sennert
SI/USGS Weekly Volcanic Activity Report Editor
Global Volcanism Program
http://www.volcano.si.edu/reports/usgs/
Smithsonian Institution, National Museum of Natural History
Department of Mineral Sciences, MRC-119
Washington, D.C., 20560
Phone: 202.633.1805
Fax: 202.357.2476
------------------------------------
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