Smithsonian / USGS Weekly Volcanic Activity Report 14-20 December 2022

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3-3-3-3-3-3-3-3-3-3-3-3-3


From: "Kuhn, Sally" <KUHNS@xxxxxx>


Smithsonian / USGS Weekly Volcanic Activity Report

14-20 December 2022



Sally Kuhn Sennert - Weekly Report Editor (kuhns@xxxxxx)

URL: https://urldefense.com/v3/__https://volcano.si.edu/reports_weekly.cfm__;!!IKRxdwAv5BmarQ!da_8a5mZcsDwDU5gEXg2ioCV-HzLz2wFIijIVptfy6NoE9hiz77589MW1bUXQSGsZjN3PuVJjY2_tVqe$ 
<https://urldefense.com/v3/__https://volcano.si.edu/reports_weekly.cfm__;!!IKRxdwAv5BmarQ!Z3Ir8q9N6O7-dybk3rtTVs70HeQ_SO_aAN4PyPY2dQivZ-ioMfHvF6XbnoxFN9ueqcwaAOvHq9I$>





New Activity/Unrest: Ahyi, Mariana Islands (USA)  | Cotopaxi, Ecuador  |
Etna, Sicily (Italy)  | Klyuchevskoy, Central Kamchatka (Russia)  | Lascar,
Northern Chile  | Semeru, Eastern Java



Ongoing Activity: Aira, Kyushu (Japan)  | Alaid, Kuril Islands (Russia)  |
Bezymianny, Central Kamchatka (Russia)  | Ebeko, Paramushir Island
(Russia)  | Great Sitkin, Andreanof Islands (USA)  | Karymsky, Eastern
Kamchatka (Russia)  | Kerinci, Central Sumatra  | Krakatau, Sunda Strait  |
Merapi, Central Java  | Nevado del Ruiz, Colombia  | Pavlof, Alaska
Peninsula, Alaska  | Popocatepetl, Mexico  | Rincon de la Vieja, Costa
Rica  | San Miguel, Eastern El Salvador  | Sheveluch, Central Kamchatka
(Russia)  | Suwanosejima, Ryukyu Islands (Japan)





The Weekly Volcanic Activity Report is a cooperative project between the
Smithsonian's Global Volcanism Program and the US Geological Survey's
Volcano Hazards Program. Updated by 2300 UTC every Wednesday, these reports
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 about recent activity are published in
issues of the Bulletin of the Global Volcanism Network.



Note that 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





Ahyi  | Mariana Islands (USA)  | 20.42°N, 145.03°E  | Summit elev. -75 m



Unrest continued to be detected at Ahyi Seamount during 14-20 December.
Wake Island hydrophone sensors detected daily signals consistent with
explosions. A possible underwater plume was observed in satellite images on
18 December, and definite but diffuse plumes were visible to the SSE of the
vent during 19-20 December. The Aviation Color Code remained at Yellow (the
second lowest level on a four-color scale) and the Volcano Alert Level
remained at Advisory (the second lowest level on a four-level scale).



Geologic Summary. Ahyi seamount is a large conical submarine volcano that
rises to within 75 m of the sea surface about 18 km SE of the island of
Farallon de Pajaros (Uracas) in the northern Marianas. Water discoloration
has been observed there, and in 1979 the crew of a fishing boat felt shocks
over the summit area of the seamount, followed by upwelling of
sulfur-bearing water. On 24-25 April 2001 an explosive eruption was
detected seismically by a station on Rangiroa Atoll, Tuamotu Archipelago.
The event was well constrained (+/- 15 km) at a location near the southern
base of Ahyi. An eruption in April-May 2014 was detected by NOAA divers,
hydroacoustic sensors, and seismic stations.



Source: US Geological Survey https://urldefense.com/v3/__https://www.usgs.gov/__;!!IKRxdwAv5BmarQ!da_8a5mZcsDwDU5gEXg2ioCV-HzLz2wFIijIVptfy6NoE9hiz77589MW1bUXQSGsZjN3PuVJjaH24Ber$ 
<https://urldefense.com/v3/__https://www.usgs.gov/__;!!IKRxdwAv5BmarQ!Z3Ir8q9N6O7-dybk3rtTVs70HeQ_SO_aAN4PyPY2dQivZ-ioMfHvF6XbnoxFN9ueqcwanPOD41o$>





Cotopaxi  | Ecuador  | 0.677°S, 78.436°W  | Summit elev. 5911 m



IG reported that the low-level eruption at Cotopaxi continued during 14-20
December, characterized by daily steam-and-gas emissions with low ash
content. At 0626 on 14 December an ash emission rose 500 m above the crater
rim and drifted W, causing ashfall within Parque Nacional Cotopaxi. Weather
clouds sometimes obscured views of the volcano; between weather clouds
during 14-16 December steam-and gas plumes with low ash content were seen
rising as high as 500 m above the crater rim and drifting W. Several
emissions with low or very low ash content rose as high as 800 m above the
crater rim and drifted W and SW during 16-17 December; similar emissions
rose as high as 1.1 km above the crater rim and drifted W and SW during
18-20 December based on webcam views and Washington VAAC notices. Ashfall
was reported in San Pedro de Taboada (40 km
<https://urldefense.com/v3/__https://www.google.com/maps/search/San*Pedro*de*Taboada*(40*km?entry=gmail&source=g__;KysrKys!!IKRxdwAv5BmarQ!da_8a5mZcsDwDU5gEXg2ioCV-HzLz2wFIijIVptfy6NoE9hiz77589MW1bUXQSGsZjN3PuVJjd46Ng1_$ >
N),
Uyumbicho (30 km NNW), Güitig Alta, Güitig Baja, Conocoto (42 km N), Sur de
Quito, Chimbacalle (48 km NNW), La Magdalena (48 km NNW), Barrio Nuevo,
Villaflora (48 km
<https://urldefense.com/v3/__https://www.google.com/maps/search/Barrio*Nuevo,*Villaflora*(48*km?entry=gmail&source=g__;KysrKw!!IKRxdwAv5BmarQ!da_8a5mZcsDwDU5gEXg2ioCV-HzLz2wFIijIVptfy6NoE9hiz77589MW1bUXQSGsZjN3PuVJjUMOhPKz$ >
NNW),
Miraflores, and La Floresta (50 km N) during 19-20 December. Servicio
Nacional de Gestión de Riesgos y Emergencias (SNGRE) maintained the Alert
Level at Yellow (the second lowest level on a four-color scale).



Geologic Summary. The symmetrical, glacier-covered, Cotopaxi stratovolcano
is Ecuador's most well-known volcano and one of its most active. The
steep-sided cone is capped by nested summit craters, the largest of which
is about 550 x 800 m in diameter. Deep valleys scoured by lahars radiate
from the summit of the andesitic volcano, and large andesitic lava flows
extend to its base. The modern edifice has been constructed since a major
collapse sometime prior to about 5,000 years ago. Pyroclastic flows (often
confused in historical accounts with lava flows) have accompanied many
explosive eruptions, and lahars have frequently devastated adjacent
valleys. Strong eruptions took place in 1744, 1768, and 1877. Pyroclastic
flows descended all sides of the volcano in 1877, and lahars traveled more
than 100 km into the Pacific Ocean and western Amazon basin. Smaller
eruptions have been frequent since that time.



Sources: Instituto Geofísico-Escuela Politécnica Nacional (IG)
https://urldefense.com/v3/__http://www.igepn.edu.ec/__;!!IKRxdwAv5BmarQ!da_8a5mZcsDwDU5gEXg2ioCV-HzLz2wFIijIVptfy6NoE9hiz77589MW1bUXQSGsZjN3PuVJjUrBlVXi$ 
<https://urldefense.com/v3/__http://www.igepn.edu.ec/__;!!IKRxdwAv5BmarQ!Z3Ir8q9N6O7-dybk3rtTVs70HeQ_SO_aAN4PyPY2dQivZ-ioMfHvF6XbnoxFN9ueqcwaZfY1uQE$>
;

Servicio Nacional de Gestión de Riesgos y Emergencias (SNGRE)
https://urldefense.com/v3/__https://www.gestionderiesgos.gob.ec/__;!!IKRxdwAv5BmarQ!da_8a5mZcsDwDU5gEXg2ioCV-HzLz2wFIijIVptfy6NoE9hiz77589MW1bUXQSGsZjN3PuVJjUrNfbO0$ 
<https://urldefense.com/v3/__https://www.gestionderiesgos.gob.ec/__;!!IKRxdwAv5BmarQ!Z3Ir8q9N6O7-dybk3rtTVs70HeQ_SO_aAN4PyPY2dQivZ-ioMfHvF6XbnoxFN9ueqcwag0awdvg$>





Etna  | Sicily (Italy)  | 37.748°N, 14.999°E  | Summit elev. 3357 m



INGV reported that the vents at the NE base of Etnaâ??s SE Crater, in the
Valle del Leone, continued to feed lava flows during 7-18 December. The
active flow field consisted of a main lava flow and several breakouts that
fed smaller lava flows. A small hornito formed at the vent area and ejected
pieces of lava.



Geologic Summary. Mount Etna, towering above Catania on the island of
Sicily, has one of the world's longest documented records of volcanism,
dating back to 1500 BCE. Historical lava flows of basaltic composition
cover much of the surface of this massive volcano, whose edifice is the
highest and most voluminous in Italy. The Mongibello stratovolcano,
truncated by several small calderas, was constructed during the late
Pleistocene and Holocene over an older shield volcano. The most prominent
morphological feature of Etna is the Valle del Bove, a 5 x 10 km caldera
open to the east. Two styles of eruptive activity typically occur,
sometimes simultaneously. Persistent explosive eruptions, sometimes with
minor lava emissions, take place from one or more summit craters. Flank
vents, typically with higher effusion rates, are less frequently active and
originate from fissures that open progressively downward from near the
summit (usually accompanied by Strombolian eruptions at the upper end).
Cinder cones are commonly constructed over the vents of lower-flank lava
flows. Lava flows extend to the foot of the volcano on all sides and have
reached the sea over a broad area on the SE flank.



Source: Sezione di Catania - Osservatorio Etneo (INGV)
https://urldefense.com/v3/__http://www.ct.ingv.it/__;!!IKRxdwAv5BmarQ!da_8a5mZcsDwDU5gEXg2ioCV-HzLz2wFIijIVptfy6NoE9hiz77589MW1bUXQSGsZjN3PuVJjTi-xjdO$ 
<https://urldefense.com/v3/__http://www.ct.ingv.it/__;!!IKRxdwAv5BmarQ!Z3Ir8q9N6O7-dybk3rtTVs70HeQ_SO_aAN4PyPY2dQivZ-ioMfHvF6XbnoxFN9ueqcwaj6JpepY$>





Klyuchevskoy  | Central Kamchatka (Russia)  | 56.056°N, 160.642°E  | Summit
elev. 4754 m



KVERT reported that the explosive Strombolian eruption at Klyuchevskoy that
began on 16 November had decreased. The Kamchatka Branch of Geophysical
Services (KBGS; Russian Academy of Sciences) noted that possible ash plumes
rose as high as 150 m above the summit on 1 December. KVERT began to
characterize the activity as moderate on 6 December and noted that the
periodic thermal anomalies identified in satellite images had become weak
on 9 December. The Aviation Color Code remained at Yellow (the second
lowest level on a four-color scale).



Geologic Summary. Klyuchevskoy (also spelled Kliuchevskoi) is Kamchatka's
highest and most active volcano. Since its origin about 6000 years ago, the
beautifully symmetrical, 4835-m-high basaltic stratovolcano has produced
frequent moderate-volume explosive and effusive eruptions without major
periods of inactivity. It rises above a saddle NE of sharp-peaked Kamen
volcano and lies SE of the broad Ushkovsky massif. More than 100 flank
eruptions have occurred during the past roughly 3000 years, with most
lateral craters and cones occurring along radial fissures between the
unconfined NE-to-SE flanks of the conical volcano between 500 m and 3600 m
elevation. The morphology of the 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 numerous major explosive and
effusive eruptions from flank craters.



Sources: Kamchatkan Volcanic Eruption Response Team (KVERT)
https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!da_8a5mZcsDwDU5gEXg2ioCV-HzLz2wFIijIVptfy6NoE9hiz77589MW1bUXQSGsZjN3PuVJjbVNxZA0$ 
<https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!Z3Ir8q9N6O7-dybk3rtTVs70HeQ_SO_aAN4PyPY2dQivZ-ioMfHvF6XbnoxFN9ueqcwaNxHIZLg$>
;

Institute of Volcanology and Geodynamics, Russian Academy of Natural
Science https://urldefense.com/v3/__http://www.kscnet.ru/ivs/index.php__;!!IKRxdwAv5BmarQ!da_8a5mZcsDwDU5gEXg2ioCV-HzLz2wFIijIVptfy6NoE9hiz77589MW1bUXQSGsZjN3PuVJjVmbnPoQ$ 
<https://urldefense.com/v3/__http://www.kscnet.ru/ivs/index.php__;!!IKRxdwAv5BmarQ!Z3Ir8q9N6O7-dybk3rtTVs70HeQ_SO_aAN4PyPY2dQivZ-ioMfHvF6XbnoxFN9ueqcwaPHTFH9M$>





Lascar  | Northern Chile  | 23.37°S, 67.73°W  | Summit elev. 5592 m



SERNAGEOMIN reported that seismic signals characterized as moderate were
recorded on 19 December and located near Láscarâ??s main crater at shallow
depths. The seismicity was the most notable recorded since the eruption on
10 December. The Alert Level remained at Yellow (the second lowest level on
a four-color scale) and the public were warned to stay at least 5 km away
from the crater. ONEMI maintained the Alert Level Yellow (the middle level
on a three-color scale) for San Pedro de Atacama (70 km NW).



Geologic Summary. Láscar is the most active volcano of the northern Chilean
Andes. The andesitic-to-dacitic stratovolcano contains six overlapping
summit craters. Prominent lava flows descend its NW flanks. An older,
higher stratovolcano 5 km E, Volcán Aguas Calientes, displays a
well-developed summit crater and a probable Holocene lava flow near its
summit (de Silva and Francis, 1991). Láscar consists of two major edifices;
activity began at the eastern volcano and then shifted to the western cone.
The largest eruption took place about 26,500 years ago, and following the
eruption of the Tumbres scoria flow about 9000 years ago, activity shifted
back to the eastern edifice, where three overlapping craters were formed.
Frequent small-to-moderate explosive eruptions have been recorded since the
mid-19th century, along with periodic larger eruptions that produced
ashfall hundreds of kilometers away. The largest historical eruption took
place in 1993, producing pyroclastic flows to 8.5 km NW of the summit and
ashfall in Buenos Aires.



Source: Servicio Nacional de Geología y Minería (SERNAGEOMIN)
https://urldefense.com/v3/__http://www.sernageomin.cl/__;!!IKRxdwAv5BmarQ!da_8a5mZcsDwDU5gEXg2ioCV-HzLz2wFIijIVptfy6NoE9hiz77589MW1bUXQSGsZjN3PuVJjfGwL_M8$ 
<https://urldefense.com/v3/__http://www.sernageomin.cl/__;!!IKRxdwAv5BmarQ!Z3Ir8q9N6O7-dybk3rtTVs70HeQ_SO_aAN4PyPY2dQivZ-ioMfHvF6XbnoxFN9ueqcwaeGqegsU$>





Semeru  | Eastern Java  | 8.108°S, 112.922°E  | Summit elev. 3657 m



PVMBG reported that the eruption at Semeru continued during 16-20 December.
At 0455 on 16 December an eruptive event produced a dense white, gray, and
brown plume that rose 1 km above the summit and drifted N. At 0500 on 18
December a dense gray ash plume rose 300 m and drifted N and NE. At 0623
and 0755 that same day dense white-and-gray ash plumes rose 1 km and 700 m,
respectively, and drifted N. At 0516 and 0703 on 19 December white-and-gray
ash plumes rose 400-700 m and drifted N and NE. At 1558 a dense
gray-to-brown ash plume rose 1.5 km and drifted N and NE. At 0545 on 20
December an ash plume rose 600 m and drifted N. The Alert Level remained at
3 (on a scale of 1-4). The public was warned to stay at least 5 km away
from the summit, and 500 m from Kobokan drainages within 17 km of the
summit, along with other drainages originating on Semeru, including the
Bang, Kembar, and Sat, due to lahar, avalanche, and pyroclastic flow
hazards.



Geologic Summary. Semeru, the highest volcano on Java, and one of its most
active, lies at the southern end of a volcanic massif extending north to
the Tengger caldera. The steep-sided volcano, also referred to as Mahameru
(Great Mountain), rises above coastal plains to the south. Gunung Semeru
was constructed south of the overlapping Ajek-ajek and Jambangan calderas.
A line of lake-filled maars was constructed along a N-S trend cutting
through the summit, and cinder cones and lava domes occupy the eastern and
NE flanks. Summit topography is complicated by the shifting of craters from
NW to SE. Frequent 19th and 20th century eruptions were dominated by
small-to-moderate explosions from the summit crater, with occasional lava
flows and larger explosive eruptions accompanied by pyroclastic flows that
have reached the lower flanks of the volcano.



Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known
as CVGHM) https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!da_8a5mZcsDwDU5gEXg2ioCV-HzLz2wFIijIVptfy6NoE9hiz77589MW1bUXQSGsZjN3PuVJjYzJSzcE$ 
<https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!Z3Ir8q9N6O7-dybk3rtTVs70HeQ_SO_aAN4PyPY2dQivZ-ioMfHvF6XbnoxFN9ueqcwajEQpX3g$>





Ongoing Activity





Aira  | Kyushu (Japan)  | 31.593°N, 130.657°E  | Summit elev. 1117 m



JMA reported ongoing eruptive activity at Minamidake Crater (at Aira
Calderaâ??s Sakurajima volcano) during 12-19 December. Crater incandescence
was visible nightly. Two explosions on 14 December produced eruption plumes
that rose as high as 1.7 km and disappeared into weather clouds. Blocks
were ejected as far as 700 m. An explosion at 0805 on 17 December produced
a plume that rose 700 m and into the clouds. Blocks were ejected 900 m. The
Alert Level remained at 3 (on a 5-level scale), and residents were warned
to stay 2 km away from the crater.



Geologic Summary. The Aira caldera in the northern half of Kagoshima Bay
contains the post-caldera Sakurajima volcano, one of Japan's most active.
Eruption of the voluminous Ito pyroclastic flow accompanied formation of
the 17 x 23 km caldera about 22,000 years ago. The smaller Wakamiko caldera
was formed during the early Holocene in the NE corner of the Aira caldera,
along with several post-caldera cones. The construction of Sakurajima began
about 13,000 years ago on the southern rim of Aira caldera and built an
island that was finally joined to the Osumi Peninsula during the major
explosive and effusive eruption of 1914. Activity at the Kitadake summit
cone ended about 4850 years ago, after which eruptions took place at
Minamidake. 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: Japan Meteorological Agency (JMA) https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!da_8a5mZcsDwDU5gEXg2ioCV-HzLz2wFIijIVptfy6NoE9hiz77589MW1bUXQSGsZjN3PuVJjdzuphp1$ 
<https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!Z3Ir8q9N6O7-dybk3rtTVs70HeQ_SO_aAN4PyPY2dQivZ-ioMfHvF6XbnoxFN9ueqcwaHNU59BU$>





Alaid  | Kuril Islands (Russia)  | 50.861°N, 155.565°E  | Summit elev. 2285
m



KVERT reported that the eruption at Alaid was ongoing during 8-15 December.
A thermal anomaly was identified in satellite images on 8, 12, and 14
December; weather clouds obscured observations on the other days. The
Aviation Color Code remained at Orange (the second highest level on a
four-color scale). Dates are based on UTC times; specific events are in
local time where noted.



Geologic Summary. The highest and northernmost volcano of the Kuril
Islands, Alaid is a symmetrical stratovolcano when viewed from the north,
but has a 1.5-km-wide summit crater that is breached open to the south.
This basaltic to basaltic-andesite volcano is the northernmost of a chain
constructed west of the main Kuril archipelago. Numerous pyroclastic cones
are present the lower flanks, particularly on the NW and SE sides,
including an offshore cone formed during the 1933-34 eruption. Strong
explosive eruptions have occurred from the summit crater beginning in the
18th century. Reports of eruptions in 1770, 1789, 1821, 1829, 1843, 1848,
and 1858 were considered incorrect by Gorshkov (1970). Explosive eruptions
in 1790 and 1981 were among the largest reported in the Kuril Islands.



Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!da_8a5mZcsDwDU5gEXg2ioCV-HzLz2wFIijIVptfy6NoE9hiz77589MW1bUXQSGsZjN3PuVJjbVNxZA0$ 
<https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!Z3Ir8q9N6O7-dybk3rtTVs70HeQ_SO_aAN4PyPY2dQivZ-ioMfHvF6XbnoxFN9ueqcwaNxHIZLg$>





Bezymianny  | Central Kamchatka (Russia)  | 55.972°N, 160.595°E  | Summit
elev. 2882 m



KVERT reported that during 8-15 December a daily thermal anomaly over
Bezymianny was identified in satellite images. The Aviation Color Code
remained at Yellow (the second lowest level on a four-color scale). Dates
are based on UTC times; specific events are in local time where noted.



Geologic Summary. The modern Bezymianny, much smaller than its massive
neighbors Kamen and Kliuchevskoi on the Kamchatka Peninsula, was formed
about 4,700 years ago over a late-Pleistocene lava-dome complex and an
ancestral edifice built about 11,000-7,000 years ago. Three periods of
intensified activity have occurred during the past 3,000 years. The latest
period, which was preceded by a 1,000-year quiescence, began with the
dramatic 1955-56 eruption. This eruption, similar to that of St. Helens in
1980, produced a large open crater that was formed by collapse of the
summit and an associated lateral blast. Subsequent episodic but ongoing
lava-dome growth, accompanied by intermittent explosive activity and
pyroclastic flows, has largely filled the 1956 crater.



Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!da_8a5mZcsDwDU5gEXg2ioCV-HzLz2wFIijIVptfy6NoE9hiz77589MW1bUXQSGsZjN3PuVJjbVNxZA0$ 
<https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!Z3Ir8q9N6O7-dybk3rtTVs70HeQ_SO_aAN4PyPY2dQivZ-ioMfHvF6XbnoxFN9ueqcwaNxHIZLg$>





Ebeko  | Paramushir Island (Russia)  | 50.686°N, 156.014°E  | Summit elev.
1103 m



KVERT reported that moderate activity at Ebeko was ongoing during 8-15
December. According to volcanologists in Severo-Kurilsk (Paramushir Island,
about 7 km E) explosions on 9 December generated ash plumes that rose to
2.6 km (8,500 ft) a.s.l. and drifted E. The volcano was obscured by weather
clouds on the other days of the week. The Aviation Color Code remained at
Orange (the second highest level on a four-color scale). Dates are based on
UTC times; specific events are in local time where noted.



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. Blocky lava flows extend west from Ebeko and SE from the
neighboring Nezametnyi cone. The eastern part of the southern crater
contains strong solfataras and a large boiling spring. The central crater
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, on the outer flanks of the
cone, and in lateral explosion craters.



Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!da_8a5mZcsDwDU5gEXg2ioCV-HzLz2wFIijIVptfy6NoE9hiz77589MW1bUXQSGsZjN3PuVJjbVNxZA0$ 
<https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!Z3Ir8q9N6O7-dybk3rtTVs70HeQ_SO_aAN4PyPY2dQivZ-ioMfHvF6XbnoxFN9ueqcwaNxHIZLg$>





Great Sitkin  | Andreanof Islands (USA)  | 52.076°N, 176.13°W  | Summit
elev. 1740 m



AVO reported that slow lava effusion likely continued at Great Sitkin
during 13-20 December, though satellite and webcam observations were mostly
obscured by clouds. Nothing notable was observed in clear webcam and
satellite views during 19-20 December. No significant seismic activity was
detected. The Volcano Alert Level remained at Watch (the second highest
level on a four-level scale) and the Aviation Color Code remained at Orange
(the second highest level on a four-color scale).



Geologic Summary. The Great Sitkin volcano forms much of the northern side
of Great Sitkin Island. A younger parasitic volcano capped by a small, 0.8
x 1.2 km ice-filled summit caldera was constructed within a large
late-Pleistocene or early Holocene scarp formed by massive edifice failure
that truncated an ancestral volcano and produced a submarine debris
avalanche. Deposits from this and an older debris avalanche from a source
to the south cover a broad area of the ocean floor north of the volcano.
The summit lies along the eastern rim of the younger collapse scarp.
Deposits from an earlier caldera-forming eruption of unknown age cover the
flanks of the island to a depth up to 6 m. The small younger caldera was
partially filled by lava domes emplaced in 1945 and 1974, and five small
older flank lava domes, two of which lie on the coastline, were constructed
along northwest- and NNW-trending lines. Hot springs, mud pots, and
fumaroles occur near the head of Big Fox Creek, south of the volcano.
Historical eruptions have been recorded since the late-19th century.



Source: US Geological Survey Alaska Volcano Observatory (AVO)
https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!da_8a5mZcsDwDU5gEXg2ioCV-HzLz2wFIijIVptfy6NoE9hiz77589MW1bUXQSGsZjN3PuVJjV9cymSX$ 
<https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!Z3Ir8q9N6O7-dybk3rtTVs70HeQ_SO_aAN4PyPY2dQivZ-ioMfHvF6XbnoxFN9ueqcwaszNBgKo$>





Karymsky  | Eastern Kamchatka (Russia)  | 54.049°N, 159.443°E  | Summit
elev. 1513 m



KVERT reported that a thermal anomaly at Karymsky was identified in
satellite images on 12 and 13 December. Gas-and-steam emissions persisted.
The Aviation Color Code remained at Yellow (the second lowest level on a
four-color scale). Dates are based on UTC times; specific events are in
local time where noted.



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 during the early Holocene. The caldera cuts
the south side of the Pleistocene Dvor volcano and is located outside the
north margin of the large mid-Pleistocene Polovinka caldera, which contains
the smaller Akademia Nauk and Odnoboky calderas. Most seismicity preceding
Karymsky eruptions originated beneath Akademia Nauk caldera, located
immediately south. The caldera enclosing Karymsky formed about 7600-7700
radiocarbon years ago; construction of the stratovolcano began about 2000
years later. The latest eruptive period began about 500 years ago,
following a 2300-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.



Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!da_8a5mZcsDwDU5gEXg2ioCV-HzLz2wFIijIVptfy6NoE9hiz77589MW1bUXQSGsZjN3PuVJjbVNxZA0$ 
<https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!Z3Ir8q9N6O7-dybk3rtTVs70HeQ_SO_aAN4PyPY2dQivZ-ioMfHvF6XbnoxFN9ueqcwaNxHIZLg$>





Kerinci  | Central Sumatra  | 1.697°S, 101.264°E  | Summit elev. 3800 m



PVMBG reported that daily white steam-and-gas plumes rose as high as 150 m
above Kerinciâ??s summit and drifted NE and NW during 14-17 December. Brown
plumes rose 100 m above the summit and drifted NW and E during 17-19
December. The Aviation Color Code remained at Orange (the second highest
level on a four-color scale). The Alert Level remained at 2 (on a scale of
1-4), and the public was warned to remain outside of the 3-km exclusion
zone.



Geologic Summary. Gunung Kerinci in central Sumatra forms Indonesia's
highest volcano and is one of the most active in Sumatra. It is capped by
an unvegetated young summit cone that was constructed NE of an older crater
remnant. There is a deep 600-m-wide summit crater often partially filled by
a small crater lake that lies on the NE crater floor, opposite the SW-rim
summit. The massive 13 x 25 km wide volcano towers 2400-3300 m above
surrounding plains and is elongated in a N-S direction. Frequently active,
Kerinci has been the source of numerous moderate explosive eruptions since
its first recorded eruption in 1838.



Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known
as CVGHM) https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!da_8a5mZcsDwDU5gEXg2ioCV-HzLz2wFIijIVptfy6NoE9hiz77589MW1bUXQSGsZjN3PuVJjYzJSzcE$ 
<https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!Z3Ir8q9N6O7-dybk3rtTVs70HeQ_SO_aAN4PyPY2dQivZ-ioMfHvF6XbnoxFN9ueqcwajEQpX3g$>





Krakatau  | Sunda Strait  | 6.102°S, 105.423°E  | Summit elev. 155 m



PVMBG reported that at 1031 on 15 December an eruptive event at Anak
Krakatau produced a dense gray ash plume that rose 700 m above summit and
drifted NE. Four minutes later a white-and-gray ash plume rose 100 m and
drifted NE. At 1910 a gray ash plume rose 100 m and drifted E. An image
from 1936 showed incandescent material being ejected above vent. Weather
clouds often prevented views of the volcano during 16-19 December, though
white plumes were occasionally seen rising as high as 50 m above the
summit. The Alert Level remained at 3 (on a scale of 1-4), and the public
was warned to stay at least 5 km away from the crater.



Geologic Summary. The renowned volcano Krakatau (frequently misstated as
Krakatoa) lies in the Sunda Strait between Java and Sumatra. Collapse of
the ancestral edifice, perhaps in 416 or 535 CE, formed a 7-km-wide
caldera. Remnants of that volcano are preserved in Verlaten and Lang
Islands; subsequently Rakata, Danan, and Perbuwatan volcanoes were formed,
coalescing to create the pre-1883 Krakatau Island. Caldera collapse during
the catastrophic 1883 eruption destroyed Danan and Perbuwatan, and left
only a remnant of Rakata. This eruption caused more than 36,000 fatalities,
most as a result of tsunamis that swept the adjacent coastlines of Sumatra
and Java. Pyroclastic surges traveled 40 km across the Sunda Strait and
reached the Sumatra coast. After a quiescence of less than a half century,
the post-collapse cone of Anak Krakatau (Child of Krakatau) was constructed
within the 1883 caldera at a point between the former cones of Danan and
Perbuwatan. Anak Krakatau has been the site of frequent eruptions since
1927.



Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known
as CVGHM) https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!da_8a5mZcsDwDU5gEXg2ioCV-HzLz2wFIijIVptfy6NoE9hiz77589MW1bUXQSGsZjN3PuVJjYzJSzcE$ 
<https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!Z3Ir8q9N6O7-dybk3rtTVs70HeQ_SO_aAN4PyPY2dQivZ-ioMfHvF6XbnoxFN9ueqcwajEQpX3g$>





Merapi  | Central Java  | 7.54°S, 110.446°E  | Summit elev. 2910 m



BPPTKG reported that the eruption at Merapi continued during 9-15 December
and seismicity remained at high levels. The SW lava dome produced four lava
avalanches that traveled as far as 1.5 km down the SW flank (upstream in
the Kali Bebeng drainage). No significant morphological changes to the
central and SW lava domes were evident. The Alert Level remained at 3 (on a
scale of 1-4), and the public was warned to stay 3-7 km away from the
summit based on location.



Geologic Summary. Merapi, one of Indonesia's most active volcanoes, lies in
one of the world's most densely populated areas and dominates the landscape
immediately north of the major city of Yogyakarta. It is the youngest and
southernmost of a volcanic chain extending NNW to Ungaran volcano. Growth
of Old Merapi during the Pleistocene ended with major edifice collapse
perhaps about 2,000 years ago, leaving a large arcuate scarp cutting the
eroded older Batulawang volcano. Subsequent growth of the steep-sided Young
Merapi edifice, its upper part unvegetated due to frequent activity, began
SW of the earlier collapse scarp. Pyroclastic flows and lahars accompanying
growth and collapse of the steep-sided active summit lava dome have
devastated cultivated lands on the western-to-southern flanks and caused
many fatalities.



Source: Balai Penyelidikan dan Pengembangan Teknologi Kebencanaan Geologi
(BPPTKG) https://urldefense.com/v3/__http://www.merapi.bgl.esdm.go.id/__;!!IKRxdwAv5BmarQ!da_8a5mZcsDwDU5gEXg2ioCV-HzLz2wFIijIVptfy6NoE9hiz77589MW1bUXQSGsZjN3PuVJjdEy34Xt$ 
<https://urldefense.com/v3/__http://www.merapi.bgl.esdm.go.id/__;!!IKRxdwAv5BmarQ!Z3Ir8q9N6O7-dybk3rtTVs70HeQ_SO_aAN4PyPY2dQivZ-ioMfHvF6XbnoxFN9ueqcwa4_3dD0E$>





Nevado del Ruiz  | Colombia  | 4.892°N, 75.324°W  | Summit elev. 5279 m



Servicio Geológico Colombianoâ??s (SGC) reported that seismicity at Nevado
del Ruiz began to increase at around 1550 on 13 December. The signals
indicated moving fluids within the volcanoâ??s conduit, and some were
associated with pulsating gas-and-ash emissions seen from several
surrounding municipalities. Ashfall was reported on 14 December in several
municipalities including Dosquebradas (40 km WSW), Santa Rosa de Cabal (34
km W), and Pereira (40 km WSW in Risaralda), Manizales (27 km NW) and
Villamaría (26 km NW in Caldas), and in the Los Nevados National Natural
Park sector. The Alert Level remained at 3 (Yellow; the second lowest level
on a four-color scale).



Geologic Summary. Nevado del Ruiz is a broad, glacier-covered volcano in
central Colombia that covers more than 200 km2. Three major edifices,
composed of andesitic and dacitic lavas and andesitic pyroclastics, have
been constructed since the beginning of the Pleistocene. The modern cone
consists of a broad cluster of lava domes built within the caldera of an
older edifice. The 1-km-wide, 240-m-deep Arenas crater occupies the summit.
The prominent La Olleta pyroclastic cone located on the SW flank may also
have been active in historical time. Steep headwalls of massive landslides
cut the flanks. Melting of its summit icecap during historical eruptions,
which date back to the 16th century, has resulted in devastating lahars,
including one in 1985 that was South America's deadliest eruption.



Source: Servicio Geológico Colombiano (SGC)
https://urldefense.com/v3/__https://www2.sgc.gov.co/volcanes/index.html__;!!IKRxdwAv5BmarQ!da_8a5mZcsDwDU5gEXg2ioCV-HzLz2wFIijIVptfy6NoE9hiz77589MW1bUXQSGsZjN3PuVJjYr7GP5X$ 
<https://urldefense.com/v3/__https://www2.sgc.gov.co/volcanes/index.html__;!!IKRxdwAv5BmarQ!Z3Ir8q9N6O7-dybk3rtTVs70HeQ_SO_aAN4PyPY2dQivZ-ioMfHvF6XbnoxFN9ueqcwalXPPisg$>





Pavlof  | Alaska Peninsula, Alaska  | 55.417°N, 161.894°W  | Summit elev.
2493 m



AVO reported that no elevated surface temperatures or incandescent lava at
Pavlof had been observed in satellite and webcam images since 2 December.
Seismicity remained above background levels with intermittent seismic
tremor, though explosions had not been recorded since 7 December. On 17
December AVO lowered the Volcano Alert Level to Advisory (the second lowest
level on a four-level scale) and the Aviation Color Code to Yellow (the
second lowest level on a four-color scale).



Geologic Summary. The most active volcano of the Aleutian arc, Pavlof is a
2519-m-high Holocene stratovolcano that was constructed along a line of
vents extending NE from the Emmons Lake caldera. Pavlof and its twin
volcano to the NE, 2142-m-high Pavlof Sister, form a dramatic pair of
symmetrical, glacier-covered stratovolcanoes that tower above Pavlof and
Volcano bays. A third cone, Little Pavlof, is a smaller volcano on the SW
flank of Pavlof volcano, near the rim of Emmons Lake caldera. Unlike Pavlof
Sister, Pavlof has been frequently active in historical time, typically
producing Strombolian to Vulcanian explosive eruptions from the summit
vents and occasional lava flows. The active vents lie near the summit on
the north and east sides. The largest historical eruption took place in
1911, at the end of a 5-year-long eruptive episode, when a fissure opened
on the N flank, ejecting large blocks and issuing lava flows.



Source: US Geological Survey Alaska Volcano Observatory (AVO)
https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!da_8a5mZcsDwDU5gEXg2ioCV-HzLz2wFIijIVptfy6NoE9hiz77589MW1bUXQSGsZjN3PuVJjV9cymSX$ 
<https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!Z3Ir8q9N6O7-dybk3rtTVs70HeQ_SO_aAN4PyPY2dQivZ-ioMfHvF6XbnoxFN9ueqcwaszNBgKo$>





Popocatepetl  | Mexico  | 19.023°N, 98.622°W  | Summit elev. 5393 m



CENAPRED reported that there were 53-196 steam-and-gas emissions, sometimes
containing minor amounts of ash, rising from Popocatépetl each day during
13-20 December. Explosions were recorded at 0747 and 0849 on 15 December. A
series of 12 explosions were recorded midweek, at 2107 and 2143 on 17
December and at 0102, 0247, 0404, 0440, 0604, 0614, 0639, 0741, 0752, and
0957 on 18 December. Some of the explosions ejected incandescent material
onto the upper flanks based on posted images and video. Two minor
explosions were detected at 1323 and 2252 on 18 December. A minor explosion
was recorded at 0250 on 19 December and two moderate ones occurred at 0045
and 0639 that same day. The Alert Level remained at Yellow, Phase Two (the
middle level on a three-color scale).



Geologic Summary. Volcán Popocatépetl, whose name is the Aztec word for
smoking mountain, rises 70 km SE of Mexico City to form North America's
2nd-highest volcano. The glacier-clad stratovolcano contains a
steep-walled, 400 x 600 m wide crater. The generally symmetrical volcano is
modified by the sharp-peaked Ventorrillo on the NW, a remnant of an earlier
volcano. At least three previous major cones were destroyed by
gravitational failure during the Pleistocene, producing massive
debris-avalanche deposits covering broad areas to the south. The modern
volcano was constructed south of the late-Pleistocene to Holocene El Fraile
cone. Three major Plinian eruptions, the most recent of which took place
about 800 CE, have occurred since the mid-Holocene, accompanied by
pyroclastic flows and voluminous lahars that swept basins below the
volcano. Frequent historical eruptions, first recorded in Aztec codices,
have occurred since Pre-Columbian time.



Source: Centro Nacional de Prevencion de Desastres (CENAPRED)
https://urldefense.com/v3/__https://www.gob.mx/cenapred__;!!IKRxdwAv5BmarQ!da_8a5mZcsDwDU5gEXg2ioCV-HzLz2wFIijIVptfy6NoE9hiz77589MW1bUXQSGsZjN3PuVJjZe4UjnS$ 
<https://urldefense.com/v3/__https://www.gob.mx/cenapred__;!!IKRxdwAv5BmarQ!Z3Ir8q9N6O7-dybk3rtTVs70HeQ_SO_aAN4PyPY2dQivZ-ioMfHvF6XbnoxFN9ueqcwaipMAxh0$>





Rincon de la Vieja  | Costa Rica  | 10.83°N, 85.324°W  | Summit elev. 1916 m



OVSICORI-UNA reported that small phreatic explosions continued at Rincón de
la Vieja during 14-20 December. A small phreatic explosion at 0828 on 14
December produced a steam plume that rose 500 m above the crater rim. An
associated sulfur dioxide anomaly was registered at a station located to
the W of the crater. Small phreatic events were also recorded at 1433 on 15
December, at 0314 and 2042 on 16 December, at 1958 on 17 December, and 0119
on 20 December, though cloudy weather conditions prevented visual
confirmation.



Geologic Summary. Rincón de la Vieja, the largest volcano in NW Costa Rica,
is a remote volcanic complex in the Guanacaste Range. The volcano consists
of an elongated, arcuate NW-SE-trending ridge constructed within the
15-km-wide early Pleistocene Guachipelín caldera, whose rim is exposed on
the south side. Sometimes known as the "Colossus of Guanacaste," it has an
estimated volume of 130 km3 and contains at least nine major eruptive
centers. Activity has migrated to the SE, where the youngest-looking
craters are located. The twin cone of Santa María volcano, the highest peak
of the complex, is located at the eastern end of a smaller, 5-km-wide
caldera and has a 500-m-wide crater. A Plinian eruption producing the 0.25
km3 Río Blanca tephra about 3,500 years ago was the last major magmatic
eruption. All subsequent eruptions, including numerous historical eruptions
possibly dating back to the 16th century, have been from the prominent
active crater containing a 500-m-wide acid lake located ENE of Von Seebach
crater.



Source: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad
Nacional (OVSICORI-UNA) https://urldefense.com/v3/__http://www.ovsicori.una.ac.cr/__;!!IKRxdwAv5BmarQ!da_8a5mZcsDwDU5gEXg2ioCV-HzLz2wFIijIVptfy6NoE9hiz77589MW1bUXQSGsZjN3PuVJjWiCMAut$ 
<https://urldefense.com/v3/__http://www.ovsicori.una.ac.cr/__;!!IKRxdwAv5BmarQ!Z3Ir8q9N6O7-dybk3rtTVs70HeQ_SO_aAN4PyPY2dQivZ-ioMfHvF6XbnoxFN9ueqcwaQ0E0EFI$>





San Miguel  | Eastern El Salvador  | 13.434°N, 88.269°W  | Summit elev.
2130 m



On 14 December MARN reported that activity at San Miguel continued to
decrease. They noted that there were no major changes to seismicity and gas
emissions, though minor explosions were occasionally detected by the
seismic network and manifested as small gas emissions. Sulfur dioxide
emissions were below the baseline of 300 tons per day.



Geologic Summary. The symmetrical cone of San Miguel, one of the most
active volcanoes in El Salvador, rises from near sea level to form one of
the country's most prominent landmarks. A broad, deep, crater complex that
has been frequently modified by eruptions recorded since the early 16th
century caps the truncated unvegetated summit, also known locally as
Chaparrastique. Flanks eruptions of the basaltic-andesitic volcano have
produced many lava flows, including several during the 17th-19th centuries
that extended to the N, NE, and SE. The SE-flank flows are the largest and
form broad, sparsely vegetated lava fields crossed by highways and a
railroad skirting the base of the volcano. Flank vent locations have
migrated higher on the edifice during historical time, and the most recent
activity has consisted of minor ash eruptions from the summit crater.



Source: Ministerio de Medio Ambiente y Recursos Naturales (MARN)
https://urldefense.com/v3/__https://marn.gob.sv/__;!!IKRxdwAv5BmarQ!da_8a5mZcsDwDU5gEXg2ioCV-HzLz2wFIijIVptfy6NoE9hiz77589MW1bUXQSGsZjN3PuVJjSqwFfed$ 
<https://urldefense.com/v3/__https://marn.gob.sv/__;!!IKRxdwAv5BmarQ!Z3Ir8q9N6O7-dybk3rtTVs70HeQ_SO_aAN4PyPY2dQivZ-ioMfHvF6XbnoxFN9ueqcwa7mTRqbA$>





Sheveluch  | Central Kamchatka (Russia)  | 56.653°N, 161.36°E  | Summit
elev. 3283 m



KVERT reported that the ongoing eruption at Sheveluch during 8-15 December
was generally characterized by explosions, hot avalanches, lava-dome
extrusion, and strong fumarolic activity. A daily thermal anomaly was
identified in satellite images. The Aviation Color Code remained at Orange
(the second highest level on a four-color scale). Dates are based on UTC
times; specific events are in local time where noted.



Geologic Summary. The high, isolated massif of Sheveluch volcano (also
spelled Shiveluch) rises above the lowlands NNE of the Kliuchevskaya
volcano group. The 1,300 km3 andesitic volcano is one of Kamchatka's
largest and most active volcanic structures, with at least 60 large
eruptions during the Holocene. The summit of roughly 65,000-year-old Stary
Shiveluch is truncated by a broad 9-km-wide late-Pleistocene caldera
breached to the south. Many lava domes occur on its outer flanks. The
Molodoy Shiveluch lava dome complex was constructed during the Holocene
within the large open caldera; Holocene lava dome extrusion also took place
on the flanks of Stary Shiveluch. Widespread tephra layers from these
eruptions have provided valuable time markers for dating volcanic events in
Kamchatka. Frequent collapses of dome complexes, most recently in 1964,
have produced debris avalanches whose deposits cover much of the floor of
the breached caldera.



Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!da_8a5mZcsDwDU5gEXg2ioCV-HzLz2wFIijIVptfy6NoE9hiz77589MW1bUXQSGsZjN3PuVJjbVNxZA0$ 
<https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!Z3Ir8q9N6O7-dybk3rtTVs70HeQ_SO_aAN4PyPY2dQivZ-ioMfHvF6XbnoxFN9ueqcwaNxHIZLg$>





Suwanosejima  | Ryukyu Islands (Japan)  | 29.638°N, 129.714°E  | Summit
elev. 796 m



JMA reported that the eruption at Suwanosejima's Ontake Crater continued
during 12-19 December. No explosions were recorded. Eruption plumes rose at
least 1.7 km above the crater rim and blocks were ejected as far as 100 m
from the vent. Crater incandescence was visible at night during 12-16
December and ashfall was occasionally reported in Toshima village (3.5 km
SSW) during 16-19 December. The Alert Level remained at 3 (on a 5-level
scale), and residents were warned to stay 2 km away from the crater.



Geologic Summary. The 8-km-long island of Suwanosejima in the northern
Ryukyu Islands consists of an andesitic stratovolcano with two historically
active summit craters. The summit is truncated by a large breached crater
extending to the sea on the east flank that was formed by edifice collapse.
One of Japan's most frequently active volcanoes, it was in a state of
intermittent Strombolian activity from Otake, the NE summit crater, between
1949 and 1996, after which periods of inactivity lengthened. The largest
recorded eruption took place in 1813-14, when thick scoria deposits
blanketed residential areas, and the SW crater produced two lava flows that
reached the western coast. At the end of the eruption the summit of Otake
collapsed, forming a large debris avalanche and creating the open Sakuchi
caldera, which extends to the eastern coast. The island remained
uninhabited for about 70 years after the 1813-1814 eruption. Lava flows
reached the eastern coast of the island in 1884. Only about 50 people live
on the island.



Source: Japan Meteorological Agency (JMA) https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!da_8a5mZcsDwDU5gEXg2ioCV-HzLz2wFIijIVptfy6NoE9hiz77589MW1bUXQSGsZjN3PuVJjdzuphp1$ 
<https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!Z3Ir8q9N6O7-dybk3rtTVs70HeQ_SO_aAN4PyPY2dQivZ-ioMfHvF6XbnoxFN9ueqcwaHNU59BU$>



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ASU - http://www.asu.edu/

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End of Volcano Digest - 19 Dec 2022 to 21 Dec 2022 (#2022-132)
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