Smithsonian / USGS Weekly Volcanic Activity Report 11-17 October 2023

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4-4-4-4-4-4-4-4-4-4-4-4-4


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


Smithsonian / USGS Weekly Volcanic Activity Report

11-17 October 2023



Sally Sennert - Weekly Report Editor (kuhns@xxxxxx)

URL: https://urldefense.com/v3/__https://volcano.si.edu/reports_weekly.cfm__;!!IKRxdwAv5BmarQ!et_mTBjbPzS2f7LTXLQ_6yu5qKEYFRL1ZMG1PsYvlHvIYM_gaVT0bwI3iHGXoMvTXWrHvyKMVNcmo9GH$ 
<https://urldefense.com/v3/__https://volcano.si.edu/reports_weekly.cfm__;!!IKRxdwAv5BmarQ!YuS5-SmP6GWjV_aG8uky_VbU0AFLmobGWJuNojkPcVwY_xsxe5hbWkYXMQgRCZ2cCfcMMguxrf8$>





New Activity/Unrest: Bezymianny, Central Kamchatka (Russia)  | Home Reef,
Tonga Ridge  | Klyuchevskoy, Central Kamchatka (Russia)



Ongoing Activity: Aira, Kyushu (Japan)  | Colima, Mexico  | Fuego,
South-Central Guatemala  | Great Sitkin, Andreanof Islands (USA)  |
Lewotolok, Lembata Island  | Mayon, Luzon (Philippines)  | Merapi, Central
Java  | Popocatepetl, Mexico  | Reventador, Ecuador  | Sangay, Ecuador  |
Santa Maria, Southwestern Guatemala  | Semeru, Eastern Java  | Sheveluch,
Central Kamchatka (Russia)  | Shishaldin, Fox Islands (USA)  |
Suwanosejima, Ryukyu Islands (Japan)  | Taal, Luzon (Philippines)  |
Villarrica, Central Chile  | Wrangell, Eastern Alaska





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





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



KVERT reported that activity at Bezymianny was significantly elevated
during 0700-0830 on 17 October and was characterized by large collapses on
the E flanks of the lava dome based on satellite and webcam images. These
collapses generated hot avalanches of material and produced ash-and-gas
plumes that rose as high as 3.5 km a.s.l. and drifted 15 km NE. At 1419 the
Aviation Color Code was raised to Orange (the third level on a four-color
scale). Lava extrusion continued at least through 1727 and ash plumes had
drifted as far as 86 km NE. All times are local.



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!et_mTBjbPzS2f7LTXLQ_6yu5qKEYFRL1ZMG1PsYvlHvIYM_gaVT0bwI3iHGXoMvTXWrHvyKMVFERjn9s$ 
<https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!YuS5-SmP6GWjV_aG8uky_VbU0AFLmobGWJuNojkPcVwY_xsxe5hbWkYXMQgRCZ2cCfcM-iIId2Q$>





Home Reef  | Tonga Ridge  | 18.992°S, 174.775°W  | Summit elev. -10 m



The Tonga Geological Services reported that Home Reef was erupting with a
total of 11 eruptive events detected in satellite data during 12-17
October. On 14 October the Aviation Color Code was Yellow and the Hazard
Alert was Orange; on 17 October the Aviation Color Code was lowered to
Green and the Hazard Alert was lowered to Yellow, though mariners continued
to be advised to stay 4 km away from the island. According to the
Wellington VAAC a pilot observed an ash plume below 300 m (1,000 ft) a.s.l.
in the vicinity of the volcano on 17 October, though the Tonga
Meteorological Services stated that the emissions were mainly composed of
steam. The most recent dimensions of the island were estimated to be about
424 m N-S and 223 m E-W, with an approximate total surface area of 17
acres, based on a 10 October satellite image. The island had steep
headlands on the E half and a more gradual slope on the W half.



Geologic Summary. Home Reef, a submarine volcano midway between Metis Shoal
and Late Island in the central Tonga islands, was first reported active in
the mid-19th century, when an ephemeral island formed. An eruption in 1984
produced a 12-km-high eruption plume, large amounts of floating pumice, and
an ephemeral 500 x 1,500 m island, with cliffs 30-50 m high that enclosed a
water-filled crater. In 2006 an island-forming eruption produced widespread
dacitic pumice rafts that drifted as far as Australia. Another island was
built during a September-October 2022 eruption.



Sources: Tonga Geological Services, Government of Tonga
https://urldefense.com/v3/__https://www.facebook.com/tongageologicalservice__;!!IKRxdwAv5BmarQ!et_mTBjbPzS2f7LTXLQ_6yu5qKEYFRL1ZMG1PsYvlHvIYM_gaVT0bwI3iHGXoMvTXWrHvyKMVKjZOwO2$ 
<https://urldefense.com/v3/__https://www.facebook.com/tongageologicalservice__;!!IKRxdwAv5BmarQ!YuS5-SmP6GWjV_aG8uky_VbU0AFLmobGWJuNojkPcVwY_xsxe5hbWkYXMQgRCZ2cCfcM45k4nBk$>
;

Wellington Volcanic Ash Advisory Center (VAAC) https://urldefense.com/v3/__http://vaac.metservice.com/__;!!IKRxdwAv5BmarQ!et_mTBjbPzS2f7LTXLQ_6yu5qKEYFRL1ZMG1PsYvlHvIYM_gaVT0bwI3iHGXoMvTXWrHvyKMVPLOiAxL$ 
<https://urldefense.com/v3/__http://vaac.metservice.com/__;!!IKRxdwAv5BmarQ!YuS5-SmP6GWjV_aG8uky_VbU0AFLmobGWJuNojkPcVwY_xsxe5hbWkYXMQgRCZ2cCfcMH0Gyo9w$>





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



KVERT reported that the Strombolian eruption at Klyuchevskoy continued
during 11-16 October and fed lava flows the descended the Apakhonchichsky
drainage on the SE flank. Activity was notable during 11-12 October,
characterized by the presence of ash in gas-and-steam plumes and an
increase in the lava effusion rate. KVERT raised the Aviation Color Code to
Orange (the third level on a four-color scale) as a result. According to
observers at the Kamchatka Volcanological Station, lava effusion was almost
continuous and incandescent material was ejected as high as 300 m above the
crater rim. On 16 October lava on the SE flank melted snow and ice, causing
phreatic explosions and large collapses of material from the margins of the
flow. Dates and times are in UTC; specific events are in local time where
noted.



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!et_mTBjbPzS2f7LTXLQ_6yu5qKEYFRL1ZMG1PsYvlHvIYM_gaVT0bwI3iHGXoMvTXWrHvyKMVFERjn9s$ 
<https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!YuS5-SmP6GWjV_aG8uky_VbU0AFLmobGWJuNojkPcVwY_xsxe5hbWkYXMQgRCZ2cCfcM-iIId2Q$>
;

Kamchatka Volcanological Station https://urldefense.com/v3/__http://volkstat.ru/__;!!IKRxdwAv5BmarQ!et_mTBjbPzS2f7LTXLQ_6yu5qKEYFRL1ZMG1PsYvlHvIYM_gaVT0bwI3iHGXoMvTXWrHvyKMVNV4wKia$ 
<https://urldefense.com/v3/__http://volkstat.ru/__;!!IKRxdwAv5BmarQ!YuS5-SmP6GWjV_aG8uky_VbU0AFLmobGWJuNojkPcVwY_xsxe5hbWkYXMQgRCZ2cCfcMw5P0f14$>





Ongoing Activity





Aira  | Kyushu (Japan)  | 31.5772°N, 130.6589°E  | Summit elev. 1117 m



JMA reported ongoing activity at Minamidake Crater (Aira Calderaâ??s
Sakurajima volcano) during 9-16 October, with incandescence at the crater
observed nightly. During the week there were a total of 18 eruptive events
and 18 explosions. Ash plumes rose as high as 2.6 km above the crater rim
and large blocks were ejected 800-900 m from the vent. The Alert Level
remained at 3 (on a 5-level scale), and the public was warned to stay 2 km
away from both craters.



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 caldera, along
with several post-caldera cones. The construction of Sakurajima began about
13,000 years ago on the southern rim and built an island that was joined to
the Osumi Peninsula during the major explosive and effusive eruption of
1914. Activity at the Kitadake summit cone ended about 4,850 years ago,
after which eruptions took place at Minamidake. Frequent eruptions since
the 8th century have deposited ash on the city of Kagoshima, located across
Kagoshima Bay only 8 km from the summit. The largest recorded eruption took
place during 1471-76.



Source: Japan Meteorological Agency (JMA) https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!et_mTBjbPzS2f7LTXLQ_6yu5qKEYFRL1ZMG1PsYvlHvIYM_gaVT0bwI3iHGXoMvTXWrHvyKMVL3lr1Qx$ 
<https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!YuS5-SmP6GWjV_aG8uky_VbU0AFLmobGWJuNojkPcVwY_xsxe5hbWkYXMQgRCZ2cCfcMT67ew5o$>





Colima  | Mexico  | 19.514°N, 103.62°W  | Summit elev. 3850 m



On 13 October the Centro Universitario de Estudios Vulcanológicos (CUEV) -
Universidad de Colima reported that during the previous week three lahars
descended the Zarco (WSW), Montegrande (S), and La Arena drainages,
triggered by Hurricane Lidia. In general, steam-and-gas emissions were low
and rose from the NE part of the crater.



Geologic Summary. The Colima complex is the most prominent volcanic center
of the western Mexican Volcanic Belt. It consists of two southward-younging
volcanoes, Nevado de Colima (the high point of the complex) on the north
and the historically active Volcán de Colima at the south. A group of
late-Pleistocene cinder cones is located on the floor of the Colima graben
west and east of the complex. Volcán de Colima (also known as Volcán Fuego)
is a youthful stratovolcano constructed within a 5-km-wide scarp, breached
to the south, that has been the source of large debris avalanches. Major
slope failures have occurred repeatedly from both the Nevado and Colima
cones, producing thick debris-avalanche deposits on three sides of the
complex. Frequent recorded eruptions date back to the 16th century.
Occasional major explosive eruptions have destroyed the summit (most
recently in 1913) and left a deep, steep-sided crater that was slowly
refilled and then overtopped by lava dome growth.



Source: Centro Universitario de Estudios Vulcanológicos (CUEV) -
Universidad de Colima https://urldefense.com/v3/__http://portal.ucol.mx/cueiv/contacto.htm__;!!IKRxdwAv5BmarQ!et_mTBjbPzS2f7LTXLQ_6yu5qKEYFRL1ZMG1PsYvlHvIYM_gaVT0bwI3iHGXoMvTXWrHvyKMVI5OuNMg$ 
<https://urldefense.com/v3/__http://portal.ucol.mx/cueiv/contacto.htm__;!!IKRxdwAv5BmarQ!YuS5-SmP6GWjV_aG8uky_VbU0AFLmobGWJuNojkPcVwY_xsxe5hbWkYXMQgRCZ2cCfcMocWVOtc$>





Fuego  | South-Central Guatemala  | 14.473°N, 90.88°W  | Summit elev. 3763 m



INSIVUMEH reported that, in general, 3-9 explosions per hour were recorded
at Fuego during 10-17 October, though the rate of explosions was not noted
on some of the days. The explosions generated ash-and-gas plumes that rose
as high as 1.1 km above the crater rim and drifted as far as 30 km mainly
SW, W, NW, and N. Minor ashfall was reported on a few of the days in areas
downwind including Morelia (9 km SW), Panimaché I and II (8 km SW), Santa
Sofía (12 km SW), Sangre de Cristo (8 km W), Acatenango (8 km E), San Pedro
Yepocapa (8 km NW), La Soledad (7 km N), La Rochela (8 km SSW), and Las
Palmas. Weak rumbling was heard daily, and shock waves were occasionally
detected. Explosions caused daily block avalanches to descend various
drainages including the Ceniza (SSW), Seca (W), Trinidad (S), Taniluyá
(SW), Honda (E), and El Jute (ESE), and Las Lajas (SE). The explosions
ejected incandescent material as high as 300 m above the summit on some of
the days. In the afternoon of 11 October lahars descended the Las Lajas, El
Jute, and Ceniza drainages, carrying tree branches, trunks, and blocks as
large as 1.5 m in diameter.



Geologic Summary. Volcán Fuego, one of Central America's most active
volcanoes, is also one of three large stratovolcanoes overlooking
Guatemala's former capital, Antigua. The scarp of an older edifice, Meseta,
lies between Fuego and Acatenango to the north. Construction of Meseta
dates back to about 230,000 years and continued until the late Pleistocene
or early Holocene. Collapse of Meseta may have produced the massive
Escuintla debris-avalanche deposit, which extends about 50 km onto the
Pacific coastal plain. Growth of the modern Fuego volcano followed,
continuing the southward migration of volcanism that began at the mostly
andesitic Acatenango. Eruptions at Fuego have become more mafic with time,
and most historical activity has produced basaltic rocks. Frequent vigorous
historical eruptions have been recorded since the onset of the Spanish era
in 1524, and have produced major ashfalls, along with occasional
pyroclastic flows and lava flows.



Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e
Hidrologia (INSIVUMEH) https://urldefense.com/v3/__http://www.insivumeh.gob.gt/__;!!IKRxdwAv5BmarQ!et_mTBjbPzS2f7LTXLQ_6yu5qKEYFRL1ZMG1PsYvlHvIYM_gaVT0bwI3iHGXoMvTXWrHvyKMVFmEUp_A$ 
<https://urldefense.com/v3/__http://www.insivumeh.gob.gt/__;!!IKRxdwAv5BmarQ!YuS5-SmP6GWjV_aG8uky_VbU0AFLmobGWJuNojkPcVwY_xsxe5hbWkYXMQgRCZ2cCfcM9TMRkT4$>





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 10-17 October and was confirmed by radar data on 15 October. A thick
flow in the summit crater mainly expanded E. Weakly elevated surface
temperatures were identified in satellite data during 10-11 October.
Seismicity was low and only a couple of earthquakes were detected during
15-16 October. Weather clouds often obscured satellite and webcam views.
The Volcano Alert Level remained at Watch (the third level on a four-level
scale) and the Aviation Color Code remained at Orange (the third color 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!et_mTBjbPzS2f7LTXLQ_6yu5qKEYFRL1ZMG1PsYvlHvIYM_gaVT0bwI3iHGXoMvTXWrHvyKMVFcIeVR9$ 
<https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!YuS5-SmP6GWjV_aG8uky_VbU0AFLmobGWJuNojkPcVwY_xsxe5hbWkYXMQgRCZ2cCfcM7JryAnY$>





Lewotolok  | Lembata Island  | 8.274°S, 123.508°E  | Summit elev. 1431 m



PVMBG reported that the eruption at Lewotolok continued during 11-17
October. White-and-gray ash plumes rose as high as 400 m above the summit
and W, NW, and E during 11-12 and 14 October. On the other days during the
week white steam-and-gas plumes rose as high as 500 m and drifted NW. At
2047 on 14 October a webcam image captured incandescent material that was
ejected above the summit. The Alert Level remained at 2 (on a scale of 1-4)
and the public was warned to stay at least 2 km away from the summit crater.



Geologic Summary. The Lewotolok (or Lewotolo) stratovolcano occupies the
eastern end of an elongated peninsula extending north into the Flores Sea,
connected to Lembata (formerly Lomblen) Island by a narrow isthmus. It is
symmetrical when viewed from the north and east. 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. Eruptions
recorded since 1660 have consisted of explosive activity from the summit
crater.



Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known
as CVGHM) https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!et_mTBjbPzS2f7LTXLQ_6yu5qKEYFRL1ZMG1PsYvlHvIYM_gaVT0bwI3iHGXoMvTXWrHvyKMVJicX4Um$ 
<https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!YuS5-SmP6GWjV_aG8uky_VbU0AFLmobGWJuNojkPcVwY_xsxe5hbWkYXMQgRCZ2cCfcM8emzYEs$>





Mayon  | Luzon (Philippines)  | 13.257°N, 123.685°E  | Summit elev. 2462 m



PHIVOLCS reported that slow lava effusion at Mayonâ??s summit crater
continued during 11-17 October. The lengths of the lava flow in the Mi-Isi
(S), Bonga (SE), and Basud (E) drainages remained at 2.8 km, 3.4 km, and
1.1 km, respectively. Collapses at the lava dome and from the margins of
the lava flows produced incandescent rockfalls and occasional pyroclastic
density currents (PDCs, or pyroclastic flows) that descended the flanks as
far as 4 km. Each day seismic stations recorded 100-126 rockfall events and
1-3 PDC events. There were 1-2 daily volcanic earthquakes during 10-14
October, and 26-37 daily volcanic earthquakes during 15-17 October that
also included 24-32 tremor events that lasted 1-32 minutes each. Sulfur
dioxide emissions measured almost daily averaged between 797 and 1,255
tonnes per day, with the highest value recorded on 12 October. The Alert
Level remained at 3 (on a 0-5 scale) and residents were reminded to stay
away from the 6-km-radius Permanent Danger Zone (PDZ). PHIVOLCS recommended
that civil aviation authorities advise pilots to avoid flying close to the
summit.



Geologic Summary. Symmetrical Mayon, which rises above the Albay Gulf NW of
Legazpi City, is the most active volcano of the Philippines. The steep
upper slopes are capped by a small summit crater. Recorded eruptions since
1616 CE range from Strombolian to basaltic Plinian, with cyclical activity
beginning with basaltic eruptions, followed by longer term andesitic lava
flows. Eruptions occur predominately from the central conduit and have also
produced lava flows that travel far down the flanks. Pyroclastic flows and
mudflows have commonly swept down many of the approximately 40 ravines that
radiate from the summit and have often damaged populated lowland areas. A
violent eruption in 1814 killed more than 1,200 people and devastated
several towns.



Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)
https://urldefense.com/v3/__http://www.phivolcs.dost.gov.ph/__;!!IKRxdwAv5BmarQ!et_mTBjbPzS2f7LTXLQ_6yu5qKEYFRL1ZMG1PsYvlHvIYM_gaVT0bwI3iHGXoMvTXWrHvyKMVPXdLi1f$ 
<https://urldefense.com/v3/__http://www.phivolcs.dost.gov.ph/__;!!IKRxdwAv5BmarQ!YuS5-SmP6GWjV_aG8uky_VbU0AFLmobGWJuNojkPcVwY_xsxe5hbWkYXMQgRCZ2cCfcMzRu0xZ0$>





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



BPPTKG reported that the eruption at Merapi (on Java) continued during 6-12
October and seismicity remained at elevated levels. The SW lava dome
produced a total of 163 lava avalanches that descended the S and SW flanks;
18 traveled as far as 1.6 km down the upper part of the Boyong drainage and
145 traveled as far as 2 km down the upper Bebeng drainage. Morphological
changes to the SW lava dome were due to continuous collapses of material.
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!et_mTBjbPzS2f7LTXLQ_6yu5qKEYFRL1ZMG1PsYvlHvIYM_gaVT0bwI3iHGXoMvTXWrHvyKMVCfOEcxU$ 
<https://urldefense.com/v3/__http://www.merapi.bgl.esdm.go.id/__;!!IKRxdwAv5BmarQ!YuS5-SmP6GWjV_aG8uky_VbU0AFLmobGWJuNojkPcVwY_xsxe5hbWkYXMQgRCZ2cCfcMv-V66Y0$>





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



CENAPRED reported that eruptive activity continued at Popocatépetl during
10-17 October. Long-period events totaling 87-402 per day were accompanied
by steam-and-gas plumes that sometimes contained minor amounts of ash. Some
of the plumes drifted NW and W, though cloudy weather conditions sometimes
prevented visual observations. Periods of low-amplitude and high-frequency
volcanic tremor were recorded daily, each lasting 23-462 minutes. According
to the Washington VAAC, a large, discrete ash plume was identified in a
satellite image at 1026 on 12 October rising to 6.7 km (22,000 ft) a.s.l.
and drifting NE. A thermal anomaly was also visible. A minor explosion was
recorded at 0405 on 13 October by the seismic network; the VAAC reported
that an ash plume was seen in satellite and webcam images at 0421 drifting
almost 30 km N at an altitude of 6.1 km (20,000 ft) a.s.l. A satellite
image from 0101 on 14 October showed ash fanning out to the NW at 6.7 km
a.s.l. and an image from 0701 showed a continuously emitted ash plume
drifting WNW and NW at the same altitude; the VAAC noted that the webcam
was not operational. CENAPRED stated that a moderate explosion was recorded
at 1419 on 14 October. Video taken by observers and posted on social media
showed a dark ash plume rising from the volcano. At 1831 on 14 October ash
emissions were ongoing and visible in webcam and satellite images drifting
WNW and NW according to the VAAC. At 0626 on 15 October an ash plume was
visible in satellite and webcam images slowly drifting W at an altitude of
6.4 km (21,000 ft) a.s.l. The Alert Level remained at Yellow, Phase Two
(the second level on a three-color scale) and the public was warned to stay
12 km away from the crater.



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.



Sources: Centro Nacional de Prevencion de Desastres (CENAPRED)
https://urldefense.com/v3/__https://www.gob.mx/cenapred__;!!IKRxdwAv5BmarQ!et_mTBjbPzS2f7LTXLQ_6yu5qKEYFRL1ZMG1PsYvlHvIYM_gaVT0bwI3iHGXoMvTXWrHvyKMVH5mutIG$ 
<https://urldefense.com/v3/__https://www.gob.mx/cenapred__;!!IKRxdwAv5BmarQ!YuS5-SmP6GWjV_aG8uky_VbU0AFLmobGWJuNojkPcVwY_xsxe5hbWkYXMQgRCZ2cCfcM6wp-2yQ$>
;

El Informante https://urldefense.com/v3/__https://twitter.com/ElInformanteMX/status/1713593796175552922__;!!IKRxdwAv5BmarQ!et_mTBjbPzS2f7LTXLQ_6yu5qKEYFRL1ZMG1PsYvlHvIYM_gaVT0bwI3iHGXoMvTXWrHvyKMVNCRrSkm$ 
<https://urldefense.com/v3/__https://twitter.com/ElInformanteMX/status/1713593796175552922__;!!IKRxdwAv5BmarQ!YuS5-SmP6GWjV_aG8uky_VbU0AFLmobGWJuNojkPcVwY_xsxe5hbWkYXMQgRCZ2cCfcMcr4ItfA$>





Reventador  | Ecuador  | 0.077°S, 77.656°W  | Summit elev. 3562 m



IG-EPN reported that the eruption at Reventador was ongoing during 10-17
October. Seismicity was characterized by 15-43 daily explosions,
long-period earthquakes, harmonic tremor, and tremor associated with
emissions. Several daily ash-and-gas plumes rose as high as 1.3 km above
the crater rim and drifted in multiple directions. Daily crater
incandescence was visible during both overnight and morning hours.
Incandescent material was ejected as high as 600 m above the crater rim
several times during 10-11 October. Avalanches of incandescent material
descended the flanks, concentrating down the SE flank during the beginning
of the week, and traveling as far as 800 m from the summit. Weather
conditions sometimes prevented views of the volcano. Secretaría de Gestión
de Riesgos maintained the Alert Level at Orange (the second highest level
on a four-color scale).



Geologic Summary. Volcán El Reventador is the most frequently active of a
chain of Ecuadorian volcanoes in the Cordillera Real, well east of the
principal volcanic axis. The forested, dominantly andesitic stratovolcano
has 4-km-wide avalanche scarp open to the E formed by edifice collapse. A
young, unvegetated, cone rises from the amphitheater floor to a height
comparable to the rim. It has been the source of numerous lava flows as
well as explosive eruptions visible from Quito, about 90 km ESE. Frequent
lahars in this region of heavy rainfall have left extensive deposits on the
scarp slope. The largest recorded eruption took place in 2002, producing a
17-km-high eruption column, pyroclastic flows that traveled up to 8 km, and
lava flows from summit and flank vents.



Sources: Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN)
https://urldefense.com/v3/__http://www.igepn.edu.ec/__;!!IKRxdwAv5BmarQ!et_mTBjbPzS2f7LTXLQ_6yu5qKEYFRL1ZMG1PsYvlHvIYM_gaVT0bwI3iHGXoMvTXWrHvyKMVD21xV2D$ 
<https://urldefense.com/v3/__http://www.igepn.edu.ec/__;!!IKRxdwAv5BmarQ!YuS5-SmP6GWjV_aG8uky_VbU0AFLmobGWJuNojkPcVwY_xsxe5hbWkYXMQgRCZ2cCfcMym_cXTU$>
;

Secretaría de Gestión de Riesgos (SGR) https://urldefense.com/v3/__http://www.gestionderiesgos.gob.ec/__;!!IKRxdwAv5BmarQ!et_mTBjbPzS2f7LTXLQ_6yu5qKEYFRL1ZMG1PsYvlHvIYM_gaVT0bwI3iHGXoMvTXWrHvyKMVL-gGNfA$ 
<https://urldefense.com/v3/__http://www.gestionderiesgos.gob.ec/__;!!IKRxdwAv5BmarQ!YuS5-SmP6GWjV_aG8uky_VbU0AFLmobGWJuNojkPcVwY_xsxe5hbWkYXMQgRCZ2cCfcM-UUQzlI$>





Sangay  | Ecuador  | 2.005°S, 78.341°W  | Summit elev. 5286 m



IG-EPN reported a high level of eruptive activity at Sangay during 10-17
October, with seismic stations recording 292-802 daily explosions. Several
daily ash-and-gas plumes rose as high as 1.5 km above the crater rim and
drifted N, NW, W, and SW. During overnight and morning hours webcam images
showed incandescent material descending the SE flank as far as 1.8 km from
the crater several times daily during overnight and early morning hours.
Incandescence at the crater was often visible; incandescent material was
ejected 500 m above the crater rim during 10-11 October. Secretaría de
Gestión de Riesgos maintained the Alert Level at Yellow (the second highest
level on a four-color scale).



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



Sources: Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN)
https://urldefense.com/v3/__http://www.igepn.edu.ec/__;!!IKRxdwAv5BmarQ!et_mTBjbPzS2f7LTXLQ_6yu5qKEYFRL1ZMG1PsYvlHvIYM_gaVT0bwI3iHGXoMvTXWrHvyKMVD21xV2D$ 
<https://urldefense.com/v3/__http://www.igepn.edu.ec/__;!!IKRxdwAv5BmarQ!YuS5-SmP6GWjV_aG8uky_VbU0AFLmobGWJuNojkPcVwY_xsxe5hbWkYXMQgRCZ2cCfcMym_cXTU$>
;

Secretaría de Gestión de Riesgos (SGR) https://urldefense.com/v3/__http://www.gestionderiesgos.gob.ec/__;!!IKRxdwAv5BmarQ!et_mTBjbPzS2f7LTXLQ_6yu5qKEYFRL1ZMG1PsYvlHvIYM_gaVT0bwI3iHGXoMvTXWrHvyKMVL-gGNfA$ 
<https://urldefense.com/v3/__http://www.gestionderiesgos.gob.ec/__;!!IKRxdwAv5BmarQ!YuS5-SmP6GWjV_aG8uky_VbU0AFLmobGWJuNojkPcVwY_xsxe5hbWkYXMQgRCZ2cCfcM-UUQzlI$>





Santa Maria  | Southwestern Guatemala  | 14.757°N, 91.552°W  | Summit elev.
3745 m



INSIVUMEH reported that eruptive activity continued at Santa Mariaâ??s
Santiaguito lava dome complex during 11-17 October with lava extrusion at
Caliente dome. Incandescence from the dome was visible during most nights
and early mornings, and occasionally from the lava flow on the WSW flank.
Explosions triggered incandescent avalanches that descended the domeâ??s
flanks in all directions. Block avalanches descended drainages on the SW,
S, SE, and E flanks; during 12-13 and 16-17 October the avalanches were
occasionally accompanied by small pyroclastic flows. Daily weak-to-moderate
explosions generated gas-and-ash plumes that rose 800-1,000 m above the
dome and drifted in multiple directions. During 13-14 October explosions
occurred at a rate of 1-2 per hour and produced block-and-ash flows that
descended the SW, S, and SE flanks and left gray ash deposits.



Geologic Summary. Symmetrical, forest-covered Santa María volcano is part
of a chain of large stratovolcanoes that rise above the Pacific coastal
plain of Guatemala. The sharp-topped, conical profile is cut on the SW
flank by a 1.5-km-wide crater. The oval-shaped crater extends from just
below the summit to the lower flank, and was formed during a catastrophic
eruption in 1902. The renowned Plinian eruption of 1902 that devastated
much of SW Guatemala followed a long repose period after construction of
the large basaltic-andesite stratovolcano. The massive 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 vents, with activity progressing W towards the most recent, Caliente.
Dome growth has been accompanied by almost continuous minor explosions,
with periodic lava extrusion, larger explosions, pyroclastic flows, and
lahars.



Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e
Hidrologia (INSIVUMEH) https://urldefense.com/v3/__http://www.insivumeh.gob.gt/__;!!IKRxdwAv5BmarQ!et_mTBjbPzS2f7LTXLQ_6yu5qKEYFRL1ZMG1PsYvlHvIYM_gaVT0bwI3iHGXoMvTXWrHvyKMVFmEUp_A$ 
<https://urldefense.com/v3/__http://www.insivumeh.gob.gt/__;!!IKRxdwAv5BmarQ!YuS5-SmP6GWjV_aG8uky_VbU0AFLmobGWJuNojkPcVwY_xsxe5hbWkYXMQgRCZ2cCfcM9TMRkT4$>





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



PVMBG reported that eruptive activity continued at Semeru during 11-17
October, though weather conditions sometimes prevented visual observations.
White-and-gray ash plumes rose 200-700 m above the summit and drifted N,
SE, S, and SW during 11-12 and 14-17 October. The Alert Level remained at 3
(third highest on a scale of 1-4). The public was warned to stay at least 5
km away from the summit in all directions, 13 km from the summit to the SE,
500 m from the banks of the Kobokan drainage as far as 17 km from the
summit, and to avoid other drainages 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!et_mTBjbPzS2f7LTXLQ_6yu5qKEYFRL1ZMG1PsYvlHvIYM_gaVT0bwI3iHGXoMvTXWrHvyKMVJicX4Um$ 
<https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!YuS5-SmP6GWjV_aG8uky_VbU0AFLmobGWJuNojkPcVwY_xsxe5hbWkYXMQgRCZ2cCfcM8emzYEs$>





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



KVERT reported that the eruption at Sheveluch continued during 5-12
October. A daily thermal anomaly was identified in satellite images and a
plume of resuspended ash drifted 90 km ESE on 11 October. The Aviation
Color Code remained at Orange (the third 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!et_mTBjbPzS2f7LTXLQ_6yu5qKEYFRL1ZMG1PsYvlHvIYM_gaVT0bwI3iHGXoMvTXWrHvyKMVFERjn9s$ 
<https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!YuS5-SmP6GWjV_aG8uky_VbU0AFLmobGWJuNojkPcVwY_xsxe5hbWkYXMQgRCZ2cCfcM-iIId2Q$>





Shishaldin  | Fox Islands (USA)  | 54.756°N, 163.97°W  | Summit elev. 2857 m



AVO reported that activity at Shishaldin during 10-17 October was
characterized by daily sulfur dioxide gas emissions (except on 12 October)
and frequent small earthquakes. Daily elevated surface temperatures were
identified in satellite images. Steam-and-gas plumes observed in webcam
images were reported each day, though weather conditions occasionally
prevented views. The emissions were robust during 14-16 October, likely
generated by the interaction of hot material and snow and ice. The Volcano
Alert Level remained at Watch (the third level on a four-level scale) and
the Aviation Color Code remained at Orange (the third color on a four-color
scale).



Geologic Summary. The symmetrical glacier-covered Shishaldin is the highest
and one of the most active volcanoes of the Aleutian Islands. It is the
westernmost of three large stratovolcanoes in the eastern half of Unimak
Island. The Aleuts named the volcano Sisquk, meaning "mountain which points
the way when I am lost." Constructed atop an older glacially dissected
edifice, it is largely basaltic in composition. Remnants of an older
ancestral volcano are exposed on the W and NE sides at 1,500-1,800 m
elevation. There are over two dozen pyroclastic cones on its NW flank,
which is blanketed by massive aa lava flows. Frequent explosive activity,
primarily consisting of Strombolian ash eruptions from the small summit
crater, but sometimes producing lava flows, has been recorded since the
18th century. A steam plume often rises from the summit crater.



Source: US Geological Survey Alaska Volcano Observatory (AVO)
https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!et_mTBjbPzS2f7LTXLQ_6yu5qKEYFRL1ZMG1PsYvlHvIYM_gaVT0bwI3iHGXoMvTXWrHvyKMVFcIeVR9$ 
<https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!YuS5-SmP6GWjV_aG8uky_VbU0AFLmobGWJuNojkPcVwY_xsxe5hbWkYXMQgRCZ2cCfcM7JryAnY$>





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 9-16 October and crater incandescence was visible nightly. During
11-12 and 16 October eruptive events generated plumes that rose as high as
1.5 km above the crater rim and drifted W, SW, and SE, and ejected large
blocks as far as 400 m from the vent. A total of eight explosions were
recorded by the seismic network at 1522 on 14 October, at 0337, 0433, 0555,
1008, and 1539 on 15 October, and at 0454 and 0517 on 16 October. Ash
plumes from the explosions rose as high as 900 m and drifted SE. Ash fell
in Toshima village (3.5 km SSW). The Alert Level remained at 2 (on a
5-level scale) and the public was warned to stay at least 1 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!et_mTBjbPzS2f7LTXLQ_6yu5qKEYFRL1ZMG1PsYvlHvIYM_gaVT0bwI3iHGXoMvTXWrHvyKMVL3lr1Qx$ 
<https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!YuS5-SmP6GWjV_aG8uky_VbU0AFLmobGWJuNojkPcVwY_xsxe5hbWkYXMQgRCZ2cCfcMT67ew5o$>





Taal  | Luzon (Philippines)  | 14.0106°N, 120.9975°E  | Summit elev. 311 m



PHIVOLCS reported increased and continuous gas emissions at Taal in a
special report issued on 12 October. Pronounced upwelling of gasses and hot
fluids in the lake produced short plumes that drifted SW. Sulfur dioxide
emissions were as high as 9,762 tonnes per day (t/d), the highest
measurement recorded in 2023; emissions in September and October averaged
3,781 t/d. These upwellings in the lake continued during 14-16 October and
sulfur dioxide emissions averaged 4,878 t/d on 14 October. The Alert Level
remained at 1 (on a scale of 0-5), and PHIVOLCS reminded the public that
the entire Taal Volcano Island was a Permanent Danger Zone (PDZ).



Geologic Summary. Taal is one of the most active volcanoes in the
Philippines and has produced some powerful eruptions. The 15 x 20 km
Talisay (Taal) caldera is largely filled by Lake Taal, whose 267 km2
surface lies only 3 m above sea level. The maximum depth of the lake is 160
m, with several submerged eruptive centers. The 5-km-wide Volcano Island in
north-central Lake Taal is the location of all observed eruptions. The
island is composed of coalescing small stratovolcanoes, tuff rings, and
scoria cones. Powerful pyroclastic flows and surges have caused many
fatalities.



Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)
https://urldefense.com/v3/__http://www.phivolcs.dost.gov.ph/__;!!IKRxdwAv5BmarQ!et_mTBjbPzS2f7LTXLQ_6yu5qKEYFRL1ZMG1PsYvlHvIYM_gaVT0bwI3iHGXoMvTXWrHvyKMVPXdLi1f$ 
<https://urldefense.com/v3/__http://www.phivolcs.dost.gov.ph/__;!!IKRxdwAv5BmarQ!YuS5-SmP6GWjV_aG8uky_VbU0AFLmobGWJuNojkPcVwY_xsxe5hbWkYXMQgRCZ2cCfcMzRu0xZ0$>





Villarrica  | Central Chile  | 39.42°S, 71.93°W  | Summit elev. 2847 m



POVI reported that Strombolian activity at Villarrica continued to be
observed in webcam images during 11-16 October. Lava fountains were
observed during 11-12 October; incandescent material was ejected as high as
125 m above the crater rim and incandescent bombs were ejected onto the
upper flanks. Strombolian explosions were less vigorous during 12-16
October with ballistics rising no higher than 100 m above the crater rim.
Some incandescent material was ejected onto the upper N flank during 15-16
October. According to SERNAGEOMIN, the Alert Level remained at Yellow (the
third level on a four-level scale) and the public was warned to stay 2 km
away from the crater. SENAPRED maintained the Alert Level at Yellow (the
middle level on a three-color scale) for the communities of Villarrica,
Pucón (16 km N), Curarrehue, and Panguipulli.



Geologic Summary. The glacier-covered Villarrica stratovolcano, in the
northern Lakes District of central Chile, is ~15 km south of the city of
Pucon. A 2-km-wide caldera that formed about 3,500 years ago is located at
the base of the presently active, dominantly basaltic to basaltic-andesite
cone at the NW margin of a 6-km-wide Pleistocene caldera. More than 30
scoria cones and fissure vents are present on the flanks. Plinian eruptions
and pyroclastic flows that have extended up to 20 km from the volcano were
produced during the Holocene. Lava flows up to 18 km long have issued from
summit and flank vents. Eruptions documented since 1558 CE have consisted
largely of mild-to-moderate explosive activity with occasional lava
effusion. Glaciers cover 40 km2 of the volcano, and lahars have damaged
towns on its flanks.



Sources: Proyecto Observación Villarrica Internet (POVI) https://urldefense.com/v3/__http://www.povi.cl/__;!!IKRxdwAv5BmarQ!et_mTBjbPzS2f7LTXLQ_6yu5qKEYFRL1ZMG1PsYvlHvIYM_gaVT0bwI3iHGXoMvTXWrHvyKMVE5sfSuq$ 
<https://urldefense.com/v3/__http://www.povi.cl/__;!!IKRxdwAv5BmarQ!YuS5-SmP6GWjV_aG8uky_VbU0AFLmobGWJuNojkPcVwY_xsxe5hbWkYXMQgRCZ2cCfcMmbv57T8$>
;

Servicio Nacional de Geología y Minería (SERNAGEOMIN)
https://urldefense.com/v3/__http://www.sernageomin.cl/__;!!IKRxdwAv5BmarQ!et_mTBjbPzS2f7LTXLQ_6yu5qKEYFRL1ZMG1PsYvlHvIYM_gaVT0bwI3iHGXoMvTXWrHvyKMVE8naqJ1$ 
<https://urldefense.com/v3/__http://www.sernageomin.cl/__;!!IKRxdwAv5BmarQ!YuS5-SmP6GWjV_aG8uky_VbU0AFLmobGWJuNojkPcVwY_xsxe5hbWkYXMQgRCZ2cCfcM9VlqOtk$>
;

Sistema y Servicio Nacional de Prevención y Repuesta Ante Desastres
(SENAPRED) https://urldefense.com/v3/__https://senapred.cl/__;!!IKRxdwAv5BmarQ!et_mTBjbPzS2f7LTXLQ_6yu5qKEYFRL1ZMG1PsYvlHvIYM_gaVT0bwI3iHGXoMvTXWrHvyKMVHAdZaHr$ 
<https://urldefense.com/v3/__https://senapred.cl/__;!!IKRxdwAv5BmarQ!YuS5-SmP6GWjV_aG8uky_VbU0AFLmobGWJuNojkPcVwY_xsxe5hbWkYXMQgRCZ2cCfcMbJwkHj4$>





Wrangell  | Eastern Alaska  | 62.006°N, 144.017°W  | Summit elev. 4278 m



On 13 October AVO changed both the Aviation Color Code and the Volcano
Alert Level for Wrangell to Unassigned because of a station outage and the
inability to reliably detect unrest at the volcano. AVO will continue using
satellite, regional infrasound, and lightning data, and reports from pilots
and ground observers to detect signs of eruptive activity.



Geologic Summary. With a diameter of 30 km at 2000 m elevation, Mount
Wrangell is one of the world's largest continental-margin volcanoes. The
massive andesitic shield volcano has produced fluid lava flows as long as
58 km and contains an ice-filled caldera 4-6 km in diameter and 1 km deep,
located within an ancestral 15-km-wide caldera. Most of the edifice was
constructed during eruptions between about 600,000 and 200,000 years ago.
Formation of the summit caldera followed sometime between about 200,000 and
50,000 years ago. Three post-caldera craters are located at the broad
summit, along the northern and western caldera rim. A steep-sided flank
cinder cone, Mount Zanetti, is located 6 km NW of the summit. The
westernmost cone has been the source of infrequent historical eruptions
beginning in the 18th century. Increased heat flux in recent years has
melted large volumes of ice in the northern crater.



Source: US Geological Survey Alaska Volcano Observatory (AVO)
https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!et_mTBjbPzS2f7LTXLQ_6yu5qKEYFRL1ZMG1PsYvlHvIYM_gaVT0bwI3iHGXoMvTXWrHvyKMVFcIeVR9$ 
<https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!YuS5-SmP6GWjV_aG8uky_VbU0AFLmobGWJuNojkPcVwY_xsxe5hbWkYXMQgRCZ2cCfcM7JryAnY$>


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End of Volcano Digest - 16 Oct 2023 to 18 Oct 2023 (#2023-100)
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