Smithsonian / USGS Weekly Volcanic Activity Report 2-8 February 2022

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


Smithsonian / USGS Weekly Volcanic Activity Report

2-8 February 2022



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

URL: https://urldefense.com/v3/__https://volcano.si.edu/reports_weekly.cfm__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdI_KK4LFY$ 
<https://urldefense.com/v3/__https://volcano.si.edu/reports_weekly.cfm__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwvF8uwsw$>





New Activity/Unrest: Ambrym, Vanuatu  | Chikurachki, Paramushir Island
(Russia)  | Hunga Tonga-Hunga Ha'apai, Tonga Ridge  | Krakatau, Sunda
Strait  | Taal, Luzon (Philippines)  | Villarrica, Central Chile  | Wolf,
Isla Isabela (Galapagos)



Ongoing Activity: Aira, Kyushu (Japan)  | Ambae, Vanuatu  | Davidof,
Aleutian Islands (USA)  | Etna, Sicily (Italy)  | Great Sitkin, Andreanof
Islands (USA)  | Kilauea, Hawaiian Islands (USA)  | Lewotolok, Lembata
Island  | Merapi, Central Java  | Pavlof, Alaska Peninsula, Alaska  |
Popocatepetl, Mexico  | Rincon de la Vieja, Costa Rica  | Sangay, Ecuador
| Santa Maria, Southwestern Guatemala  | Semeru, Eastern Java  |
Semisopochnoi, Aleutian Islands (USA)  | Sheveluch, Central Kamchatka
(Russia)  | Suwanosejima, Ryukyu Islands (Japan)  | Turrialba, Costa Rica
| Yasur, Vanuatu





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





Ambrym  | Vanuatu  | 16.25°S, 168.12°E  | Summit elev. 1334 m



On 2 February the Vanuatu Meteorology and Geo-Hazards Department (VMGD)
reported that sulfur dioxide gas emissions from Ambrym were detected in
satellite images drifting E. The Alert Level remained at 2 (on a scale of
0-5). VMGD warned the public to stay outside of the Permanent Danger Zone
A, defined as a 1-km radius around Benbow Crater and a 2-km radius around
Marum Crater, and additionally to stay 500 m away from the ground cracks
created by the December 2018 eruption.



Geologic Summary. Ambrym, a large basaltic volcano with a 12-km-wide
caldera, is one of the most active volcanoes of the New Hebrides Arc. A
thick, almost exclusively pyroclastic sequence, initially dacitic then
basaltic, overlies lava flows of a pre-caldera shield volcano. The caldera
was formed during a major Plinian eruption with dacitic pyroclastic flows
about 1,900 years ago. Post-caldera eruptions, primarily from Marum and
Benbow cones, have partially filled the caldera floor and produced lava
flows that ponded on the floor or overflowed through gaps in the caldera
rim. Post-caldera eruptions have also formed a series of scoria cones and
maars along a fissure system oriented ENE-WSW. Eruptions have apparently
occurred almost yearly during historical time from cones within the caldera
or from flank vents. However, from 1850 to 1950, reporting was mostly
limited to extra-caldera eruptions that would have affected local
populations.



Source: Vanuatu Meteorology and Geo-Hazards Department (VMGD)
https://urldefense.com/v3/__http://www.geohazards.gov.vu/__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdI7d0thpY$ 
<https://urldefense.com/v3/__http://www.geohazards.gov.vu/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwm_X5l_0$>





Chikurachki  | Paramushir Island (Russia)  | 50.324°N, 155.461°E  | Summit
elev. 1781 m



KVERT reported that the eruption at Chikurachki that began around 0300 on
31 January was over by 2 February. Explosions generated ash plumes that
rose as high as 5 km (16,400 ft) a.s.l. and drifted as far as 255 km W, SW,
S, and SE. The Aviation Color Code was lowered to Yellow on 3 February and
to Green on 5 February, the lowest color on a four-color scale.



Geologic Summary. Chikurachki, the highest volcano on Paramushir Island in
the northern Kuriles, is actually a relatively small cone constructed on a
high Pleistocene volcanic edifice. Oxidized basaltic-to-andesitic scoria
deposits covering the upper part of the young cone give it a distinctive
red color. Frequent basaltic plinian eruptions have occurred during the
Holocene. Lava flows from 1781-m-high Chikurachki reached the sea and form
capes on the NW coast; several young lava flows also emerge from beneath
the scoria blanket on the eastern flank. The Tatarinov group of six
volcanic centers is located immediately to the south of Chikurachki, and
the Lomonosov cinder cone group, the source of an early Holocene lava flow
that reached the saddle between it and Fuss Peak to the west, lies at the
southern end of the N-S-trending Chikurachki-Tatarinov complex. In contrast
to the frequently active Chikurachki, the Tatarinov volcanoes are
extensively modified by erosion and have a more complex structure.
Tephrochronology gives evidence of only one eruption in historical time
from Tatarinov, although its southern cone contains a sulfur-encrusted
crater with fumaroles that were active along the margin of a crater lake
until 1959.



Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdI7-3vz34$ 
<https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwIUtd3Qg$>





Hunga Tonga-Hunga Ha'apai  | Tonga Ridge  | 20.536°S, 175.382°W  | Summit
elev. 114 m



On 4 February the Tonga Geological Services (TGS) posted drone footage of
the Good Samaritan Beach, located on the NE side of Tongatapu, showing that
tsunamis from the 15 January Hunga Tonga-Hunga Ha'apai eruption reached
areas at 15 m elevation, 200 m inland. A 6 February post provided details
of what happened when tsunamis reached Mango Island (75 km ENE), stating
that waves 12 m high went over the church tower, reached 500 m inland, and
pushed buildings and structures against the inland wall of trees. Residents
fled to an area that was 30 m elevation, 700 m from the coast, and stayed
there all night as ash fell. TGS noted that clean-up efforts were
continuing on the islands and communications were slowly being restored.



Geologic Summary. The small andesitic islands of Hunga Tonga and Hunga
Ha'apai are part of the western and northern remnants of the rim (~6 km
diameter) of a largely submarine caldera located about 30 km SSE of Falcon
Island. The topmost sequence of welded and unwelded ignimbrite units from a
caldera-forming eruption was 14C dated to 1040-1180 CE (Cronin et al.,
2017; Brenna et al. 2022). At least two additional welded pumice-rich
ignimbrite units and nonwelded pyroclastic flow deposits, below paleosols
and other volcaniclastic deposits, indicated more very large previous
eruptions (Cronin et al., 2017; Brenna et al. 2022). Several submarine
eruptions have occurred at this caldera system since the first recorded
eruption in 1912, including 1937 and S of the islands in 1988. A short
eruption in 2009 added land to to Hunga Ha'apai. At that time the two
islands were each about 2 km long, displaying inward-facing sea cliffs with
lava and tephra layers dipping gently away from the caldera. An eruption
during December 2014-January 2015 was centered between the islands, and
combined them into one larger structure. Major explosive eruptions in late
2021 initially reshaped the central part of the combined island before
stronger activity in mid-January 2022 removed most of the 2014-15 material;
an even larger eruption the next day sent an eruption plume high into the
stratosphere, triggered shock waves through the atmosphere and tsunami
across the Pacific Ocean, and left only small remnants of the islands above
the ocean surface.



Source: Tonga Geological Services, Government of Tonga
https://urldefense.com/v3/__https://www.facebook.com/tongageologicalservice__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdI7bQpsWw$ 
<https://urldefense.com/v3/__https://www.facebook.com/tongageologicalservice__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELw8Wf4WG8$>





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



PVMBG reported that as many as 10 eruptive events at Anak Krakatau were
recorded during 3-5 February, with dense, gray-black ash plumes rising
800-1,000 m above the vent and drifting N, NE, E, and S. Ash emissions were
first visible at 1000 on 3 February, and incandescence above the crater was
observed at night. 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 crater.



Geologic Summary. The renowned volcano Krakatau (frequently misstated as
Krakatoa) lies in the Sunda Strait between Java and Sumatra. Collapse of
the ancestral Krakatau edifice, perhaps in 416 or 535 CE, formed a
7-km-wide caldera. Remnants of this ancestral 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, the 2nd
largest in Indonesia during historical time, caused more than 36,000
fatalities, most as a result of devastating 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!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdIii16zoI$ 
<https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwa92JAxc$>





Taal  | Luzon (Philippines)  | 14.002°N, 120.993°E  | Summit elev. 311 m



PHIVOLCS reported that unrest at Taal continued during 1-8 February, with
persistent low-level background tremor, hot volcanic fluids circulating in
the crater lake, and daily gas-and-steam plumes rising as high as 1.5 km
above the lake that drifted SW. Sulfur dioxide emissions continued to be
elevated, averaging 7,008-7,902 tonnes/day on 2 and 4 February.



Each day during 1-3 February the seismic network recorded as many as 152
volcanic earthquakes, 114 low-frequency volcanic earthquakes per day, five
hybrid events, and 33 daily episodes of volcanic tremor each lasting 1-2
minutes. One short-lived (two minutes) phreatomagmatic burst recorded at
1555 on 2 February produced a plume that rose 300 m from the lake and
drifted SW. Two low-frequency earthquakes were noted during 3-4 February
and one volcanic earthquake was recorded during 7-8 February. Tilt,
continuous GPS, and InSAR data all indicated that Taal Volcano Island and
the Taal region had begun deflating in October 2021. The Volcano Alert
Level remained at a 2 (on a scale of 0-5). PHIVOLCS reminded the public
that the entire Taal Volcano Island is a Permanent Danger Zone (PDZ) and
warned against extended stays on Taal Lake.



Geologic Summary. Taal is one of the most active volcanoes in the
Philippines and has produced some of its most powerful historical
eruptions. Though not topographically prominent, its prehistorical
eruptions have greatly changed the landscape of SW Luzon. 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, and several eruptive centers lie submerged beneath the lake. The
5-km-wide Volcano Island in north-central Lake Taal is the location of all
historical eruptions. The island is composed of coalescing small
stratovolcanoes, tuff rings, and scoria cones that have grown about 25% in
area during historical time. Powerful pyroclastic flows and surges from
historical eruptions have caused many fatalities.



Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)
https://urldefense.com/v3/__http://www.phivolcs.dost.gov.ph/__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdIAZsryk0$ 
<https://urldefense.com/v3/__http://www.phivolcs.dost.gov.ph/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwmpgtLFo$>





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



The Buenos Aires VAAC reported that an ash plume from Villarrica rose
2.7-4.6 km (9,000-15,000 ft) a.s.l. and drifted E at 1050 on 2 February
based on webcam images and information from SERNAGEOMIN. By 1130 the ash
plume was barely visible in satellite images. Webcam images showed
continuous emissions of gas with sporadic puffs of ash that rose as high as
4.9 km (16,000 ft) a.s.l. The puffs of ash were diffuse by 1730, and by
2330 no emissions were visible in webcam and satellite images.



Geologic Summary. Glacier-clad Villarrica, one of Chile's most active
volcanoes, rises above the lake and town of the same name. It is the
westernmost of three large stratovolcanoes that trend perpendicular to the
Andean chain. A 6-km-wide caldera formed during the late Pleistocene. A
2-km-wide caldera that formed about 3500 years ago is located at the base
of the presently active, dominantly basaltic to basaltic-andesitic cone at
the NW margin of the Pleistocene caldera. More than 30 scoria cones and
fissure vents dot 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. Historical eruptions, documented since 1558, 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.



Source: Buenos Aires Volcanic Ash Advisory Center (VAAC)
https://urldefense.com/v3/__http://www.smn.gov.ar/vaac/buenosaires/productos.php__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdIRndUNzE$ 
<https://urldefense.com/v3/__http://www.smn.gov.ar/vaac/buenosaires/productos.php__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwhmBqv24$>





Wolf  | Isla Isabela (Galapagos)  | 0.02°N, 91.35°W  | Summit elev. 1710 m



IG reported that the eruption at Wolf continued during 1-8 February. Daily
thermal alert counts, anywhere from a few to well over two hundred,
indicated active and advancing lava flows on the SE flank. Gas emissions
were identified in satellite images on most days.



Geologic Summary. Wolf, the highest volcano of the Galápagos Islands,
straddles the equator at the north end of the archipelago's largest island,
Isabela. The 1710-m-high edifice has steeper slopes than most other Isabela
volcanoes, reaching angles up to 35 degrees. A 6 x 7 km caldera, at 700 m
one of the deepest of the Galápagos Islands, is located at the summit. A
prominent bench on the west side of the caldera rises 450 above the caldera
floor, much of which is covered by a lava flow erupted in 1982. Radial
fissures concentrated along diffuse rift zones extend down the north, NW,
and SE flanks, and submarine vents lie beyond the north and NW fissures.
Similar unvegetated flows originating from a circumferential chain of
spatter and scoria cones on the eastern caldera rim drape the forested
flanks to the sea. The proportion of aa lava flows at Volcán Wolf exceeds
that of other Galápagos volcanoes. An eruption in in 1797 was the first
documented historical eruption in the Galápagos Islands.



Source: Instituto Geofísico-Escuela Politécnica Nacional (IG)
https://urldefense.com/v3/__http://www.igepn.edu.ec/__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdI4zb0hIQ$ 
<https://urldefense.com/v3/__http://www.igepn.edu.ec/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELw0-RW__w$>





Ongoing Activity





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



JMA reported that very small eruptive events were recorded at Minamidake
Crater (at Aira Calderaâ??s Sakurajima volcano) during 31 January-4 February.
Ejected incandescent material was visible at night during 4-7 February. 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!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdIwhGY79E$ 
<https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwsKxzB88$>





Ambae  | Vanuatu  | 15.389°S, 167.835°E  | Summit elev. 1496 m



On 5 February the Vanuatu Meteorology and Geo-Hazards Department (VMGD)
reported that the cone in Ambaeâ??s Lake Voui continued to grow and produce
steam, gas, and ash emissions. Images from two webcams (in Saratamata,
Ambae Island and in Enar, Pentecost Island) showed the plumes rising above
the summit and drifting S and SE. The Alert Level remained at 2 (on a scale
of 0-5) and the public was warned to stay outside of the Danger Zone
defined as a 2-km radius around the active vents in Lake Voui and away from
drainages during heavy rains.



Geologic Summary. The island of Ambae, also known as Aoba, is a massive
2,500 km3 basaltic shield that is the most voluminous volcano of the New
Hebrides archipelago. A pronounced NE-SW-trending rift zone dotted with
scoria cones gives the 16 x 38 km island an elongated form. A broad
pyroclastic cone containing three crater lakes (Manaro Ngoru, Voui, and
Manaro Lakua) is located at the summit within the youngest of at least two
nested calderas, the largest of which is 6 km in diameter. That large
central edifice is also called Manaro Voui or Lombenben volcano.
Post-caldera explosive eruptions formed the summit craters about 360 years
ago. A tuff cone was constructed within Lake Voui (or Vui) about 60 years
later. The latest known flank eruption, about 300 years ago, destroyed the
population of the Nduindui area near the western coast.



Source: Vanuatu Meteorology and Geo-Hazards Department (VMGD)
https://urldefense.com/v3/__http://www.geohazards.gov.vu/__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdI7d0thpY$ 
<https://urldefense.com/v3/__http://www.geohazards.gov.vu/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwm_X5l_0$>





Davidof  | Aleutian Islands (USA)  | 51.97°N, 178.33°E  | Summit elev. 328 m



An earthquake swarm, either related to tectonic processes or volcanic
unrest, began in the vicinity of Davidof on 24 January. The swarm continued
at low levels during 1-8 February with daily small earthquakes. The
Aviation Color Code remained at Yellow and the Volcano Alert Level remained
at Advisory.



Geologic Summary. A cluster of small islands between Segula and Little
Sitkin in the western Aleutians, the largest of which is Davidof, are
remnants of a stratovolcano that collapsed during the late Tertiary,
forming a 2.7-km-wide caldera. The islands include Khvostof, Pyramid, Lopy,
and Davidof; the latter three form the eastern rim of the mostly submarine
caldera, sometimes referred to as the "Aleutian Krakatau." The islands were
constructed above a roughly 100-m-deep submarine platform extending NW to
Segula Island; the floor of the caldera lies 80 m below sea level. The
islands are vegetated, but lava flows are recognizable, and Smith et al.
(1978) suggested a possible Holocene age.



Source: US Geological Survey Alaska Volcano Observatory (AVO)
https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdIpT_OAjo$ 
<https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwALOazBw$>





Etna  | Sicily (Italy)  | 37.748°N, 14.999°E  | Summit elev. 3320 m



INGV reported that sporadic explosive activity at Etnaâ??s Southeast Crater
(SEC) resumed at 0115 on 30 January, producing diffuse ash emissions that
rapidly dispersed near the summit, and weak Strombolian activity was
visible the next day. Webcam views were intermittent due to weather clouds
the next day, but by the morning of 2 February all activity had definitely
stopped. Minor and variable gas emissions rose from the Northeast Crater,
Bocca Nuova, and Voragine Crater.



Geologic Summary. Mount Etna, towering above Catania, Sicily's second
largest city, has one of the world's longest documented records of
historical volcanism, dating back to 1500 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
horseshoe-shaped 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!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdIvXiAAik$ 
<https://urldefense.com/v3/__http://www.ct.ingv.it/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwZboak1w$>





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



AVO reported that slow lava effusion at Great Sitkin continued during 2-8
February, though cloudy conditions often prevented satellite and webcam
views. Seismicity remained slightly elevated. The flow field expanded with
up to 100 m of advancement of the S, W, and N flank lava flows. Elevated
surface temperatures were periodically identified in satellite images. A
steam plume was visible in webcam images during 5-6 February. The Aviation
Color Code and the Volcano Alert Level remained at Orange and Watch,
respectively.



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!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdIpT_OAjo$ 
<https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwALOazBw$>





Kilauea  | Hawaiian Islands (USA)  | 19.421°N, 155.287°W  | Summit elev.
1222 m



HVO reported that lava effusion at the vent of the main cone in the lower W
wall of Kilaueaâ??s Halema`uma`u Crater continued during 2-8 February. The
lake level fluctuated, likely reflecting variable lava supply along with
periods of inflation and deflation. A small spatter cone, less than 6 m
tall, located near the E end of the crater produced lava fountains that
were 10 m tall in the evening of 1 February. The fountains fed a short flow
confined to the E margin of the crater. Effusion from the W vent paused
during around 0900-1730 on 2 February. During the rest of the week the
effusion rate fluctuated; the lake continued to circulate, although less
when the effusion rate was lower. Multiple ooze-outs of lava along the N,
E, and S margins of the crater were visible. The Aviation Color Code and
the Volcano Alert Level remained at Orange and Watch, respectively.



Geologic Summary. Kilauea overlaps the E flank of the massive Mauna Loa
shield volcano in the island of Hawaii. Eruptions are prominent in
Polynesian legends; written documentation since 1820 records frequent
summit and flank lava flow eruptions interspersed with periods of long-term
lava lake activity at Halemaumau crater in the summit caldera until 1924.
The 3 x 5 km caldera was formed in several stages about 1,500 years ago and
during the 18th century; eruptions have also originated from the lengthy
East and Southwest rift zones, which extend to the ocean in both
directions. About 90% of the surface of the basaltic shield volcano is
formed of lava flows less than about 1,100 years old; 70% of the surface is
younger than 600 years. The long-term eruption from the East rift zone
between 1983 and 2018 produced lava flows covering more than 100 km2,
destroyed hundreds of houses, and added new coastline.



Source: US Geological Survey Hawaiian Volcano Observatory (HVO)
https://urldefense.com/v3/__https://volcanoes.usgs.gov/observatories/hvo/__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdIBKuB8zI$ 
<https://urldefense.com/v3/__https://volcanoes.usgs.gov/observatories/hvo/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwbKH96k4$>





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



PVMBG reported that the eruption at Lewotolok continued during 1-7
February, though weather conditions sometimes prevented visual
confirmation. Rumbling and weak banging noises were heard throughout the
week. Crater incandescence from active lava effusion was periodically
observed. White, gray, and black ash plumes rose 100-400 m above the summit
during 3-4 and 6-8 February. Incandescent material was ejected 300 m SE
during 7-8 February. The Alert Level remained at 3 (on a scale of 1-4) and
the public was warned to stay 3 km away from the summit crater and 4 km
away from the crater on the SE flank.



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!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdIii16zoI$ 
<https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwa92JAxc$>





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



BPPTKG reported no significant morphological changes at Merapiâ??s lava
domes, located just below the SW rim and in the summit crater, during 28
January-3 February. Seismicity remained at high levels and earthquakes were
more intense than the previous week. In the SW-flank Bebeng drainage there
were as many as 133 lava avalanches that traveled a maximum of 2 km and two
pyroclastic flows that extended 2-2.5 km; one lava avalanche also went 300
m NW. The Alert Level remained at 3 (on a scale of 1-4), and the public was
warned to stay 3-5 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!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdIdbuDimE$ 
<https://urldefense.com/v3/__http://www.merapi.bgl.esdm.go.id/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwywfS2bg$>





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



AVO reported that the eruption at Pavlof was ongoing during 1-8 February
with lava effusion on the upper SE flank feeding a branching flow on the E
flank. Seismicity was elevated with periods of tremor and elevated surface
temperatures were identified in satellite images; both were consistent was
continuing lava effusion. The Volcano Alert Level remained at Watch and the
Aviation Color Code remained at Orange.



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!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdIpT_OAjo$ 
<https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwALOazBw$>





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



CENAPRED reported that each day during 1-8 February there were 25-77
steam-and-gas emissions with diffuse ash rising from Popocatépetl and
drifting ENE. 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!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdInUlk4OY$ 
<https://urldefense.com/v3/__https://www.gob.mx/cenapred__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwp2dNwF4$>





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



OVSICORI-UNA reported that an eruption at Rincón de la Vieja was recorded
at 1853 on 2 February. No plumes were visible due to weather conditions.



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!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdI5yyGjUc$ 
<https://urldefense.com/v3/__http://www.ovsicori.una.ac.cr/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwAvYzhI4$>





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



IG reported a high level of activity at Sangay during 2-7 February, and
seismicity was characterized by daily explosions, long-period earthquakes,
and signals indicating emissions. Weather clouds and rain often prevented
visual and webcam observations of the volcano, though almost daily
ash-and-gas plumes were identified in satellite images by the Washington
VAAC or in webcam views; plumes rose as high as 1.5 km above the volcano
and drifted in multiple directions. Multiple daily thermal anomalies over
the volcano were visible in satellite data. Several ash emissions were
observed in satellite images on 8February; at 0430 an ash plume rose more
than 7 km above the summit, the highest a plume had risen since the current
eruption started in 2019. Ashfall was reported in areas to the NW, in the
provinces of Chimborazo and Bolivar.



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
horseshoe-shaped 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 sculpted by heavy rains into
steep-walled canyons up to 600 m deep. The earliest report of a historical
eruption was in 1628. More or less 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.



Source: Instituto Geofísico-Escuela Politécnica Nacional (IG)
https://urldefense.com/v3/__http://www.igepn.edu.ec/__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdI4zb0hIQ$ 
<https://urldefense.com/v3/__http://www.igepn.edu.ec/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELw0-RW__w$>





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



INSIVUMEH reported that activity at Santa Maríaâ??s Santiaguito lava-dome
complex had increased on 29 January and remained elevated. Block-and-ash
flows on 3 February descended the W and SW flanks and generated ash clouds
that rose 600-800 m high and drifted W and NW. Ashfall was reported in San
Martin Sacatepéquez (11 km NW), Llanos del Pinal (6 km NNE), Xecaracoj (7
km NNE), Loma Linda (6 km WSW), and El Palmar (12 km SSW), all in the
department of Quetzaltenango. The report noted that during 30 January-3
February a total of 20 pyroclastic flows had traveled 1-3 km down the San
Isidro drainage. Block-and-ash flows descended the W, SW, and NE flanks
during 3-4 February. A lahar descended the San Isidro River, a SSW-flank
tributary of the Tambor River, on 8 February.



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.



Sources: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e
Hidrologia (INSIVUMEH) https://urldefense.com/v3/__http://www.insivumeh.gob.gt/__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdIMspNHKo$ 
<https://urldefense.com/v3/__http://www.insivumeh.gob.gt/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELw9FQtYqQ$>
;

Coordinadora Nacional para la Reducción de Desastres (CONRED)
https://urldefense.com/v3/__http://conred.gob.gt/__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdINpQMhzI$ 
<https://urldefense.com/v3/__http://conred.gob.gt/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwwJSm2pY$>





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



PVMBG reported that the eruption at Semeru continued during 1-8 February,
though weather conditions often prevented visual confirmation. Crater
incandescence was visible during 1-2 and 7-8 February. White steam-and-gas
plumes rose as high as 1.2 km above the crater rim during 2-3 February.
Eruptive events produced gray-to-white ash plumes that rose 300-700 m
during 2-4 and 7-8 February. The active lava flow on the SE flank was 3.5
km long; avalanches from the end of the flow traveled 100-200 m down the
drainage during 7-8 February. The Alert Level remained at 3 (on a scale of
1-4). The public was warned to stay at least 500 m away 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!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdIii16zoI$ 
<https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwa92JAxc$>





Semisopochnoi  | Aleutian Islands (USA)  | 51.93°N, 179.58°E  | Summit
elev. 1221 m



AVO reported that low-level eruptive activity at Semisopochnoi's North
Cerberus cone continued during 1-8 February. Seismicity was elevated, and
explosions were occasionally detected in both seismic and infrasound data
during 4-8 February. Steam and low-level ash emissions likely occurred
daily, though due to weather clouds they were only confirmed in satellite
and webcam images during 1-2 and 5-8 February. The Aviation Color Code
remained at Orange and the Volcano Alert Level remained at Watch.



Geologic Summary. Semisopochnoi, the largest subaerial volcano of the
western Aleutians, is 20 km wide at sea level and contains an 8-km-wide
caldera. It formed as a result of collapse of a low-angle, dominantly
basaltic volcano following the eruption of a large volume of dacitic
pumice. The high point of the island is Anvil Peak, a double-peaked
late-Pleistocene cone that forms much of the island's northern part. The
three-peaked Mount Cerberus was constructed within the caldera during the
Holocene. Each of the peaks contains a summit crater; lava flows on the N
flank of Cerberus appear younger than those on the south side. Other
post-caldera volcanoes include the symmetrical Sugarloaf Peak SSE of the
caldera and Lakeshore Cone, a small cinder cone at the edge of Fenner Lake
in the NE part of the caldera. Most documented eruptions have originated
from Cerberus, although Coats (1950) considered that both Sugarloaf and
Lakeshore Cone could have been recently active.



Source: US Geological Survey Alaska Volcano Observatory (AVO)
https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdIpT_OAjo$ 
<https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwALOazBw$>





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



KVERT reported that a thermal anomaly over Sheveluch was identified in
satellite images during 28 January-4 February. 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 1300 km3 volcano is one of Kamchatka's largest and most
active volcanic structures. 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 dot its outer flanks. The Molodoy
Shiveluch lava dome complex was constructed during the Holocene within the
large horseshoe-shaped caldera; Holocene lava dome extrusion also took
place on the flanks of Stary Shiveluch. At least 60 large eruptions have
occurred during the Holocene, making it the most vigorous andesitic volcano
of the Kuril-Kamchatka arc. 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!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdI7-3vz34$ 
<https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwIUtd3Qg$>





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



JMA reported that volcanic plumes from Suwanosejima's Ontake Crater rose as
high as 2.2 km above the crater rim during 31 January-7 February. Ashfall
was reported in Toshima village (3.5 km SSW). The Alert Level remained at 3
and the public was warned to stay 2 km away from the crater.



Geologic Summary. The 8-km-long, spindle-shaped 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. Suwanosejima, one of Japan's most frequently active
volcanoes, was in a state of intermittent strombolian activity from Otake,
the NE summit crater, that began in 1949 and lasted until 1996, after which
periods of inactivity lengthened. The largest historical 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 horseshoe-shaped 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!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdIwhGY79E$ 
<https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwsKxzB88$>





Turrialba  | Costa Rica  | 10.025°N, 83.767°W  | Summit elev. 3340 m



OVSICORI-UNA reported that at 1259 on 6 February a small phreatic eruption
at Turrialbaâ??s Cráter Oeste produced an ash plume that rose 100 m above the
crater rim. A thermal anomaly from the floor of Cráter Oeste was identified
in satellite images on 4 February. The anomaly was last seen in the same
location on 25 January, and twice in 2021, during clear weather conditions;
the location of the anomaly was the same in those images since March 2021,
and likely represented a hot crack venting on the crater floor. Two
incandescent points in the crater were visible in overnight webcam images
during 7-8 February.



Geologic Summary. Turrialba, the easternmost of Costa Rica's Holocene
volcanoes, is a large vegetated basaltic-to-dacitic stratovolcano located
across a broad saddle NE of Irazú volcano overlooking the city of Cartago.
The massive edifice covers an area of 500 km2. Three well-defined craters
occur at the upper SW end of a broad 800 x 2200 m summit depression that is
breached to the NE. Most activity originated from the summit vent complex,
but two pyroclastic cones are located on the SW flank. Five major explosive
eruptions have occurred during the past 3500 years. A series of explosive
eruptions during the 19th century were sometimes accompanied by pyroclastic
flows. Fumarolic activity continues at the central and SW summit craters.



Source: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad
Nacional (OVSICORI-UNA) https://urldefense.com/v3/__http://www.ovsicori.una.ac.cr/__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdI5yyGjUc$ 
<https://urldefense.com/v3/__http://www.ovsicori.una.ac.cr/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwAvYzhI4$>





Yasur  | Vanuatu  | 19.532°S, 169.447°E  | Summit elev. 361 m



On 2 February the Vanuatu Meteorology and Geo-Hazards Department (VMGD)
reported that sulfur dioxide gas emissions from Yasurâ??s active lava lake
were detected drifting NW in satellite images. The Alert Level remained at
2 (on a scale of 0-4) and the public was reminded not to enter the
restricted area within 600 m around the cone, defined by Danger Zone A on
the hazard map.



Geologic Summary. Yasur, the best-known and most frequently visited of the
Vanuatu volcanoes, has been in more-or-less continuous Strombolian and
Vulcanian activity since Captain Cook observed ash eruptions in 1774. This
style of activity may have continued for the past 800 years. Located at the
SE tip of Tanna Island, this mostly unvegetated pyroclastic cone has a
nearly circular, 400-m-wide summit crater. The active cone is largely
contained within the small Yenkahe caldera, and is the youngest of a group
of Holocene volcanic centers constructed over the down-dropped NE flank of
the Pleistocene Tukosmeru volcano. The Yenkahe horst is located within the
Siwi ring fracture, a 4-km-wide, horseshoe-shaped caldera associated with
eruption of the andesitic Siwi pyroclastic sequence. Active tectonism along
the Yenkahe horst accompanying eruptions has raised Port Resolution harbor
more than 20 m during the past century.



Source: Vanuatu Meteorology and Geo-Hazards Department (VMGD)
https://urldefense.com/v3/__http://www.geohazards.gov.vu/__;!!IKRxdwAv5BmarQ!PcVvfuZjsLGLUtpIzJKSmVA1AwOgumgmgjqqnAIPTVBdOJ4ftJ9WKqdI7d0thpY$ 
<https://urldefense.com/v3/__http://www.geohazards.gov.vu/__;!!IKRxdwAv5BmarQ!OfBy9U5CL45S8CLcI6-bBXWzQWbrirTl-S6QA8Zio4Uq-EP9YFYbDELwm_X5l_0$>



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End of Volcano Digest - 9 Feb 2022 to 10 Feb 2022 (#2022-19)
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