Smithsonian / USGS Weekly Volcanic Activity Report 13 -19 April 2022

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1-1-1-1-1-1-1-1-1-1-1-1-1-1


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


Smithsonian / USGS Weekly Volcanic Activity Report

13 -19 April 2022



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

URL: https://urldefense.com/v3/__https://volcano.si.edu/reports_weekly.cfm__;!!IKRxdwAv5BmarQ!OD1HG9ZImh6O5_1WS6T-eg8h4rhhcVtyqXr4yWq4JjEQbi5gMQz2A3zROxilyYs$ 
<https://urldefense.com/v3/__https://volcano.si.edu/reports_weekly.cfm__;!!IKRxdwAv5BmarQ!KjAbhgxuJ9OaULhDE8E7ae-V6IYswRxfyBrXd674BPU75kq_l07pVkb0CXvmJJA$>





New Activity/Unrest: Bezymianny, Central Kamchatka (Russia)  | Edgecumbe,
Southeastern Alaska (USA)  | Karymsky, Eastern Kamchatka (Russia)  |
Krakatau, Sunda Strait  | Poas, Costa Rica  | Ruang, Sangihe Islands  |
Ruapehu, North Island (New Zealand)



Ongoing Activity: Aira, Kyushu (Japan)  | Asosan, Kyushu (Japan)  | Dukono,
Halmahera  | Great Sitkin, Andreanof Islands (USA)  | Kilauea, Hawaiian
Islands (USA)  | Lewotolok, Lembata Island  | Manam, Northeast of New
Guinea  | Merapi, Central Java  | Pavlof, Alaska Peninsula, Alaska  |
Reventador, Ecuador  | Sangay, Ecuador  | Semeru, Eastern Java  |
Semisopochnoi, Aleutian Islands (USA)  | Sheveluch, Central Kamchatka
(Russia)  | Suwanosejima, Ryukyu Islands (Japan)  | Wolf, Isla Isabela
(Galapagos)





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 the effusive eruption at Bezymianny continued during
8-15 April, along with incandescence at the lava dome, avalanches
descending the SE flank, and steam-and-ash emissions. A daily thermal
anomaly over the dome was identified in satellite images. The Aviation
Color Code remained at Yellow (the second lowest level on a four-color
scale). Dates are based on UTC times; specific events are in local time
where noted.



Geologic Summary. Prior to its noted 1955-56 eruption, Bezymianny had been
considered extinct. The modern volcano, much smaller in size than its
massive neighbors Kamen and Kliuchevskoi, was formed about 4700 years ago
over a late-Pleistocene lava-dome complex and an ancestral edifice built
about 11,000-7000 years ago. Three periods of intensified activity have
occurred during the past 3000 years. The latest period, which was preceded
by a 1000-year quiescence, began with the dramatic 1955-56 eruption. This
eruption, similar to that of St. Helens in 1980, produced a large
horseshoe-shaped 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.



Sources: Kamchatkan Volcanic Eruption Response Team (KVERT)
https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!OD1HG9ZImh6O5_1WS6T-eg8h4rhhcVtyqXr4yWq4JjEQbi5gMQz2A3zR4jzOd5U$ 
<https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!KjAbhgxuJ9OaULhDE8E7ae-V6IYswRxfyBrXd674BPU75kq_l07pVkb0_CDYT-c$>
;

Institute of Volcanology and Seismology (IVS) of the Far Eastern Branch of
the Russian Academy of Sciences (FEB RAS) https://urldefense.com/v3/__http://www.kscnet.ru/ivs/__;!!IKRxdwAv5BmarQ!OD1HG9ZImh6O5_1WS6T-eg8h4rhhcVtyqXr4yWq4JjEQbi5gMQz2A3zRXQlwzLE$ 
<https://urldefense.com/v3/__http://www.kscnet.ru/ivs/__;!!IKRxdwAv5BmarQ!KjAbhgxuJ9OaULhDE8E7ae-V6IYswRxfyBrXd674BPU75kq_l07pVkb0bHJP2OY$>





Edgecumbe  | Southeastern Alaska (USA)  | 57.05°N, 135.75°W  | Summit elev.
970 m



AVO stated that a seismic swarm beneath Kruzof Island near Edgecumbe began
at about 0200 on 11 April, and by 15 April several hundred earthquakes had
been recorded. The number of events was unusual for that volcano. The
magnitudes were generally M 1.7 or smaller, though a M 2.8 was detected on
11 April. The events were located at depths of less than 10 km, though the
exact locations were difficult to constrain due to the lack of a local
seismic network on the island; the closest station was in Sitka, 25 km E.
The source of the swarm was unknown, and related either to tectonic
processes or volcanic unrest, or a combination of both. Both the Volcano
Alert Level and Aviation Color Code were Unassigned due to the lack of
dedicated, local instrumentation. AVO noted that additional data from
distant seismic stations was being analyzed, and several years of Synthetic
Aperture Radar (SAR) data was being evaluated for topographical changes. No
surficial changes were visible in recent satellite images and webcams views.



Geologic Summary. The Pleistocene-to-Holocene Edgecumbe volcanic field
covers about 260 km2 of Kruzov Island west of Sitka in the SE panhandle of
Alaska. The basaltic-to-dacitic field is dominated by the large composite
cones of Mount Edgecumbe, Crater Ridge, and Shell Mountain, and has an
unusual tectonic setting only 16 km E of the Queen Charlotte-Fairweather
transform fault separating the North American and Pacific plates. Mount
Edgecumbe is a stratovolcano with a well-defined crater, and is the largest
volcano of the field. Crater Ridge is truncated by a 1.6-km-wide,
240-m-deep caldera. These and other vents are oriented along a SW-NE line.
Volcanic activity originated about 600,000 years ago along fissures cutting
Kruzof Island. A series of major silicic explosive eruptions took place
about 9000-13,000 radiocarbon years ago. The latest dated eruptions were
phreatomagmatic explosions during the mid-Holocene, and all postglacial
activity has been pyroclastic. Reports of historical eruptions of Mount
Edgecumbe are unsubstantiated.



Source: US Geological Survey Alaska Volcano Observatory (AVO)
https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!OD1HG9ZImh6O5_1WS6T-eg8h4rhhcVtyqXr4yWq4JjEQbi5gMQz2A3zR-R1gdT0$ 
<https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!KjAbhgxuJ9OaULhDE8E7ae-V6IYswRxfyBrXd674BPU75kq_l07pVkb0hF1OvOA$>





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



KVERT reported that a thermal anomaly over Karymsky was visible in
satellite images on 9 and 11-12 April; the volcano was quiet or obscured by
clouds on the other days during 8-15 April. Explosions produced ash plumes
that rose to 6 km (19,700 ft) a.s.l. and drifted SSW, based on satellite
data acquired at 0810 on 20 April, local time. Explosions continued and
within an hour produced larger ash plumes that rose 9.8-10 km
(32,100-32,800 ft) a.s.l. and drifted almost 30 km NE. KVERT raised the
Aviation Color Code to Red (the highest level on a four-color scale). Dates
are based on UTC times; specific events are in local time where noted.



Geologic Summary. Karymsky, the most active volcano of Kamchatka's eastern
volcanic zone, is a symmetrical stratovolcano constructed within a
5-km-wide caldera that formed during the early Holocene. The caldera cuts
the south side of the Pleistocene Dvor volcano and is located outside the
north margin of the large mid-Pleistocene Polovinka caldera, which contains
the smaller Akademia Nauk and Odnoboky calderas. Most seismicity preceding
Karymsky eruptions originated beneath Akademia Nauk caldera, located
immediately south. The caldera enclosing Karymsky formed about 7600-7700
radiocarbon years ago; construction of the stratovolcano began about 2000
years later. The latest eruptive period began about 500 years ago,
following a 2300-year quiescence. Much of the cone is mantled by lava flows
less than 200 years old. Historical eruptions have been vulcanian or
vulcanian-strombolian with moderate explosive activity and occasional lava
flows from the summit crater.



Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!OD1HG9ZImh6O5_1WS6T-eg8h4rhhcVtyqXr4yWq4JjEQbi5gMQz2A3zR4jzOd5U$ 
<https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!KjAbhgxuJ9OaULhDE8E7ae-V6IYswRxfyBrXd674BPU75kq_l07pVkb0_CDYT-c$>





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



PVMBG reported that several ash emissions from Anak Krakatau were visible
in webcam images and described by observers during 15 and 17-19 April. The
ash plumes were variably whitish gray, gray, and black, with all but one
characterized as dense. Events at 0327, 1034, and 1837 on 15 April produced
ash plumes that rose 0.7-1 km above the summit and drifted SW. Ash plumes
at 0925, 1830, and 2215 on 17 April rose 500-800 m above the summit and
drifted SW; Strombolian activity produced the ash plume at 1830. On 18
April events at 0358, 0419, 0714, 1246, 1330, and 1558 generated ash plumes
that rose as high as 2 km and drifted SW. Ash plumes were visible on 19
April, rising 50-500 m above the summit and drifting SE and NE. 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!OD1HG9ZImh6O5_1WS6T-eg8h4rhhcVtyqXr4yWq4JjEQbi5gMQz2A3zR_s5P1U8$ 
<https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!KjAbhgxuJ9OaULhDE8E7ae-V6IYswRxfyBrXd674BPU75kq_l07pVkb0TkGQo9Q$>





Poas  | Costa Rica  | 10.2°N, 84.233°W  | Summit elev. 2697 m



OVSICORI-UNA reported that submarine fumaroles in the S part of Poásâ??s Boca
A lake and subaerial fumaroles along the E margins continued to produce
low-temperature gas emissions during 13-19 April. The lake water continued
to convect, and was light gray in color, since the phreatic explosion that
had occurred on 6 April at â??Orange Fumarolaâ?? located in a fumarolic field
along the inner N crater wall. For a period of time on 17 April a gas
monitoring station in Coronado measured a higher concentration of sulfur
dioxide aerosols, between 8.5 and 17.6 micrograms of gas per cubic meter of
ambient air, which was higher than the daily average of 6.7. Some residents
reported respiratory discomfort such as sneezing, coughing, and shortness
of breath.



Geologic Summary. The broad vegetated edifice of Poás, one of the most
active volcanoes of Costa Rica, contains three craters along a N-S line.
The frequently visited multi-hued summit crater lakes of the
basaltic-to-dacitic volcano are easily accessible by vehicle from the
nearby capital city of San José. A N-S-trending fissure cutting the complex
stratovolcano extends to the lower N flank, where it has produced the Congo
stratovolcano and several lake-filled maars. The southernmost of the two
summit crater lakes, Botos, last erupted about 7,500 years ago. The more
prominent geothermally heated northern lake, Laguna Caliente, is one of the
world's most acidic natural lakes, with a pH of near zero. It has been the
site of frequent phreatic and phreatomagmatic eruptions since an eruption
was reported in 1828. Eruptions often include geyser-like ejections of
crater-lake water.



Source: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad
Nacional (OVSICORI-UNA) https://urldefense.com/v3/__http://www.ovsicori.una.ac.cr/__;!!IKRxdwAv5BmarQ!OD1HG9ZImh6O5_1WS6T-eg8h4rhhcVtyqXr4yWq4JjEQbi5gMQz2A3zRttd3-oI$ 
<https://urldefense.com/v3/__http://www.ovsicori.una.ac.cr/__;!!IKRxdwAv5BmarQ!KjAbhgxuJ9OaULhDE8E7ae-V6IYswRxfyBrXd674BPU75kq_l07pVkb0a0soyY8$>





Ruang  | Sangihe Islands  | 2.3°N, 125.37°E  | Summit elev. 725 m



PVMBG reported that at least 121 deep volcanic earthquakes at Ruang were
recorded during 1-16 April, though the number of those events began to
increase on 7 April. No visible changes to the crater were noted, but
weather conditions sometimes prevented views. Seismicity significantly
changed on 16 April, characterized by 50 deep volcanic earthquakes, two
local tectonic earthquakes, and four felt earthquakes. That same day the
Alert Level was raised to 2 (on a scale of 1-4) and residents and tourists
were warned to stay 1.5 km away from the active craters and 2.5 km on the
E, SE, S, and SW flanks. Elevated seismicity continued to be recorded
through 18 April.



Geologic Summary. Ruang volcano, not to be confused with the better known
Raung volcano on Java, is the southernmost volcano in the Sangihe Island
arc, north of Sulawesi Island. The 4 x 5 km island volcano rises to 725 m
across a narrow strait SW of the larger Tagulandang Island. The summit
contains a crater partially filled by a lava dome initially emplaced in
1904. Explosive eruptions recorded since 1808 have often been accompanied
by lava dome formation and pyroclastic flows that have damaged inhabited
areas.



Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known
as CVGHM) https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!OD1HG9ZImh6O5_1WS6T-eg8h4rhhcVtyqXr4yWq4JjEQbi5gMQz2A3zR_s5P1U8$ 
<https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!KjAbhgxuJ9OaULhDE8E7ae-V6IYswRxfyBrXd674BPU75kq_l07pVkb0TkGQo9Q$>





Ruapehu  | North Island (New Zealand)  | 39.28°S, 175.57°E  | Summit elev.
2797 m



On 20 April GeoNet reported that elevated unrest at Ruapehu had continued
during the previous week. Scientists observed upwelling in the lake over
the N vent area and visible sulfur slicks on the lakeâ??s surface during an
observation flight. The lake water temperature had stabilized at 37 degrees
Celsius and continued to be medium gray in color. The lake observations
were within normal ranges for a typical heating cycle. Tremor levels remain
elevated, though, representing the longest period of tremor recorded over
the previous 20 years. The Volcanic Alert Level remained at 2 (on a scale
from 0-5) and the Aviation Color Code remained at Yellow.



Geologic Summary. Ruapehu, one of New Zealand's most active volcanoes, is a
complex stratovolcano constructed during at least four cone-building
episodes dating back to about 200,000 years ago. The dominantly andesitic
110 km3 volcanic massif is elongated in a NNE-SSW direction and surrounded
by another 100 km3 ring plain of volcaniclastic debris, including the
NW-flank Murimoto debris-avalanche deposit. A series of subplinian
eruptions took place between about 22,600 and 10,000 years ago, but
pyroclastic flows have been infrequent. The broad summait area and flank
contain at least six vents active during the Holocene. Frequent
mild-to-moderate explosive eruptions have been recorded from the Te Wai
a-Moe (Crater Lake) vent, and tephra characteristics suggest that the
crater lake may have formed as recently as 3,000 years ago. Lahars
resulting from phreatic eruptions at the summit crater lake are a hazard to
a ski area on the upper flanks and lower river valleys.



Source: GeoNet https://urldefense.com/v3/__http://www.geonet.org.nz/__;!!IKRxdwAv5BmarQ!OD1HG9ZImh6O5_1WS6T-eg8h4rhhcVtyqXr4yWq4JjEQbi5gMQz2A3zRk-JLfYU$ 
<https://urldefense.com/v3/__http://www.geonet.org.nz/__;!!IKRxdwAv5BmarQ!KjAbhgxuJ9OaULhDE8E7ae-V6IYswRxfyBrXd674BPU75kq_l07pVkb0WppkYeQ$>





Ongoing Activity





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



JMA reported that very small eruptive events at Minamidake Crater (at Aira
Calderaâ??s Sakurajima volcano) were recorded during 11-18 April. Crater
incandescence was periodically visible at night. 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!OD1HG9ZImh6O5_1WS6T-eg8h4rhhcVtyqXr4yWq4JjEQbi5gMQz2A3zR9HdZyho$ 
<https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!KjAbhgxuJ9OaULhDE8E7ae-V6IYswRxfyBrXd674BPU75kq_l07pVkb0rrT4lWo$>





Asosan  | Kyushu (Japan)  | 32.884°N, 131.104°E  | Summit elev. 1592 m



JMA reported that no eruptions had been recorded at Asosan after the end of
the last eruption in October 2021. Crater incandescence, which had been
occasionally visible since December 2021, was absent beginning on 27
February. Deflation began around 27 February but stabilized in April.
Observations of the crater from 17 March revealed that it had deepened,
compared to pre-eruption conditions, and that water had returned. Sulfur
dioxide emissions had increased to 1,600 tons per day on 25 March, but four
observations made during 29 March-12 April showed values in the range of
800-1,200 tons per day. Though these values were higher than those measured
in September 2021, before the eruption, they represented a decreasing
trend. During a field visit on 7 April scientists observed white emissions
rising from Nakadake Crater and gray pools of hot water on the crater
floor. A hot spring was active on the S side of the pools. The area of the
water represented about 40 percent of the crater floor and the water
temperature was 71 degrees Celsius. JMA lowered the Alert Level to 1 (on a
scale of 1-5) on 15 April, noting that the likelihood of an eruption
affecting an area within a radius of 1 km had decreased.



Geologic Summary. The 24-km-wide Asosan caldera was formed during four
major explosive eruptions from 300,000 to 90,000 years ago. These produced
voluminous pyroclastic flows that covered much of Kyushu. The last of
these, the Aso-4 eruption, produced more than 600 km3 of airfall tephra and
pyroclastic-flow deposits. A group of 17 central cones was constructed in
the middle of the caldera, one of which, Nakadake, is one of Japan's most
active volcanoes. It was the location of Japan's first documented
historical eruption in 553 CE. The Nakadake complex has remained active
throughout the Holocene. Several other cones have been active during the
Holocene, including the Kometsuka scoria cone as recently as about 210 CE.
Historical eruptions have largely consisted of basaltic to
basaltic-andesite ash emission with periodic strombolian and
phreatomagmatic activity. The summit crater of Nakadake is accessible by
toll road and cable car, and is one of Kyushu's most popular tourist
destinations.



Source: Japan Meteorological Agency (JMA) https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!OD1HG9ZImh6O5_1WS6T-eg8h4rhhcVtyqXr4yWq4JjEQbi5gMQz2A3zR9HdZyho$ 
<https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!KjAbhgxuJ9OaULhDE8E7ae-V6IYswRxfyBrXd674BPU75kq_l07pVkb0rrT4lWo$>





Dukono  | Halmahera  | 1.693°N, 127.894°E  | Summit elev. 1229 m



Based on satellite and wind model data, the Darwin VAAC reported that
during 13-18 April ash plumes from Dukono rose to 2.1 km (7,000 ft) a.s.l.
and drifted NE, E, SE, and S. The Alert Level remained at 2 (on a scale of
1-4), and the public was warned to remain outside of the 2-km exclusion
zone.



Geologic Summary. Reports from this remote volcano in northernmost
Halmahera are rare, but Dukono has been one of Indonesia's most active
volcanoes. More-or-less continuous explosive eruptions, sometimes
accompanied by lava flows, occurred from 1933 until at least the mid-1990s,
when routine observations were curtailed. During a major eruption in 1550,
a lava flow filled in the strait between Halmahera and the north-flank cone
of Gunung Mamuya. This complex volcano presents a broad, low profile with
multiple summit peaks and overlapping craters. Malupang Wariang, 1 km SW of
the summit crater complex, contains a 700 x 570 m crater that has also been
active during historical time.



Sources: Darwin Volcanic Ash Advisory Centre (VAAC)
https://urldefense.com/v3/__http://www.bom.gov.au/aviation/volcanic-ash/darwin-va-advisory.shtml__;!!IKRxdwAv5BmarQ!OD1HG9ZImh6O5_1WS6T-eg8h4rhhcVtyqXr4yWq4JjEQbi5gMQz2A3zREP8e_cU$ 
<https://urldefense.com/v3/__http://www.bom.gov.au/aviation/volcanic-ash/darwin-va-advisory.shtml__;!!IKRxdwAv5BmarQ!KjAbhgxuJ9OaULhDE8E7ae-V6IYswRxfyBrXd674BPU75kq_l07pVkb0CFVEKVk$>
;

Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!OD1HG9ZImh6O5_1WS6T-eg8h4rhhcVtyqXr4yWq4JjEQbi5gMQz2A3zR_s5P1U8$ 
<https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!KjAbhgxuJ9OaULhDE8E7ae-V6IYswRxfyBrXd674BPU75kq_l07pVkb0TkGQo9Q$>





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 13-19
April, based on high-resolution satellite data. Weather clouds prevented
visual observations on most days. Very low seismicity persisted. 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!OD1HG9ZImh6O5_1WS6T-eg8h4rhhcVtyqXr4yWq4JjEQbi5gMQz2A3zR-R1gdT0$ 
<https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!KjAbhgxuJ9OaULhDE8E7ae-V6IYswRxfyBrXd674BPU75kq_l07pVkb0hF1OvOA$>





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



HVO reported that lava continued to effuse from a vent in the lower W wall
of Kilaueaâ??s Halema`uma`u Crater during 12-19 April, entering an active
lava lake and flowing onto the crater floor. The surface of the lava lake
was active all week, and the height of the lake fluctuated. Flows
occasionally overtopped perched levees. At 2315 on 10 April a flow emerged
from the S side on the vent that covered areas along the southwest and
western margins, and was active through 14 April. Breakouts along the N,
NE, and S parts of the crater were visible during 14-19 April. 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!OD1HG9ZImh6O5_1WS6T-eg8h4rhhcVtyqXr4yWq4JjEQbi5gMQz2A3zR_uu0q3Y$ 
<https://urldefense.com/v3/__https://volcanoes.usgs.gov/observatories/hvo/__;!!IKRxdwAv5BmarQ!KjAbhgxuJ9OaULhDE8E7ae-V6IYswRxfyBrXd674BPU75kq_l07pVkb02jVbMXg$>





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



PVMBG reported that the eruption at Lewotolok continued during 12-19 April.
Daily white-and-gray ash plumes rose as high as 50-500 m above the summit
and drifted W, NW, and E. 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!OD1HG9ZImh6O5_1WS6T-eg8h4rhhcVtyqXr4yWq4JjEQbi5gMQz2A3zR_s5P1U8$ 
<https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!KjAbhgxuJ9OaULhDE8E7ae-V6IYswRxfyBrXd674BPU75kq_l07pVkb0TkGQo9Q$>





Manam  | Northeast of New Guinea  | 4.08°S, 145.037°E  | Summit elev. 1807 m



The Darwin VAAC reported that on 18 April ash plumes from Manam rose to
13.7 km (45,000 ft) a.s.l. and drifted N based on information from RVO,
satellite images, and weather models. Ash had dissipated by 1540. At 2000
an ash plume was visible in a satellite image through a break in weather
cloud cover drifted NE at an altitude of 4.9 km (16,000 ft) a.s.l. Ash had
dissipated by 0830 on 19 April.



Geologic Summary. The 10-km-wide island of Manam, lying 13 km off the
northern coast of mainland Papua New Guinea, is one of the country's most
active volcanoes. Four large radial valleys extend from the unvegetated
summit of the conical basaltic-andesitic stratovolcano to its lower flanks.
These valleys channel lava flows and pyroclastic avalanches that have
sometimes reached the coast. Five small satellitic centers are located near
the island's shoreline on the northern, southern, and western sides. Two
summit craters are present; both are active, although most observed
eruptions have originated from the southern crater, concentrating eruptive
products during much of the past century into the SE valley. Frequent
eruptions, typically of mild-to-moderate scale, have been recorded since
1616. Occasional larger eruptions have produced pyroclastic flows and lava
flows that reached flat-lying coastal areas and entered the sea, sometimes
impacting populated areas.



Source: Darwin Volcanic Ash Advisory Centre (VAAC)
https://urldefense.com/v3/__http://www.bom.gov.au/aviation/volcanic-ash/darwin-va-advisory.shtml__;!!IKRxdwAv5BmarQ!OD1HG9ZImh6O5_1WS6T-eg8h4rhhcVtyqXr4yWq4JjEQbi5gMQz2A3zREP8e_cU$ 
<https://urldefense.com/v3/__http://www.bom.gov.au/aviation/volcanic-ash/darwin-va-advisory.shtml__;!!IKRxdwAv5BmarQ!KjAbhgxuJ9OaULhDE8E7ae-V6IYswRxfyBrXd674BPU75kq_l07pVkb0CFVEKVk$>





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



BPPTKG reported that the eruption at Merapi continued during 8-14 April.
The volumes of the SW lava dome and the central lava dome were unchanged
from the previous week, and seismicity remained at high levels. As many as
112 lava avalanches originating from two areas on the SW dome traveled a
maximum of 2 km down the Bebeng drainage on the SW flank. 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!OD1HG9ZImh6O5_1WS6T-eg8h4rhhcVtyqXr4yWq4JjEQbi5gMQz2A3zR1O2vEAU$ 
<https://urldefense.com/v3/__http://www.merapi.bgl.esdm.go.id/__;!!IKRxdwAv5BmarQ!KjAbhgxuJ9OaULhDE8E7ae-V6IYswRxfyBrXd674BPU75kq_l07pVkb0_ag-o5U$>





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



AVO reported that the eruption at a vent on Pavlofâ??s upper E flank was
ongoing during 12-19 April, though weather conditions sometimes prevented
visual observations. Seismic tremor persisted and elevated surface
temperatures were identified in satellite images almost daily. Steam
emissions were seen rising above the summit in webcam images on 16 April.
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!OD1HG9ZImh6O5_1WS6T-eg8h4rhhcVtyqXr4yWq4JjEQbi5gMQz2A3zR-R1gdT0$ 
<https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!KjAbhgxuJ9OaULhDE8E7ae-V6IYswRxfyBrXd674BPU75kq_l07pVkb0hF1OvOA$>





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



IG staff observed high levels of activity at Reventador during a field
visit from 4 to 7 April, and noted sporadic emissions with moderate ash
content. They viewed the volcano with a thermal camera and saw an active
lava flow on the upper NNE flank, producing rock avalanches as it advanced.
The flow was 1.7-2 km long and effused from a vent about 200 m below the
summit on the NNE flank. Two inactive and cooling flows were located
adjacent to the active flow. Activity continued to be high during 12-19
April, though cloudy weather conditions frequently prevented visual
observations. Steam, gas, and ash plumes, often observed multiple times a
day with the webcam or reported by the Washington VAAC, rose as high as 1
km above the summit crater and drifted W and NW. Crater incandescence was
visible most nights and early mornings; incandescent material was visible
descending the flanks during 13-14 April.



Geologic Summary. 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 Volcán El Reventador
stratovolcano rises to 3562 m above the jungles of the western Amazon
basin. A 4-km-wide caldera widely breached to the east was formed by
edifice collapse and is partially filled by a young, unvegetated
stratovolcano that rises about 1300 m above the caldera floor to a height
comparable to the caldera rim. It has been the source of numerous lava
flows as well as explosive eruptions that were visible from Quito in
historical time. Frequent lahars in this region of heavy rainfall have
constructed a debris plain on the eastern floor of the caldera. The largest
historical 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.



Source: Instituto Geofísico-Escuela Politécnica Nacional (IG)
https://urldefense.com/v3/__http://www.igepn.edu.ec/__;!!IKRxdwAv5BmarQ!OD1HG9ZImh6O5_1WS6T-eg8h4rhhcVtyqXr4yWq4JjEQbi5gMQz2A3zRICvI9Aw$ 
<https://urldefense.com/v3/__http://www.igepn.edu.ec/__;!!IKRxdwAv5BmarQ!KjAbhgxuJ9OaULhDE8E7ae-V6IYswRxfyBrXd674BPU75kq_l07pVkb0kjeDnp0$>





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



IG reported that the eruption at Sangay continued at a high level, with
lava flows effusing from the �uñurcu, Central, and Norte vents. Explosions
originated from a western vent that reactivated in late 2021, and from
Central vent. The Norte vent, on the N flank, had opened on 2 December
2021. Activity levels were slightly higher during 4-6 April, characterized
by a higher rate of lava effusion and a satellite-detected thermal anomaly
at the Norte vent on 4 April, along with a diffuse but continuously-emitted
volcanic cloud that rose 1.7 km above the crater rim and drifted up to 650
km W during 5-6 April. Low-frequency tremor was also recorded during 5-6
April. Even though the eruption plume drifted notably farther than average
distances recorded during 2019-2022, only minor ashfall was reported in
Chauzán San Alfonso (40 km W, in Guamote canton, Chimborazo province).
During 12-18 April weather clouds and rain often prevented visual and
webcam observations of the volcano, though daily ash-and-gas plumes were
identified in satellite images by the Washington VAAC or in webcam views;
plumes rose less than 2 km above the volcano and drifted W and NW. Minor
ashfall was reported in Chauzán San Alfonso. The seismic network detected
signals indicating descending lahars during 12-13 and 15 April.



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!OD1HG9ZImh6O5_1WS6T-eg8h4rhhcVtyqXr4yWq4JjEQbi5gMQz2A3zRICvI9Aw$ 
<https://urldefense.com/v3/__http://www.igepn.edu.ec/__;!!IKRxdwAv5BmarQ!KjAbhgxuJ9OaULhDE8E7ae-V6IYswRxfyBrXd674BPU75kq_l07pVkb0kjeDnp0$>





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



PVMBG reported that the eruption at Semeru continued during 13-19 April.
Daily ash plumes were visible rising 300-400 m above the summit and drifted
N and S, even though cloudy weather sometimes prevented visual
observations. 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!OD1HG9ZImh6O5_1WS6T-eg8h4rhhcVtyqXr4yWq4JjEQbi5gMQz2A3zR_s5P1U8$ 
<https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!KjAbhgxuJ9OaULhDE8E7ae-V6IYswRxfyBrXd674BPU75kq_l07pVkb0TkGQo9Q$>





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 12-19 April. Periods of seismic tremor were
detected daily and occasional small explosions were recorded in seismic and
regional infrasound data on most days. Weather cloud cover often hindered
webcam and satellite views; minor, low-level ash plumes were visible in
webcam images during 16-19 April. 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!OD1HG9ZImh6O5_1WS6T-eg8h4rhhcVtyqXr4yWq4JjEQbi5gMQz2A3zR-R1gdT0$ 
<https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!KjAbhgxuJ9OaULhDE8E7ae-V6IYswRxfyBrXd674BPU75kq_l07pVkb0hF1OvOA$>





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 8-15 April, and lava-dome extrusion continued.
Explosions on 9 April produced ash plumes that rose as high as 12 km
(39,400 ft) a.s.l. and drifted more than 2,000 km NE during 9-10 April.
Explosions during 13-14 April generated ash plumes that rose to 6-6.5 km
(19,700-21,300 ft) a.s.l. and drifted 80-110 km SW and S. 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!OD1HG9ZImh6O5_1WS6T-eg8h4rhhcVtyqXr4yWq4JjEQbi5gMQz2A3zR4jzOd5U$ 
<https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!KjAbhgxuJ9OaULhDE8E7ae-V6IYswRxfyBrXd674BPU75kq_l07pVkb0_CDYT-c$>





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



JMA reported that eruptive activity continued to be recorded at
Suwanosejima's Ontake Crater during 11-18 April. One explosion produced an
eruption plume that rose as high as 2.7 km above the crater rim. Ashfall
was reported in Toshima village (3.5 km SSW) and in other areas as far as 5
km away. No explosions were recorded during 15-18 April, though emissions
rose 1.1 km. 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!OD1HG9ZImh6O5_1WS6T-eg8h4rhhcVtyqXr4yWq4JjEQbi5gMQz2A3zR9HdZyho$ 
<https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!KjAbhgxuJ9OaULhDE8E7ae-V6IYswRxfyBrXd674BPU75kq_l07pVkb0rrT4lWo$>





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



IG reported that the eruption at Wolf continued during 13-18 April. Lava
flows continued to advance towards the coast based on thermal data;
satellite images showed minor advancement during 11-16 April and the end of
the flow near the coastline.



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.



Sources: Instituto Geofísico-Escuela Politécnica Nacional (IG)
https://urldefense.com/v3/__http://www.igepn.edu.ec/__;!!IKRxdwAv5BmarQ!OD1HG9ZImh6O5_1WS6T-eg8h4rhhcVtyqXr4yWq4JjEQbi5gMQz2A3zRICvI9Aw$ 
<https://urldefense.com/v3/__http://www.igepn.edu.ec/__;!!IKRxdwAv5BmarQ!KjAbhgxuJ9OaULhDE8E7ae-V6IYswRxfyBrXd674BPU75kq_l07pVkb0kjeDnp0$>
;

Sentinel Hub https://urldefense.com/v3/__https://sentinel-hub.com/explore/sentinel-playground__;!!IKRxdwAv5BmarQ!OD1HG9ZImh6O5_1WS6T-eg8h4rhhcVtyqXr4yWq4JjEQbi5gMQz2A3zR0XUbSzE$ 
<https://urldefense.com/v3/__https://sentinel-hub.com/explore/sentinel-playground__;!!IKRxdwAv5BmarQ!KjAbhgxuJ9OaULhDE8E7ae-V6IYswRxfyBrXd674BPU75kq_l07pVkb0BPDjcZM$>



1-1-1-1-1-1-1-1-1-1-1-1-1-1



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End of Volcano Digest - 18 Apr 2022 to 21 Apr 2022 (#2022-44)
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