Smithsonian / USGS Weekly Volcanic Activity Report 19-25 May 2021

Rachel Holsteen-Bruyere <rbruyere@xxxxxxx> · Fri, 28 May 2021 12:10:14 -0700

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

19-25 May 2021

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

URL: https://urldefense.com/v3/__https://volcano.si.edu/reports_weekly.cfm__;!!IKRxdwAv5BmarQ!MMRc5FYrcpi6gLEwRppelbE8KbBOepukG9EjqGEN8KoIv5FqzAstSy09r2xruRI$ 
<https://urldefense.com/v3/__https://volcano.si.edu/reports_weekly.cfm__;!!IKRxdwAv5BmarQ!KPTAYJWofP2voIBWN6xBjFd8XV-dwNnbAv_OGX4pKaFPmJVQmyxZrqyFJwfHBjU$>

New Activity/Unrest: Great Sitkin, Andreanof Islands (USA)  | Manam, Papua
New Guinea  | Nyiragongo, DR Congo

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

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

An increase in local earthquake activity at Great Sitkin during 24-25 May
prompted AVO to raise the Aviation Color Code to Orange and the Volcano
Alert Level to Watch on 25 May. An explosive eruption began later that day
at 2104; the Aviation Color Code and the Volcano Alert Level were raised to
Red/Warning, respectively. The explosions lasted for 1-2 minutes and
produced an ash plume rising to 4.6 km (15,000 ft) a.s.l. that was observed
by local mariners. Witnesses 42 km away heard â??a very loud explosion.â??
After the explosive period seismicity decreased and satellite image images
showed a detached plume drifting E. Around mid-morning on 26 May AVO
lowered the Aviation Color Code and the Volcano Alert Level to Orange/
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!MMRc5FYrcpi6gLEwRppelbE8KbBOepukG9EjqGEN8KoIv5FqzAstSy093DDdxXo$ 
<https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!KPTAYJWofP2voIBWN6xBjFd8XV-dwNnbAv_OGX4pKaFPmJVQmyxZrqyF7GazViI$>

Manam  | Papua New Guinea  | 4.08Â°S, 145.037Â°E  | Summit elev. 1807 m

The Darwin VAAC reported that during 20-21 May ash plumes from Manam rose
to 2.1 km (7,000 ft) a.s.l. and drifted NW.

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!MMRc5FYrcpi6gLEwRppelbE8KbBOepukG9EjqGEN8KoIv5FqzAstSy09lujSCVg$ 
<https://urldefense.com/v3/__http://www.bom.gov.au/aviation/volcanic-ash/darwin-va-advisory.shtml__;!!IKRxdwAv5BmarQ!KPTAYJWofP2voIBWN6xBjFd8XV-dwNnbAv_OGX4pKaFPmJVQmyxZrqyFhH9aURc$>

Nyiragongo  | DR Congo  | 1.52Â°S, 29.25Â°E  | Summit elev. 3470 m

At around 1815 on 22 May seismicity at Nyiragongo spiked, around the same
time observers reported at least two fissures opening on the lower S
flanks, NW of Kibati (8 km SSE) and Rukoko (10 km S). Lava from the first
fissure, originating near the Shaheru crater, flowed E over a major road
(N2) and then S. The second fissure produced lava flows that traveled S,
overtaking and setting fire to many houses and structures in communities
north of Goma, just W of Monigi (12 km S). Video posted on social media
showed lava fountaining from the fissures, a glowing red sky, and residents
running through the streets. About 1,000 homes and buildings were destroyed
and about 25,000 people were displaced. The lava cut off electricity and
water supplies to some areas. The flow may have been as wide as 1 km and
stopped 1.25 km from the Goma International Airport, in the SE part of the
city, during 22-23 May. According to the Toulouse VAAC ash plumes may have
initially rose to 13.7 km (45,000 ft) a.s.l., though subsequent estimates
put the ash plumes mostly at 6.1-9.1 km (20,000-30,000 ft) a.s.l. during
22-23 May. Satellite images and local scientists indicated that the summit
lava lake had drained before the flank fissures had opened, but began
refilling afterward; collapses in the summit crater were the likely cause
of the ash plumes.

Initial reports indicated that about 32 people had died: about 12 from lava
and gas asphyxiation while crossing lava flows, and most of the rest from
accidents while fleeing. Several people, including many children, remained
missing, though families were continuing to be reunited.

Seismic data during 22-24 May showed events seemingly propagating from the
summit area to the S into Lake Kivu. Several strong earthquakes shook
buildings in Goma, causing some to collapse and injure people; a news
article noted that tremor was felt about every 30 minutes beginning around
noon on 23 May. Both airports in Goma closed for security reasons. A M 5.1
earthquake with a hypocenter beneath Lake Kivu was recorded at 1037 on 24
May. The VAAC noted that ashfall around the volcano and in surrounding
towns was visible in satellite data. Cracks a few 10s of centimeters wide
opened in different parts of the city on 25 May. The cracks stretched for
several hundred meters from the northern city limit down to the lake, and
were nearly 100 m long near the airport. Some cracks were hot and emitting
gasses, and some were flaming. Ash plumes rose to 6.1 km (20,000 ft) a.s.l.
and drifted S; ground-based reports indicated ash in the atmosphere above
Goma. Seismicity remained intense on 25 May with more than 130 earthquakes
between M 2 and 5 recorded in a 24-hour period. News reports indicated
hundreds of damaged buildings in neighboring Rwanda.

Geologic Summary. One of Africa's most notable volcanoes, Nyiragongo
contained a lava lake in its deep summit crater that was active for half a
century before draining catastrophically through its outer flanks in 1977.
The steep slopes of a stratovolcano contrast to the low profile of its
neighboring shield volcano, Nyamuragira. Benches in the steep-walled,
1.2-km-wide summit crater mark levels of former lava lakes, which have been
observed since the late-19th century. Two older stratovolcanoes, Baruta and
Shaheru, are partially overlapped by Nyiragongo on the north and south.
About 100 parasitic cones are located primarily along radial fissures south
of Shaheru, east of the summit, and along a NE-SW zone extending as far as
Lake Kivu. Many cones are buried by voluminous lava flows that extend long
distances down the flanks, which is characterized by the eruption of
foiditic rocks. The extremely fluid 1977 lava flows caused many fatalities,
as did lava flows that inundated portions of the major city of Goma in
January 2002.

Sources: Agence France-Presse (AFP)
https://urldefense.com/v3/__https://fr.africanews.com/2021/05/24/volcan-nyiragongo-un-seisme-de-magnitude-5-1-ressenti-au-rwanda/?utm_term=Autofeed__;!!IKRxdwAv5BmarQ!MMRc5FYrcpi6gLEwRppelbE8KbBOepukG9EjqGEN8KoIv5FqzAstSy09OLQylGw$ 
<https://urldefense.com/v3/__https://fr.africanews.com/2021/05/24/volcan-nyiragongo-un-seisme-de-magnitude-5-1-ressenti-au-rwanda/?utm_term=Autofeed__;!!IKRxdwAv5BmarQ!KPTAYJWofP2voIBWN6xBjFd8XV-dwNnbAv_OGX4pKaFPmJVQmyxZrqyF7bzb32c$>
;

Agence France-Presse (AFP)
https://urldefense.com/v3/__https://news.yahoo.com/volcano-aftershocks-rattle-dr-congo-103805544.html__;!!IKRxdwAv5BmarQ!MMRc5FYrcpi6gLEwRppelbE8KbBOepukG9EjqGEN8KoIv5FqzAstSy096jpUvrc$ 
<https://urldefense.com/v3/__https://news.yahoo.com/volcano-aftershocks-rattle-dr-congo-103805544.html__;!!IKRxdwAv5BmarQ!KPTAYJWofP2voIBWN6xBjFd8XV-dwNnbAv_OGX4pKaFPmJVQmyxZrqyFezSnFC0$>
;

Agence France-Presse (AFP)
https://urldefense.com/v3/__https://fr.africanews.com/2021/05/25/rdc-des-fissures-detectees-a-goma-au-pied-du-volcan-nyiragongo/?utm_term=Autofeed__;!!IKRxdwAv5BmarQ!MMRc5FYrcpi6gLEwRppelbE8KbBOepukG9EjqGEN8KoIv5FqzAstSy09guRscdk$ 
<https://urldefense.com/v3/__https://fr.africanews.com/2021/05/25/rdc-des-fissures-detectees-a-goma-au-pied-du-volcan-nyiragongo/?utm_term=Autofeed__;!!IKRxdwAv5BmarQ!KPTAYJWofP2voIBWN6xBjFd8XV-dwNnbAv_OGX4pKaFPmJVQmyxZrqyFbSW6vf4$>
;

Washington Post
https://urldefense.com/v3/__https://www.washingtonpost.com/world/residents-search-for-dead-killed-by-congos-volcano-eruption/2021/05/24/196b70b6-bca5-11eb-922a-c40c9774bc48_story.html__;!!IKRxdwAv5BmarQ!MMRc5FYrcpi6gLEwRppelbE8KbBOepukG9EjqGEN8KoIv5FqzAstSy09T95ryQ8$ 
<https://urldefense.com/v3/__https://www.washingtonpost.com/world/residents-search-for-dead-killed-by-congos-volcano-eruption/2021/05/24/196b70b6-bca5-11eb-922a-c40c9774bc48_story.html__;!!IKRxdwAv5BmarQ!KPTAYJWofP2voIBWN6xBjFd8XV-dwNnbAv_OGX4pKaFPmJVQmyxZrqyFkJ8_s5g$>
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Reuters
https://urldefense.com/v3/__https://www.reuters.com/business/environment/tremors-shake-congo-city-close-schools-shops-after-volcanic-eruption-2021-05-24/__;!!IKRxdwAv5BmarQ!MMRc5FYrcpi6gLEwRppelbE8KbBOepukG9EjqGEN8KoIv5FqzAstSy09WORcwhQ$ 
<https://urldefense.com/v3/__https://www.reuters.com/business/environment/tremors-shake-congo-city-close-schools-shops-after-volcanic-eruption-2021-05-24/__;!!IKRxdwAv5BmarQ!KPTAYJWofP2voIBWN6xBjFd8XV-dwNnbAv_OGX4pKaFPmJVQmyxZrqyFRyzm4-w$>;
GeoRiskA https://urldefense.com/v3/__https://georiska.africamuseum.be/en__;!!IKRxdwAv5BmarQ!MMRc5FYrcpi6gLEwRppelbE8KbBOepukG9EjqGEN8KoIv5FqzAstSy09jMVnYHk$ 
<https://urldefense.com/v3/__https://georiska.africamuseum.be/en__;!!IKRxdwAv5BmarQ!KPTAYJWofP2voIBWN6xBjFd8XV-dwNnbAv_OGX4pKaFPmJVQmyxZrqyFZWwwggc$>
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IGIHE
https://urldefense.com/v3/__https://igihe.com/amakuru/u-rwanda/article/rubavu-umutingito-ukomeje-gusenya-inzu-z-abaturage-umusigiti-wangiritse-n__;!!IKRxdwAv5BmarQ!MMRc5FYrcpi6gLEwRppelbE8KbBOepukG9EjqGEN8KoIv5FqzAstSy09M3Uwi7U$ 
<https://urldefense.com/v3/__https://igihe.com/amakuru/u-rwanda/article/rubavu-umutingito-ukomeje-gusenya-inzu-z-abaturage-umusigiti-wangiritse-n__;!!IKRxdwAv5BmarQ!KPTAYJWofP2voIBWN6xBjFd8XV-dwNnbAv_OGX4pKaFPmJVQmyxZrqyFm8BzDr0$>
;

Simon Carn https://urldefense.com/v3/__http://www.volcarno.com/__;!!IKRxdwAv5BmarQ!MMRc5FYrcpi6gLEwRppelbE8KbBOepukG9EjqGEN8KoIv5FqzAstSy09dxaWG-8$ 
<https://urldefense.com/v3/__http://www.volcarno.com/__;!!IKRxdwAv5BmarQ!KPTAYJWofP2voIBWN6xBjFd8XV-dwNnbAv_OGX4pKaFPmJVQmyxZrqyFnLsHmPk$>

Ongoing Activity

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

JMA reported that during 21-24 May incandescence from Minamidake Crater (at
Aira Calderaâ??s Sakurajima volcano) was visible nightly. A very small
eruptive event was recorded on 23 May. 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!MMRc5FYrcpi6gLEwRppelbE8KbBOepukG9EjqGEN8KoIv5FqzAstSy09TzlgLuY$ 
<https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!KPTAYJWofP2voIBWN6xBjFd8XV-dwNnbAv_OGX4pKaFPmJVQmyxZrqyFrfoOcbw$>

Dukono  | Halmahera (Indonesia)  | 1.693Â°N, 127.894Â°E  | Summit elev. 1229 m

Based on satellite and wind model data, the Darwin VAAC reported that
during 18-23 and 25 May ash plumes from Dukono rose to 2.1-2.4 km
(7,000-8,000 ft) a.s.l. and drifted in multiple directions. 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!MMRc5FYrcpi6gLEwRppelbE8KbBOepukG9EjqGEN8KoIv5FqzAstSy09lujSCVg$ 
<https://urldefense.com/v3/__http://www.bom.gov.au/aviation/volcanic-ash/darwin-va-advisory.shtml__;!!IKRxdwAv5BmarQ!KPTAYJWofP2voIBWN6xBjFd8XV-dwNnbAv_OGX4pKaFPmJVQmyxZrqyFhH9aURc$>
;

Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!MMRc5FYrcpi6gLEwRppelbE8KbBOepukG9EjqGEN8KoIv5FqzAstSy09D_7e4jM$ 
<https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!KPTAYJWofP2voIBWN6xBjFd8XV-dwNnbAv_OGX4pKaFPmJVQmyxZrqyFSSwMq5Q$>

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

Volcanologists in Severo-Kurilsk (Paramushir Island), about 7 km E of
Ebeko, observed explosions during 14-20 May that sent ash plumes to 3.5 km
(11,500 ft) a.s.l. and drifted N, NE, E, and SE. The Aviation Color Code
remained at Orange (the second highest level on a four-color scale).

Geologic Summary. The flat-topped summit of the central cone of Ebeko
volcano, one of the most active in the Kuril Islands, occupies the northern
end of Paramushir Island. Three summit craters located along a SSW-NNE line
form Ebeko volcano proper, at the northern end of a complex of five
volcanic cones. Blocky lava flows extend west from Ebeko and SE from the
neighboring Nezametnyi cone. The eastern part of the southern crater
contains strong solfataras and a large boiling spring. The central crater
is filled by a lake about 20 m deep whose shores are lined with steaming
solfataras; the northern crater lies across a narrow, low barrier from the
central crater and contains a small, cold crescentic lake. Historical
activity, recorded since the late-18th century, has been restricted to
small-to-moderate explosive eruptions from the summit craters. Intense
fumarolic activity occurs in the summit craters, on the outer flanks of the
cone, and in lateral explosion craters.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!MMRc5FYrcpi6gLEwRppelbE8KbBOepukG9EjqGEN8KoIv5FqzAstSy09ILy7YBg$ 
<https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!KPTAYJWofP2voIBWN6xBjFd8XV-dwNnbAv_OGX4pKaFPmJVQmyxZrqyFcCjhngM$>

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

INGV reported episodes of lava fountaining at Etnaâ??s Southeast Crater (SEC)
on 19 and 22 May that continued the recent pattern of Strombolian
explosions followed by lava fountaining and lava flows. Strombolian
activity began at 2340 on 19 May and produced ash plumes that drifted E.
Activity intensified and lava fountains formed at 0234 on 20 May. At the
same time lava overflowed the SEC and traveled SW, and within a few hours
had reached 2,800 m elevation. The activity lasted about three and a half
hours and then abruptly ended. The next episode during 0134-0454 on 22 May
included Strombolian explosions and ash plumes that drifted SE; lava
fountaining began at 0302 and flows traveled SW, overlapping the flows from
19 May. Explosions produced ash plumes that drifted SE around 0830 and
1014. Strombolian explosions intensified around 2031, producing dense ash
plumes that drifted E. Lava fountains formed about two hours later, sending
flows down the E and SW flanks; fountaining was over by 0038 on 23 May. A
series of explosions were visible during 0351-0403, producing dense ash
plumes that drifted E. Two ash plumes were observed rising from SECâ??s E
crater during the night and the day on 23 May. Intense explosive activity
at SEC began at 1820 on 25 May, producing ash plumes that rose to 3.5 km
(11,500 ft) a.s.l. and drifted E. Strombolian activity commenced at 1845
and lava fountains were visible around 2023. Lava flows were visible at
2244 and ash plumes drifted E at an altitude of 6 km (19,700 ft) a.s.l.
Activity ceased by 0026 on 26 May.

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!MMRc5FYrcpi6gLEwRppelbE8KbBOepukG9EjqGEN8KoIv5FqzAstSy09AFVplV8$ 
<https://urldefense.com/v3/__http://www.ct.ingv.it/__;!!IKRxdwAv5BmarQ!KPTAYJWofP2voIBWN6xBjFd8XV-dwNnbAv_OGX4pKaFPmJVQmyxZrqyFN9uLSbA$>

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

KVERT reported that a weak thermal anomaly over Karymsky was visible in
satellite images on 13-14 and 19 May. The Aviation Color Code remained at
Orange (the second highest level on a four-color scale).

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!MMRc5FYrcpi6gLEwRppelbE8KbBOepukG9EjqGEN8KoIv5FqzAstSy09ILy7YBg$ 
<https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!KPTAYJWofP2voIBWN6xBjFd8XV-dwNnbAv_OGX4pKaFPmJVQmyxZrqyFcCjhngM$>

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

HVO reported that lava at Kilauea's Halema`uma`u Crater lava lake
circulated in a 20-m-diameter area on 19 May but was stagnant and crusted
over on other days through 25 May. A few minor oozes of lava between the W
vent and main island were occasionally visible. The depth of the lava lake
was 229 m and had remained unchanged since 11 May. Sulfur dioxide emissions
were 100-150 tons per day during 19-23 May, close to the less than 50
tonnes per day measured during the non-eruptive period from late 2018 to
late 2020. The Aviation Color Code remained at Orange and the Volcano Alert
Level remained at Watch.

Geologic Summary. Kilauea, which overlaps the E flank of the massive Mauna
Loa shield volcano, has been Hawaii's most active volcano during historical
time. Eruptions are prominent in Polynesian legends; written documentation
extending back to only 1820 records frequent summit and flank lava flow
eruptions that were interspersed with periods of long-term lava lake
activity that lasted until 1924 at Halemaumau crater, within the summit
caldera. The 3 x 5 km caldera was formed in several stages about 1500 years
ago and during the 18th century; eruptions have also originated from the
lengthy East and SW rift zones, which extend to the sea on both sides of
the volcano. About 90% of the surface of the basaltic shield volcano is
formed of lava flows less than about 1100 years old; 70% of the volcano's
surface is younger than 600 years. A long-term eruption from the East rift
zone that began in 1983 has produced lava flows covering more than 100 km2,
destroying nearly 200 houses and adding new coastline to the island.

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)
https://urldefense.com/v3/__https://volcanoes.usgs.gov/observatories/hvo/__;!!IKRxdwAv5BmarQ!MMRc5FYrcpi6gLEwRppelbE8KbBOepukG9EjqGEN8KoIv5FqzAstSy09brjmdoA$ 
<https://urldefense.com/v3/__https://volcanoes.usgs.gov/observatories/hvo/__;!!IKRxdwAv5BmarQ!KPTAYJWofP2voIBWN6xBjFd8XV-dwNnbAv_OGX4pKaFPmJVQmyxZrqyFR9wfSmU$>

Krysuvik-Trolladyngja  | Iceland  | 63.917Â°N, 22.067Â°W  | Summit elev. 360 m

The fissure eruption in the W part of the KrÃ½suvÃk-TrÃ¶lladyngja volcanic
system, close to Fagradalsfjall on the Reykjanes Peninsula, continued
during 19-25 May. Lava fountains rose from the fifth vent and continued to
feed the lava flows. According to news sources, lava during 20-21 May
overtook the eastern earthen dam that had been constructed at the head of
NÃ¡tthaga valley in an attempt to prevent flows from descending towards
Highway 427 (SuÃ°urstrandarvegur) to the S, and burying fiber optic cables.
By 22 May the lava was about 2.5 km from the road. The Aviation Color Code
remained at Orange due to the lack of ash and tephra emissions. Authorities
warned of increased gas emissions hazards.

Geologic Summary. The KrÃ½suvÃk-TrÃ¶lladyngja volcanic system is described by
the Catalogue of Icelandic Volcanoes as an approximately 50-km-long
composite fissure swarm trending about N38Â°E, including a 30-km-long swarm
of fissures, with no central volcano. It is one of the volcanic systems
arranged en-echelon along the Reykjanes Peninsula west of Kleifarvatn lake.
The Fagradalsfjall and KrÃ½suvÃk fissure swarms are considered splits or
secondary swarms of the KrÃ½suvÃkâ??TrÃ¶lladyngja volcanic system. Small shield
volcanoes have produced a large portion of the erupted volume within the
system. Several eruptions have taken place since the settlement of Iceland,
including the eruption of a large basaltic lava flow from the Ogmundargigar
crater row around the 12th century. The latest eruption, identified through
tephrochronology, took place during the 14th century.

Sources: Icelandic Meteorological Office (IMO) https://urldefense.com/v3/__http://en.vedur.is/__;!!IKRxdwAv5BmarQ!MMRc5FYrcpi6gLEwRppelbE8KbBOepukG9EjqGEN8KoIv5FqzAstSy09WJnDdxw$ 
<https://urldefense.com/v3/__http://en.vedur.is/__;!!IKRxdwAv5BmarQ!KPTAYJWofP2voIBWN6xBjFd8XV-dwNnbAv_OGX4pKaFPmJVQmyxZrqyFXHRb3kA$>
;

Icelandic National Broadcasting Service (RUV)
https://urldefense.com/v3/__https://www.ruv.is/frett/2021/03/18/eldgosid-i-geldingadolum-i-beinni-utsendingu__;!!IKRxdwAv5BmarQ!MMRc5FYrcpi6gLEwRppelbE8KbBOepukG9EjqGEN8KoIv5FqzAstSy097k8pyK4$ 
<https://urldefense.com/v3/__https://www.ruv.is/frett/2021/03/18/eldgosid-i-geldingadolum-i-beinni-utsendingu__;!!IKRxdwAv5BmarQ!KPTAYJWofP2voIBWN6xBjFd8XV-dwNnbAv_OGX4pKaFPmJVQmyxZrqyFcThl3RM$>

Lewotolok  | Lembata Island (Indonesia)  | 8.274Â°S, 123.508Â°E  | Summit
elev. 1431 m

PVMBG reported that white-and-gray plumes from Lewotolok rose as high as
800 m and drifted W and E during 18-24 May. Rumbling was heard almost
daily. Crater incandescent was visible on 18 May and on 22 May incandescent
material was ejected 400-700 m to the SE. 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.

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!MMRc5FYrcpi6gLEwRppelbE8KbBOepukG9EjqGEN8KoIv5FqzAstSy09D_7e4jM$ 
<https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!KPTAYJWofP2voIBWN6xBjFd8XV-dwNnbAv_OGX4pKaFPmJVQmyxZrqyFSSwMq5Q$>

Merapi  | Central Java (Indonesia)  | 7.54Â°S, 110.446Â°E  | Summit elev.
2910 m

BPPTKG reported that the lava dome just below Merapiâ??s SW rim and the lava
dome in the summit crater both continued to extrude lava during 14-20 May.
The SW rim lava-dome volume was an estimated 1.284 million cubic meters,
with a growth rate of about 11,700 cubic meters per day, and continued to
shed material down the flank. A total of seven pyroclastic flows traveled a
maximum of 2 km down the SW flank. Incandescent avalanches, recorded 58
times, traveled as far as 2 km down the SW flank and once went 800 m SE.
The summit lava dome had not changed since the previous week. The Alert
Level remained at 3 (on a scale of 1-4), and the public was warned to stay
5 km away from the summit.

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!MMRc5FYrcpi6gLEwRppelbE8KbBOepukG9EjqGEN8KoIv5FqzAstSy09A5FchC8$ 
<https://urldefense.com/v3/__http://www.merapi.bgl.esdm.go.id/__;!!IKRxdwAv5BmarQ!KPTAYJWofP2voIBWN6xBjFd8XV-dwNnbAv_OGX4pKaFPmJVQmyxZrqyFxoZlqLs$>

Pacaya  | Guatemala  | 14.382Â°N, 90.601Â°W  | Summit elev. 2569 m

In a special 15 May bulletin INSIVUMEH noted that lava effusion at Pacaya
ceased and activity instead was characterized by explosive activity at the
summit crater. Ash-and-gas plumes rose 1 km and drifted downwind, causing
ashfall in San Francisco de Sales, ConcepciÃ³n El Cedro, Aldea El
Patrocinio, and San Miguel Petapa. Explosions ejected material up to 100 m
above the summit. Ash plumes rose around 500 m above the summit and drifted
5-10 km N, NW, SW, and S during 18-21 and 24-25 May. Some explosions were
recorded by the seismic network during 22-23 May; white-and-blue gas plumes
rose 300-700 m and drifted 5 km W during 23-24 May.

Geologic Summary. Eruptions from Pacaya, one of Guatemala's most active
volcanoes, are frequently visible from Guatemala City, the nation's
capital. This complex basaltic volcano was constructed just outside the
southern topographic rim of the 14 x 16 km Pleistocene AmatitlÃ¡n caldera. A
cluster of dacitic lava domes occupies the southern caldera floor. The
post-caldera Pacaya massif includes the ancestral Pacaya Viejo and Cerro
Grande stratovolcanoes and the currently active Mackenney stratovolcano.
Collapse of Pacaya Viejo between 600 and 1500 years ago produced a
debris-avalanche deposit that extends 25 km onto the Pacific coastal plain
and left an arcuate somma rim inside which the modern Pacaya volcano
(Mackenney cone) grew. A subsidiary crater, Cerro Chino, was constructed on
the NW somma rim and was last active in the 19th century. During the past
several decades, activity has consisted of frequent strombolian eruptions
with intermittent lava flow extrusion that has partially filled in the
caldera moat and armored the flanks of Mackenney cone, punctuated by
occasional larger explosive eruptions that partially destroy the summit of
the growing young stratovolcano.

Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e
Hidrologia (INSIVUMEH) https://urldefense.com/v3/__http://www.insivumeh.gob.gt/__;!!IKRxdwAv5BmarQ!MMRc5FYrcpi6gLEwRppelbE8KbBOepukG9EjqGEN8KoIv5FqzAstSy09IhWmA38$ 
<https://urldefense.com/v3/__http://www.insivumeh.gob.gt/__;!!IKRxdwAv5BmarQ!KPTAYJWofP2voIBWN6xBjFd8XV-dwNnbAv_OGX4pKaFPmJVQmyxZrqyFxiMRuXs$>

Piton de la Fournaise  | Reunion Island (France)  | 21.244Â°S, 55.708Â°E  |
Summit elev. 2632 m

OVPF reported that gas emissions rose from the cones at Piton de la
Fournaise during 18-19 and 22-23 May; inclement weather conditions
prevented visual observations on days in between. The eruption likely
ceased around 0200 on 24 May, when tremor subsided, though inclement
weather again prevented visual confirmation. The Alert Level remained at
2-2.

Geologic Summary. The massive Piton de la Fournaise basaltic shield volcano
on the French island of RÃ©union in the western Indian Ocean is one of the
world's most active volcanoes. Much of its more than 530,000-year history
overlapped with eruptions of the deeply dissected Piton des Neiges shield
volcano to the NW. Three calderas formed at about 250,000, 65,000, and less
than 5000 years ago by progressive eastward slumping of the volcano.
Numerous pyroclastic cones dot the floor of the calderas and their outer
flanks. Most historical eruptions have originated from the summit and
flanks of Dolomieu, a 400-m-high lava shield that has grown within the
youngest caldera, which is 8 km wide and breached to below sea level on the
eastern side. More than 150 eruptions, most of which have produced fluid
basaltic lava flows, have occurred since the 17th century. Only six
eruptions, in 1708, 1774, 1776, 1800, 1977, and 1986, have originated from
fissures on the outer flanks of the caldera. The Piton de la Fournaise
Volcano Observatory, one of several operated by the Institut de Physique du
Globe de Paris, monitors this very active volcano.

Source: Observatoire Volcanologique du Piton de la Fournaise (OVPF)
https://urldefense.com/v3/__http://www.ipgp.fr/__;!!IKRxdwAv5BmarQ!MMRc5FYrcpi6gLEwRppelbE8KbBOepukG9EjqGEN8KoIv5FqzAstSy099rGIBKY$ 
<https://urldefense.com/v3/__http://www.ipgp.fr/__;!!IKRxdwAv5BmarQ!KPTAYJWofP2voIBWN6xBjFd8XV-dwNnbAv_OGX4pKaFPmJVQmyxZrqyFVe6SkNw$>

Semeru  | Eastern Java (Indonesia)  | 8.108Â°S, 112.922Â°E  | Summit elev.
3657 m

PVMBG reported that Semeru continued to erupt during 18-25 May.
Gray-and-white plumes rose 100-700 m above the summit and drifted S, SW,
and N during 18-23 May. Avalanches of material occurred four times on 18
May, traveling as far as 500 m down the Kobokan drainage. Ash plumes rose
600 and 400 m and drifted N on 21 and 22 May, respectively. The Alert Level
remained at 2 (on a scale of 1-4), with a general exclusion zone of 1 km
and extensions to 5 km in the SSE sector.

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!MMRc5FYrcpi6gLEwRppelbE8KbBOepukG9EjqGEN8KoIv5FqzAstSy09D_7e4jM$ 
<https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!KPTAYJWofP2voIBWN6xBjFd8XV-dwNnbAv_OGX4pKaFPmJVQmyxZrqyFSSwMq5Q$>

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

AVO reported that sulfur dioxide and steam plumes from Semisopochnoi were
possibly visible in satellite images during 19-20 May. Satellite images on
21 May showed a sulfur dioxide gas plume drifting 160 km SE. Steam plumes
rose from Cerberus on 24 May. 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!MMRc5FYrcpi6gLEwRppelbE8KbBOepukG9EjqGEN8KoIv5FqzAstSy093DDdxXo$ 
<https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!KPTAYJWofP2voIBWN6xBjFd8XV-dwNnbAv_OGX4pKaFPmJVQmyxZrqyF7GazViI$>

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

KVERT reported that a thermal anomaly over Sheveluch was identified in
satellite images during 14-21 May. The Aviation Color Code remained at
Orange (the second highest level on a four-color scale).

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!MMRc5FYrcpi6gLEwRppelbE8KbBOepukG9EjqGEN8KoIv5FqzAstSy09ILy7YBg$ 
<https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!KPTAYJWofP2voIBWN6xBjFd8XV-dwNnbAv_OGX4pKaFPmJVQmyxZrqyFcCjhngM$>

Sinabung  | Indonesia  | 3.17Â°N, 98.392Â°E  | Summit elev. 2460 m

PVMBG reported that the eruption at Sinabung continued during 19-25 May.
Pyroclastic flows traveled 3 km down the E and SE flanks at 0448 on 19 May.
A dense gray ash plume rose as high as 3.5 km above the summit and drifted
E and S. White-and-gray plumes rose 100-400 m and drifted NE, E, SE, and S
on 20 May. The Alert Level remained at 3 (on a scale of 1-4), with a
general exclusion zone of 3 km and extensions to 5 km in the SE sector and
4 km in the NE sector.

Geologic Summary. Gunung Sinabung is a Pleistocene-to-Holocene
stratovolcano with many lava flows on its flanks. The migration of summit
vents along a N-S line gives the summit crater complex an elongated form.
The youngest crater of this conical andesitic-to-dacitic edifice is at the
southern end of the four overlapping summit craters. The youngest deposit
is a SE-flank pyroclastic flow 14C dated by Hendrasto et al. (2012) at
740-880 CE. An unconfirmed eruption was noted in 1881, and solfataric
activity was seen at the summit and upper flanks in 1912. No confirmed
historical eruptions were recorded prior to explosive eruptions during
August-September 2010 that produced ash plumes to 5 km above the summit.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known
as CVGHM) https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!MMRc5FYrcpi6gLEwRppelbE8KbBOepukG9EjqGEN8KoIv5FqzAstSy09D_7e4jM$ 
<https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!KPTAYJWofP2voIBWN6xBjFd8XV-dwNnbAv_OGX4pKaFPmJVQmyxZrqyFSSwMq5Q$>

Soufriere St. Vincent  | St. Vincent  | 13.33Â°N, 61.18Â°W  | Summit elev.
1220 m

University of the West Indies Seismic Research Centre (UWI-SRC) and
National Emergency Management Organisation (NEMO) reported that seismicity
at SoufriÃ¨re St. Vincent (often simply referred to as â??La Soufriereâ??)
remained low during 17-24 May, with a few long-period and volcano-tectonic
earthquakes occasionally recorded. Persistent steaming from the crater was
visible on days when weather permitted views, and thermal anomalies
continued to be identified in satellite data. Sulfur dioxide emissions were
461 tons per day on 20 May. NEMO noted that the total number of displaced
people was 22,759 on 15 May though the number continued to fluctuate as
people arrived at shelters while others returned home or changed locations.
The Alert Level remained at Orange.

Geologic Summary. SoufriÃ¨re St. Vincent is the northernmost and youngest
volcano on St. Vincent Island. The NE rim of the 1.6-km wide summit crater
is cut by a crater formed in 1812. The crater itself lies on the SW margin
of a larger 2.2-km-wide caldera, which is breached widely to the SW as a
result of slope failure. Frequent explosive eruptions after about 4,300
years ago produced pyroclastic deposits of the Yellow Tephra Formation,
which cover much of the island. The first historical eruption took place in
1718; it and the 1812 eruption produced major explosions. Much of the
northern end of the island was devastated by a major eruption in 1902 that
coincided with the catastrophic Mont PelÃ©e eruption on Martinique. A lava
dome was emplaced in the summit crater in 1971 during a strictly effusive
eruption, forming an island within a lake that filled the crater. A series
of explosive eruptions in 1979 destroyed the 1971 dome and ejected the
lake; a new dome was then built.

Sources: University of the West Indies Seismic Research Centre (UWI-SRC)
https://urldefense.com/v3/__http://www.uwiseismic.com/__;!!IKRxdwAv5BmarQ!MMRc5FYrcpi6gLEwRppelbE8KbBOepukG9EjqGEN8KoIv5FqzAstSy09Sx4mFpE$ 
<https://urldefense.com/v3/__http://www.uwiseismic.com/__;!!IKRxdwAv5BmarQ!KPTAYJWofP2voIBWN6xBjFd8XV-dwNnbAv_OGX4pKaFPmJVQmyxZrqyFoi4--Bc$>
;

National Emergency Management Organisation (NEMO), Government of Saint
Vincent and the Grenadines https://urldefense.com/v3/__http://nemo.gov.lc/__;!!IKRxdwAv5BmarQ!MMRc5FYrcpi6gLEwRppelbE8KbBOepukG9EjqGEN8KoIv5FqzAstSy09rQLVeAM$ 
<https://urldefense.com/v3/__http://nemo.gov.lc/__;!!IKRxdwAv5BmarQ!KPTAYJWofP2voIBWN6xBjFd8XV-dwNnbAv_OGX4pKaFPmJVQmyxZrqyFr3oHM8w$>

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

JMA reported that intermittent eruptive activity at Suwanosejima's Ontake
Crater produced plumes that rose as high as 1.6 km above the crater rim
during 14-21 May. Large volcanic bombs were ejected 300 m from the crater.
Crater incandescence was visible overnight during 18-19 May. The Alert
Level remained at 2 and the public was warned to stay 1 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!MMRc5FYrcpi6gLEwRppelbE8KbBOepukG9EjqGEN8KoIv5FqzAstSy09TzlgLuY$ 
<https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!KPTAYJWofP2voIBWN6xBjFd8XV-dwNnbAv_OGX4pKaFPmJVQmyxZrqyFrfoOcbw$>

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

PHIVOLCS reported that unrest at Taal continued during 19-25 May. Low-level
background tremor that had begun at 0905 on 8 April continued. During 19-21
May there were 2-30 daily low-frequency events, 10-169 daily volcanic
earthquakes, and 8-139 periods of volcanic tremor with variable durations
(1-37 minutes); no earthquakes were recorded during 22-25 May. Most of the
earthquakes were very shallow (less than 5 km deep) beneath Taal Volcano
Island (TVI) and the NE part of Taal Lake. Daily upwelling of hot volcanic
fluids in the crater lake was accompanied by sometimes voluminous steam
plumes that were as tall as 2 km. Sulfur dioxide emissions were 2,811-3,611
tonnes/day. Slow and steady inflation of the Taal region was recorded by
multiple instruments after the January 2020 eruption. PHIVOLCS noted the
continuing state of elevated unrest, reminding the public that the Alert
Level for Taal remained at 2 (on a scale of 0-5). PHIVOLCS strongly
recommended no entry onto the island, and access to the Main Crater, Daang
Kastila fissure (along the walking trail), and boating on Taal Lake was
strictly prohibited.

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)
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End of Volcano Digest - 26 May 2021 to 28 May 2021 (#2021-53)
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