Smithsonian / USGS Weekly Volcanic Activity Report 10-16 May 2023

Rachel Holsteen-Bruyere <rbruyere@xxxxxxx> · Wed, 17 May 2023 13:17:44 -0700

2-2-2-2-2-2-2-2-2-2-2-2-2

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

Smithsonian / USGS Weekly Volcanic Activity Report

10-16 May 2023

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

URL: https://urldefense.com/v3/__https://volcano.si.edu/reports_weekly.cfm__;!!IKRxdwAv5BmarQ!ZgZ3SbR3tK5TswuR-lg8RPjEjwtapwiGo9f8HvZNaEIEnac_E1RaC-TSyVCXd4X85G5GuiJG-A9Bivg6$ 
<https://urldefense.com/v3/__https://volcano.si.edu/reports_weekly.cfm__;!!IKRxdwAv5BmarQ!fQRZUjHoOsVVb6G4FfPnWsSREugsWgCx4nvC0pe6k-QElj0E8b2ntw6p-Jq0SzrR9Uai_rbTm_g$>

New Activity/Unrest: Fuego, South-Central Guatemala  | Kita-Ioto, Volcano
Islands

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

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

INSIVUMEH reported that a range of 1-7 weak explosions per hour were
recorded at Fuego during 10-16 May. The explosions generated ash plumes
that rose to a maximum height of 850 m above the crater and drifted up to
12 km E, SE, S, and SW. Occasional weak avalanches of material were visible
near the crater. During 9-10 May wind entrained loose ash that was
deposited along the Ceniza, Las Lajas, and Seca drainages. On 12 May a
minor lahar descended the Ceniza drainage, carrying branches, tree trunks,
and volcanic blocks up to 1.5 m in diameter. Minor incandescent over the
crater was visible overnight during 12-13 and 15-16 May. Wind entrained ash
deposits during 15-16 May causing localized â??curtainsâ?? of ash.

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

Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e
Hidrologia (INSIVUMEH) https://urldefense.com/v3/__http://www.insivumeh.gob.gt/__;!!IKRxdwAv5BmarQ!ZgZ3SbR3tK5TswuR-lg8RPjEjwtapwiGo9f8HvZNaEIEnac_E1RaC-TSyVCXd4X85G5GuiJG-CcFnmfC$ 
<https://urldefense.com/v3/__http://www.insivumeh.gob.gt/__;!!IKRxdwAv5BmarQ!fQRZUjHoOsVVb6G4FfPnWsSREugsWgCx4nvC0pe6k-QElj0E8b2ntw6p-Jq0SzrR9UaiWyGUudc$>

Kita-Ioto  | Volcano Islands  | 25.424Â°N, 141.284Â°E  | Summit elev. 792 m

Japan Coast Guard reported that a small area of bluish-white discolored
water above Funka Asane, a submarine vent 4-5 km NW of Kita-Ioto, was
visible on 11 May. This was the first time discolored water was seen over
the vent in about two years.

Geologic Summary. No historical eruptions have occurred from the deeply
eroded Kita-Ioto stratovolcano, which forms a steep-sided basaltic cone
rising about 800 m above the sea. However, eruptions have been recorded
since the 18th century from Funka Asane, a submarine vent 4-5 km NW of the
island. Kita-Ioto is the northernmost of the Kazan Retto (Volcano Islands),
located in the middle of the Izu-Marianas arc.

Source: Japan Coast Guard https://urldefense.com/v3/__http://www.kaiho.mlit.go.jp/index.html__;!!IKRxdwAv5BmarQ!ZgZ3SbR3tK5TswuR-lg8RPjEjwtapwiGo9f8HvZNaEIEnac_E1RaC-TSyVCXd4X85G5GuiJG-Ec-flaw$ 
<https://urldefense.com/v3/__http://www.kaiho.mlit.go.jp/index.html__;!!IKRxdwAv5BmarQ!fQRZUjHoOsVVb6G4FfPnWsSREugsWgCx4nvC0pe6k-QElj0E8b2ntw6p-Jq0SzrR9UaiOdTmOKM$>

Ongoing Activity

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

JMA reported ongoing activity at both Minamidake Crater and Showa Crater
(Aira Calderaâ??s Sakurajima volcano) during 8-15 May. Crater incandescence
was observed nightly at Minamidake Crater. On 8 May sulfur dioxide
emissions were extremely high at 3,900 tons per day. At 1315 on 9 May an
explosion at Minamidake generated an ash plume that rose 1.2 km above the
crater rim and drifted SW, and ejected blocks 1.1 km from the vent.
Eruptive events at 1527, 1724, and 1817 on 11 May produced ash plumes that
rose as high as 1.3 km and drifted NW and W. At Showa Crater eruptive
events recorded at 1009, 1303, and 1401 on 8 May, at 0550, 0726, 2204, and
2321 on 11 May, at 1831 on 12 May, and at 0859 on 14 May produced ash
plumes that rose as high as 1.7 km above the crater rim and drifted in
multiple directions. Sulfur dioxide emissions were somewhat high on 12 May,
averaging 1,800 tons per day. The Alert Level remained at 3 (on a 5-level
scale), and residents were warned to stay 2 km away from both craters.

Geologic Summary. The Aira caldera in the northern half of Kagoshima Bay
contains the post-caldera Sakurajima volcano, one of Japan's most active.
Eruption of the voluminous Ito pyroclastic flow accompanied formation of
the 17 x 23 km caldera about 22,000 years ago. The smaller Wakamiko caldera
was formed during the early Holocene in the NE corner of the 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!ZgZ3SbR3tK5TswuR-lg8RPjEjwtapwiGo9f8HvZNaEIEnac_E1RaC-TSyVCXd4X85G5GuiJG-KLVitO0$ 
<https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!fQRZUjHoOsVVb6G4FfPnWsSREugsWgCx4nvC0pe6k-QElj0E8b2ntw6p-Jq0SzrR9UaiADGS1uU$>

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

KVERT reported that activity at Bezymianny was generally characterized by
gas-and-steam emissions, incandescence at the lava dome, and hot avalanches
from the lava dome during 4-11 May. A daily thermal anomaly was identified
daily in satellite images. The Aviation Color Code remained at Yellow (the
second lowest level on a four-color scale). Dates are based on UTC times;
specific events are in local time where noted.

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

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!ZgZ3SbR3tK5TswuR-lg8RPjEjwtapwiGo9f8HvZNaEIEnac_E1RaC-TSyVCXd4X85G5GuiJG-MCsCJGF$ 
<https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!fQRZUjHoOsVVb6G4FfPnWsSREugsWgCx4nvC0pe6k-QElj0E8b2ntw6p-Jq0SzrR9UaiXIlaJis$>

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

IG reported that moderate eruptive activity continued at Cotopaxi during
9-16 May. Daily seismic activity was characterized by long-period
earthquakes and tremors indicating emissions; a few volcano-tectonic
earthquakes were recorded during the week. Emissions of steam, gas, and
variable amounts of ash were observed on most days. During 9-10 May plumes
with moderate amounts of ash rose 2-3 km above the crater rim and drifted
SW, N, and NE. Ashfall was reported in areas to the SW, including San
JoaquÃn and San AgustÃn de Callo. On 11 May gas-and-steam plumes rose 700 m
above the summit and drifted to the E and SE. Emissions with moderate ash
content on 12 May rose 1-2 km above the crater rim and drifted to the SE;
later that day ash plumes rose 700 m. On 13 May steam-and-gas emissions
with low or no ash content rose 900 m above the summit and drifted S, and
gas-and-ash plumes rose 800 m and drifted SE. On 15 May steam-and-ash
plumes rose 400 m and drifted W and SW. Weather clouds often prevented
views during 14-16 May. Servicio Nacional de GestiÃ³n de Riesgos y
Emergencias (SNGRE) maintained the Alert Level at Yellow (the second lowest
level on a four-color scale).

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

Sources: Instituto GeofÃsico-Escuela PolitÃ©cnica Nacional (IG)
https://urldefense.com/v3/__http://www.igepn.edu.ec/__;!!IKRxdwAv5BmarQ!ZgZ3SbR3tK5TswuR-lg8RPjEjwtapwiGo9f8HvZNaEIEnac_E1RaC-TSyVCXd4X85G5GuiJG-ISkKo6K$ 
<https://urldefense.com/v3/__http://www.igepn.edu.ec/__;!!IKRxdwAv5BmarQ!fQRZUjHoOsVVb6G4FfPnWsSREugsWgCx4nvC0pe6k-QElj0E8b2ntw6p-Jq0SzrR9UaiYZRG1RM$>
;

Servicio Nacional de GestiÃ³n de Riesgos y Emergencias (SNGRE)
https://urldefense.com/v3/__https://www.gestionderiesgos.gob.ec/__;!!IKRxdwAv5BmarQ!ZgZ3SbR3tK5TswuR-lg8RPjEjwtapwiGo9f8HvZNaEIEnac_E1RaC-TSyVCXd4X85G5GuiJG-PiyRIoW$ 
<https://urldefense.com/v3/__https://www.gestionderiesgos.gob.ec/__;!!IKRxdwAv5BmarQ!fQRZUjHoOsVVb6G4FfPnWsSREugsWgCx4nvC0pe6k-QElj0E8b2ntw6p-Jq0SzrR9UaiuJybbL8$>

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

PVMBG reported that the eruption at Dukono was ongoing during 10-15 May.
Daily dense white-and-gray ash plumes rose as high as 700 m above the
summit and drifted E and N. 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.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known
as CVGHM) https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!ZgZ3SbR3tK5TswuR-lg8RPjEjwtapwiGo9f8HvZNaEIEnac_E1RaC-TSyVCXd4X85G5GuiJG-CuWAo0U$ 
<https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!fQRZUjHoOsVVb6G4FfPnWsSREugsWgCx4nvC0pe6k-QElj0E8b2ntw6p-Jq0SzrR9UaiF87kk-8$>

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

KVERT reported that moderate activity at Ebeko was ongoing during 4-11 May.
According to volcanologists in Severo-Kurilsk (Paramushir Island, about 7
km E) explosions during 4, 6-7, and 9-10 May generated ash plumes that rose
as high as 4 km (13,100 ft) a.s.l. and drifted E. A thermal anomaly was
identified in satellite images on 9 May. The Aviation Color Code remained
at Orange (the second highest level on a four-color scale). Dates are based
on UTC times; specific events are in local time where noted.

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

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!ZgZ3SbR3tK5TswuR-lg8RPjEjwtapwiGo9f8HvZNaEIEnac_E1RaC-TSyVCXd4X85G5GuiJG-MCsCJGF$ 
<https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!fQRZUjHoOsVVb6G4FfPnWsSREugsWgCx4nvC0pe6k-QElj0E8b2ntw6p-Jq0SzrR9UaiXIlaJis$>

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

INGV reported that an explosion at Etnaâ??s SE Crater occurred at 0839 on 14
May and produced an ash emission that rapidly dispersed around the summit
area. The Aviation Color Code was raised to Yellow at 0902 and then lowered
back to Green at 1830 on 14 May. No significant variations in the seismic
data were associated with the explosion.

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

Source: Sezione di Catania - Osservatorio Etneo (INGV)
https://urldefense.com/v3/__http://www.ct.ingv.it/__;!!IKRxdwAv5BmarQ!ZgZ3SbR3tK5TswuR-lg8RPjEjwtapwiGo9f8HvZNaEIEnac_E1RaC-TSyVCXd4X85G5GuiJG-G6Sd_8-$ 
<https://urldefense.com/v3/__http://www.ct.ingv.it/__;!!IKRxdwAv5BmarQ!fQRZUjHoOsVVb6G4FfPnWsSREugsWgCx4nvC0pe6k-QElj0E8b2ntw6p-Jq0SzrR9UaiRkth-ZU$>

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

AVO reported that lava likely continued to erupt at the summit of Great
Sitkin during 9-16 May. Satellite data acquired on 11 May showed that the
thick lava continued to expand towards the E but remained confined to the
summit crater. Seismicity was low. Nothing significant was seen in
satellite and webcam images during most of the week due to persistent
weather clouds obscuring views. The Volcano Alert Level remained at Watch
(the second highest level on a four-level scale) and the Aviation Color
Code remained at Orange (the second highest level on a four-color scale).

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

Source: US Geological Survey Alaska Volcano Observatory (AVO)
https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!ZgZ3SbR3tK5TswuR-lg8RPjEjwtapwiGo9f8HvZNaEIEnac_E1RaC-TSyVCXd4X85G5GuiJG-A9ddB2t$ 
<https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!fQRZUjHoOsVVb6G4FfPnWsSREugsWgCx4nvC0pe6k-QElj0E8b2ntw6p-Jq0SzrR9UaiTL-SRds$>

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

During 10-13 May PVMBG reported that white-and-gray and white-and-brown ash
plumes generally rose as high as 200 m above Anak Krakatauâ??s summit and
drifted SW and NW, though a few Volcano Observatory Notices for Aviation
(VONAs) described higher plumes. At 1241 on 11 May a gray ash plume rose 1
km above summit and drifted SW. At 0920 on 12 May a dense gray ash plume
rose 2.5 km and drifted SW. At 2320 a dense gray ash plume rose 1.5 km and
drifted SW. An accompanying webcam image showed incandescent material being
ejected above the vent. At 0710 on 13 May a dense gray ash plume rose 2 km
and drifted SW. The Alert Level remained at 3 (on a scale of 1-4), and the
public was warned to stay at least 5 km away from the crater.

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

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known
as CVGHM) https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!ZgZ3SbR3tK5TswuR-lg8RPjEjwtapwiGo9f8HvZNaEIEnac_E1RaC-TSyVCXd4X85G5GuiJG-CuWAo0U$ 
<https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!fQRZUjHoOsVVb6G4FfPnWsSREugsWgCx4nvC0pe6k-QElj0E8b2ntw6p-Jq0SzrR9UaiF87kk-8$>

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

PVMBG reported that the eruption at Lewotolok was ongoing during 9-16 May.
Almost daily white-and-gray ash plumes generally rose as high as 500 m
above the summit and drifted in variable directions. At 0632 on 11 May a
white-to-gray ash plume rose 500 m and drifted SW. At 0645 and 0957 on 11
May white-to-gray ash plumes rose 400-600 m and drifted E and SE,
respectively. Nighttime webcam images of incandescent material being
ejected above the summit were posted in daily reports during 10-13 May. The
Alert Level remained at 2 (on a scale of 1-4) and the public was warned to
stay 2 km away from the summit crater.

Geologic Summary. The Lewotolok (or Lewotolo) stratovolcano occupies the
eastern end of an elongated peninsula extending north into the Flores Sea,
connected to Lembata (formerly Lomblen) Island by a narrow isthmus. It is
symmetrical when viewed from the north and east. A small cone with a
130-m-wide crater constructed at the SE side of a larger crater forms the
volcano's high point. Many lava flows have reached the coastline. Eruptions
recorded since 1660 have consisted of explosive activity from the summit
crater.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known
as CVGHM) https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!ZgZ3SbR3tK5TswuR-lg8RPjEjwtapwiGo9f8HvZNaEIEnac_E1RaC-TSyVCXd4X85G5GuiJG-CuWAo0U$ 
<https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!fQRZUjHoOsVVb6G4FfPnWsSREugsWgCx4nvC0pe6k-QElj0E8b2ntw6p-Jq0SzrR9UaiF87kk-8$>

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

BPPTKG reported that the eruption at Merapi (on Java) continued during 5-11
May and seismicity remained at elevated levels. The SW lava dome produced
106 lava avalanches that traveled as far as 1.8 km down the SW flank
(upstream in the Bebeng drainages). Morphological changes to the SW lava
dome due to continuing collapses of material were evident in webcam images.
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!ZgZ3SbR3tK5TswuR-lg8RPjEjwtapwiGo9f8HvZNaEIEnac_E1RaC-TSyVCXd4X85G5GuiJG-PdWvToX$ 
<https://urldefense.com/v3/__http://www.merapi.bgl.esdm.go.id/__;!!IKRxdwAv5BmarQ!fQRZUjHoOsVVb6G4FfPnWsSREugsWgCx4nvC0pe6k-QElj0E8b2ntw6p-Jq0SzrR9UaiOSylUOI$>

Nyamulagira  | DR Congo  | 1.408Â°S, 29.2Â°E  | Summit elev. 3058 m

The Observatoire Volcanologique de Goma (OVG) reported that the lava lake
in Nyamulagiraâ??s summit crater continued to be active during 30 April-6
May. A Sentinel satellite image from 7 May showed active lava flows
traveling towards the NW part of the crater. Another image on 12 May showed
active flows along the NE margin of the dark and cooler 7 May flows.
Weather clouds and possible volcanic emissions obscured parts of the crater.

Geologic Summary. Africa's most active volcano, Nyamulagira (also known as
Nyamuragira), is a massive high-potassium basaltic shield about 25 km N of
Lake Kivu and 13 km NNW of the steep-sided Nyiragongo volcano. The summit
is truncated by a small 2 x 2.3 km caldera that has walls up to about 100 m
high. Documented eruptions have occurred within the summit caldera, as well
as from the numerous flank fissures and cinder cones. A lava lake in the
summit crater, active since at least 1921, drained in 1938, at the time of
a major flank eruption. Recent lava flows extend down the flanks more than
30 km from the summit as far as Lake Kivu; extensive lava flows from this
volcano have covered 1,500 km2 of the western branch of the East African
Rift.

Sources: Observatoire Volcanologique de Goma (OVG)
https://urldefense.com/v3/__http://observatoirevolcanologiquedegoma.org/__;!!IKRxdwAv5BmarQ!ZgZ3SbR3tK5TswuR-lg8RPjEjwtapwiGo9f8HvZNaEIEnac_E1RaC-TSyVCXd4X85G5GuiJG-FYh7Tuv$ 
<https://urldefense.com/v3/__http://observatoirevolcanologiquedegoma.org/__;!!IKRxdwAv5BmarQ!fQRZUjHoOsVVb6G4FfPnWsSREugsWgCx4nvC0pe6k-QElj0E8b2ntw6p-Jq0SzrR9UaiZX-dbtM$>
;

Sentinel Hub https://urldefense.com/v3/__https://sentinel-hub.com/explore/sentinel-playground__;!!IKRxdwAv5BmarQ!ZgZ3SbR3tK5TswuR-lg8RPjEjwtapwiGo9f8HvZNaEIEnac_E1RaC-TSyVCXd4X85G5GuiJG-DxOXM6F$ 
<https://urldefense.com/v3/__https://sentinel-hub.com/explore/sentinel-playground__;!!IKRxdwAv5BmarQ!fQRZUjHoOsVVb6G4FfPnWsSREugsWgCx4nvC0pe6k-QElj0E8b2ntw6p-Jq0SzrR9UaikSl_0KM$>

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

CENAPRED reported that there were 127-281 daily steam, gas, and ash
emissions and minor-to-moderate explosions recorded at PopocatÃ©petl during
9-16 May. Plumes mostly drifted SE, ESE, and ENE. On 9 May minor explosions
were recorded at 1141, 2009, and 2310, and on 10 May moderate explosions
were recorded at 0152 and 0316. Ashfall was reported in Tlalmanalco (30 km
NW) and Tetela del VolcÃ¡n (20 km SW) in Morelos during 9-10 May. On 11 May
minor explosions were recorded at 0135, 0215, and 1621, while moderate
explosions were recorded at 0526, 0811, 0838, 1601, and 1646. Minor
explosions occurred at 1318 and 1452 on 12 May. On 13 May minor explosions
occurred at 0012, 0805, and 2146, and a moderate explosion occurred at
1012. Ashfall was reported in the municipalities of Nealtican (20 km E),
Huejotzingo (21 km E), and Domingo Arenas (20 km NE). On 14 May minor
explosions were recorded at 0605, 0711, 0831, 1413, 1439, and 2312;
moderate explosions were recorded at 1253, 1444, 1608, and 1941. On 15 May
the network detected minor explosions at 0033 and 0051, and moderate
explosions at 0352, 0512, 0617, 0852, 1051, 1232, and 1613. Minor amounts
of ash fell in the municipalities of Puebla (43 km E) and Atlixco (24 km
SE) and moderate amounts fell in municipalities near the volcano to the S.
Weather clouds prevented views on 16 May. According to the Washington VAAC
daily ash plumes were identified in satellite images rising 6.1-7.3 km
(20,000-24,000 ft) a.s.l. (0.7-1.9 km above the crater rim) and drifting E
and SE. The Alert Level remained at Yellow, Phase Two (the middle level on
a three-color scale). CENAPRED urged people to respect the exclusion radius
of 12 km and to not ascend the volcano.

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

Sources: Centro Nacional de Prevencion de Desastres (CENAPRED)
https://urldefense.com/v3/__https://www.gob.mx/cenapred__;!!IKRxdwAv5BmarQ!ZgZ3SbR3tK5TswuR-lg8RPjEjwtapwiGo9f8HvZNaEIEnac_E1RaC-TSyVCXd4X85G5GuiJG-L7KW55j$ 
<https://urldefense.com/v3/__https://www.gob.mx/cenapred__;!!IKRxdwAv5BmarQ!fQRZUjHoOsVVb6G4FfPnWsSREugsWgCx4nvC0pe6k-QElj0E8b2ntw6p-Jq0SzrR9UaixDLojLM$>
;

Washington Volcanic Ash Advisory Center (VAAC)
https://urldefense.com/v3/__http://www.ssd.noaa.gov/VAAC/messages.html__;!!IKRxdwAv5BmarQ!ZgZ3SbR3tK5TswuR-lg8RPjEjwtapwiGo9f8HvZNaEIEnac_E1RaC-TSyVCXd4X85G5GuiJG-K2FmVrA$ 
<https://urldefense.com/v3/__http://www.ssd.noaa.gov/VAAC/messages.html__;!!IKRxdwAv5BmarQ!fQRZUjHoOsVVb6G4FfPnWsSREugsWgCx4nvC0pe6k-QElj0E8b2ntw6p-Jq0SzrR9Uai8h2bShs$>

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

IG reported that the eruption at Reventador was ongoing during 10-16 May.
Seismicity was characterized by explosions, long-period earthquakes,
harmonic tremors, and emission-related tremors. Steam, gas, and ash plumes
were observed in some webcam images, though weather conditions occasionally
obscured views. Ash emissions on 12 May rose 500 m above the crater rim and
drifted N. On 14 May a steam-and-ash plume rose 250 m and drifted NE. On 16
May an ash plume rose as high as 1 km above the crater and drifted W and
SW. Incandescence at the crater was visible at night during 10-12 and 16
May, and incandescent blocks rolled 200-700 m down the flanks. Servicio
Nacional de GestiÃ³n de Riesgos y Emergencias (SNGRE) maintained the Alert
Level at Orange (the second highest level on a four-color scale).

Geologic Summary. VolcÃ¡n El Reventador is the most frequently active of a
chain of Ecuadorian volcanoes in the Cordillera Real, well east of the
principal volcanic axis. The forested, dominantly andesitic stratovolcano
has 4-km-wide avalanche scarp open to the E formed by edifice collapse. A
young, unvegetated, cone rises from the amphitheater floor about 1,300 m to
a height comparable to the rim. It has been the source of numerous lava
flows as well as explosive eruptions visible from Quito, about 90 km ESE.
Frequent lahars in this region of heavy rainfall have constructed a debris
plain on the eastern floor of the scarp. The largest recorded eruption took
place in 2002, producing a 17-km-high eruption column, pyroclastic flows
that traveled up to 8 km, and lava flows from summit and flank vents.

Sources: Instituto GeofÃsico-Escuela PolitÃ©cnica Nacional (IG)
https://urldefense.com/v3/__http://www.igepn.edu.ec/__;!!IKRxdwAv5BmarQ!ZgZ3SbR3tK5TswuR-lg8RPjEjwtapwiGo9f8HvZNaEIEnac_E1RaC-TSyVCXd4X85G5GuiJG-ISkKo6K$ 
<https://urldefense.com/v3/__http://www.igepn.edu.ec/__;!!IKRxdwAv5BmarQ!fQRZUjHoOsVVb6G4FfPnWsSREugsWgCx4nvC0pe6k-QElj0E8b2ntw6p-Jq0SzrR9UaiYZRG1RM$>
;

Servicio Nacional de GestiÃ³n de Riesgos y Emergencias (SNGRE)
https://urldefense.com/v3/__https://www.gestionderiesgos.gob.ec/__;!!IKRxdwAv5BmarQ!ZgZ3SbR3tK5TswuR-lg8RPjEjwtapwiGo9f8HvZNaEIEnac_E1RaC-TSyVCXd4X85G5GuiJG-PiyRIoW$ 
<https://urldefense.com/v3/__https://www.gestionderiesgos.gob.ec/__;!!IKRxdwAv5BmarQ!fQRZUjHoOsVVb6G4FfPnWsSREugsWgCx4nvC0pe6k-QElj0E8b2ntw6p-Jq0SzrR9UaiuJybbL8$>

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

OVSICORI-UNA reported that periodic phreatic eruptions occurred at RincÃ³n
de la Vieja during 9-16 May. Phreatic events recorded at 1945 on 9 May, at
1419 on 10 May, and at 1100 on 11 May produced plumes that rose less than
1.5 km above the crater rim. Additional phreatic activity were recorded at
2232 on 11 May, and at both 2332 and 2338 on 12 May, though it was not
known if emissions were generated. A short-lived explosive event at 0258 on
14 May ejected material onto the N flank and caused lahars to descend the
Penjamo, Azul, and Azufrado rivers. Phreatic events at 1155 and 1748 that
same day produced emissions that rose 500 m and 1.5 km above the crater
rim, respectively. Gas emissions were occasionally visible during 15-16 May.

Geologic Summary. RincÃ³n de la Vieja, the largest volcano in NW Costa Rica,
is a remote volcanic complex in the Guanacaste Range. The volcano consists
of an elongated, arcuate NW-SE-trending ridge constructed within the
15-km-wide early Pleistocene GuachipelÃn caldera, whose rim is exposed on
the south side. Sometimes known as the "Colossus of Guanacaste," it has an
estimated volume of 130 km3 and contains at least nine major eruptive
centers. Activity has migrated to the SE, where the youngest-looking
craters are located. The twin cone of Santa MarÃa volcano, the highest peak
of the complex, is located at the eastern end of a smaller, 5-km-wide
caldera and has a 500-m-wide crater. A Plinian eruption producing the 0.25
km3 RÃo Blanca tephra about 3,500 years ago was the last major magmatic
eruption. All subsequent eruptions, including numerous historical eruptions
possibly dating back to the 16th century, have been from the prominent
active crater containing a 500-m-wide acid lake located ENE of Von Seebach
crater.

Source: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad
Nacional (OVSICORI-UNA) https://urldefense.com/v3/__http://www.ovsicori.una.ac.cr/__;!!IKRxdwAv5BmarQ!ZgZ3SbR3tK5TswuR-lg8RPjEjwtapwiGo9f8HvZNaEIEnac_E1RaC-TSyVCXd4X85G5GuiJG-O0TH_1r$ 
<https://urldefense.com/v3/__http://www.ovsicori.una.ac.cr/__;!!IKRxdwAv5BmarQ!fQRZUjHoOsVVb6G4FfPnWsSREugsWgCx4nvC0pe6k-QElj0E8b2ntw6p-Jq0SzrR9Uai6EG9YZM$>

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

IG reported a high level of activity at Sangay during 9-16 May, though
weather clouds prevented visual observations during most of the week. Ash
plumes rose 500 m and drifted SW on 9 May. A webcam image from 1833 on 14
May showed lava flowing 500 m down the SE flank. Servicio Nacional de
GestiÃ³n de Riesgos y Emergencias (SNGRE) maintained the Alert Level at
Yellow (the second lowest level on a four-color scale).

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

Sources: Instituto GeofÃsico-Escuela PolitÃ©cnica Nacional (IG)
https://urldefense.com/v3/__http://www.igepn.edu.ec/__;!!IKRxdwAv5BmarQ!ZgZ3SbR3tK5TswuR-lg8RPjEjwtapwiGo9f8HvZNaEIEnac_E1RaC-TSyVCXd4X85G5GuiJG-ISkKo6K$ 
<https://urldefense.com/v3/__http://www.igepn.edu.ec/__;!!IKRxdwAv5BmarQ!fQRZUjHoOsVVb6G4FfPnWsSREugsWgCx4nvC0pe6k-QElj0E8b2ntw6p-Jq0SzrR9UaiYZRG1RM$>
;

Servicio Nacional de GestiÃ³n de Riesgos y Emergencias (SNGRE)
https://urldefense.com/v3/__https://www.gestionderiesgos.gob.ec/__;!!IKRxdwAv5BmarQ!ZgZ3SbR3tK5TswuR-lg8RPjEjwtapwiGo9f8HvZNaEIEnac_E1RaC-TSyVCXd4X85G5GuiJG-PiyRIoW$ 
<https://urldefense.com/v3/__https://www.gestionderiesgos.gob.ec/__;!!IKRxdwAv5BmarQ!fQRZUjHoOsVVb6G4FfPnWsSREugsWgCx4nvC0pe6k-QElj0E8b2ntw6p-Jq0SzrR9UaiuJybbL8$>

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

INSIVUMEH reported that the eruption at Santa MarÃaâ??s Santiaguito lava-dome
complex continued during 10-16 May. Effusion from the Caliente dome complex
fed lava flows that descended the San Isidro and ZanjÃ³n Seco drainages on
the W and SW flanks; the main lava flow was 4.3 km long and remained
active. Daily weak-to-moderate explosions generated gas, steam, and ash
plumes that generally rose up to 800 m above the crater and drifted SE, S,
SW, and W. Explosions were sometimes accompanied by block-and-ash flows
that descended multiple flanks of the dome. Incandescence from the dome and
lava flows was visible during the nights and early mornings. An average of
40 explosions per day were recorded during 9-10 and 13-14 May, generating
ash plumes that rose up to 1 km above the dome and drifted S and SW.
Ashfall was reported in Fincas El Patrocinio, El Faro (7 km S), Las MarÃas
(10 km S), and others nearby on 10 May.

Geologic Summary. Symmetrical, forest-covered Santa MarÃa volcano is part
of a chain of large stratovolcanoes that rise above the Pacific coastal
plain of Guatemala. The sharp-topped, conical profile is cut on the SW
flank by a 1.5-km-wide crater. The oval-shaped crater extends from just
below the summit to the lower flank, and was formed during a catastrophic
eruption in 1902. The renowned Plinian eruption of 1902 that devastated
much of SW Guatemala followed a long repose period after construction of
the large basaltic-andesite stratovolcano. The massive dacitic Santiaguito
lava-dome complex has been growing at the base of the 1902 crater since
1922. Compound dome growth at Santiaguito has occurred episodically from
four vents, with activity progressing W towards the most recent, Caliente.
Dome growth has been accompanied by almost continuous minor explosions,
with periodic lava extrusion, larger explosions, pyroclastic flows, and
lahars.

Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e
Hidrologia (INSIVUMEH) https://urldefense.com/v3/__http://www.insivumeh.gob.gt/__;!!IKRxdwAv5BmarQ!ZgZ3SbR3tK5TswuR-lg8RPjEjwtapwiGo9f8HvZNaEIEnac_E1RaC-TSyVCXd4X85G5GuiJG-CcFnmfC$ 
<https://urldefense.com/v3/__http://www.insivumeh.gob.gt/__;!!IKRxdwAv5BmarQ!fQRZUjHoOsVVb6G4FfPnWsSREugsWgCx4nvC0pe6k-QElj0E8b2ntw6p-Jq0SzrR9UaiWyGUudc$>

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

PVMBG reported that the eruption at Semeru continued during 10-16 May and a
few Volcano Observatory Notices for Aviation (VONAs) describing ash
emissions were issued during the week. White-to-gray ash plumes that were
sometimes dense rose 500-700 m above the summit and drifted S, SW, W, and N
at 1115 on 10 May, at 0725 and 0830 on 12 May, at 0858, 1010, and 1241 on
13 May, at 0523 and 1656 on 14 May, and at 0757 on 16 May. The Alert Level
remained at 3 (third highest on a scale of 1-4). The public was warned to
stay at least 5 km away from the summit in all directions, 13 km from the
summit to the SE, 100 m from the banks of the Kobokan drainage as far as 17
km from the summit, and to avoid other drainages including the Bang,
Kembar, and Sat, due to lahar, avalanche, and pyroclastic flow hazards.

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

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known
as CVGHM) https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!ZgZ3SbR3tK5TswuR-lg8RPjEjwtapwiGo9f8HvZNaEIEnac_E1RaC-TSyVCXd4X85G5GuiJG-CuWAo0U$ 
<https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!fQRZUjHoOsVVb6G4FfPnWsSREugsWgCx4nvC0pe6k-QElj0E8b2ntw6p-Jq0SzrR9UaiF87kk-8$>

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

AVO reported that low-level unrest continued at Semisopochnoi during 9-16
May. Weather clouds mostly obscured satellite and webcam views. Volcanic
tremor was detected during 9-10 May; there was no evidence of explosive or
earthquake activity in the geophysics data during the rest of the week. The
Volcano Alert Level remained at Watch (the second highest level on a
four-level scale) and the Aviation Color Code remained at Orange (the
second highest level on a four-color scale).

Geologic Summary. 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 (renamed Mount Young in 2023) was constructed
within the caldera during the Holocene. Each of the peaks contains a summit
crater; lava flows on the N flank 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 Young, 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!ZgZ3SbR3tK5TswuR-lg8RPjEjwtapwiGo9f8HvZNaEIEnac_E1RaC-TSyVCXd4X85G5GuiJG-A9ddB2t$ 
<https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!fQRZUjHoOsVVb6G4FfPnWsSREugsWgCx4nvC0pe6k-QElj0E8b2ntw6p-Jq0SzrR9UaiTL-SRds$>

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

KVERT reported that the ongoing eruption at Sheveluch was generally
characterized by occasional explosions, continuing lava-dome growth,
incandescence, and strong fumarolic activity during 4-11 May. A thermal
anomaly over the active crater and Karan lava dome area was identified in
satellite images all week. Intense fumarolic activity was likely associated
with dome growth. During 8-9 May ash from pyroclastic flow deposits on the
SE flank were resuspended by winds and blown 60 km W based on satellite
images. The Aviation Color Code remained at Orange (the second highest
level on a four-color scale). Dates are based on UTC times; specific events
are in local time where noted.

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

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!ZgZ3SbR3tK5TswuR-lg8RPjEjwtapwiGo9f8HvZNaEIEnac_E1RaC-TSyVCXd4X85G5GuiJG-MCsCJGF$ 
<https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!fQRZUjHoOsVVb6G4FfPnWsSREugsWgCx4nvC0pe6k-QElj0E8b2ntw6p-Jq0SzrR9UaiXIlaJis$>

St. Helens  | Washington  | 46.2Â°N, 122.18Â°W  | Summit elev. 2549 m

USGS reported that at 2045 on 14 May a debris flow in Mount St. Helens'
South Coldwater Creek destroyed a Highway SR 504 bridge, cutting off access
and power to Johnston Ridge Observatory. While the loss of power
interrupted a major telemetry hub, other stations remined operational and
continued to provide data; the debris flow was recorded in seismic data
from nearby stations. The source material in the flow originated from the
climactic 1980 debris avalanche and eruption of Mount St. Helens. According
to a news article at least 11 people had to spend the night at the Johnston
Ridge Observatory and were airlifted out the next day. Officials noted that
the highway will be closed for an indefinite amount of time.

Geologic Summary. Prior to 1980, Mount St. Helens formed a conical,
youthful volcano sometimes known as the Fujisan of America. During the 1980
eruption the upper 400 m of the summit was removed by slope failure,
leaving a 2 x 3.5 km horseshoe-shaped crater now partially filled by a lava
dome. Mount St. Helens was formed during nine eruptive periods beginning
about 40-50,000 years ago and has been the most active volcano in the
Cascade Range during the Holocene. Prior to 2,200 years ago, tephra, lava
domes, and pyroclastic flows were erupted, forming the older edifice, but
few lava flows extended beyond the base of the volcano. The modern edifice
consists of basaltic as well as andesitic and dacitic products from summit
and flank vents. Historical eruptions in the 19th century originated from
the Goat Rocks area on the north flank, and were witnessed by early
settlers.

Sources: US Geological Survey Cascades Volcano Observatory (CVO)
https://urldefense.com/v3/__https://volcanoes.usgs.gov/observatories/cvo/__;!!IKRxdwAv5BmarQ!ZgZ3SbR3tK5TswuR-lg8RPjEjwtapwiGo9f8HvZNaEIEnac_E1RaC-TSyVCXd4X85G5GuiJG-JtZMyea$ 
<https://urldefense.com/v3/__https://volcanoes.usgs.gov/observatories/cvo/__;!!IKRxdwAv5BmarQ!fQRZUjHoOsVVb6G4FfPnWsSREugsWgCx4nvC0pe6k-QElj0E8b2ntw6p-Jq0SzrR9Uai3C8cJwg$>
;

KING-TV
https://urldefense.com/v3/__https://www.king5.com/article/news/local/sr-504-coldwater-lake-mount-st-helens-closed-debris-slide/281-6d452110-62d0-4f42-aa97-006444eae332__;!!IKRxdwAv5BmarQ!ZgZ3SbR3tK5TswuR-lg8RPjEjwtapwiGo9f8HvZNaEIEnac_E1RaC-TSyVCXd4X85G5GuiJG-AuIrJOV$ 
<https://urldefense.com/v3/__https://www.king5.com/article/news/local/sr-504-coldwater-lake-mount-st-helens-closed-debris-slide/281-6d452110-62d0-4f42-aa97-006444eae332__;!!IKRxdwAv5BmarQ!fQRZUjHoOsVVb6G4FfPnWsSREugsWgCx4nvC0pe6k-QElj0E8b2ntw6p-Jq0SzrR9Uai1mS_R1A$>

Stromboli  | Aeolian Islands (Italy)  | 38.789Â°N, 15.213Â°E  | Summit elev.
924 m

INGV reported ongoing Strombolian activity at Stromboli during 8-14 May.
Activity was centered at two vents (one each at craters N1 and N2) in Area
N, within the upper part of the Sciara del Fuoco, and from three vents in
the Area C-S (South-Central Crater area) in the crater terrace area.
Explosions at the N1 and N2 craters in Area N were low intensity and
ejected coarse material (bombs and lapilli), sometimes mixed with ash at
N1, as high as 80 m at a rate of 4-9 explosions per hour. Medium- to
high-intensity explosions at the two vents in sector S2 (Area C-S) ejected
ash sometimes mixed with coarse material at an average rate of 5-8
explosions per hour. Low-intensity gas explosions occurred at S1 in Area
C-S. No significant activity was identified in Sector C in Area C-S.

Geologic Summary. Spectacular incandescent nighttime explosions at
Stromboli have long attracted visitors to the "Lighthouse of the
Mediterranean" in the NE Aeolian Islands. This volcano has lent its name to
the frequent mild explosive activity that has characterized its eruptions
throughout much of historical time. The small island is the emergent summit
of a volcano that grew in two main eruptive cycles, the last of which
formed the western portion of the island. The Neostromboli eruptive period
took place between about 13,000 and 5,000 years ago. The active summit
vents are located at the head of the Sciara del Fuoco, a prominent scarp
that formed about 5,000 years ago due to a series of slope failures which
extends to below sea level. The modern volcano has been constructed within
this scarp, which funnels pyroclastic ejecta and lava flows to the NW.
Essentially continuous mild Strombolian explosions, sometimes accompanied
by lava flows, have been recorded for more than a millennium.

Source: Sezione di Catania - Osservatorio Etneo (INGV)
https://urldefense.com/v3/__http://www.ct.ingv.it/__;!!IKRxdwAv5BmarQ!ZgZ3SbR3tK5TswuR-lg8RPjEjwtapwiGo9f8HvZNaEIEnac_E1RaC-TSyVCXd4X85G5GuiJG-G6Sd_8-$ 
<https://urldefense.com/v3/__http://www.ct.ingv.it/__;!!IKRxdwAv5BmarQ!fQRZUjHoOsVVb6G4FfPnWsSREugsWgCx4nvC0pe6k-QElj0E8b2ntw6p-Jq0SzrR9UaiRkth-ZU$>

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

JMA reported that the eruption at Suwanosejima's Ontake Crater continued
during 8-15 May and crater incandescence was reported nightly. Explosions
recorded at 0701, 1200, and 2330 on 8 May produced ash plumes that rose as
high as 1 km above the crater rim and mainly drifted SE. Explosions were
also recorded at 1358 and 1648, though characteristics of associated
emissions were unknown. Eruptive events at 2001 on 8 May, 1753 on 9 May,
0405, 0647, and 1236 on 11 May, and 1919 on 13 May generated ash plumes
that rose as high as 1.3 km and generally drifted S, SW, and N. The Alert
Level remained at 3 (on a 5-level scale) and residents were warned to stay
2 km away from the crater.

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

Source: Japan Meteorological Agency (JMA) https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!ZgZ3SbR3tK5TswuR-lg8RPjEjwtapwiGo9f8HvZNaEIEnac_E1RaC-TSyVCXd4X85G5GuiJG-KLVitO0$ 
<https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!fQRZUjHoOsVVb6G4FfPnWsSREugsWgCx4nvC0pe6k-QElj0E8b2ntw6p-Jq0SzrR9UaiADGS1uU$>

2-2-2-2-2-2-2-2-2-2-2-2-2

==============================================================

Volcano Listserv is a collaborative venture among Arizona State University
(ASU), Portland State University (PSU), the Global Volcanism Program (GVP)
of the Smithsonian Institution's National Museum of Natural History, and
the International Association for Volcanology and Chemistry of the Earth's
Interior (IAVCEI).

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

PSU - https://urldefense.com/v3/__http://pdx.edu/__;!!IKRxdwAv5BmarQ!ZgZ3SbR3tK5TswuR-lg8RPjEjwtapwiGo9f8HvZNaEIEnac_E1RaC-TSyVCXd4X85G5GuiJG-FAVO74j$ 

GVP - https://urldefense.com/v3/__http://www.volcano.si.edu/__;!!IKRxdwAv5BmarQ!ZgZ3SbR3tK5TswuR-lg8RPjEjwtapwiGo9f8HvZNaEIEnac_E1RaC-TSyVCXd4X85G5GuiJG-PJjqGuN$ 

IAVCEI - https://urldefense.com/v3/__https://www.iavceivolcano.org/__;!!IKRxdwAv5BmarQ!ZgZ3SbR3tK5TswuR-lg8RPjEjwtapwiGo9f8HvZNaEIEnac_E1RaC-TSyVCXd4X85G5GuiJG-GbQRwlF$ 

To unsubscribe from the volcano list, send the message:

signoff volcano

to: listserv@xxxxxxx, or write to: volcano-request@xxxxxxx.

To contribute to the volcano list, send your message to:

volcano@xxxxxxx.  Please do not send attachments.

==============================================================

------------------------------

End of Volcano Digest - 16 May 2023 to 17 May 2023 (#2023-51)
*************************************************************