Smithsonian / USGS Weekly Volcanic Activity Report 13-19 September 2023

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6-6-6-6-6-6-6-6-6-6-6-6-6


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


Smithsonian / USGS Weekly Volcanic Activity Report

13-19 September 2023



Sally Sennert - Weekly Report Editor (kuhns@xxxxxx)

URL: https://urldefense.com/v3/__https://volcano.si.edu/reports_weekly.cfm__;!!IKRxdwAv5BmarQ!a7tlA1LwzkXOWEequ-FLs6-Wu77jmMY3ElmyJbwozggxgfsAEw4Rag-Vf_mEQeh0yfIBR5yyWe60g28E$ 
<https://urldefense.com/v3/__https://volcano.si.edu/reports_weekly.cfm__;!!IKRxdwAv5BmarQ!bYHBzLuf1F4y8AA-aUCfBpSvITcIJa9pbyBvPwxSONULYC6FQlICaIAKBpuwZPr3N55lP8OE3yY$>





New Activity/Unrest: Kilauea, Hawaiian Islands (USA)  | Ruby, Mariana
Islands (USA)



Ongoing Activity: Aira, Kyushu (Japan)  | Dukono, Halmahera  | Ebeko,
Paramushir Island (Russia)  | Fuego, South-Central Guatemala  | Gamalama,
Halmahera  | Great Sitkin, Andreanof Islands (USA)  | Karangetang, Sangihe
Islands  | Klyuchevskoy, Central Kamchatka (Russia)  | Lewotolok, Lembata
Island  | Mayon, Luzon (Philippines)  | Merapi, Central Java  | Santa
Maria, Southwestern Guatemala  | Semeru, Eastern Java  | Sheveluch, Central
Kamchatka (Russia)  | Shishaldin, Fox Islands (USA)  | Suwanosejima, Ryukyu
Islands (Japan)  | Taal, Luzon (Philippines)  | Ubinas, Peru  | Ulawun, New
Britain (Papua New Guinea)  | Villarrica, Central Chile  | Yasur, Vanuatu





The Weekly Volcanic Activity Report is a cooperative project between the
Smithsonian's Global Volcanism Program and the US Geological Survey's
Volcano Hazards Program. Updated by 2300 UTC every Wednesday, these reports
are preliminary and subject to change as events are studied in more detail.
This is not a comprehensive list of all of Earth's volcanoes erupting
during the week, but rather a summary of activity at volcanoes that meet
criteria discussed in detail in the "Criteria and Disclaimers" section.
Carefully reviewed, detailed reports about recent activity are published in
issues of the Bulletin of the Global Volcanism Network.



Note that many news agencies do not archive the articles they post on the
Internet, and therefore the links to some sources may not be active. To
obtain information about the cited articles that are no longer available on
the Internet contact the source.







New Activity/Unrest





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



HVO reported that the eruption located at the W side of the down-dropped
block within Kilaueaâ??s Halema`uma`u Crater had ceased after activity
declined over a few days. During 12-14 September multiple active vents,
that were roughly E-W-trending and spanned a distance of about 750 m,
produced lava fountains that rose as high as 10 m. Ramparts built by
spatter were almost 20 m tall on the S sides (downwind side) of the vents.
Lava from the vents flowed onto the N and W parts of the crater floor on 12
September, onto the N and E parts on 13 September, and only onto the W part
by 14 September; the distances of the active flows progressively decreased.
The area N of the active vents had become perched and was 3 m higher than
the surrounding surface. Sulfur dioxide emissions averaged 20,000 tonnes
per day (t/d) on the afternoon of 13 September, down significantly from
190,000 t/d measured just after the onset of the eruption. Effusion rates
had decreased but remained at high levels.



Vigorous spattering and lava fountains that rose 10-15 m were visible at
the westernmost large spatter cone during 14-15 September. Minor spattering
at the next cone to the E did not rise above its rim. Lava continued to
flow from the vents and travel N and W, confined to the W part of the
down-dropped block and the NE parts of Halema`uma`u. A laser rangefinder
pointed at the W portion of the crater continued to record uplift from the
magmatic intrusion beneath the caldera since the onset of the eruption; the
total local uplift was 6 m by 13 September, 9 m by 14 September, and 10 m
by 15 September. Field crews observed that eruptive activity had greatly
diminished or ceased at several of the vents by the morning of 15
September. Lava was no longer flowing onto the crater floor but active lava
was ponded in an area N of the vents. Intermittent spattering was visible
overnight at the large, westernmost cone but beginning at around 0700 on 16
September webcam images recorded minor to no fountaining. By 1115
spattering ceased and by noon the ponded lava had stagnated. Tremor levels
indicting fluid movement decreased during 15-16 September and retuned to
pre-eruption levels by 1700 on 16 September. Sulfur dioxide emission rates
had also decreased and were 800 t/d by 16 September, only slightly above
the 100-200 t/d typical of non-eruptive periods. At 0902 on 17 September
HVO lowered the Volcano Alert Level to Advisory (the second level on a
four-level scale) and the Aviation Color Code was lowered to Yellow (the
second color on a four-color scale).



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



Source: US Geological Survey Hawaiian Volcano Observatory (HVO)
https://urldefense.com/v3/__https://volcanoes.usgs.gov/observatories/hvo/__;!!IKRxdwAv5BmarQ!a7tlA1LwzkXOWEequ-FLs6-Wu77jmMY3ElmyJbwozggxgfsAEw4Rag-Vf_mEQeh0yfIBR5yyWTyeNMjA$ 
<https://urldefense.com/v3/__https://volcanoes.usgs.gov/observatories/hvo/__;!!IKRxdwAv5BmarQ!bYHBzLuf1F4y8AA-aUCfBpSvITcIJa9pbyBvPwxSONULYC6FQlICaIAKBpuwZPr3N55lKiRrOfE$>





Ruby  | Mariana Islands (USA)  | 15.605°N, 145.572°E  | Summit elev. -209 m



The US Geological Survey reported that an eruption began at Ruby on 15
September. A submarine plume of discolored water was identified in
satellite images at around 0650 but there was no activity above the water
surface. Eruption signals began at 1427 on 15 September based on
retrospective analysis of seismo-acoustic data from a geophysical
monitoring station on Saipan, 50 km SE. The activity was also recorded on
other regional geophysical monitoring networks in the Pacific. The
submarine plume had detached from the source vent by the morning of 16
September and no additional activity was recorded by geophysical networks.
The Volcano Alert Level was raised to Advisory (the second level on a
four-level scale) and the Aviation Color Code was raised to Yellow (the
second level on a four-color scale).



Geologic Summary. Ruby is a basaltic submarine volcano that rises to within
about 200 m of the ocean surface near the southern end of the Mariana arc
NW of Saipan. An eruption was detected in 1966 by sonar signals (Norris and
Johnson, 1969). In 1995 submarine explosions were heard, accompanied by a
fish kill, sulfurous odors, bubbling water, and the detection of volcanic
tremor.



Source: US Geological Survey https://urldefense.com/v3/__https://www.usgs.gov/__;!!IKRxdwAv5BmarQ!a7tlA1LwzkXOWEequ-FLs6-Wu77jmMY3ElmyJbwozggxgfsAEw4Rag-Vf_mEQeh0yfIBR5yyWQ1qu6Ml$ 
<https://urldefense.com/v3/__https://www.usgs.gov/__;!!IKRxdwAv5BmarQ!bYHBzLuf1F4y8AA-aUCfBpSvITcIJa9pbyBvPwxSONULYC6FQlICaIAKBpuwZPr3N55lF866NjI$>





Ongoing Activity





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



JMA reported ongoing activity at Minamidake Crater (Aira Calderaâ??s
Sakurajima volcano) during 11-18 September and incandescence at the crater
was observed nightly. Sulfur dioxide emissions averaged 1,900 tons per day
on 11 September. An explosion at 0018 on 11 September produced an ash plume
that rose 1.1 km above the crater rim and ejected large blocks 300-500 m
from the crater. An eruptive event at 1642 produced an ash plume that rose
1.3 km. At 2211 on 13 September an explosion produced an ash plume that
rose 1.7 km and drifted N and ejected large blocks 500-700 m from the
crater. The Alert Level remained at 3 (on a 5-level scale), and the public
was warned to stay 2 km away from both craters.



Geologic Summary. The Aira caldera in the northern half of Kagoshima Bay
contains the post-caldera Sakurajima volcano, one of Japan's most active.
Eruption of the voluminous Ito pyroclastic flow accompanied formation of
the 17 x 23 km caldera about 22,000 years ago. The smaller Wakamiko caldera
was formed during the early Holocene in the NE corner of the caldera, along
with several post-caldera cones. The construction of Sakurajima began about
13,000 years ago on the southern rim and built an island that was joined to
the Osumi Peninsula during the major explosive and effusive eruption of
1914. Activity at the Kitadake summit cone ended about 4,850 years ago,
after which eruptions took place at Minamidake. Frequent eruptions since
the 8th century have deposited ash on the city of Kagoshima, located across
Kagoshima Bay only 8 km from the summit. The largest recorded eruption took
place during 1471-76.



Source: Japan Meteorological Agency (JMA) https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!a7tlA1LwzkXOWEequ-FLs6-Wu77jmMY3ElmyJbwozggxgfsAEw4Rag-Vf_mEQeh0yfIBR5yyWWlBfoQl$ 
<https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!bYHBzLuf1F4y8AA-aUCfBpSvITcIJa9pbyBvPwxSONULYC6FQlICaIAKBpuwZPr3N55l9aELYHA$>





Dukono  | Halmahera  | 1.6992°N, 127.8783°E  | Summit elev. 1273 m



PVMBG reported that the eruption at Dukono was ongoing during 13-17
September. Dense white-and-gray plumes rose as high as 350 m above the
summit and drifted E and W. The Alert Level remained at Level 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, have occurred since 1933. During a major
eruption in 1550 CE, a lava flow filled in the strait between Halmahera and
the N-flank Gunung Mamuya cone. 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!a7tlA1LwzkXOWEequ-FLs6-Wu77jmMY3ElmyJbwozggxgfsAEw4Rag-Vf_mEQeh0yfIBR5yyWQ9BxdbW$ 
<https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!bYHBzLuf1F4y8AA-aUCfBpSvITcIJa9pbyBvPwxSONULYC6FQlICaIAKBpuwZPr3N55lF3o38xA$>





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



KVERT reported that moderate explosive activity at Ebeko was ongoing during
7-14 September. A thermal anomaly was identified in satellite images during
9-11 September; weather clouds obscured views on other days. According to
volcanologists in Severo-Kurilsk (Paramushir Island, about 7 km E),
explosions during 10-11 and 13-14 September generated ash plumes that rose
as high as 3 km (10,000 ft) a.s.l and drifted to the E. The Aviation Color
Code remained at Orange (the third level on a four-color scale). Dates are
based on UTC times; specific events are in local time where noted.



Geologic Summary. The 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!a7tlA1LwzkXOWEequ-FLs6-Wu77jmMY3ElmyJbwozggxgfsAEw4Rag-Vf_mEQeh0yfIBR5yyWWYoWaLR$ 
<https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!bYHBzLuf1F4y8AA-aUCfBpSvITcIJa9pbyBvPwxSONULYC6FQlICaIAKBpuwZPr3N55lWZsVMCo$>





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



INSIVUMEH reported that 4-10 explosions per hour were recorded at Fuego
during 13-19 September, generating ash-and-gas plumes that rose as high as
1.1 km above the crater rim. The ash plumes drifted as far as 30 km W and
SW, causing minor ashfall in areas downwind including Morelia (9 km SW),
Panimaché I and II (8 km SW), Palo Verde (10 km WSW), Sangre de Cristo (8
km W), El Porvenir (8 km SE), and Yepocapa (9 km WNW). Daily shock waves
rattled structures in communities around the volcano and rumbling was often
heard. Explosions caused daily block avalanches to descend the Ceniza
(SSW), Seca (W), Trinidad (S), Taniluyá (SW), Honda, Las Lajas (SE), and/or
El Jute (ESE) drainages. The explosions also ejected incandescent material
as high as 200 m above the summit.



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



Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e
Hidrologia (INSIVUMEH) https://urldefense.com/v3/__http://www.insivumeh.gob.gt/__;!!IKRxdwAv5BmarQ!a7tlA1LwzkXOWEequ-FLs6-Wu77jmMY3ElmyJbwozggxgfsAEw4Rag-Vf_mEQeh0yfIBR5yyWYdPi96l$ 
<https://urldefense.com/v3/__http://www.insivumeh.gob.gt/__;!!IKRxdwAv5BmarQ!bYHBzLuf1F4y8AA-aUCfBpSvITcIJa9pbyBvPwxSONULYC6FQlICaIAKBpuwZPr3N55lcekMFAg$>





Gamalama  | Halmahera  | 0.81°N, 127.3322°E  | Summit elev. 1714 m



Although there was no eruptive activity reported, in a 19 September press
release, PVMBG noted that the number of daily deep volcanic earthquakes at
Gamalama increased in early September and remained above average. The
seismic network recorded a total of 16 deep volcanic earthquake events on 8
September and an average of nine events per day through 18 September; 1-2
events per day are generally recorded. The number of earthquakes indicating
emissions also increased during 8-18 September, though diffuse white plumes
only rose as high as 100 m above the summit whereas typically they can rise
as high as 300 m. PVMBG noted that the most likely hazard would be a
phreatic event that could ejected material within the 1.5-km radius, though
ash may be carried farther by wind. The Alert Level remained at 2 (on a
scale of 1-4); visitors and residents were warned not to approach the
crater within a 1.5-km radius.



Geologic Summary. Gamalama is a near-conical stratovolcano that comprises
the entire island of Ternate off the western coast of Halmahera, and is one
of Indonesia's most active volcanoes. The island was a major regional
center in the Portuguese and Dutch spice trade for several centuries, which
contributed to the extensive documentation of activity. Three cones,
progressively younger to the north, form the summit. Several maars and
vents define a rift zone, parallel to the Halmahera island arc, that cuts
the volcano; the S-flank Ngade maar formed after about 14,500â??13,000 cal.
BP (Faral et al., 2022). Eruptions, recorded frequently since the 16th
century, typically originated from the summit craters, although flank
eruptions have occurred in 1763, 1770, 1775, and 1962-63.



Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known
as CVGHM) https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!a7tlA1LwzkXOWEequ-FLs6-Wu77jmMY3ElmyJbwozggxgfsAEw4Rag-Vf_mEQeh0yfIBR5yyWQ9BxdbW$ 
<https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!bYHBzLuf1F4y8AA-aUCfBpSvITcIJa9pbyBvPwxSONULYC6FQlICaIAKBpuwZPr3N55lF3o38xA$>





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



AVO reported that slow lava effusion likely continued at Great Sitkin
during 13-19 September, producing a thick flow in the summit crater that
mainly expanded E. A few daily earthquakes were recorded by the seismic
network and seismicity was characterized as low. Weather clouds often
prevented satellite and webcam observations, though no activity was
observed on a few of the days with partly cloudy weather. The Volcano Alert
Level remained at Watch (the third level on a four-level scale) and the
Aviation Color Code remained at Orange (the third color on a four-color
scale).



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



Source: US Geological Survey Alaska Volcano Observatory (AVO)
https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!a7tlA1LwzkXOWEequ-FLs6-Wu77jmMY3ElmyJbwozggxgfsAEw4Rag-Vf_mEQeh0yfIBR5yyWQdwuCI_$ 
<https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!bYHBzLuf1F4y8AA-aUCfBpSvITcIJa9pbyBvPwxSONULYC6FQlICaIAKBpuwZPr3N55lAjj3Hb0$>





Karangetang  | Sangihe Islands  | 2.781°N, 125.407°E  | Summit elev. 1797 m



PVMBG reported that dense white gas-and-steam plumes from Karangetang were
visible on most days during 13-19 September rising as high as 300 m above
Main and North craters and drifting mainly NW, N, and NE. Weather clouds
sometimes prevented views of the summit. According to news articles,
seismicity during 1-7 September indicated lava from the SW side of Main
Crater (S crater) continued to effuse but at a decreased rate, and that the
number of earthquakes indicating avalanches had also decreased, according
to PVMBG. Lava avalanches traveled as far as 1.5 km down the Batuawang and
Kahetang drainages on the S flank and rarely descended the SW flank. Lava
effusion at Main Crater was not visible during 8-15 September, though
sounds of avalanches were sometimes intense, and rumbling was also
occasionally heard. Incandescence emanated from both Main and North
craters. The number of avalanches continued to decrease. The Alert Level
remained at 3 (on a scale of 1-4) and the public were advised to stay 2.5
km away from Main Crater with an extension to 3.5 km on the S and SE flanks.



Geologic Summary. Karangetang (Api Siau) volcano lies at the northern end
of the island of Siau, about 125 km NNE of the NE-most point of Sulawesi.
The stratovolcano contains five summit craters along a N-S line. It is one
of Indonesia's most active volcanoes, with more than 40 eruptions recorded
since 1675 and many additional small eruptions that were not documented
(Neumann van Padang, 1951). Twentieth-century eruptions have included
frequent explosive activity sometimes accompanied by pyroclastic flows and
lahars. Lava dome growth has occurred in the summit craters; collapse of
lava flow fronts have produced pyroclastic flows.



Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known
as CVGHM) https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!a7tlA1LwzkXOWEequ-FLs6-Wu77jmMY3ElmyJbwozggxgfsAEw4Rag-Vf_mEQeh0yfIBR5yyWQ9BxdbW$ 
<https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!bYHBzLuf1F4y8AA-aUCfBpSvITcIJa9pbyBvPwxSONULYC6FQlICaIAKBpuwZPr3N55lF3o38xA$>
;

Antara News
https://urldefense.com/v3/__https://www.antaranews.com/berita/3724125/aktivitas-gempa-guguran-gunung-karangetang-semakin-menurun__;!!IKRxdwAv5BmarQ!a7tlA1LwzkXOWEequ-FLs6-Wu77jmMY3ElmyJbwozggxgfsAEw4Rag-Vf_mEQeh0yfIBR5yyWStsf4Q5$ 
<https://urldefense.com/v3/__https://www.antaranews.com/berita/3724125/aktivitas-gempa-guguran-gunung-karangetang-semakin-menurun__;!!IKRxdwAv5BmarQ!bYHBzLuf1F4y8AA-aUCfBpSvITcIJa9pbyBvPwxSONULYC6FQlICaIAKBpuwZPr3N55l6Iwun-o$>
;

Antara News
https://urldefense.com/v3/__https://www.antaranews.com/berita/3725823/pvmbg-erupsi-efusif-gunung-karangetang-masih-terjadi__;!!IKRxdwAv5BmarQ!a7tlA1LwzkXOWEequ-FLs6-Wu77jmMY3ElmyJbwozggxgfsAEw4Rag-Vf_mEQeh0yfIBR5yyWQswM1RM$ 
<https://urldefense.com/v3/__https://www.antaranews.com/berita/3725823/pvmbg-erupsi-efusif-gunung-karangetang-masih-terjadi__;!!IKRxdwAv5BmarQ!bYHBzLuf1F4y8AA-aUCfBpSvITcIJa9pbyBvPwxSONULYC6FQlICaIAKBpuwZPr3N55lrAiQJKM$>
;

Antara News
https://urldefense.com/v3/__https://www.antaranews.com/berita/3727086/warga-diajak-patuhi-radius-bahaya-meski-guguran-lava-karangetang-turun__;!!IKRxdwAv5BmarQ!a7tlA1LwzkXOWEequ-FLs6-Wu77jmMY3ElmyJbwozggxgfsAEw4Rag-Vf_mEQeh0yfIBR5yyWSyl_4BO$ 
<https://urldefense.com/v3/__https://www.antaranews.com/berita/3727086/warga-diajak-patuhi-radius-bahaya-meski-guguran-lava-karangetang-turun__;!!IKRxdwAv5BmarQ!bYHBzLuf1F4y8AA-aUCfBpSvITcIJa9pbyBvPwxSONULYC6FQlICaIAKBpuwZPr3N55l4qRw99A$>
;

Antara News
https://urldefense.com/v3/__https://www.antaranews.com/berita/3733587/pvmbg-catat-32-gempa-guguran-gunung-karangetang-selama-sepekan__;!!IKRxdwAv5BmarQ!a7tlA1LwzkXOWEequ-FLs6-Wu77jmMY3ElmyJbwozggxgfsAEw4Rag-Vf_mEQeh0yfIBR5yyWQb5ZgXG$ 
<https://urldefense.com/v3/__https://www.antaranews.com/berita/3733587/pvmbg-catat-32-gempa-guguran-gunung-karangetang-selama-sepekan__;!!IKRxdwAv5BmarQ!bYHBzLuf1F4y8AA-aUCfBpSvITcIJa9pbyBvPwxSONULYC6FQlICaIAKBpuwZPr3N55lb35f5pY$>
;

Antara News
https://urldefense.com/v3/__https://www.antaranews.com/berita/3734748/warga-diimbau-mewaspadai-dampak-aktivitas-gunung-karangetang__;!!IKRxdwAv5BmarQ!a7tlA1LwzkXOWEequ-FLs6-Wu77jmMY3ElmyJbwozggxgfsAEw4Rag-Vf_mEQeh0yfIBR5yyWZj3Bin_$ 
<https://urldefense.com/v3/__https://www.antaranews.com/berita/3734748/warga-diimbau-mewaspadai-dampak-aktivitas-gunung-karangetang__;!!IKRxdwAv5BmarQ!bYHBzLuf1F4y8AA-aUCfBpSvITcIJa9pbyBvPwxSONULYC6FQlICaIAKBpuwZPr3N55lkUU_5kI$>





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



KVERT reported that the explosive Strombolian eruption at Klyuchevskoy
continued during 7-14 September. A daily bright thermal anomaly was
identified in satellite images. Lava fountaining fed flows that advanced
down the Apakhonchichsky and Kozyrevsky drainages on the SE flank. Plumes
of resuspended ash drifted 550 km E and SE during 9-11 September. The
Aviation Color Code remained at Yellow (the second level on a four-color
scale). Dates are based on UTC times; specific events are in local time
where noted.



Geologic Summary. Klyuchevskoy (also spelled Kliuchevskoi) is Kamchatka's
highest and most active volcano. Since its origin about 6000 years ago, the
beautifully symmetrical, 4835-m-high basaltic stratovolcano has produced
frequent moderate-volume explosive and effusive eruptions without major
periods of inactivity. It rises above a saddle NE of sharp-peaked Kamen
volcano and lies SE of the broad Ushkovsky massif. More than 100 flank
eruptions have occurred during the past roughly 3000 years, with most
lateral craters and cones occurring along radial fissures between the
unconfined NE-to-SE flanks of the conical volcano between 500 m and 3600 m
elevation. The morphology of the 700-m-wide summit crater has been
frequently modified by historical eruptions, which have been recorded since
the late-17th century. Historical eruptions have originated primarily from
the summit crater, but have also included numerous major explosive and
effusive eruptions from flank craters.



Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!a7tlA1LwzkXOWEequ-FLs6-Wu77jmMY3ElmyJbwozggxgfsAEw4Rag-Vf_mEQeh0yfIBR5yyWWYoWaLR$ 
<https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!bYHBzLuf1F4y8AA-aUCfBpSvITcIJa9pbyBvPwxSONULYC6FQlICaIAKBpuwZPr3N55lWZsVMCo$>





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



PVMBG reported that the eruption at Lewotolok continued during 12-19
September. According to the Darwin VAAC an ash plume rose 600 m above the
summit and drifted WNW on 12 September. PVMBG noted that white-and-gray
plumes rose 250-400 m above the summit and drifted W and NW on 13 and 16
September. White steam-and-gas plumes rose as high as 300 m and drifted W
and NW on the other days. Webcam images captured incandescent material
being ejected above the summit at 0101 on 13 September and summit
incandescence at 1830 on 16 September. The Alert Level remained at 2 (on a
scale of 1-4) and the public was warned to stay at least 2 km away from the
summit crater.



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



Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known
as CVGHM) https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!a7tlA1LwzkXOWEequ-FLs6-Wu77jmMY3ElmyJbwozggxgfsAEw4Rag-Vf_mEQeh0yfIBR5yyWQ9BxdbW$ 
<https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!bYHBzLuf1F4y8AA-aUCfBpSvITcIJa9pbyBvPwxSONULYC6FQlICaIAKBpuwZPr3N55lF3o38xA$>
;

Darwin Volcanic Ash Advisory Centre (VAAC)
https://urldefense.com/v3/__http://www.bom.gov.au/aviation/volcanic-ash/darwin-va-advisory.shtml__;!!IKRxdwAv5BmarQ!a7tlA1LwzkXOWEequ-FLs6-Wu77jmMY3ElmyJbwozggxgfsAEw4Rag-Vf_mEQeh0yfIBR5yyWXl5A4_W$ 
<https://urldefense.com/v3/__http://www.bom.gov.au/aviation/volcanic-ash/darwin-va-advisory.shtml__;!!IKRxdwAv5BmarQ!bYHBzLuf1F4y8AA-aUCfBpSvITcIJa9pbyBvPwxSONULYC6FQlICaIAKBpuwZPr3N55lvnch_D0$>





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



PHIVOLCS reported that the eruption at Mayon continued during 12-19
September. The lengths of the lava flow in the Mi-Isi (S), Bonga (SE), and
Basud (E) drainages remained at 2.8 km, 3.4 km, and 1.1 km, respectively.
Collapses at the lava dome and from the margins of the lava flows produced
rockfalls and pyroclastic density currents (PDCs, or pyroclastic flows)
that descended the flanks as far as 4 km. Each day seismic stations
recorded 101-160 rockfall events, 1-6 PDC events, and 3-12 daily volcanic
earthquakes. During 12-13 September the volcanic earthquake signals
included one indicating an ash emission and a tremor event that lasted one
minute. Daily sulfur dioxide emissions averaged between 765 and 1,551
tonnes per day, with the highest value recorded on 16 September. Electronic
Distance Measuring (EDM), precise leveling, continuous GPS, and electronic
tilt monitoring data showed that the volcano remained generally inflated
relative to baseline levels; tilt and GPS monitoring data indicated
pronounced inflation of the mid SE flank since the beginning of August
2023. The Alert Level remained at 3 (on a 0-5 scale) and residents were
reminded to stay away from the 6-km-radius Permanent Danger Zone (PDZ).
PHIVOLCS recommended that civil aviation authorities advise pilots to avoid
flying close to the summit.



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



Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)
https://urldefense.com/v3/__http://www.phivolcs.dost.gov.ph/__;!!IKRxdwAv5BmarQ!a7tlA1LwzkXOWEequ-FLs6-Wu77jmMY3ElmyJbwozggxgfsAEw4Rag-Vf_mEQeh0yfIBR5yyWXifroB9$ 
<https://urldefense.com/v3/__http://www.phivolcs.dost.gov.ph/__;!!IKRxdwAv5BmarQ!bYHBzLuf1F4y8AA-aUCfBpSvITcIJa9pbyBvPwxSONULYC6FQlICaIAKBpuwZPr3N55l2toZLn8$>





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



BPPTKG reported that the eruption at Merapi (on Java) continued during 8-14
September and seismicity remained at elevated levels. The SW lava dome
produced a total of 162 lava avalanches that descended the S and SW flanks;
10 traveled as far as 1.5 km down the upper part of the Boyong drainage,
151 traveled as far as 2 km down the upper Bebeng drainage, and one
traveled 1.2 km down the Sat/Putih drainage. Morphological changes to the
SW lava dome were due to continuing collapses of material. The Alert Level
remained at 3 (on a scale of 1-4), and the public was warned to stay 3-7 km
away from the summit based on location.



Geologic Summary. Merapi, one of Indonesia's most active volcanoes, lies in
one of the world's most densely populated areas and dominates the landscape
immediately north of the major city of Yogyakarta. It is the youngest and
southernmost of a volcanic chain extending NNW to Ungaran volcano. Growth
of Old Merapi during the Pleistocene ended with major edifice collapse
perhaps about 2,000 years ago, leaving a large arcuate scarp cutting the
eroded older Batulawang volcano. Subsequent growth of the steep-sided Young
Merapi edifice, its upper part unvegetated due to frequent activity, began
SW of the earlier collapse scarp. Pyroclastic flows and lahars accompanying
growth and collapse of the steep-sided active summit lava dome have
devastated cultivated lands on the western-to-southern flanks and caused
many fatalities.



Source: Balai Penyelidikan dan Pengembangan Teknologi Kebencanaan Geologi
(BPPTKG) https://urldefense.com/v3/__http://www.merapi.bgl.esdm.go.id/__;!!IKRxdwAv5BmarQ!a7tlA1LwzkXOWEequ-FLs6-Wu77jmMY3ElmyJbwozggxgfsAEw4Rag-Vf_mEQeh0yfIBR5yyWQyvp0ie$ 
<https://urldefense.com/v3/__http://www.merapi.bgl.esdm.go.id/__;!!IKRxdwAv5BmarQ!bYHBzLuf1F4y8AA-aUCfBpSvITcIJa9pbyBvPwxSONULYC6FQlICaIAKBpuwZPr3N55lZGTob-Q$>





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



INSIVUMEH reported that eruptive activity continued at Santa Mariaâ??s
Santiaguito lava dome complex during 12-19 September. Incandescence from
the dome was visible during most nights and early mornings, and
occasionally from the lava flow on the WSW flank. Lava extrusion continued.
Daily weak-to-moderate explosions generated gas-and-ash plumes that rose
900-1,000 m above the dome and drifted NW, W, and SW. Some explosions
triggered incandescent avalanches that descended the domeâ??s flanks in all
directions, and occasionally into drainages on the S, SE, and E flanks.
Deposits from block-and-ash-flows accumulated on top of the lava flows in
the Zanjón, Seco, and San Isidro drainages.



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



Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e
Hidrologia (INSIVUMEH) https://urldefense.com/v3/__http://www.insivumeh.gob.gt/__;!!IKRxdwAv5BmarQ!a7tlA1LwzkXOWEequ-FLs6-Wu77jmMY3ElmyJbwozggxgfsAEw4Rag-Vf_mEQeh0yfIBR5yyWYdPi96l$ 
<https://urldefense.com/v3/__http://www.insivumeh.gob.gt/__;!!IKRxdwAv5BmarQ!bYHBzLuf1F4y8AA-aUCfBpSvITcIJa9pbyBvPwxSONULYC6FQlICaIAKBpuwZPr3N55lcekMFAg$>





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



PVMBG reported that eruptive activity continued at Semeru during 13-19
September. White-and-gray ash plumes rose 200-300 m above the summit and
drifted W on 14 September. According to the Darwin VAAC a diffuse ash plume
was identified in a satellite image rising to 4.2 km (14,000 ft) a.s.l.
(610 m above the summit) and drifting SW at 0640 on 15 September. The Alert
Level remained at 3 (third highest on a scale of 1-4). The public was
warned to stay at least 5 km away from the summit in all directions, 13 km
from the summit to the SE, 500 m from the banks of the Kobokan drainage as
far as 17 km from the summit, and to avoid other drainages including the
Bang, Kembar, and Sat, due to lahar, avalanche, and pyroclastic flow
hazards.



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



Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known
as CVGHM) https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!a7tlA1LwzkXOWEequ-FLs6-Wu77jmMY3ElmyJbwozggxgfsAEw4Rag-Vf_mEQeh0yfIBR5yyWQ9BxdbW$ 
<https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!bYHBzLuf1F4y8AA-aUCfBpSvITcIJa9pbyBvPwxSONULYC6FQlICaIAKBpuwZPr3N55lF3o38xA$>
;

Darwin Volcanic Ash Advisory Centre (VAAC)
https://urldefense.com/v3/__http://www.bom.gov.au/aviation/volcanic-ash/darwin-va-advisory.shtml__;!!IKRxdwAv5BmarQ!a7tlA1LwzkXOWEequ-FLs6-Wu77jmMY3ElmyJbwozggxgfsAEw4Rag-Vf_mEQeh0yfIBR5yyWXl5A4_W$ 
<https://urldefense.com/v3/__http://www.bom.gov.au/aviation/volcanic-ash/darwin-va-advisory.shtml__;!!IKRxdwAv5BmarQ!bYHBzLuf1F4y8AA-aUCfBpSvITcIJa9pbyBvPwxSONULYC6FQlICaIAKBpuwZPr3N55lvnch_D0$>





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



KVERT reported that the eruption at Sheveluch continued during 7-14
September. Thermal anomalies were identified in satellite images on all
days except 14 September (due to weather clouds). Plumes of resuspended ash
drifted 160 km SE and E during 9-11 September. The Aviation Color Code
remained at Orange (the third level on a four-color scale). Dates are based
on UTC times; specific events are in local time where noted.



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



Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!a7tlA1LwzkXOWEequ-FLs6-Wu77jmMY3ElmyJbwozggxgfsAEw4Rag-Vf_mEQeh0yfIBR5yyWWYoWaLR$ 
<https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!bYHBzLuf1F4y8AA-aUCfBpSvITcIJa9pbyBvPwxSONULYC6FQlICaIAKBpuwZPr3N55lWZsVMCo$>





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



AVO reported that the eruption at Shishaldin continued during 13-19
September. Eruptive activity increased during 13-14 September. Elevated
surface temperatures began to be identified in satellite images during the
afternoon of 13 September and they increased later that night. Seismic
tremor amplitudes began to increase at around 1800 and small explosions
were detected in seismic and infrasound data. Incandescent lava at the
summit was seen in a webcam image at 0134 on 14 September during a period
of elevated tremor. No ash emissions were visible though high weather
clouds may have obscured them.



Seismic tremor began to increase sometime around 0900 on 15 September and
rapidly intensified. An explosive eruption began at around 1710, prompting
AVO to the Aviation Color Code to Red (the highest color on a four-color
scale) and the Volcano Alert Level to Warning (the highest level on a
four-level scale). Within about 30 minutes ash plumes drifted E below a
weather cloud deck at 8.2 km (27,000 ft) a.s.l., unseen in satellite views.
The National Weather Service estimated that an ash-rich plume rose as high
as 12.8 km (42,000 ft) a.s.l. and produced volcanic lightning. The upper
parts of the plume detached by 1830, at about the same time that seismicity
dramatically decreased. Lightning was again detected beginning around 1930,
suggesting that ash emissions continued. Ongoing explosions were detected
in infrasound data, at a lower level than during the most energetic phase
of this event. Trace amounts of ash fell in False Pass (38 km ENE) during
1800-2030. Lightning was last detected at 2048. By 2124 the intensity of
the eruption had decreased, and ash emissions were likely rising to
altitudes less than 6.7 km (22,000 ft) a.s.l. Seismicity returned to
pre-eruption levels; at 1244 on 16 September AVO lowered the Volcano Alert
Level to Watch and the Aviation Color Code to Orange. A plume of sulfur
dioxide emitted during 14-15 September was detected over the North Pacific.
Seismicity remained elevated with tremor and small daily earthquakes
occurring over 16-18 September. Elevated surface temperatures at the summit
were identified in satellite data and minor steam emissions were visible in
webcam views.



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



Source: US Geological Survey Alaska Volcano Observatory (AVO)
https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!a7tlA1LwzkXOWEequ-FLs6-Wu77jmMY3ElmyJbwozggxgfsAEw4Rag-Vf_mEQeh0yfIBR5yyWQdwuCI_$ 
<https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!bYHBzLuf1F4y8AA-aUCfBpSvITcIJa9pbyBvPwxSONULYC6FQlICaIAKBpuwZPr3N55lAjj3Hb0$>





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



JMA reported that the eruption at Suwanosejima's Ontake Crater continued
during 11-18 September. Eruptive events at 0511 and 1228 on 15 September
produced ash plumes that rose 1-1.8 km above the crater rim and drifted N
and NW, respectively. Blocks were ejected as far as 300 m from the crater.
The Alert Level remained at 2 (on a 5-level scale) and the public was
warned to stay at least 1 km away from the crater.



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



Source: Japan Meteorological Agency (JMA) https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!a7tlA1LwzkXOWEequ-FLs6-Wu77jmMY3ElmyJbwozggxgfsAEw4Rag-Vf_mEQeh0yfIBR5yyWWlBfoQl$ 
<https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!bYHBzLuf1F4y8AA-aUCfBpSvITcIJa9pbyBvPwxSONULYC6FQlICaIAKBpuwZPr3N55l9aELYHA$>





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



PHIVOLCS reported ongoing unrest at Taal during 13-18 September. Daily
emissions of gas-and-steam rose from Main Crater Lake generally as high as
2.4 km, were sometimes voluminous, and drifted ENE, ESE, SW, and NW.
Upwelling gasses and fluids in the lake were visible during daily
observations. During 14-18 September there were 2-4 daily volcanic
earthquakes recorded by the seismic network, including 1-3 daily periods of
tremor each lasting 1-2 minutes long. Sulfur dioxide emissions averaged
3,264 tonnes per day on 15 September and coupled with taller steam-and-gas
plumes that rose as high as 3 km, caused vog over Taal Lake beginning at
around 1000. PHIVOLCS noted that vog had been affecting the Taal region
since the first week of September. The Alert Level remained at 1 (on a
scale of 0-5), and PHIVOLCS reminded the public that the entire Taal
Volcano Island was a Permanent Danger Zone (PDZ).



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



Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)
https://urldefense.com/v3/__http://www.phivolcs.dost.gov.ph/__;!!IKRxdwAv5BmarQ!a7tlA1LwzkXOWEequ-FLs6-Wu77jmMY3ElmyJbwozggxgfsAEw4Rag-Vf_mEQeh0yfIBR5yyWXifroB9$ 
<https://urldefense.com/v3/__http://www.phivolcs.dost.gov.ph/__;!!IKRxdwAv5BmarQ!bYHBzLuf1F4y8AA-aUCfBpSvITcIJa9pbyBvPwxSONULYC6FQlICaIAKBpuwZPr3N55l2toZLn8$>





Ubinas  | Peru  | 16.355°S, 70.903°W  | Summit elev. 5672 m



Instituto Geofísico del Perú (IGP) reported that the eruption at Ubinas
continued during 11-17 September at low-to-moderate levels. There were
daily averages of 144 volcano-tectonic earthquakes indicating rock
fracturing and 86 long-period earthquakes signifying the movement of gas
and magma. One explosion was recorded on 14 September. INGEMMET noted that
sulfur dioxide emissions were at low levels during 14-15 September,
averaging 900 tons per day. Ash-and-steam plumes rose 1.6 km above the
crater rim and drifted SE and NE, causing ashfall in areas within 5 km
downwind. IGP noted that seismic signals associated with ash emissions were
recorded for an average of three hours per day during 14-16 September. Ash,
gas, and steam emissions visible in webcam images rose as high as 2.6 km
above the crater rim and drifted as far as 15 km NE, E, and SE. Deformation
data indicated a slight trend of inflation with variations less than 5 mm.
The Alert Level remained at Orange (the third level on a four-color scale)
and the public was warned to stay 4 km away from the crater.



Geologic Summary. A small, 1.4-km-wide caldera cuts the top of Ubinas,
Perú's most active volcano, giving it a truncated appearance. It is the
northernmost of three young volcanoes located along a regional structural
lineament about 50 km behind the main volcanic front. The growth and
destruction of Ubinas I was followed by construction of Ubinas II beginning
in the mid-Pleistocene. The upper slopes of the andesitic-to-rhyolitic
Ubinas II stratovolcano are composed primarily of andesitic and
trachyandesitic lava flows and steepen to nearly 45 degrees. The
steep-walled, 150-m-deep summit caldera contains an ash cone with a
500-m-wide funnel-shaped vent that is 200 m deep. Debris-avalanche deposits
from the collapse of the SE flank about 3,700 years ago extend 10 km from
the volcano. Widespread Plinian pumice-fall deposits include one of
Holocene age about 1,000 years ago. Holocene lava flows are visible on the
flanks, but historical activity, documented since the 16th century, has
consisted of intermittent minor-to-moderate explosive eruptions.



Sources: Instituto Geofísico del Perú (IGP) https://urldefense.com/v3/__http://www.igp.gob.pe/__;!!IKRxdwAv5BmarQ!a7tlA1LwzkXOWEequ-FLs6-Wu77jmMY3ElmyJbwozggxgfsAEw4Rag-Vf_mEQeh0yfIBR5yyWRsaaHIY$ 
<https://urldefense.com/v3/__http://www.igp.gob.pe/__;!!IKRxdwAv5BmarQ!bYHBzLuf1F4y8AA-aUCfBpSvITcIJa9pbyBvPwxSONULYC6FQlICaIAKBpuwZPr3N55lit7G0eY$>
;

Instituto Geológico Minero y Metalúrgico (INGEMMET)
https://urldefense.com/v3/__http://www.ingemmet.gob.pe/__;!!IKRxdwAv5BmarQ!a7tlA1LwzkXOWEequ-FLs6-Wu77jmMY3ElmyJbwozggxgfsAEw4Rag-Vf_mEQeh0yfIBR5yyWRp-aJ0S$ 
<https://urldefense.com/v3/__http://www.ingemmet.gob.pe/__;!!IKRxdwAv5BmarQ!bYHBzLuf1F4y8AA-aUCfBpSvITcIJa9pbyBvPwxSONULYC6FQlICaIAKBpuwZPr3N55l6B37izs$>





Ulawun  | New Britain (Papua New Guinea)  | 5.05°S, 151.33°E  | Summit
elev. 2334 m



Rabaul Volcano Observatory (RVO) reported a small eruption at Ulawun during
14-15 September. Minor incandescence at the summit crater was first visible
at around 2107 on 14 September from Ulamona Observatory. The incandescence
intensified, and eruption plumes reflecting the glow were visible in webcam
images drifting NE. Starting at about 0004 and lasting to about 0800 on 15
September there were brief periods when the plumes appeared darker, likely
due to denser and more intense emissions. The plumes drifted W and WSW.
Rumbling noises were reported, though they became less frequent by 0800.
The Alert Level was raised to Stage 2 (the second level on the four-level
scale).



Staff from the West New Britain Provincial Disaster Office conducted a
field inspection on 15 September and found only minor ashfall around the
volcano. During 0800 on 15 September to 1430 on 19 September the volcano
was quiet; small volumes of diffuse white emissions sometimes rose from the
summit and drifted W and WSW. On 19 September RVO recommended that the
Alert Level should be lowered to Stage 1.



Increased seismicity coincided with the eruption. During most of 14
September RSAM values were 200-300, though they began to increase at about
1955 and reached a value of around 800 by midnight. RSAM continued to
increase; values reached 1,600 by 0100 on 15 September, rapidly increased
during 0100-0200, and reached a value of 4,060 almost two hours later at
0300. Seismicity was dominated by continuous low-frequency volcanic
tremors. Seismicity began to decline at 0700, reached background levels by
0900, and remained low with values of 200-450. During 16-19 September
seismicity was characterized by low level volcanic tremors with sporadic
occurrences of discrete, small, low-frequency volcanic events. RSAM values
were around 200.



Geologic Summary. The symmetrical basaltic-to-andesitic Ulawun
stratovolcano is the highest volcano of the Bismarck arc, and one of Papua
New Guinea's most frequently active. The volcano, also known as the Father,
rises above the N coast of the island of New Britain across a low saddle NE
of Bamus volcano, the South Son. The upper 1,000 m is unvegetated. A
prominent E-W escarpment on the south may be the result of large-scale
slumping. Satellitic cones occupy the NW and E flanks. A steep-walled
valley cuts the NW side, and a flank lava-flow complex lies to the south of
this valley. Historical eruptions date back to the beginning of the 18th
century. Twentieth-century eruptions were mildly explosive until 1967, but
after 1970 several larger eruptions produced lava flows and basaltic
pyroclastic flows, greatly modifying the summit crater.



Source: Rabaul Volcano Observatory (RVO)
https://urldefense.com/v3/__https://webdev.datec.net.pg/geohazards/category/volcanoes/__;!!IKRxdwAv5BmarQ!a7tlA1LwzkXOWEequ-FLs6-Wu77jmMY3ElmyJbwozggxgfsAEw4Rag-Vf_mEQeh0yfIBR5yyWXHQXJzc$ 
<https://urldefense.com/v3/__https://webdev.datec.net.pg/geohazards/category/volcanoes/__;!!IKRxdwAv5BmarQ!bYHBzLuf1F4y8AA-aUCfBpSvITcIJa9pbyBvPwxSONULYC6FQlICaIAKBpuwZPr3N55lRFNwuWk$>





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



SERNAGEOMIN reported that the eruption in Villarricaâ??s summit crater was
ongoing during 13-19 September. Long-period (LP) earthquakes were recorded
at 0622 on 15 September and at 0426 and 0723 on 16 September; weather
conditions prevented views of the summit during these events. An LP
earthquake at 0130 on 18 September was associated with crater incandescence
and a gas-and-steam plume that rose 120 m above the crater rim. The
Volcanic Alert level remained at Yellow (the second highest on a four-level
scale) according to SERNAGEOMIN and the public was warned to stay 500 m
away from the crater. SENAPRED maintained the Alert Level at Yellow (the
middle level on a three-color scale) for the communities of Villarrica,
Pucón (16 km N), Curarrehue, and Panguipulli.



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



Sources: Servicio Nacional de Geología y Minería (SERNAGEOMIN)
https://urldefense.com/v3/__http://www.sernageomin.cl/__;!!IKRxdwAv5BmarQ!a7tlA1LwzkXOWEequ-FLs6-Wu77jmMY3ElmyJbwozggxgfsAEw4Rag-Vf_mEQeh0yfIBR5yyWd-eVUej$ 
<https://urldefense.com/v3/__http://www.sernageomin.cl/__;!!IKRxdwAv5BmarQ!bYHBzLuf1F4y8AA-aUCfBpSvITcIJa9pbyBvPwxSONULYC6FQlICaIAKBpuwZPr3N55lpODdVh4$>
;

Sistema y Servicio Nacional de Prevención y Repuesta Ante Desastres
(SENAPRED) https://urldefense.com/v3/__https://senapred.cl/__;!!IKRxdwAv5BmarQ!a7tlA1LwzkXOWEequ-FLs6-Wu77jmMY3ElmyJbwozggxgfsAEw4Rag-Vf_mEQeh0yfIBR5yyWbSYdkvE$ 
<https://urldefense.com/v3/__https://senapred.cl/__;!!IKRxdwAv5BmarQ!bYHBzLuf1F4y8AA-aUCfBpSvITcIJa9pbyBvPwxSONULYC6FQlICaIAKBpuwZPr3N55lFt17ELk$>





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



Vanuatu Meteorology and Geohazards Department (VMGD) reported that Yasur
emitted a substantial ash cloud during 1400-1700 on 12 September based on
reports from nearby observers. The plumes drifted SE; VMGD warned that
areas around White Sands, 3 km N, may experience impacts from ashfall and
gas. The volcano had returned to normal levels by the next day. The Alert
Level remained at 2 (the middle level on a scale of 0-4).



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



Source: Vanuatu Meteorology and Geo-Hazards Department (VMGD)
https://urldefense.com/v3/__http://www.geohazards.gov.vu/__;!!IKRxdwAv5BmarQ!a7tlA1LwzkXOWEequ-FLs6-Wu77jmMY3ElmyJbwozggxgfsAEw4Rag-Vf_mEQeh0yfIBR5yyWdnf4mld$ 
<https://urldefense.com/v3/__http://www.geohazards.gov.vu/__;!!IKRxdwAv5BmarQ!bYHBzLuf1F4y8AA-aUCfBpSvITcIJa9pbyBvPwxSONULYC6FQlICaIAKBpuwZPr3N55lOqZimUA$>




6-6-6-6-6-6-6-6-6-6-6-6-6



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End of Volcano Digest - 18 Sep 2023 to 20 Sep 2023 (#2023-90)
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