Smithsonian / USGS Weekly Volcanic Activity Report 22-28 September 2021

[Rachel Holsteen-Bruyere <rbruyere@xxxxxxx>]

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


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


Smithsonian / USGS Weekly Volcanic Activity Report
22-28 September 2021

Sally Kuhn Sennert - Weekly Report Editor (kuhns@xxxxxx<mailto:kuhns@xxxxxx
>)
URL:
https://urldefense.com/v3/__https://volcano.si.edu/reports_weekly.cfm__;!!IKRxdwAv5BmarQ!LwYgwElZiUqsXrlVIMJa-LMtYJLyrIXBaqraPQumc06jt20YkC4x-8KW_ubAgsg$


New Activity/Unrest: La Palma, Spain  | Nyiragongo, DR Congo

Ongoing Activity: Aira, Kyushu (Japan)  | Ebeko, Paramushir Island
(Russia)  | Fuego, Guatemala  | Great Sitkin, Andreanof Islands (USA)  |
Karymsky, Eastern Kamchatka (Russia)  | Katmai, United States  |
Klyuchevskoy, Central Kamchatka (Russia)  | Langila, New Britain (Papua New
Guinea)  | Lewotolok, Lembata Island (Indonesia)  | Merapi, Central Java
(Indonesia)  | Pavlof, United States  | Ruapehu, North Island (New
Zealand)  | Santa Maria, Guatemala  | Semisopochnoi, Aleutian Islands
(USA)  | Sheveluch, Central Kamchatka (Russia)  | Suwanosejima, Ryukyu
Islands (Japan)  | Tengger Caldera, Eastern Java (Indonesia)  |
Whakaari/White Island, North Island (New Zealand)


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


La Palma  | Spain  | 28.57°N, 17.83°W  | Summit elev. 2426 m

The eruption at La Palma continued during 21-28 September, characterized by
Strombolian explosions, lava fountaining from multiple vents, advancing
lava flows, and sometimes dense, daily ash emissions. A strong increase in
tremor amplitude during the afternoon of 21 September was coincident with
intensifying Strombolian activity. Explosive activity again increased on 22
September and dense plumes with abundant amounts of ash rose 3-4.6 km
(10,000-15,000 ft) a.s.l. and caused ashfall in areas downwind; ash
deposits were 3 cm thick in an unspecified area 1 km from the vents. The
main lava flow advanced W towards the coast. Ash emissions significantly
increased on 23 September with plumes rising as high as 5 km (16,400 ft)
a.s.l. A series of powerful explosions began at 1720 and shock waves could
be seen propagating through the emission plumes. Vigorous lava fountaining
was continuous. Volcanic tremor amplitude was high and variable, peaking at
1500 on 24 September with the highest values since the eruption started.
The peak occurred just before two new vents opened on the flank of the main
cone, and then notably decreased afterwards, but remained at high levels.
Lava from the new vents rapidly traveled more than 1 km downslope, covering
older flows, before slowing to 60-80 meters per hour. According to a news
report, the explosions ejected tephra outside of the exclusion zone. An
evacuation order was issued in the early afternoon for Tajuya, Tacande de
Abajo, and part of Tacande de Arriba, affecting 300-400 people. Three
airlines suspended flights to La Palma. The lava flow field had expanded to
1.9 square kilometers, destroyed more than 420 buildings, and covered 15.2
km of roads.

Tremor amplitude decreased around noon on 25 September, along with the
intensity of the Strombolian explosions. During 25-26 September ash fell in
nearby municipalities and as far as the E coast of the island. On 26
September the PEVOLCA steering committee recommended that residents who had
evacuated two days earlier could return. The report described two main lava
flows, with a highly fluid northern flow and a southern flow that was 2.5
km long. Sulfur dioxide emissions remained significant with an average rate
of 25,000 tons per day, and ash plumes rose as high as 3 km above the
vents. Lava continued to advance and flowed through Todoque, crossing the
LP-213 road, just W of the main part of the town, at around 1900. The flow
was 600 m across at the widest part and the leading edge was 4-6 m tall.
Lava fountaining and low-intensity Strombolian explosions persisted.
Copernicus EMS estimated that the lava covered 2.37 square kilometers, had
destroyed 513 houses, and covered 18.9 km of roads. Multiple lava fountains
feeding flows were visible on 27 September though the activity waned for a
period of about eight hours. By the evening activity had resumed and
low-intensity Strombolian explosions were visible.

Beginning at 0245 on 28 September lava fountains fed a new
high-temperature, fast-moving flow that descended on top of older flank
flows. The leading edge of the main flow continued to advance W and covered
banana greenhouses, burning the plastic and igniting a storage of
fertilizer resulting in small explosions and a brown odorous plume. About
140 more structures were covered by flows. In preparation for a possible
ocean entry, authorities recommended that residents within a 5 km radius of
the coastline keep their doors and windows closed, to stay away from
windows in case they break, and to cover faces and skin in case of ashfall.
Dense ash-and-gas plumes continued to rise from the main vents, as high as
5 km; the rising plume created gravity waves that looked like ripples
moving away from the top of the plume. Late in the day lava reached the
coastal area, descended a 100-m-high sea cliff, and by 2302 reached the
ocean at Playa de los Guirres. Black-and-white plumes rose from where the
lava contacted the water.

Geologic Summary. The 47-km-long wedge-shaped island of La Palma, the
NW-most of the Canary Islands, is composed of two large volcanic centers.
The older northern one is cut by the massive steep-walled Caldera
Taburiente, one of several massive collapse scarps produced by edifice
failure to the SW. The younger Cumbre Vieja, the southern volcano, is one
of the most active in the Canaries. The elongated volcano dates back to
about 125,000 years ago and is oriented N-S. Eruptions during the past
7,000 years have formed abundant cinder cones and craters along the axis of
Cumbre Vieja, producing fissure-fed lava flows that descend steeply to the
sea. Eruptions recorded since the 15th century have produced mild explosive
activity and lava flows that damaged populated areas. The southern tip of
the island is mantled by a broad lava field emplaced during the 1677-1678
eruption. Lava flows also reached the sea in 1585, 1646, 1712, 1949, and
1971.

Sources: Instituto Geográfico Nacional (IGN)
https://urldefense.com/v3/__https://www.ign.es/web/ign/portal__;!!IKRxdwAv5BmarQ!LwYgwElZiUqsXrlVIMJa-LMtYJLyrIXBaqraPQumc06jt20YkC4x-8KWDOk7YnM$
 ;
Instituto Volcanológico de Canarias (INVOLCAN)
https://urldefense.com/v3/__http://www.involcan.org/__;!!IKRxdwAv5BmarQ!LwYgwElZiUqsXrlVIMJa-LMtYJLyrIXBaqraPQumc06jt20YkC4x-8KWNRJ9tdM$
 ;
Gobierno de Canaries
https://urldefense.com/v3/__https://www3.gobiernodecanarias.org/noticias/el-frente-de-lava-se-situa-en-el-limite-entre-los-municipios-de-los-llanos-y-tazacorte/__;!!IKRxdwAv5BmarQ!LwYgwElZiUqsXrlVIMJa-LMtYJLyrIXBaqraPQumc06jt20YkC4x-8KWCy1VNJc$
 ;
EL PAÃ?S
https://urldefense.com/v3/__https://elpais.com/espana/2021-09-28/ultimas-noticias-del-volcan-en-erupcion-en-la-palma-en-directo-la-ultima-hora-de-cumbre-vieja-en-canarias.html__;!!IKRxdwAv5BmarQ!LwYgwElZiUqsXrlVIMJa-LMtYJLyrIXBaqraPQumc06jt20YkC4x-8KWcy57Gyc$
 ;
CNN
https://urldefense.com/v3/__https://www.cnn.com/2021/09/27/europe/canary-islands-la-palma-volcano-lava-lock-down-intl/index.html__;!!IKRxdwAv5BmarQ!LwYgwElZiUqsXrlVIMJa-LMtYJLyrIXBaqraPQumc06jt20YkC4x-8KWLpnE0G4$
 ;
EL PAÃ?S
https://urldefense.com/v3/__https://elpais.com/espana/2021-09-29/ultimas-noticias-del-volcan-en-erupcion-en-la-palma-en-directo-la-ultima-hora-de-cumbre-vieja-en-canarias.html__;!!IKRxdwAv5BmarQ!LwYgwElZiUqsXrlVIMJa-LMtYJLyrIXBaqraPQumc06jt20YkC4x-8KWnS2kiXs$
 ;
Toulouse Volcanic Ash Advisory Centre (VAAC)
https://urldefense.com/v3/__http://vaac.meteo.fr/__;!!IKRxdwAv5BmarQ!LwYgwElZiUqsXrlVIMJa-LMtYJLyrIXBaqraPQumc06jt20YkC4x-8KWHx8-fm0$
 ;
Copernicus Emergency Management Service
https://urldefense.com/v3/__https://emergency.copernicus.eu/__;!!IKRxdwAv5BmarQ!LwYgwElZiUqsXrlVIMJa-LMtYJLyrIXBaqraPQumc06jt20YkC4x-8KWCLvw8WE$


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

OVG reported that lava had returned to Nyiragongo's summit crater based on
a 29 September Sentinel satellite image.

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

Source: Observatoire Volcanologique de Goma (OVG)
https://urldefense.com/v3/__http://observatoirevolcanologiquedegoma.org/__;!!IKRxdwAv5BmarQ!LwYgwElZiUqsXrlVIMJa-LMtYJLyrIXBaqraPQumc06jt20YkC4x-8KW-rUBySY$


Ongoing Activity


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

JMA reported that incandescence from Minamidake Crater (at Aira Caldera's
Sakurajima volcano) was visible on most nights during 20-27 September. The
trend of inflation first detected on 13 September had begun to slow down by
21 September. The sulfur dioxide emission rate was high at 2,600 tons per
day on 22 September. An eruptive event at 0110 on 23 September and two more
during 24-27 September produced plumes that rose 1.1 km above the crater
rim. The Alert Level remained at 3 (on a 5-level scale), and residents were
warned to stay 2 km away from the crater.

Geologic Summary. The Aira caldera in the northern half of Kagoshima Bay
contains the post-caldera Sakurajima volcano, one of Japan's most active.
Eruption of the voluminous Ito pyroclastic flow accompanied formation of
the 17 x 23 km caldera about 22,000 years ago. The smaller Wakamiko caldera
was formed during the early Holocene in the NE corner of the Aira caldera,
along with several post-caldera cones. The construction of Sakurajima began
about 13,000 years ago on the southern rim of Aira caldera and built an
island that was finally joined to the Osumi Peninsula during the major
explosive and effusive eruption of 1914. Activity at the Kitadake summit
cone ended about 4850 years ago, after which eruptions took place at
Minamidake. Frequent historical eruptions, recorded since the 8th century,
have deposited ash on Kagoshima, one of Kyushu's largest cities, located
across Kagoshima Bay only 8 km from the summit. The largest historical
eruption took place during 1471-76.

Source: Japan Meteorological Agency (JMA)
https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!LwYgwElZiUqsXrlVIMJa-LMtYJLyrIXBaqraPQumc06jt20YkC4x-8KWjiIK4U4$


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

According to volcanologists in Severo-Kurilsk (Paramushir Island), about 7
km E of Ebeko, explosions on 20 September produced ash plumes that rose as
high as 1.7 km (5,600 ft) a.s.l. and drifted SE. The Aviation Color Code
remained at Orange (the second highest level on a four-color scale).

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

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!LwYgwElZiUqsXrlVIMJa-LMtYJLyrIXBaqraPQumc06jt20YkC4x-8KWzOTiAjU$


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

INSIVUMEH reported that during the night of 21-22 September a possible lava
flow had traveled 400 m down Fuego's Ceniza drainage on the SSW flank. Ash
rose along the flow forming a curtain that extended above the summit; ash
fell in communities to the W and SW. Explosions at a rate of 6-11 per hour
produced ash plumes that rose as high as 800 m above the summit and drifted
W and SW.

INSIVUMEH and CONRED reported that activity significantly increased on 23
September. Seismic activity intensified during the early morning and
Strombolian activity at the summit was visible. Incandescent material was
ejected 100-300 m high. Lava flows traveled 1 km down the Ceniza (SSW) and
Trinidad (S) drainages, and sent block-and-ash flows down the Ceniza,
Trinidad, Taniluyá, Las Lajas, and Santa Teresa (W) drainages to vegetated
areas. Shock waves were detected within a 10 km radius. At 0540 a
pyroclastic flow traveled 4-6 km down the Ceniza drainage, reaching the
base of the volcano. According to CONRED a pyroclastic flow descended the
Ceniza and Trinidad drainages 2-4 km. Explosions generated ash plumes that
rose as high as 2.3 km above the summit and drifted 30 km W and SW. The
activity began to decline around noon the next day, based on seismicity,
acoustic data, and field observations. A few hours later RSAM data
suggested that the period of elevated activity had ended after about 32
hours from the onset. Lava flows were no longer active by 25 September.

During 24-28 September there were that 6-12 explosions per hour generating
ash plumes as high as 1.1 km above the crater rim and shock waves that
often rattled buildings within 10 km of the volcano. Ash plumes mostly
drifted as far as 15 km W and SW, causing daily ashfall in several areas
downwind, including Morelia (9 km SW), Panimaché I and II (8 km SW), Santa
Sofía (12 km SW), Finca Palo Verde, and San Pedro Yepocapa (8 km NW). Block
avalanches descended the Ceniza (SSW), Seca (W), Trinidad (S), Taniluyá
(SW), Las Lajas (SE), and Honda drainages, often reaching vegetated areas.
Explosions ejected incandescent material 100-300 m above the summit on most
days.

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.

Sources: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e
Hidrologia (INSIVUMEH)
https://urldefense.com/v3/__http://www.insivumeh.gob.gt/__;!!IKRxdwAv5BmarQ!LwYgwElZiUqsXrlVIMJa-LMtYJLyrIXBaqraPQumc06jt20YkC4x-8KWzKsqsI8$
 ;
Coordinadora Nacional para la Reducción de Desastres (CONRED)
https://urldefense.com/v3/__http://conred.gob.gt/__;!!IKRxdwAv5BmarQ!LwYgwElZiUqsXrlVIMJa-LMtYJLyrIXBaqraPQumc06jt20YkC4x-8KWAnl2HBI$


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

AVO reported that lava effusion continued at Great Sitkin during 22-28
September, though weather clouds sometimes prevented webcam and satellite
views. Seismicity remained elevated and was characterized by small
earthquakes consistent with lava effusion. By 24 September the dome had
overtopped the S and W crater rims and flowed 305 m down the S flank and
195 m down the W flank. The dome was about 25 m thick and had grown to
1,170 m E to W and 925 m N to S in dimension. The Aviation Color Code and
the Volcano Alert Level remained at Orange and Watch, respectively.

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

Source: US Geological Survey Alaska Volcano Observatory (AVO)
https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!LwYgwElZiUqsXrlVIMJa-LMtYJLyrIXBaqraPQumc06jt20YkC4x-8KWB2d1U0M$


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

KVERT reported that a thermal anomaly over Karymsky was identified in
satellite images during 16-18 and 22 September. Ash plumes rose as high as
4.5 km (14,800 ft) a.s.l. and drifted 180 km E during 16, 18-19, and 22
September. The Aviation Color Code remained at Orange (the second highest
level on a four-color scale).

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

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!LwYgwElZiUqsXrlVIMJa-LMtYJLyrIXBaqraPQumc06jt20YkC4x-8KWzOTiAjU$


Katmai  | United States  | 58.28°N, 154.963°W  | Summit elev. 2047 m

AVO reported that beginning at 1730 on 23 September strong winds in the
vicinity of Katmai and the Valley of Ten Thousand Smokes blew
unconsolidated ash SE towards Kodiak Island at an altitude up to 1.5 km
(5,000 ft) a.s.l. The ash was originally deposited during the Novarupta
eruption in 1912. The Volcano Alert Level remained at Normal and the
Aviation Color Code remained at Green.

Geologic Summary. Prior to 1912, Mount Katmai was a compound stratovolcano
with four NE-SW-trending summits, most of which were truncated by caldera
collapse in that year. Two or more large explosive eruptions took place
from Mount Katmai during the late Pleistocene. Most of the two overlapping
pre-1912 Katmai volcanoes are Pleistocene in age, but Holocene lava flows
from a flank vent descend the SE flank of the SW stratovolcano into the
Katmai River canyon. Katmai was initially considered to be the source of
the Valley of Ten Thousand Smokes ash flow in 1912. However, the 3 x 4 km
wide caldera of 1912 is now known to have formed as a result of the
voluminous eruption at nearby Novarupta volcano. The steep walled young
caldera has a jagged rim that rises 500-1000 m above the caldera floor and
contains a 250-m-deep, still-rising lake. Lake waters have covered a small
post-collapse lava dome (Horseshoe Island) that was seen on the caldera
floor at the time of the initial ascent to the caldera rim in 1916.
Post-1912 glaciers have formed on a bench within Katmai caldera.

Source: US Geological Survey Alaska Volcano Observatory (AVO)
https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!LwYgwElZiUqsXrlVIMJa-LMtYJLyrIXBaqraPQumc06jt20YkC4x-8KWB2d1U0M$


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

KVERT reported that on 29 September high winds caused unconsolidated ash
from Klyuchevskoy's flanks to form plumes that rose to 3-5 km (9,800-16,400
ft) a.s.l. and drifted 75 km E. The Aviation Color Code was raised to
Orange (the second highest level on a four-color scale).

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!LwYgwElZiUqsXrlVIMJa-LMtYJLyrIXBaqraPQumc06jt20YkC4x-8KWzOTiAjU$


Langila  | New Britain (Papua New Guinea)  | 5.525°S, 148.42°E  | Summit
elev. 1330 m

Based on analyses of satellite imagery and wind model data, the Darwin VAAC
reported that during 24-25 September three ash plumes from Langila rose to
2.1 km (7,000 ft) a.s.l. and drifted W and NW.

Geologic Summary. Langila, one of the most active volcanoes of New Britain,
consists of a group of four small overlapping composite basaltic-andesitic
cones on the lower E flank of the extinct Talawe volcano in the Cape
Gloucester area of NW New Britain. A rectangular, 2.5-km-long crater is
breached widely to the SE; Langila was constructed NE of the breached
crater of Talawe. An extensive lava field reaches the coast on the N and NE
sides of Langila. Frequent mild-to-moderate explosive eruptions, sometimes
accompanied by lava flows, have been recorded since the 19th century from
three active craters at the summit. The youngest and smallest crater (no. 3
crater) was formed in 1960 and has a diameter of 150 m.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)
https://urldefense.com/v3/__http://www.bom.gov.au/aviation/volcanic-ash/darwin-va-advisory.shtml__;!!IKRxdwAv5BmarQ!LwYgwElZiUqsXrlVIMJa-LMtYJLyrIXBaqraPQumc06jt20YkC4x-8KWTWin9q8$


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

PVMBG reported that the eruption at Lewotolok continued during 21-28
September. White-and-gray plumes rose as high as 700 m above the summit and
drifted NW, W, and SW. Rumbling sounds were reported almost daily. The
Alert Level remained at 3 (on a scale of 1-4) and the public was warned to
stay 3 km away from the summit crater.

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

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known
as CVGHM)
https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!LwYgwElZiUqsXrlVIMJa-LMtYJLyrIXBaqraPQumc06jt20YkC4x-8KW7u7C-Tw$


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

BPPTKG reported minor morphological changes to Merapi's SW lava dome,
located just below the SW rim and in the summit crater, and no changes to
the summit crater dome during 17-23 September. The SW dome had an estimated
volume of 1.6 million cubic meters and the summit lava dome had an
estimated volume of 2.85 million cubic meters. As many as 141 lava
avalanches traveled a maximum of 2 km SW. The Alert Level remained at 3 (on
a scale of 1-4), and the public was warned to stay 3-5 km away from the
summit based on location.

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

Source: Balai Penyelidikan dan Pengembangan Teknologi Kebencanaan Geologi
(BPPTKG)
https://urldefense.com/v3/__http://www.merapi.bgl.esdm.go.id/__;!!IKRxdwAv5BmarQ!LwYgwElZiUqsXrlVIMJa-LMtYJLyrIXBaqraPQumc06jt20YkC4x-8KWs2n72kQ$


Pavlof  | United States  | 55.417°N, 161.894°W  | Summit elev. 2493 m

AVO reported that seismicity at Pavlof remained elevated during 21-28
September. Daily short-lived explosions from a vent on the upper SE flank
were detected in seismic and infrasound data. Low-level ash emissions were
visible in webcam images rising possibly several hundred meters above the
summit during 21-23 September. Steam emissions rose from the vent during
24-25 September. The Volcano Alert Level and Aviation Color Code remained
at Watch and Orange, respectively.

Geologic Summary. The most active volcano of the Aleutian arc, Pavlof is a
2519-m-high Holocene stratovolcano that was constructed along a line of
vents extending NE from the Emmons Lake caldera. Pavlof and its twin
volcano to the NE, 2142-m-high Pavlof Sister, form a dramatic pair of
symmetrical, glacier-covered stratovolcanoes that tower above Pavlof and
Volcano bays. A third cone, Little Pavlof, is a smaller volcano on the SW
flank of Pavlof volcano, near the rim of Emmons Lake caldera. Unlike Pavlof
Sister, Pavlof has been frequently active in historical time, typically
producing Strombolian to Vulcanian explosive eruptions from the summit
vents and occasional lava flows. The active vents lie near the summit on
the north and east sides. The largest historical eruption took place in
1911, at the end of a 5-year-long eruptive episode, when a fissure opened
on the N flank, ejecting large blocks and issuing lava flows.

Source: US Geological Survey Alaska Volcano Observatory (AVO)
https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!LwYgwElZiUqsXrlVIMJa-LMtYJLyrIXBaqraPQumc06jt20YkC4x-8KWB2d1U0M$


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

GeoNet reported that a heating cycle at Ruapehu's summit Crater Lake had
ended. During the previous two months the temperature of the water
increased from 20 degrees Celsius to a peak of 39.5 degrees on 4 September,
and then decreased to 28 degrees. During the cycle the color of the lake
changed from a blue-green color to a darker gray, reflecting the disturbed
lake floor sediments suspended in the water from the influx of hot fluids.
The key monitoring parameters of water level and temperature, seismic
activity, and tremor levels, were all within normal ranges. The Volcanic
Alert Level remained at 1 (minor volcanic unrest) and the Aviation Color
Code remained at Green.

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

Source: GeoNet
https://urldefense.com/v3/__http://www.geonet.org.nz/__;!!IKRxdwAv5BmarQ!LwYgwElZiUqsXrlVIMJa-LMtYJLyrIXBaqraPQumc06jt20YkC4x-8KWiEV9eYQ$


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

INSIVUMEH reported that almost daily ash plumes from Santa Maria's
Santiaguito lava-dome complex rose 500-900 m and drifted W and SW during
19-27 September, depositing ash on the flanks. Extrusion continued at the
summit dome complex, mainly from the W part of the dome. Avalanches
produced by the active dome were sometimes incandescent and predominantly
descended the W flank, though some also traveled S and SW. The avalanches
often reached vegetated areas on the flanks.

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!LwYgwElZiUqsXrlVIMJa-LMtYJLyrIXBaqraPQumc06jt20YkC4x-8KWzKsqsI8$


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

AVO reported that eruptive activity at Semisopochnoi's North Cerberus
crater continued during 22-28 September. Seismicity remained elevated;
daily explosions were recorded by seismic and infrasound networks. The
frequency and intensity of ash emissions decreased during 21-22 September
with occasional discrete ash clouds drifted W at altitudes of 3-4.6 km
(10,000-15,000 ft) a.s.l. Sulfur dioxide plumes also drifted W. Occasional
low-level ash emissions drifted NW, W, and SE during 22-26 September. The
Aviation Color Code remained at Orange and the Volcano Alert Level remained
at Watch.

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

Source: US Geological Survey Alaska Volcano Observatory (AVO)
https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!LwYgwElZiUqsXrlVIMJa-LMtYJLyrIXBaqraPQumc06jt20YkC4x-8KWB2d1U0M$


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

KVERT reported that a thermal anomaly over Sheveluch was identified in
satellite images during 17-24 September. The Aviation Color Code remained
at Orange (the second highest level on a four-color scale).

Geologic Summary. The high, isolated massif of Sheveluch volcano (also
spelled Shiveluch) rises above the lowlands NNE of the Kliuchevskaya
volcano group. The 1300 km3 volcano is one of Kamchatka's largest and most
active volcanic structures. The summit of roughly 65,000-year-old Stary
Shiveluch is truncated by a broad 9-km-wide late-Pleistocene caldera
breached to the south. Many lava domes dot its outer flanks. The Molodoy
Shiveluch lava dome complex was constructed during the Holocene within the
large horseshoe-shaped caldera; Holocene lava dome extrusion also took
place on the flanks of Stary Shiveluch. At least 60 large eruptions have
occurred during the Holocene, making it the most vigorous andesitic volcano
of the Kuril-Kamchatka arc. Widespread tephra layers from these eruptions
have provided valuable time markers for dating volcanic events in
Kamchatka. Frequent collapses of dome complexes, most recently in 1964,
have produced debris avalanches whose deposits cover much of the floor of
the breached caldera.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!LwYgwElZiUqsXrlVIMJa-LMtYJLyrIXBaqraPQumc06jt20YkC4x-8KWzOTiAjU$


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

JMA reported that the number of explosions per day at Suwanosejima's Ontake
Crater had increased on 16 September and remained elevated through 27
September. A total of 105 explosions were recorded during 20-27 September.
Eruption plumes mainly rose as high as 2.9 km above the crater rim and
material was ejected as far as 800 m away from the crater. Ashfall was
reported in Toshima village (4 km SSW). Notably, an explosion at 2349 on 20
September ejected material as far as 1.2 km SE. At 0711 on 26 September an
eruptive event produced a plume that rose 5.4 km; weather clouds prevented
confirmation of ejected bombs, but a large amount of ash fell in Toshima
village. The Alert Level remained at 3 and the public was warned to stay 2
km away from the crater.

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

Source: Japan Meteorological Agency (JMA)
https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!LwYgwElZiUqsXrlVIMJa-LMtYJLyrIXBaqraPQumc06jt20YkC4x-8KWjiIK4U4$


Tengger Caldera  | Eastern Java (Indonesia)  | 7.942°S, 112.95°E  | Summit
elev. 2329 m

PVMBG reported that during 21-27 September white gas-and-steam plumes rose
as high as 400 m above the rim of Tengger Caldera's Bromo cone and drifted
SW, W, and NW. White-and-gray plumes rose as high as 500 m during 22-23
September. A weak thermal anomaly was visible in Sentinel-2 infrared
satellite images on 22 and 27 September. The Alert Level remained at 2 (on
a scale of 1-4), and visitors were warned to stay outside of a 1-km radius
of the crater.

Geologic Summary. The 16-km-wide Tengger caldera is located at the northern
end of a volcanic massif extending from Semeru volcano. The massive
volcanic complex dates back to about 820,000 years ago and consists of five
overlapping stratovolcanoes, each truncated by a caldera. Lava domes,
pyroclastic cones, and a maar occupy the flanks of the massif. The
Ngadisari caldera at the NE end of the complex formed about 150,000 years
ago and is now drained through the Sapikerep valley. The most recent of the
calderas is the 9 x 10 km wide Sandsea caldera at the SW end of the
complex, which formed incrementally during the late Pleistocene and early
Holocene. An overlapping cluster of post-caldera cones was constructed on
the floor of the Sandsea caldera within the past several thousand years.
The youngest of these is Bromo, one of Java's most active and most
frequently visited volcanoes.

Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known
as CVGHM)
https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!LwYgwElZiUqsXrlVIMJa-LMtYJLyrIXBaqraPQumc06jt20YkC4x-8KW7u7C-Tw$
 ;
Sentinel Hub
https://urldefense.com/v3/__https://sentinel-hub.com/explore/sentinel-playground__;!!IKRxdwAv5BmarQ!LwYgwElZiUqsXrlVIMJa-LMtYJLyrIXBaqraPQumc06jt20YkC4x-8KWPjy9RTQ$


Whakaari/White Island  | North Island (New Zealand)  | 37.52°S, 177.18°E  |
Summit elev. 294 m

On 27 September GeoNet reported results from an overflight of
Whakaari/White Island the previous week. Gas measurements showed that
sulfur dioxide emissions had increased to 680 tons per day from 450 tons
per day recorded in mid-August, continuing the trend of an increasing
emission rate noted over the past few months. The gas data suggested magma
input deeper in the system. Temperatures in the main vent area notably
decreased to 189 degrees Celsius from July and August measurements of 650
degrees, possibly indicating cooling caused by groundwater infiltration.
Minor ash deposits from recent emissions were visible around the active
vents. Seismicity was characterized by low levels of volcanic tremor and
occasional low-frequency volcanic earthquakes. Subsidence continued to be
measured by satellite. The Volcanic Alert Level remained at 2 and the
Aviation Color Code remained at Yellow.

Geologic Summary. The uninhabited Whakaari/White Island is the 2 x 2.4 km
emergent summit of a 16 x 18 km submarine volcano in the Bay of Plenty
about 50 km offshore of North Island. The island consists of two
overlapping andesitic-to-dacitic stratovolcanoes. The SE side of the crater
is open at sea level, with the recent activity centered about 1 km from the
shore close to the rear crater wall. Volckner Rocks, sea stacks that are
remnants of a lava dome, lie 5 km NW. Descriptions of volcanism since 1826
have included intermittent moderate phreatic, phreatomagmatic, and
Strombolian eruptions; activity there also forms a prominent part of Maori
legends. The formation of many new vents during the 19th and 20th centuries
caused rapid changes in crater floor topography. Collapse of the crater
wall in 1914 produced a debris avalanche that buried buildings and workers
at a sulfur-mining project. Explosive activity in December 2019 took place
while tourists were present, resulting in many fatalities. The official
government name Whakaari/White Island is a combination of the full Maori
name of Te Puia o Whakaari ("The Dramatic Volcano") and White Island
(referencing the constant steam plume) given by Captain James Cook in 1769.

Source: GeoNet
https://urldefense.com/v3/__http://www.geonet.org.nz/__;!!IKRxdwAv5BmarQ!LwYgwElZiUqsXrlVIMJa-LMtYJLyrIXBaqraPQumc06jt20YkC4x-8KWiEV9eYQ$


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