Smithsonian / USGS Weekly Volcanic Activity Report 28 September-4 October 2022

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


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


Smithsonian / USGS Weekly Volcanic Activity Report

28 September-4 October 2022



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

URL: https://urldefense.com/v3/__https://volcano.si.edu/reports_weekly.cfm__;!!IKRxdwAv5BmarQ!Z4OR29m2zAzDFmACL2NxQD-IOCbJX36KWrVWML2c8JlbpAjak_7Apqnz82ccWRtI2rO3sly0QZbGCCBh$  
<https://urldefense.com/v3/__https://volcano.si.edu/reports_weekly.cfm__;!!IKRxdwAv5BmarQ!cNbFKOCH0K2KaseaMRz6MaahJmWzztc9KHkAvcihuO2NanIGPNSGjirHHMIJ_NSBWxeGqVhFdWE$>





New Activity/Unrest: Alaid, Kuril Islands (Russia)  | Home Reef, Tonga
Ridge  | Nishinoshima, Izu Islands  | Piton de la Fournaise, Reunion Island
(France)  | Trident, Alaska



Ongoing Activity: Aira, Kyushu (Japan)  | Ebeko, Paramushir Island
(Russia)  | Great Sitkin, Andreanof Islands (USA)  | Karthala, Grand Comore
Island  | Kilauea, Hawaiian Islands (USA)  | Lewotolok, Lembata Island  |
Marapi, Central Sumatra  | Merapi, Central Java  | Nevados de Chillan,
Central Chile  | Pavlof, Alaska Peninsula, Alaska  | Sabancaya, Peru  |
Semeru, Eastern Java  | Semisopochnoi, Aleutian Islands (USA)  | Sheveluch,
Central Kamchatka (Russia)  | Stromboli, Aeolian Islands (Italy)  |
Suwanosejima, Ryukyu Islands (Japan)  | Taal, Luzon (Philippines)  | Ta'u,
American Samoa (SW Pacific)  | Villarrica, Central Chile  | 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





Alaid  | Kuril Islands (Russia)  | 50.861°N, 155.565°E  | Summit elev. 2285
m



KVERT reported that a thermal anomaly over Alaid was identified in
satellite images during 22-30 September. Ash plumes were visible drifting
140 km NE and SE during 26-27 September. The Aviation Color Code remained
at Orange (the second highest level on a four-color scale). Dates are based
on UTC times; specific events are in local time where noted.



Geologic Summary. The highest and northernmost volcano of the Kuril
Islands, 2285-m-high Alaid is a symmetrical stratovolcano when viewed from
the north, but has a 1.5-km-wide summit crater that is breached widely to
the south. Alaid is the northernmost of a chain of volcanoes constructed
west of the main Kuril archipelago. Numerous pyroclastic cones dot the
lower flanks of this basaltic to basaltic-andesite volcano, particularly on
the NW and SE sides, including an offshore cone formed during the 1933-34
eruption. Strong explosive eruptions have occurred from the summit crater
beginning in the 18th century. Reports of eruptions in 1770, 1789, 1821,
1829, 1843, 1848, and 1858 were considered incorrect by Gorshkov (1970).
Explosive eruptions in 1790 and 1981 were among the largest in the Kuril
Islands during historical time.



Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!Z4OR29m2zAzDFmACL2NxQD-IOCbJX36KWrVWML2c8JlbpAjak_7Apqnz82ccWRtI2rO3sly0QWb0GQVm$  
<https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!cNbFKOCH0K2KaseaMRz6MaahJmWzztc9KHkAvcihuO2NanIGPNSGjirHHMIJ_NSBWxeGtPztGus$>





Home Reef  | Tonga Ridge  | 18.992°S, 174.775°W  | Summit elev. -10 m



The Tonga Geological Services reported that the new island at Home Reef
that emerged from the ocean on 10 September continued to grow through 4
October. Daily counts of eruptive events producing gas-and-steam plumes
were variable, though during the middle of the week they had decreased to
less than 10 events per day. By 1040 on 28 September the dimensions of the
new island were estimated to be 268 m N-S and 283 m E-W, and the highest
point on the island was about 15 m a.s.l. The island was surrounded by
plumes of discolored water within about 200 m from the shore. The plumes
were elongated to the S, and were denser with suspended material within 1
km and more diffuse at distances greater or equal to 2 km. Mariners were
advised to stay 4 km away from the volcano.



Geologic Summary. Home Reef, a submarine volcano midway between Metis Shoal
and Late Island in the central Tonga islands, was first reported active in
the mid-19th century, when an ephemeral island formed. An eruption in 1984
produced a 12-km-high eruption plume, copious amounts of floating pumice,
and an ephemeral island 500 x 1500 m wide, with cliffs 30-50 m high that
enclosed a water-filled crater. Another island-forming eruption in 2006
produced widespread dacitic pumice rafts that reached as far as Australia.



Source: Tonga Geological Services, Government of Tonga
https://urldefense.com/v3/__https://www.facebook.com/tongageologicalservice__;!!IKRxdwAv5BmarQ!Z4OR29m2zAzDFmACL2NxQD-IOCbJX36KWrVWML2c8JlbpAjak_7Apqnz82ccWRtI2rO3sly0Qfn0CTFF$  
<https://urldefense.com/v3/__https://www.facebook.com/tongageologicalservice__;!!IKRxdwAv5BmarQ!cNbFKOCH0K2KaseaMRz6MaahJmWzztc9KHkAvcihuO2NanIGPNSGjirHHMIJ_NSBWxeGBmKG6mI$>





Nishinoshima  | Izu Islands  | 27.247°N, 140.874°E  | Summit elev. 25 m



According to JMA and the Tokyo VAAC an eruption at Nishinoshima produced
ash plumes that rose to 1.8-2.6 km (6,000-8,500 ft) a.s.l. and drifted E
and W during 1-4 October.



Geologic Summary. The small island of Nishinoshima was enlarged when
several new islands coalesced during an eruption in 1973-74. Another
eruption that began offshore in 2013 completely covered the previous
exposed surface and enlarged the island again. Water discoloration has been
observed on several occasions since. The island is the summit of a massive
submarine volcano that has prominent satellitic peaks to the S, W, and NE.
The summit of the southern cone rises to within 214 m of the sea surface 9
km SSE.



Sources: Japan Meteorological Agency (JMA) https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!Z4OR29m2zAzDFmACL2NxQD-IOCbJX36KWrVWML2c8JlbpAjak_7Apqnz82ccWRtI2rO3sly0Qbq92lVW$  
<https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!cNbFKOCH0K2KaseaMRz6MaahJmWzztc9KHkAvcihuO2NanIGPNSGjirHHMIJ_NSBWxeG-rHly1w$>
;

Tokyo Volcanic Ash Advisory Center (VAAC)
https://urldefense.com/v3/__http://ds.data.jma.go.jp/svd/vaac/data/vaac_list.html__;!!IKRxdwAv5BmarQ!Z4OR29m2zAzDFmACL2NxQD-IOCbJX36KWrVWML2c8JlbpAjak_7Apqnz82ccWRtI2rO3sly0QRFt5H5f$  
<https://urldefense.com/v3/__http://ds.data.jma.go.jp/svd/vaac/data/vaac_list.html__;!!IKRxdwAv5BmarQ!cNbFKOCH0K2KaseaMRz6MaahJmWzztc9KHkAvcihuO2NanIGPNSGjirHHMIJ_NSBWxeGpnCVi1s$>





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



OVPF reported that the eruption at Piton de la Fournaise that began on 19
September was ongoing at a cone adjacent to the SW flank of Piton Kala Pélé
during 28 September-4 October. The cone ejected lava to low heights above
the rim. Lava flowed from the base of the cone in two main branches, to the
SE and E, mainly through lava tubes, as far as 3 km. By 28 September the
cone had grown to just over 8 m tall and around 27 m wide at its base.
Average daily lava flow discharge rate estimates had a mean value of 8
meters per second at the beginning of the eruption but then stabilized at
2-4 meters per second; the flow rate increased during 28-29 September to
more than 6 meters per second. Lava discharge rates were likely
underestimated due to measurements hindered by weather conditions or flows
obscured by tubes. Tremor levels and gas emissions also began increasing on
29 September and remained at high levels during the rest of the week. The
vent at the top of the cone widened and a new, smaller cone formed on the S
flank and produced lava flows. The volume of erupted lava was 2.6-5.4
million cubic meters by 30 September; peak discharge rates reached 20
meters per second at times.



Sulfur dioxide emission estimates derived from satellite data had increased
from about 610 tons per day on 28 September to 1,525 tons per day on 1
October. A well-defined gas plume, denser than those seen during previous
days, was identified in a 30 September satellite image drifting 300 km NW
at an altitude of 3 km (10,000 ft) a.s.l. A more significant sulfur dioxide
plume was identified in satellite data the next day, drifting as far as 400
km. Gas plumes drifted SW during 2-3 October. Sulfur dioxide emissions
continued to increase and were about 2,500 tons per day on 3 October. The
cone had grown to around 12 m tall and 43 m wide at the base.



During 3-4 October the ejection of lava above the cone became less intense,
and the new smaller cone was only weakly active. The southernmost lava flow
had reached 1,800 m elevation in an area 1.5 km NW of Nez coupé du
Tremblet. During 4-5 October tremor levels fluctuated. Lava effusion
increased, averaging 10 meters per second with peaks at 25 meters per
second. Lava was ejected above the main vent, which was 23 m wide; the
smaller vent was not active. The eruption stopped or paused at 0748 on 5
October based on visual observations and a sudden halt in tremor signals.



Geologic Summary. Piton de la Fournaise is a massive basaltic shield
volcano on the French island of Réunion in the western Indian Ocean. Much
of its more than 530,000-year history overlapped with eruptions of the
deeply dissected Piton des Neiges shield volcano to the NW. Three scarps
formed at about 250,000, 65,000, and less than 5,000 years ago by
progressive eastward slumping, leaving caldera-sized embayments open to the
E and SE. Numerous pyroclastic cones are present on the floor of the scarps
and their outer flanks. Most recorded eruptions have originated from the
summit and flanks of Dolomieu, a 400-m-high lava shield that has grown
within the youngest scarp, which is about 9 km wide and about 13 km from
the western wall to the ocean on the E side. More than 150 eruptions, most
of which have produced fluid basaltic lava flows, have occurred since the
17th century. Only six eruptions, in 1708, 1774, 1776, 1800, 1977, and
1986, have originated from fissures outside the scarps.



Source: Observatoire Volcanologique du Piton de la Fournaise (OVPF)
https://urldefense.com/v3/__http://www.ipgp.fr/__;!!IKRxdwAv5BmarQ!Z4OR29m2zAzDFmACL2NxQD-IOCbJX36KWrVWML2c8JlbpAjak_7Apqnz82ccWRtI2rO3sly0QZHibMzi$  
<https://urldefense.com/v3/__http://www.ipgp.fr/__;!!IKRxdwAv5BmarQ!cNbFKOCH0K2KaseaMRz6MaahJmWzztc9KHkAvcihuO2NanIGPNSGjirHHMIJ_NSBWxeGoETBREA$>





Trident  | Alaska  | 58.236°N, 155.1°W  | Summit elev. 1864 m



AVO raised the Aviation Color Code for Trident to Yellow (the second lowest
level on a four-color scale) and the Volcano Alert Level to Advisory (the
second lowest level on a four-level scale) on 29 September due to an
ongoing seismic swarm. The swarm began on 24 August and within about four
days the seismic network began detecting episodes of weak seismic tremor
and low frequency earthquakes. The events were initially located at depths
around 25 km, but then they progressively shallowed to around 5 km by 28
August. Earthquakes were located 3-6 km deep since then, though some deeper
events were recorded. AVO attributed the swarm to moving magma or magmatic
fluids and noted that seismic swarms had previously been recorded with no
subsequent eruptions.



Geologic Summary. The Trident stratovolcano cluster was named for the three
prominent peaks that were the most visible features at the summit prior to
1953. The andesitic-dacitic group consists of four overlapping
stratovolcanoes and numerous flank lava domes, including Falling Mountain
and Mt. Cerberus on the far west flank. The summit complex is located 3-5
km SE of Novarupta volcano, and merges along a ridge to the NE with Katmai.
The three oldest Trident volcanoes are glaciated and Pleistocene in age,
while the youngest, Southwest Trident, was formed during historical time.
Eruptions migrated through time from the NE to the SW. In 1953 a new lava
dome began growing on the SW flank of Trident I volcano. A series of thick
andesitic lava flows were erupted between 1953 and 1968, forming a cone
with 400-800 m of local relief. Periodic explosions took place until 1974,
and the current summit contains a 350-m-wide crater. Some of the distal
lava flows from West Trident stratovolcano collapsed into the Novarupta
vent during its 1912 eruption.



Source: US Geological Survey Alaska Volcano Observatory (AVO)
https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!Z4OR29m2zAzDFmACL2NxQD-IOCbJX36KWrVWML2c8JlbpAjak_7Apqnz82ccWRtI2rO3sly0QaenSga5$  
<https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!cNbFKOCH0K2KaseaMRz6MaahJmWzztc9KHkAvcihuO2NanIGPNSGjirHHMIJ_NSBWxeGDxqKEjU$>







Ongoing Activity





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



JMA reported that 11 eruptive events and five explosions at Minamidake
Crater (at Aira Calderaâ??s Sakurajima volcano) were recorded during 26
September-3 October. Volcanic plumes rose as high as 2.8 km above the
crater rim and large blocks were ejected as far as 1.7 km from the vent.
Incandescence at the crater was visible nightly. 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!Z4OR29m2zAzDFmACL2NxQD-IOCbJX36KWrVWML2c8JlbpAjak_7Apqnz82ccWRtI2rO3sly0Qbq92lVW$  
<https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!cNbFKOCH0K2KaseaMRz6MaahJmWzztc9KHkAvcihuO2NanIGPNSGjirHHMIJ_NSBWxeG-rHly1w$>





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



KVERT reported that moderate activity at Ebeko was ongoing. According to
volcanologists in Severo-Kurilsk (Paramushir Island, about 7 km E)
explosions generated ash plumes that rose to 3.5 km (11,500 ft) a.s.l. and
drifted E during 22-24 and 27-28 September. On 22 and 28 September the ash
plumes that drifted E and N produced ashfall in Severo-Kurilsk. A thermal
anomaly over the volcano was identified in satellite images on 23 and 28
September. The Aviation Color Code remained at Orange (the second highest
level on a four-color scale). Dates are based on UTC times; specific events
are in local time where noted.



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



Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!Z4OR29m2zAzDFmACL2NxQD-IOCbJX36KWrVWML2c8JlbpAjak_7Apqnz82ccWRtI2rO3sly0QWb0GQVm$  
<https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!cNbFKOCH0K2KaseaMRz6MaahJmWzztc9KHkAvcihuO2NanIGPNSGjirHHMIJ_NSBWxeGtPztGus$>





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



AVO reported that continuing slow lava effusion at Great Sitkin was
confirmed by a 27 September satellite image and likely continued during 28
September-4 October. Elevated surface temperatures were identified during
28-29 September; weather clouds often prevented webcam and satellite views
during the rest of the week. Seismicity remained at low levels. The Volcano
Alert Level remained at Watch (the second highest level on a four-level
scale) and the Aviation Color Code remained at Orange (the second highest
level on a four-color scale).



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



Source: US Geological Survey Alaska Volcano Observatory (AVO)
https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!Z4OR29m2zAzDFmACL2NxQD-IOCbJX36KWrVWML2c8JlbpAjak_7Apqnz82ccWRtI2rO3sly0QaenSga5$  
<https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!cNbFKOCH0K2KaseaMRz6MaahJmWzztc9KHkAvcihuO2NanIGPNSGjirHHMIJ_NSBWxeGDxqKEjU$>





Karthala  | Grand Comore Island  | 11.75°S, 43.38°E  | Summit elev. 2361 m



According to the Direction Générale de la Sécurité Civile (DGSC) â?? Comores
on 4 October, the Observatoire Volcanologique du Karthala (OVK) reported
that activity at Karthala had significantly declined during the previous
few days. OVK recommended that the Alert Level remain at Yellow (the second
lowest level on a four-level scale).



Geologic Summary. The southernmost and largest of the two shield volcanoes
forming Grand Comore Island (also known as Ngazidja Island), Karthala
contains a 3 x 4 km summit caldera generated by repeated collapse.
Elongated rift zones extend to the NNW and SE from the summit of the
Hawaiian-style basaltic shield, which has an asymmetrical profile that is
steeper to the S. The lower SE rift zone forms the Massif du Badjini, a
peninsula at the SE tip of the island. Historical eruptions have modified
the morphology of the compound, irregular summit caldera. More than twenty
eruptions have been recorded since the 19th century from the summit caldera
and vents on the N and S flanks. Many lava flows have reached the sea on
both sides of the island. An 1860 lava flow from the summit caldera
traveled ~13 km to the NW, reaching the W coast to the N of the capital
city of Moroni.



Source: Direction Générale de la Sécurité Civile â?? Comores
https://urldefense.com/v3/__https://dgsc-comores.org/__;!!IKRxdwAv5BmarQ!Z4OR29m2zAzDFmACL2NxQD-IOCbJX36KWrVWML2c8JlbpAjak_7Apqnz82ccWRtI2rO3sly0QVAnME6l$  
<https://urldefense.com/v3/__https://dgsc-comores.org/__;!!IKRxdwAv5BmarQ!cNbFKOCH0K2KaseaMRz6MaahJmWzztc9KHkAvcihuO2NanIGPNSGjirHHMIJ_NSBWxeGeEVkxUw$>





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



HVO reported that lava continued to effuse from a vent in the lower W wall
of Kilaueaâ??s Halema`uma`u Crater during 27 September-4 October, entering
the lava lake. The active part of the lake stayed at a relatively steady
level through the week, varying only slightly. Sulfur dioxide emissions
were approximately 970 and 1,800 tonnes per day on 28 and 30 September,
respectively. The Volcano Alert Level remained at Watch (the second highest
level on a four-level scale) and the Aviation Color Code remained at Orange
(the second highest level on a four-color scale).



Geologic Summary. 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!Z4OR29m2zAzDFmACL2NxQD-IOCbJX36KWrVWML2c8JlbpAjak_7Apqnz82ccWRtI2rO3sly0QVMPMaAP$  
<https://urldefense.com/v3/__https://volcanoes.usgs.gov/observatories/hvo/__;!!IKRxdwAv5BmarQ!cNbFKOCH0K2KaseaMRz6MaahJmWzztc9KHkAvcihuO2NanIGPNSGjirHHMIJ_NSBWxeG4FhK0Jo$>





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



PVMBG reported that the eruption at Lewotolok continued during 27
September-4 October. White emissions rose as high as 350 m above the summit
and drifted E, SE, W, and NW on most days. White-and-gray plumes rose as
high 500 m and drifted NW, W, and E during 29-30 September and 1-2 October.
The Alert Level remained at 3 (on a scale of 1-4) and the public was warned
to stay 3 km away from the summit crater and 4 km away from the crater on
the SE flank.



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



Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known
as CVGHM) https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!Z4OR29m2zAzDFmACL2NxQD-IOCbJX36KWrVWML2c8JlbpAjak_7Apqnz82ccWRtI2rO3sly0QZnRsH5Z$  
<https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!cNbFKOCH0K2KaseaMRz6MaahJmWzztc9KHkAvcihuO2NanIGPNSGjirHHMIJ_NSBWxeGYgbYtAE$>





Marapi  | Central Sumatra  | 0.38°S, 100.474°E  | Summit elev. 2885 m



PVMBG reported that seismicity at Marapi increased on 29 September, with
146 deep volcanic earthquakes recorded by the seismic network. Surficial
activity showed no changes. The Alert Level remained at 1 (on a scale of
1-4).



Geologic Summary. Gunung Marapi, not to be confused with the better-known
Merapi volcano on Java, is Sumatra's most active volcano. This massive
complex stratovolcano rises 2,000 m above the Bukittinggi Plain in the
Padang Highlands. A broad summit contains multiple partially overlapping
summit craters constructed within the small 1.4-km-wide Bancah caldera. The
summit craters are located along an ENE-WSW line, with volcanism migrating
to the west. More than 50 eruptions, typically consisting of
small-to-moderate explosive activity, have been recorded since the end of
the 18th century; no lava flows outside the summit craters have been
reported in historical time.



Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known
as CVGHM) https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!Z4OR29m2zAzDFmACL2NxQD-IOCbJX36KWrVWML2c8JlbpAjak_7Apqnz82ccWRtI2rO3sly0QZnRsH5Z$  
<https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!cNbFKOCH0K2KaseaMRz6MaahJmWzztc9KHkAvcihuO2NanIGPNSGjirHHMIJ_NSBWxeGYgbYtAE$>





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



BPPTKG reported that the eruption at Merapi continued during 23-29
September and seismicity remained at high levels. As many as seven lava
avalanches from the SW lava dome traveled down the Bebeng drainage on the
SW flank, reaching a maximum distance of 1.8 km. No morphological changes
to the central lava domes were evident in photographs, while the SW dome
grew about 1 m taller. 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!Z4OR29m2zAzDFmACL2NxQD-IOCbJX36KWrVWML2c8JlbpAjak_7Apqnz82ccWRtI2rO3sly0QbsF1kEb$  
<https://urldefense.com/v3/__http://www.merapi.bgl.esdm.go.id/__;!!IKRxdwAv5BmarQ!cNbFKOCH0K2KaseaMRz6MaahJmWzztc9KHkAvcihuO2NanIGPNSGjirHHMIJ_NSBWxeGQ9B1_iQ$>





Nevados de Chillan  | Central Chile  | 36.868°S, 71.378°W  | Summit elev.
3180 m



SERNAGEOMIN reported that two long-period earthquake signals were recorded
at Nevados de Chillán at 0813 on 3 October and 1630 on 4 October, and both
were followed by a dense ash emission. The ash plume from the first event
rose 760 m above the summit and drifted SSW, while the ash plume from the
second event rose as high as 1.9 km and also drifted SSW. The Alert Level
remained at Yellow, the second lowest level on a four-color scale. ONEMI
maintained an Alert Level Yellow (the middle level on a three-color scale)
for the communities of Pinto and Coihueco, and reminded residents not to
approach the crater within 2 km.



Geologic Summary. The compound volcano of Nevados de Chillán is one of the
most active of the Central Andes. Three late-Pleistocene to Holocene
stratovolcanoes were constructed along a NNW-SSE line within three nested
Pleistocene calderas, which produced ignimbrite sheets extending more than
100 km into the Central Depression of Chile. The dominantly andesitic Cerro
Blanco (Volcán Nevado) stratovolcano is located at the NW end of the
massif. Volcán Viejo (Volcán Chillán), which was the main active vent
during the 17th-19th centuries, occupies the SE end. The Volcán Nuevo
lava-dome complex formed during 1906-1945 on the NW flank of Viejo. The
Volcán Arrau dome complex was then constructed on the SE side of Volcán
Nuevo between 1973 and 1986, and eventually exceeded its height. Smaller
domes or cones are present in the 5-km valley between the two major
edifices.



Source: Servicio Nacional de Geología y Minería (SERNAGEOMIN)
https://urldefense.com/v3/__http://www.sernageomin.cl/__;!!IKRxdwAv5BmarQ!Z4OR29m2zAzDFmACL2NxQD-IOCbJX36KWrVWML2c8JlbpAjak_7Apqnz82ccWRtI2rO3sly0Qe1tNwwz$  
<https://urldefense.com/v3/__http://www.sernageomin.cl/__;!!IKRxdwAv5BmarQ!cNbFKOCH0K2KaseaMRz6MaahJmWzztc9KHkAvcihuO2NanIGPNSGjirHHMIJ_NSBWxeGbw23ORI$>





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



AVO reported that a minor eruption at a vent on Pavlofâ??s upper E flank was
ongoing during 27 September-4 October. Seismic tremor continued, and a few
small earthquakes were recorded during 28-29 September. Weather clouds
often prevented views of the volcano, though elevated surface temperatures
were identified in satellite images on a few of the days. Diffuse steam
plumes were visible in webcam views during 30 September-2 October. The
Volcano Alert Level remained at Watch (the second highest level on a
four-level scale) and the Aviation Color Code remained at Orange (the
second highest level on a four-color scale).



Geologic Summary. The 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!Z4OR29m2zAzDFmACL2NxQD-IOCbJX36KWrVWML2c8JlbpAjak_7Apqnz82ccWRtI2rO3sly0QaenSga5$  
<https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!cNbFKOCH0K2KaseaMRz6MaahJmWzztc9KHkAvcihuO2NanIGPNSGjirHHMIJ_NSBWxeGDxqKEjU$>





Sabancaya  | Peru  | 15.787°S, 71.857°W  | Summit elev. 5960 m



Instituto Geofísico del Perú (IGP) reported moderate levels of activity at
Sabancaya during 5-11 September with a daily average of 46 explosions.
Gas-and-ash plumes rose as high as 3 km above the summit and drifted NE, E,
and SE. As many as nine thermal anomalies originating from the lava dome in
the summit crater were identified in satellite data. Minor inflation
continued to be detected near Hualca Hualca (4 km N). The Alert Level
remained at Orange (the second highest level on a four-color scale) and the
public were warned to stay outside of a 12-km radius.



Geologic Summary. Sabancaya, located in the saddle NE of Ampato and SE of
Hualca Hualca volcanoes, is the youngest of these volcanic centers and the
only one to have erupted in historical time. The oldest of the three,
Nevado Hualca Hualca, is of probable late-Pliocene to early Pleistocene
age. The name Sabancaya (meaning "tongue of fire" in the Quechua language)
first appeared in records in 1595 CE, suggesting activity prior to that
date. Holocene activity has consisted of Plinian eruptions followed by
emission of voluminous andesitic and dacitic lava flows, which form an
extensive apron around the volcano on all sides but the south. Records of
historical eruptions date back to 1750.



Source: Instituto Geofísico del Perú (IGP) https://urldefense.com/v3/__http://www.igp.gob.pe/__;!!IKRxdwAv5BmarQ!Z4OR29m2zAzDFmACL2NxQD-IOCbJX36KWrVWML2c8JlbpAjak_7Apqnz82ccWRtI2rO3sly0QVrfLbbX$  
<https://urldefense.com/v3/__http://www.igp.gob.pe/__;!!IKRxdwAv5BmarQ!cNbFKOCH0K2KaseaMRz6MaahJmWzztc9KHkAvcihuO2NanIGPNSGjirHHMIJ_NSBWxeGUK5c0og$>





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



PVMBG reported that the eruption at Semeru continued during 27 September-4
October. Eruptive events at 0459 and 0726 on 2 October produced ash plumes
that rose 500-700 m above the summit and drifted S and SW. The Alert Level
remained at 3 (on a scale of 1-4). The public was warned to stay at least 5
km away from the summit, and 500 m from Kobokan drainages within 17 km of
the summit, along with other drainages originating on Semeru, including the
Bang, Kembar, and Sat, due to lahar, avalanche, and pyroclastic flow
hazards.



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



Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known
as CVGHM) https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!Z4OR29m2zAzDFmACL2NxQD-IOCbJX36KWrVWML2c8JlbpAjak_7Apqnz82ccWRtI2rO3sly0QZnRsH5Z$  
<https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!cNbFKOCH0K2KaseaMRz6MaahJmWzztc9KHkAvcihuO2NanIGPNSGjirHHMIJ_NSBWxeGYgbYtAE$>





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



On 29 September AVO lowered the Aviation Color Code for Semisopochnoi to
Yellow (the second lowest level on a four-color scale) and the Volcano
Alert Level to Advisory (the second lowest level on a four-level scale)
noting that no ash emissions or explosive activity had been detected since
14 September. Seismicity had decreased, though remained at elevated levels.
Steam emissions from the active vent in the N crater of Mount Cerberus
persisted. Seismic tremor and a small explosion were detected in seismic
and infrasound data during 3-4 October.



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!Z4OR29m2zAzDFmACL2NxQD-IOCbJX36KWrVWML2c8JlbpAjak_7Apqnz82ccWRtI2rO3sly0QaenSga5$  
<https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!cNbFKOCH0K2KaseaMRz6MaahJmWzztc9KHkAvcihuO2NanIGPNSGjirHHMIJ_NSBWxeGDxqKEjU$>





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



KVERT reported that the ongoing eruption at Sheveluch was characterized by
explosions, hot avalanches, and lava-dome extrusion during 15-22 September.
A daily thermal anomaly was identified in satellite images. Plumes of
re-suspended ash drifted 113 km E on 23 September. The Aviation Color Code
remained at Orange (the second highest level on a four-color scale). Dates
are based on UTC times; specific events are in local time where noted.



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



Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!Z4OR29m2zAzDFmACL2NxQD-IOCbJX36KWrVWML2c8JlbpAjak_7Apqnz82ccWRtI2rO3sly0QWb0GQVm$  
<https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!cNbFKOCH0K2KaseaMRz6MaahJmWzztc9KHkAvcihuO2NanIGPNSGjirHHMIJ_NSBWxeGtPztGus$>





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



INGV reported that during 26 September-2 October activity at Stromboli was
characterized by ongoing explosions from three vents in Area N (North
Crater area) and at least two vents in Area C-S (South-Central Crater
area). Low-intensity explosions from the N1 vent (Area N) ejected course
material (bombs and lapilli) 80-150 m high at a rate of 3-5 explosions per
hour. Spattering was visible at the N2 vent (Area N). Explosions from at
least two vents in Area C-S, which were not visible due to the camera
views, ejected ash and course material less than 150 m above the vent at a
rate of 1-5 events per hour.



At 1524 on 29 September an explosion at N2 generated an ash plume that rose
300 m above the summit and ejected abundant amounts of lava fragments,
lapilli, and bombs along the Sciara del Fuoco. Four subsequent,
low-intensity explosions ejected tephra 100 m high. Spattering activity at
the vent intensified afterwards and through the next day. Beginning at 1115
on 3 October a lava flow emerged from Area N and traveled down the Sciara
del Fuoco, reaching the ocean.



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



Source: Sezione di Catania - Osservatorio Etneo (INGV)
https://urldefense.com/v3/__http://www.ct.ingv.it/__;!!IKRxdwAv5BmarQ!Z4OR29m2zAzDFmACL2NxQD-IOCbJX36KWrVWML2c8JlbpAjak_7Apqnz82ccWRtI2rO3sly0QYwE8FvZ$  
<https://urldefense.com/v3/__http://www.ct.ingv.it/__;!!IKRxdwAv5BmarQ!cNbFKOCH0K2KaseaMRz6MaahJmWzztc9KHkAvcihuO2NanIGPNSGjirHHMIJ_NSBWxeGNu7YFiU$>





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 30 September-3 October. A total of 38 explosions produced eruption
plumes that rose as high as 1.6 km above the crater rim and occasionally
ejected large bombs from the vent. Crater incandescence was visible nightly
and ash sometimes fell in Toshima village (3.5 km SSW). The Alert Level
remained at 2 and the public was warned to stay 1 km away from the crater.



Geologic Summary. The 8-km-long 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!Z4OR29m2zAzDFmACL2NxQD-IOCbJX36KWrVWML2c8JlbpAjak_7Apqnz82ccWRtI2rO3sly0Qbq92lVW$  
<https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!cNbFKOCH0K2KaseaMRz6MaahJmWzztc9KHkAvcihuO2NanIGPNSGjirHHMIJ_NSBWxeG-rHly1w$>





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



In a special advisory, PHIVOLCS reported that sulfur dioxide emissions at
Taal were as high as 10,718 tonnes per day on 29 September, creating a
significant amount of vog over the caldera. Voggy conditions were reported
by residents of Laurel, Agoncillo, and Santa Teresita, Batangas. The report
noted that sulfur dioxide emissions had been increasing since 15 July and
averaged 6,612 tonnes per day in September. In early August degassing at
the volcano increased characterized by the upwelling of hot fluids in the
lake and steam-rich plumes rising as high as 2.5 km above the lakeâ??s
surface. The Alert Level remained at 1 (on a scale of 0-5), and PHIVOLCS
warned 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 of its most powerful historical
eruptions. Though not topographically prominent, its prehistorical
eruptions have greatly changed the landscape of SW Luzon. The 15 x 20 km
Talisay (Taal) caldera is largely filled by Lake Taal, whose 267 km2
surface lies only 3 m above sea level. The maximum depth of the lake is 160
m, and several eruptive centers lie submerged beneath the lake. The
5-km-wide Volcano Island in north-central Lake Taal is the location of all
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!Z4OR29m2zAzDFmACL2NxQD-IOCbJX36KWrVWML2c8JlbpAjak_7Apqnz82ccWRtI2rO3sly0QefOkplz$  
<https://urldefense.com/v3/__http://www.phivolcs.dost.gov.ph/__;!!IKRxdwAv5BmarQ!cNbFKOCH0K2KaseaMRz6MaahJmWzztc9KHkAvcihuO2NanIGPNSGjirHHMIJ_NSBWxeG0plJ8ng$>





Ta'u  | American Samoa (SW Pacific)  | 14.23°S, 169.454°W  | Summit elev.
931 m



HVO lowered the Volcano Alert Level for Taâ??u to Normal (the lowest level on
a four-level scale) and the Aviation Color Code to Green (the lowest level
on a four-color scale) on 3 October, noting that seismic activity had
dramatically decreased and maintained low levels over the past few weeks.
Analysis of data from one seismometer that had recorded earthquakes during
2005-2009 suggested that a rate of five detected earthquakes per day was
characteristic of long-term background seismicity; the current earthquakes
rates were at background levels.



Geologic Summary. The 10-km-wide Ta'u Island, located at the E end of the
Samoan islands, is ringed by sea cliffs. It is the emergent portion of the
large Lata shield volcano. A major flank collapse event around 22 ka
resulted in the steep scarps on the southern side of the island. Two
smaller shields were constructed along rift zones at the NW and NE tips of
the island. The NW corner of the island has a tuff-cone complex that
ejected large dunite xenoliths and coral blocks. Numerous Holocene
post-caldera cones occur at the summit and on the flanks.



Source: US Geological Survey Hawaiian Volcano Observatory (HVO)
https://urldefense.com/v3/__https://volcanoes.usgs.gov/observatories/hvo/__;!!IKRxdwAv5BmarQ!Z4OR29m2zAzDFmACL2NxQD-IOCbJX36KWrVWML2c8JlbpAjak_7Apqnz82ccWRtI2rO3sly0QVMPMaAP$  
<https://urldefense.com/v3/__https://volcanoes.usgs.gov/observatories/hvo/__;!!IKRxdwAv5BmarQ!cNbFKOCH0K2KaseaMRz6MaahJmWzztc9KHkAvcihuO2NanIGPNSGjirHHMIJ_NSBWxeG4FhK0Jo$>





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



On 3 October SERNAGEOMIN reported that recent passive emissions from
Villarrica contained tephra that was deposited on the upper SW flank.
Evidence suggested that there were recent fluctuations in the intensity of
activity at the lava lake in the main crater. The Alert Level remained at
Green, the lowest level on a four-color scale.



Geologic Summary. Glacier-clad Villarrica, one of Chile's most active
volcanoes, rises above the lake and town of the same name. It is the
westernmost of three large stratovolcanoes that trend perpendicular to the
Andean chain. A 6-km-wide caldera formed during the late Pleistocene. A
2-km-wide caldera that formed about 3500 years ago is located at the base
of the presently active, dominantly basaltic to basaltic-andesitic cone at
the NW margin of the Pleistocene caldera. More than 30 scoria cones and
fissure vents dot 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. Historical eruptions, documented since 1558, 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.



Source: Servicio Nacional de Geología y Minería (SERNAGEOMIN)
https://urldefense.com/v3/__http://www.sernageomin.cl/__;!!IKRxdwAv5BmarQ!Z4OR29m2zAzDFmACL2NxQD-IOCbJX36KWrVWML2c8JlbpAjak_7Apqnz82ccWRtI2rO3sly0Qe1tNwwz$  
<https://urldefense.com/v3/__http://www.sernageomin.cl/__;!!IKRxdwAv5BmarQ!cNbFKOCH0K2KaseaMRz6MaahJmWzztc9KHkAvcihuO2NanIGPNSGjirHHMIJ_NSBWxeGbw23ORI$>





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



GeoNet reported that the minor ash and sulfur dioxide emissions from the
active vent area in Whakaari/White Islandâ??s crater only occurred on 18
September based on subsequent webcam and satellite images. The most likely
cause for the emission was a gas release from small amount of magma moving
into the shallow part of the volcano, though there was no evidence of
increasing activity at the volcano. On 30 September the Aviation Color Code
was lowered to Yellow (the second lowest level on a four-color scale) and
the Volcanic Alert Level remained at 2 (on a scale of 0-5).



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!Z4OR29m2zAzDFmACL2NxQD-IOCbJX36KWrVWML2c8JlbpAjak_7Apqnz82ccWRtI2rO3sly0QbfH8H2M$  
<https://urldefense.com/v3/__http://www.geonet.org.nz/__;!!IKRxdwAv5BmarQ!cNbFKOCH0K2KaseaMRz6MaahJmWzztc9KHkAvcihuO2NanIGPNSGjirHHMIJ_NSBWxeGnKpg7XI$>



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



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End of Volcano Digest - 3 Oct 2022 to 5 Oct 2022 (#2022-103)
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