Smithsonian / USGS Weekly Volcanic Activity Report 18-24 January 2023

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


Smithsonian / USGS Weekly Volcanic Activity Report

18-24 January 2023



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

URL: https://urldefense.com/v3/__https://volcano.si.edu/reports_weekly.cfm__;!!IKRxdwAv5BmarQ!aSkL2Bd_aUOINLZ7i3LrxEyAMU34yn8PmasIcO9lseeVn0YUT5AbNLIrAB7dijeCQ2g58SVqIhm8RWgF$ 




New Activity/Unrest: Dieng Volcanic Complex, Central Java  | Kilauea,
Hawaiian Islands (USA)  | Marapi, Central Sumatra  | Semisopochnoi,
Aleutian Islands (USA)



Ongoing Activity: Ahyi, Mariana Islands (USA)  | Aira, Kyushu (Japan)  |
Cotopaxi, Ecuador  | Ebeko, Paramushir Island (Russia)  | Etna, Sicily
(Italy)  | Great Sitkin, Andreanof Islands (USA)  | Ibu, Halmahera  |
Krakatau, Sunda Strait  | Lascar, Northern Chile  | Lewotolok, Lembata
Island  | Merapi, Central Java  | Nevado del Ruiz, Colombia  | Pavlof,
Alaska Peninsula, Alaska  | Popocatepetl, Mexico  | Reventador, Ecuador  |
Sangay, Ecuador  | Semeru, Eastern Java  | Sheveluch, Central Kamchatka
(Russia)  | Suwanosejima, Ryukyu Islands (Japan)  | 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





Dieng Volcanic Complex  | Central Java  | 7.2°S, 109.879°E  | Summit elev.
2565 m



PVMBG reported that white gas plumes of varying densities rose as high as
80 m above the summit of the Dieng Volcanic Complex during 18-24 January.
Carbon dioxide emission averages decreased from an average of 3,300 parts
per million during 18-19 January to an average of 1,900 parts per million
during 22-23 January. The Alert Level remained at 2 (on a scale of 1-4) and
the public was warned to stay 1 km away from Sileri Crater and 500 m away
from the SE, S, and SW sectors of Timbang Crater.



Geologic Summary. The Dieng plateau in the highlands of central Java is
renowned both for the variety of its volcanic scenery and as a sacred area
housing Java's oldest Hindu temples, dating back to the 9th century CE. The
Dieng Volcanic Complex consists of multiple stratovolcanoes and more than
20 small Pleistocene-to-Holocene craters and cones over a 6 x 14 km area.
Prahu stratovolcano was truncated by a large Pleistocene caldera, which was
subsequently filled by a series of cones, lava domes, and craters, many
containing lakes. Lava flows cover much of the plateau, but observed
activity has been restricted to minor phreatic eruptions. Gas emissions are
a hazard at several craters and have caused fatalities. There are abundant
thermal features and high heat flow across the area.



Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known
as CVGHM) https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!aSkL2Bd_aUOINLZ7i3LrxEyAMU34yn8PmasIcO9lseeVn0YUT5AbNLIrAB7dijeCQ2g58SVqIqyPcDpO$ 





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



HVO reported that lava continued to erupt in the E portion of Kilaueaâ??s
Halemaâ??umaâ??u Crater floor during 17-24 January. Activity was concentrated
in a large, perched lava lake, covering about 10 hectares in the E half of
the crater by 17 January, and in a smaller lake to the W, in the basin of
the 2021-2022 lava lake. One dominant lava fountain, 6-7 m high, was active
in the E lake. Small daily overflows occurred along the margins of the E
lake. 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!aSkL2Bd_aUOINLZ7i3LrxEyAMU34yn8PmasIcO9lseeVn0YUT5AbNLIrAB7dijeCQ2g58SVqIv290Nlf$ 





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



PVMBG reported that the eruption at Marapi continued during 17-24 January.
White-and-gray emissions rose as high as 500 m and drifted in various
directions during 17-21 January; white steam plumes were visible on the
other days. The Alert Level remained at 2 (on a scale of 1-4) and the
public was warned to stay 3 km away from the crater.



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!aSkL2Bd_aUOINLZ7i3LrxEyAMU34yn8PmasIcO9lseeVn0YUT5AbNLIrAB7dijeCQ2g58SVqIqyPcDpO$ 





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



AVO reported that eruptive activity at Semisopochnoiâ??s Mount Young was
ongoing during 17-24 January. Seismicity was elevated with daily small
local earthquakes and occasional weak tremor. Minor steam emissions were
visible in webcam images during 17-19 January; no activity was identified
in cloudy satellite views during the rest of the week. The Aviation Color
Code remained at Orange (the second highest level on a four-color scale)
and the Volcano Alert Level remained at Watch (the second highest level on
a four-level scale).



Geologic Summary. Semisopochnoi, the largest subaerial volcano of the
western Aleutians, is 20 km wide at sea level and contains an 8-km-wide
caldera. It formed as a result of collapse of a low-angle, dominantly
basaltic volcano following the eruption of a large volume of dacitic
pumice. The high point of the island is Anvil Peak, a double-peaked
late-Pleistocene cone that forms much of the island's northern part. The
three-peaked Mount Cerberus (renamed Mount Young in 2023) was constructed
within the caldera during the Holocene. Each of the peaks contains a summit
crater; lava flows on the N flank appear younger than those on the south
side. Other post-caldera volcanoes include the symmetrical Sugarloaf Peak
SSE of the caldera and Lakeshore Cone, a small cinder cone at the edge of
Fenner Lake in the NE part of the caldera. Most documented eruptions have
originated from Young, although Coats (1950) considered that both Sugarloaf
and Lakeshore Cone could have been recently active.



Source: US Geological Survey Alaska Volcano Observatory (AVO)
https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!aSkL2Bd_aUOINLZ7i3LrxEyAMU34yn8PmasIcO9lseeVn0YUT5AbNLIrAB7dijeCQ2g58SVqIpfD46UB$ 





Ongoing Activity





Ahyi  | Mariana Islands (USA)  | 20.42°N, 145.03°E  | Summit elev. -75 m



Unrest at Ahyi Seamount was occasionally detected during 17-24 January.
Pressure sensors on Wake Island, 2,270 km E of Ahyi Seamount, detected one
small signal during 22-23 January. No activity was observed in mostly
cloudy satellite images. The Aviation Color Code remained at Yellow (the
second lowest level on a four-color scale) and the Volcano Alert Level
remained at Advisory (the second lowest level on a four-level scale).



Geologic Summary. Ahyi seamount is a large conical submarine volcano that
rises to within 75 m of the sea surface about 18 km SE of the island of
Farallon de Pajaros (Uracas) in the northern Marianas. Water discoloration
has been observed there, and in 1979 the crew of a fishing boat felt shocks
over the summit area of the seamount, followed by upwelling of
sulfur-bearing water. On 24-25 April 2001 an explosive eruption was
detected seismically by a station on Rangiroa Atoll, Tuamotu Archipelago.
The event was well constrained (+/- 15 km) at a location near the southern
base of Ahyi. An eruption in April-May 2014 was detected by NOAA divers,
hydroacoustic sensors, and seismic stations.



Source: US Geological Survey https://urldefense.com/v3/__https://www.usgs.gov/__;!!IKRxdwAv5BmarQ!aSkL2Bd_aUOINLZ7i3LrxEyAMU34yn8PmasIcO9lseeVn0YUT5AbNLIrAB7dijeCQ2g58SVqIiOr6-y4$ 





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



JMA reported ongoing eruptive activity at Minamidake Crater (at Aira
Calderaâ??s Sakurajima volcano) during 14-23 January. Crater incandescence
was visible nightly. An explosion at 1215 on 18 January produced an ash
plume that rose 1.4 km above the crater rim and ejected blocks as far as
1.1 km. Sulfur dioxide emissions were high at 1,400 tons per day. An
explosion at 0659 on 19 January generated an ash plume that rose 1.3 km and
ejected blocks 600-900 m and an explosion at 0307 on 21 January generated
an ash plume that rose 1.6 km and ejected blocks as far as 1.1 km.
Occasional very small eruptive events were recorded during 21-22 January.
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!aSkL2Bd_aUOINLZ7i3LrxEyAMU34yn8PmasIcO9lseeVn0YUT5AbNLIrAB7dijeCQ2g58SVqIvEp6gNo$ 





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



IG reported that the eruption at Cotopaxi continued during 18-24 January,
characterized by daily emissions of steam, gas, and ash. The plumes were
visible in webcam images and reported by the Washington VAAC, though
sometimes weather conditions prevented observations. They rose as high as 2
km and drifted in various directions and caused ashfall in Chillos (33 km
SW), Langualó, San Isidro Alto (20 km SW), and San Agustín del Callo (18 km
WSW) during 17-18 January and in San Isidro Alto, Chillos and Langualó
Chico during 18-19 January. Servicio Nacional de Gestión de Riesgos y
Emergencias (SNGRE) maintained the Alert Level at Yellow (the second lowest
level on a four-color scale).



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



Source: Instituto Geofísico-Escuela Politécnica Nacional (IG)
https://urldefense.com/v3/__http://www.igepn.edu.ec/__;!!IKRxdwAv5BmarQ!aSkL2Bd_aUOINLZ7i3LrxEyAMU34yn8PmasIcO9lseeVn0YUT5AbNLIrAB7dijeCQ2g58SVqIntUnI6Z$ 





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



KVERT reported that moderate activity at Ebeko was ongoing during 12-19
January. According to volcanologists in Severo-Kurilsk (Paramushir Island,
about 7 km E) explosions on 13 January generated ash plumes that rose as
high as 3 km (10,000 ft) a.s.l. and drifted SE. A thermal anomaly was
identified in satellite images on 13 and 16 January. 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!aSkL2Bd_aUOINLZ7i3LrxEyAMU34yn8PmasIcO9lseeVn0YUT5AbNLIrAB7dijeCQ2g58SVqIl9WFvsT$ 





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



INGV reported that the vents at the NE base of Etnaâ??s SE Crater, in the
Valle del Leone at about 2,800 m elevation, continued to feed lava flows
during 16-22 January, though the rate notably fluctuated. Lava effusion
progressively decreased during 16-17 January and had possibly ceased by the
late afternoon of 17 January. Effusion restarted in the early hours of 18
January, generating two lava flows. One of the flows traveled NE along the
W edge of the lava field, and the other traveled E onto the steep W wall of
Valle del Bove, reaching the base of the wall on 20 January. The effusion
rate decreased on 21 January and the again increased during the evening.
Late on 22 January a new lava flow descended the Valle del Bove, almost
reaching the base of the W wall at around 2,200 m elevation.



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



Source: Sezione di Catania - Osservatorio Etneo (INGV)
https://urldefense.com/v3/__http://www.ct.ingv.it/__;!!IKRxdwAv5BmarQ!aSkL2Bd_aUOINLZ7i3LrxEyAMU34yn8PmasIcO9lseeVn0YUT5AbNLIrAB7dijeCQ2g58SVqIlo4w7G5$ 





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



AVO reported that slightly elevated surface temperatures at Great Sitkin
were identified in satellite images on 18 January, suggesting continuing
lava effusion at a low rate primarily to the S and E. A few small
earthquakes were detected on most days by the local seismic network. No
activity was observed in mostly cloudy satellite and web camera images
during 19-24 January. 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!aSkL2Bd_aUOINLZ7i3LrxEyAMU34yn8PmasIcO9lseeVn0YUT5AbNLIrAB7dijeCQ2g58SVqIpfD46UB$ 





Ibu  | Halmahera  | 1.488°N, 127.63°E  | Summit elev. 1325 m



PVMBG reported that the eruption at Ibu continued during 17-24 January.
Daily white-and-gray plumes of variable densities rose 200-1,000 m above
the summit and drifted in multiple directions. The Alert Level remained at
a 2 (on a scale of 1-4), and the public was warned to stay at least 2 km
away from the active crater and 3.5 km away on the N side.



Geologic Summary. The truncated summit of Gunung Ibu stratovolcano along
the NW coast of Halmahera Island has large nested summit craters. The inner
crater, 1 km wide and 400 m deep, has contained several small crater lakes.
The 1.2-km-wide outer crater is breached on the N, creating a steep-walled
valley. A large cone grew ENE of the summit, and a smaller one to the WSW
has fed a lava flow down the W flank. A group of maars is located below the
N and W flanks. The first observed and recorded eruption was a small
explosion from the summit crater in 1911. Eruptive activity began again in
December 1998, producing a lava dome that eventually covered much of the
floor of the inner summit crater along with ongoing explosive ash emissions.



Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known
as CVGHM) https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!aSkL2Bd_aUOINLZ7i3LrxEyAMU34yn8PmasIcO9lseeVn0YUT5AbNLIrAB7dijeCQ2g58SVqIqyPcDpO$ 





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



PVMBG reported that the eruption at Anak Krakatau intensified at the end of
the week during 17-23 January. White steam-and-gas plumes rose as high as
200 m above the summit and drifted NE, E, and S. Strombolian activity was
visible in webcam images at 0041, 0043, and 0450 on 23 January. At 0607 and
0701 dense gray ash plumes rose 300 m above summit and drifted E. At 0758,
0759, 0808, and 0928 dense gray-to-black ash plumes rose 200-500 m and
drifted SE. Webcam photos showed progressively intensifying Strombolian
activity at 1919, 1958, and 2113 on 24 January. A dense gray ash plume rose
300 m and drifted E at 1957. The Alert Level remained at 3 (on a scale of
1-4), and the public was warned to stay at least 5 km away from the crater.



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



Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known
as CVGHM) https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!aSkL2Bd_aUOINLZ7i3LrxEyAMU34yn8PmasIcO9lseeVn0YUT5AbNLIrAB7dijeCQ2g58SVqIqyPcDpO$ 





Lascar  | Northern Chile  | 23.37°S, 67.73°W  | Summit elev. 5592 m



SERNAGEOMIN reported that after the 19 December 2022 eruption at Láscar,
activity levels had returned to baseline. During 1-15 January sulfur
dioxide emissions detected by a Differential Absorption Optical
Spectroscopy (DOAS) instrument located 6 km ESE of the crater measured an
average value of around 483 tonnes per day, with a maximum value of 881
tonnes per day on 13 January. These values were at normal levels.
Occasional low-level thermal anomalies were identified in satellite images
and corresponded to passive degassing from the vents in the summit crater.
The maximum height of white gas plumes was 1.4 km above the crater rim,
recorded on 11 January. On 19 January the Alert Level was lowered to Green
(the lowest level on a four-color scale) and the public were warned to stay
at least 700 m away from the crater. ONEMI reported that a â??Preventive
Early Warningâ?? was declared for San Pedro de Atacama (70 km NW).



Geologic Summary. Láscar is the most active volcano of the northern Chilean
Andes. The andesitic-to-dacitic stratovolcano contains six overlapping
summit craters. Prominent lava flows descend its NW flanks. An older,
higher stratovolcano 5 km E, Volcán Aguas Calientes, displays a
well-developed summit crater and a probable Holocene lava flow near its
summit (de Silva and Francis, 1991). Láscar consists of two major edifices;
activity began at the eastern volcano and then shifted to the western cone.
The largest eruption took place about 26,500 years ago, and following the
eruption of the Tumbres scoria flow about 9000 years ago, activity shifted
back to the eastern edifice, where three overlapping craters were formed.
Frequent small-to-moderate explosive eruptions have been recorded since the
mid-19th century, along with periodic larger eruptions that produced
ashfall hundreds of kilometers away. The largest historical eruption took
place in 1993, producing pyroclastic flows to 8.5 km NW of the summit and
ashfall in Buenos Aires.



Sources: Servicio Nacional de Geología y Minería (SERNAGEOMIN)
https://urldefense.com/v3/__http://www.sernageomin.cl/__;!!IKRxdwAv5BmarQ!aSkL2Bd_aUOINLZ7i3LrxEyAMU34yn8PmasIcO9lseeVn0YUT5AbNLIrAB7dijeCQ2g58SVqIrBQsyw5$ ;

Oficina Nacional de Emergencia-Ministerio del Interior (ONEMI)
https://urldefense.com/v3/__http://www.onemi.cl/__;!!IKRxdwAv5BmarQ!aSkL2Bd_aUOINLZ7i3LrxEyAMU34yn8PmasIcO9lseeVn0YUT5AbNLIrAB7dijeCQ2g58SVqIhRxQLBH$ 





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



PVMBG reported that the eruption at Lewotolok was ongoing during 17-24
January. Nighttime webcam images captured almost daily showed incandescent
material being ejected above the summit crater. White steam-and-gas plumes
were visible on most days rising as high has 250 m above the summit.
Emissions during 18-20 January were white-and-gray and rose as high as 400
m and drifted NE and E. The Alert Level remained at 2 (on a scale of 1-4)
and the public was warned to stay 2 km away from the summit crater.



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



Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known
as CVGHM) https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!aSkL2Bd_aUOINLZ7i3LrxEyAMU34yn8PmasIcO9lseeVn0YUT5AbNLIrAB7dijeCQ2g58SVqIqyPcDpO$ 





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



BPPTKG reported that the eruption at Merapi continued during 12-19 January
and seismicity remained at high levels. The SW lava dome produced three
lava avalanches that traveled as far as 1.2 km down the SW flank (upstream
in the Kali Bebeng drainage). Avalanche sounds were heard on six occasions.
No significant morphological changes to the central and SW lava domes were
evident in webcam images. The Alert Level remained at 3 (on a scale of
1-4), and the public was warned to stay 3-7 km away from the summit based
on location.



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



Source: Balai Penyelidikan dan Pengembangan Teknologi Kebencanaan Geologi
(BPPTKG) https://urldefense.com/v3/__http://www.merapi.bgl.esdm.go.id/__;!!IKRxdwAv5BmarQ!aSkL2Bd_aUOINLZ7i3LrxEyAMU34yn8PmasIcO9lseeVn0YUT5AbNLIrAB7dijeCQ2g58SVqInpqXYfw$ 





Nevado del Ruiz  | Colombia  | 4.892°N, 75.324°W  | Summit elev. 5279 m



Servicio Geológico Colombiano (SGC) reported that at 0710 on 23 January an
ash cloud rose from Nevado del Ruiz and drifted NW, causing ashfall in the
municipality of Manizales (27 km NW). The ash emission occurred
simultaneously with a seismic signal that indicated moving fluids within
the volcanoâ??s conduit. The Alert Level remained at 3 (Yellow; the second
lowest level on a four-color scale).



Geologic Summary. Nevado del Ruiz is a broad, glacier-covered volcano in
central Colombia that covers more than 200 km2. Three major edifices,
composed of andesitic and dacitic lavas and andesitic pyroclastics, have
been constructed since the beginning of the Pleistocene. The modern cone
consists of a broad cluster of lava domes built within the caldera of an
older edifice. The 1-km-wide, 240-m-deep Arenas crater occupies the summit.
The prominent La Olleta pyroclastic cone located on the SW flank may also
have been active in historical time. Steep headwalls of massive landslides
cut the flanks. Melting of its summit icecap during historical eruptions,
which date back to the 16th century, has resulted in devastating lahars,
including one in 1985 that was South America's deadliest eruption.



Source: Servicio Geológico Colombiano (SGC)
https://urldefense.com/v3/__https://www2.sgc.gov.co/volcanes/index.html__;!!IKRxdwAv5BmarQ!aSkL2Bd_aUOINLZ7i3LrxEyAMU34yn8PmasIcO9lseeVn0YUT5AbNLIrAB7dijeCQ2g58SVqIn4KNBHU$ 





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



AVO reported that the eruption at Pavlof has ended. No explosions had been
detected since 11 December and seismicity had decreased to background
levels. Weakly elevated surface temperatures and minor steaming from the
recently active vent continue to be observed intermittently in satellite
and webcam images, consistent with the cooling of previously erupted lava.
On 19 January AVO lowered the Volcano Alert Level 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).



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!aSkL2Bd_aUOINLZ7i3LrxEyAMU34yn8PmasIcO9lseeVn0YUT5AbNLIrAB7dijeCQ2g58SVqIpfD46UB$ 





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



CENAPRED reported that there were 94-206 steam-and-gas emissions, sometimes
containing ash, rising from Popocatépetl each day during 17-24 January. The
plumes drifted N, NE, and N. Minor ashfall was reported in the
municipalities of Domingo Arenas, San Nicolas de los Ranchos, Santiago
Xalizintla, in the town of San Mateo Ozolco in Calpan, state of Puebla and
in the municipalities of Tlaxcala and Papalotla, state of Tlaxcala on 17
January. On 21 January an ash plume rose as high as 3 km and drifted NNE
and one minor explosion was detected. Four explosions were recorded during
21-22 January and six were recorded during 23-24 January. The Alert Level
remained at Yellow, Phase Two (the middle level on a three-color scale).



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



Source: Centro Nacional de Prevencion de Desastres (CENAPRED)
https://urldefense.com/v3/__https://www.gob.mx/cenapred__;!!IKRxdwAv5BmarQ!aSkL2Bd_aUOINLZ7i3LrxEyAMU34yn8PmasIcO9lseeVn0YUT5AbNLIrAB7dijeCQ2g58SVqIjOp6D4g$ 





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



IG described the ongoing eruption at Reventador as moderate during 17-24
January. Daily seismicity was characterized by explosions, long-period
earthquakes, periods of harmonic tremor, and signals that indicated
emissions. The daily count of explosions ranged from 22-96; seismic data
transmission was interrupted during 22-23 January. Although weather clouds
often prevented observations of the summit, daily gas, steam, and ash
plumes were observed in IG webcam images and described in Washington VAAC
volcanic activity notifications almost daily. The plumes rose as high as
2.2 km above the volcano and drifted in multiple directions. Crater
incandescence was visible nightly and incandescent blocks were ejected onto
the flanks sometimes in all directions; incandescent blocks were also
visible rolling as far as 800 m down the flanks. Servicio Nacional de
Gestión de Riesgos y Emergencias (SNGRE) maintained the Alert Level at
Orange (the second highest level on a four-color scale).



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



Sources: Instituto Geofísico-Escuela Politécnica Nacional (IG)
https://urldefense.com/v3/__http://www.igepn.edu.ec/__;!!IKRxdwAv5BmarQ!aSkL2Bd_aUOINLZ7i3LrxEyAMU34yn8PmasIcO9lseeVn0YUT5AbNLIrAB7dijeCQ2g58SVqIntUnI6Z$ ;

Servicio Nacional de Gestión de Riesgos y Emergencias (SNGRE)
https://urldefense.com/v3/__https://www.gestionderiesgos.gob.ec/__;!!IKRxdwAv5BmarQ!aSkL2Bd_aUOINLZ7i3LrxEyAMU34yn8PmasIcO9lseeVn0YUT5AbNLIrAB7dijeCQ2g58SVqIhM1SDNG$ 





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



IG reported a high level of activity at Sangay during 17-24 January, which
included daily explosions, long-period earthquakes, and gas, steam, and ash
emissions. The daily count of explosions ranged from 53-122, though seismic
data transmission was sometimes interrupted. Almost daily gas, steam, and
ash plumes were either observed in IG webcam images or described in
Washington VAAC volcanic activity notifications; weather clouds often
prevented observations of the summit. The plumes rose as high as 1.5 km
above the volcano and drifted in multiple directions. Multiple thermal
anomalies were identified in satellite images on most days. Crater
incandescence from the crater and from material on the SE flank was visible
at night during 21-22 January. Servicio Nacional de Gestión de Riesgos y
Emergencias (SNGRE) maintained the Alert Level at Yellow (the second lowest
level on a four-color scale).



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



Sources: Instituto Geofísico-Escuela Politécnica Nacional (IG)
https://urldefense.com/v3/__http://www.igepn.edu.ec/__;!!IKRxdwAv5BmarQ!aSkL2Bd_aUOINLZ7i3LrxEyAMU34yn8PmasIcO9lseeVn0YUT5AbNLIrAB7dijeCQ2g58SVqIntUnI6Z$ ;

Servicio Nacional de Gestión de Riesgos y Emergencias (SNGRE)
https://urldefense.com/v3/__https://www.gestionderiesgos.gob.ec/__;!!IKRxdwAv5BmarQ!aSkL2Bd_aUOINLZ7i3LrxEyAMU34yn8PmasIcO9lseeVn0YUT5AbNLIrAB7dijeCQ2g58SVqIhM1SDNG$ 





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



PVMBG reported that the eruption at Semeru continued during 17-24 January.
Daily dense white-and-gray ash plumes generally rose 500-800 m above the
summit and drifted N, NE, SE, and S. Ash plumes rose as high as 1 km and
drifted SE at 0628 on 19 January. 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!aSkL2Bd_aUOINLZ7i3LrxEyAMU34yn8PmasIcO9lseeVn0YUT5AbNLIrAB7dijeCQ2g58SVqIqyPcDpO$ 





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



KVERT reported that the ongoing eruption at Sheveluch during 12-19 January
was generally characterized by explosions, hot avalanches, lava-dome
extrusion, and strong fumarolic activity. A daily thermal anomaly was
identified in satellite images. Explosions on 19 January produced ash
plumes that were identified in satellite images rising as high as 10 km
(32,800 ft) a.s.l. and drifting W at 1240 local time. KVERT raised the
Aviation Color Code to Red (the highest level on a four-color scale). In a
Volcano Observatory Notice for Aviation (VONA) posted at 1635 local time
KVERT noted that no additional plumes were identified in satellite images.
The Aviation Color Code was lowered to Orange. 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!aSkL2Bd_aUOINLZ7i3LrxEyAMU34yn8PmasIcO9lseeVn0YUT5AbNLIrAB7dijeCQ2g58SVqIl9WFvsT$ 





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 16-23 January. No explosions were recorded, though eruption plumes
rose as high as 1.2 km above the crater rim and blocks were ejected as far
as 300 m from the vent. Ashfall was occasionally reported in Toshima
village (3.5 km SSW). JMA noted that the number of explosions began
decreasing in mid-October 2022 and the last explosion was recorded on 16
November. Additionally, plume heights had occasionally risen higher than 2
km above the crater rim during October-November 2022, but starting in
December the heights had generally been at or below 1 km. Other data had
also indicated low levels of activity; the probability of material being
ejected more than 1 km away from the crater had decreased. The Alert Level
was lowered to 2 (on a 5-level scale) on 24 January, and residents were
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!aSkL2Bd_aUOINLZ7i3LrxEyAMU34yn8PmasIcO9lseeVn0YUT5AbNLIrAB7dijeCQ2g58SVqIvEp6gNo$ 





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



SERNAGEOMIN reported that the eruption at Villarrica was ongoing during
17-24 January. Daily minor Strombolian explosions from a vent on the crater
floor ejected incandescent material that generally rose as high as 100 m
above the crater rim and fell back down in and around the crater. On 19
January POVI noted that lava was ejected as high as 140 m above the crater
rim and onto the W and SW flanks. Explosion noises were heard on 19 and 22
January in areas within a radius of 10 km. The Alert Level remained at
Yellow (the second lowest level on a four-color scale). ONEMI maintained
the Alert Level at Yellow (the middle level on a three-color scale) for the
municipalities of Villarrica, Pucón (16 km N), Curarrehue, and the commune
of Panguipulli.



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.



Sources: Servicio Nacional de Geología y Minería (SERNAGEOMIN)
https://urldefense.com/v3/__http://www.sernageomin.cl/__;!!IKRxdwAv5BmarQ!aSkL2Bd_aUOINLZ7i3LrxEyAMU34yn8PmasIcO9lseeVn0YUT5AbNLIrAB7dijeCQ2g58SVqIrBQsyw5$ ;

Oficina Nacional de Emergencia-Ministerio del Interior (ONEMI)
https://urldefense.com/v3/__http://www.onemi.cl/__;!!IKRxdwAv5BmarQ!aSkL2Bd_aUOINLZ7i3LrxEyAMU34yn8PmasIcO9lseeVn0YUT5AbNLIrAB7dijeCQ2g58SVqIhRxQLBH$ ;

Proyecto Observación Villarrica Internet (POVI) https://urldefense.com/v3/__http://www.povi.cl/__;!!IKRxdwAv5BmarQ!aSkL2Bd_aUOINLZ7i3LrxEyAMU34yn8PmasIcO9lseeVn0YUT5AbNLIrAB7dijeCQ2g58SVqIk4J244m$ 





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



On 24 January GeoNet reported continuing unrest at Whakaari/White Island
characterized by minor-to-moderate gas-and-steam emissions and low levels
of gas. The activity was confirmed during an overflight on 16 January.
Sulfur dioxide gas emissions were low, averaging around 33 tonnes per day,
and carbon dioxide emissions were moderate, averaging around 705 tonnes per
day; the gas levels had declined compared to the 6 December 2022
measurements. No notable changes to the lake were visible aside from minor
fluctuations of the lake level. No signs of ash emissions or other eruptive
activity were observed. The Aviation Color Code remained at 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!aSkL2Bd_aUOINLZ7i3LrxEyAMU34yn8PmasIcO9lseeVn0YUT5AbNLIrAB7dijeCQ2g58SVqIl0ajice$ 



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

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End of Volcano Digest - 25 Jan 2023 to 26 Jan 2023 (#2023-13)
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