2-2-2-2-2-2-2-2-2-2-2-2-2 From: "Kuhn, Sally" <KUHNS@xxxxxx> Smithsonian / USGS Weekly Volcanic Activity Report 19-25 February 2025 Sally Sennert - Weekly Report Editor (kuhns@xxxxxx) URL: https://volcano.si.edu/reports_weekly.cfm <https://urldefense.com/v3/__https://volcano.si.edu/reports_weekly.cfm__;!!IKRxdwAv5BmarQ!b59a6hvmu4DfAA8PId9kUYmBoaTg6jYslSeeDcd0QPrr1Fdw2HgH_luC2xjIz5S8BBahkgau2dmlPSD3WgIzF3vX0Q$> New Activity/Unrest: Atka Volcanic Complex, United States | Bezymianny, Russia | Etna, Italy | Lascar, Chile | Lewotobi, Indonesia | Lewotolok, Indonesia | Poas, Costa Rica | Telica, Nicaragua Ongoing Activity: Ahyi, United States | Aira, Japan | Dukono, Indonesia | Great Sitkin, United States | Home Reef, Tonga | Ibu, Indonesia | Kanlaon, Philippines | Kilauea, United States | Marapi, Indonesia | Merapi, Indonesia | Nyamulagira, DR Congo | Reventador, Ecuador | Sangay, Ecuador | Santa Maria, Guatemala | Semeru, Indonesia | Sheveluch, Russia | Stromboli, Italy | Suwanosejima, Japan | Ubinas, Peru | Whakaari/White 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 Atka Volcanic Complex | United States | 52.331°N, 174.139°W | Summit elev. 1518 m A small explosion from the summit lake region of Korovin, one of the volcanoes at the Atka volcanic complex, was detected at 1926 on 20 February, prompting the Alaska Volcano Observatory (AVO) to raise the Volcano Alert Level to Watch (the second highest level on a four-level scale) and the Aviation Color Code to Orange (the second highest color on a four-color scale). The event was brief (less than 10 seconds), probably phreatic, and likely ejected a small amount of ash that was deposited within the immediate vicinity of the lake, though ash was unconfirmed. A meteorological cloud deck at altitudes of 2.4-3 (8,000-10,000 ft) a.s.l. obscured direct satellite observations, but no ash emissions were observed above the clouds. Satellite data acquired later that evening showed no evidence of hot material at the surface. There were no further explosive events detected and no noticeable change in seismic activity; at 1114 on 21 February AVO lowered the Volcano Alert Level to Advisory and the Aviation Color Code to Yellow. This type of singular explosion was common at Korovin. Several small local seismic events were detected during 21-23 February, though the overall level of seismicity was very low. Satellite and webcam observations were obscured by weather clouds. Geologic Summary. The Atka Volcanic Complex consists of a central shield and Pleistocene caldera and four notable volcanic cones. A major explosive dacitic eruption accompanied formation of the caldera about 500,000 to 300,000 years ago; approximately half of the caldera rime remains, open towards the NW. The Sarichef cone, ~5 km ESE of the caldera rim, retains a symmetrical profile, unlike most other heavily eroded features outside the caldera to the S and W. The Kliuchef stratovolcano grew within the caldera and exhibits five eruptive vents striking NE, including two at the summit, that have been active in the Holocene. A 700-m-diameter crater 1 km NE of the summit may have been the source vent for a large 1812 CE eruption. Hot springs and fumaroles are located on the flanks of Kliuchef and in a glacial valley to the SW. The most frequently active volcano of the complex is Korovin, at the NE tip of Atka Island about 5 km N of Kliuchef. An 800-m-diameter crater on the SE side of the summit contains a deep circular pit that sometimes contains a crater lake thought to be the source of phreatic ash explosions. The smaller Konia cone, slightly offset to the E, lies between Kliuchef and Korovin. Most of the lava flows in the complex are basaltic, though some dacitic flows are also present. Source: US Geological Survey Alaska Volcano Observatory (AVO) https://avo.alaska.edu/ <https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!b59a6hvmu4DfAA8PId9kUYmBoaTg6jYslSeeDcd0QPrr1Fdw2HgH_luC2xjIz5S8BBahkgau2dmlPSD3WgI8k-aStQ$> Bezymianny | Russia | 55.972°N, 160.595°E | Summit elev. 2882 m The Kamchatkan Volcanic Eruption Response Team (KVERT) reported that a bright thermal anomaly over Bezymianny was identified in satellite images during 13-20 February. According to the Institute of Volcanology and Seismology (IVS) of the Far Eastern Branch of the Russian Academy of Sciences (FEB RAS) occasional ash plumes rose as high as 1.2 km above the summit and drifted E and SE. On most days, debris avalanches were visible descending the SE and E flanks during dark hours; weather conditions sometimes obscured webcam and satellite views. The Aviation Color Code remained at Orange (the second highest level on a four-color scale). Dates are reported in UTC; specific events are in local time where noted. Geologic Summary. The modern Bezymianny, much smaller than its massive neighbors Kamen and Kliuchevskoi on the Kamchatka Peninsula, was formed about 4,700 years ago over a late-Pleistocene lava-dome complex and an edifice built about 11,000-7,000 years ago. Three periods of intensified activity have occurred during the past 3,000 years. The latest period, which was preceded by a 1,000-year quiescence, began with the dramatic 1955-56 eruption. This eruption, similar to that of St. Helens in 1980, produced a large open crater that was formed by collapse of the summit and an associated lateral blast. Subsequent episodic but ongoing lava-dome growth, accompanied by intermittent explosive activity and pyroclastic flows, has largely filled the 1956 crater. Sources: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php <https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!b59a6hvmu4DfAA8PId9kUYmBoaTg6jYslSeeDcd0QPrr1Fdw2HgH_luC2xjIz5S8BBahkgau2dmlPSD3WgJQ_eNxSQ$> ; Institute of Volcanology and Seismology (IVS) of the Far Eastern Branch of the Russian Academy of Sciences (FEB RAS) http://www.kscnet.ru/ivs/ <https://urldefense.com/v3/__http://www.kscnet.ru/ivs/__;!!IKRxdwAv5BmarQ!b59a6hvmu4DfAA8PId9kUYmBoaTg6jYslSeeDcd0QPrr1Fdw2HgH_luC2xjIz5S8BBahkgau2dmlPSD3WgLBTILRyA$> Etna | Italy | 37.748°N, 14.999°E | Summit elev. 3357 m The Sezione di Catania - Osservatorio Etneo (INGV) reported that an eruption at Etna continued during 17-23 February. Activity observed through webcams and during field inspections on 19, 22, and 24 February was characterized by the effusion of a lava flow from a fissure, explosive activity at the summit, and gas emissions at several of the craters. Strombolian activity at SE Crater was variable, though no explosions were visible during 20-21 February and for most of 22 February. The explosions produced minor ash plumes that dispersed near the summit. Sporadic and moderate explosions from three vents were visible during the evening of 22 February. The activity slightly intensified during 23 February and into 24 February; during the morning of 24 February a fourth explosive vent was identified and at about 1323 a lava flow overflowed the S rim of the crater. The lava flow from the fissure that opened at the base of Bocca Nuova Crater on 8 February continued to effuse lava. The lava flow advanced down the SW flank, descending to 1,840 m elevation during 19-20 February; lava-flow activity was confined to an area between about 3,000 and 2,500 m elevation during the rest of the week. The total flow length was 4.3 km. Based on a 24 February field inspection, scientists determined that lava effusion was occurring at the main vent and also emerging from lava tubes at lower elevations. Lava flows branched from the main flow, widening the flow field, especially near the vent. They also observed a small lava flow effusing from a new vent about 150 m higher up the flank at about 3,070 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) http://www.ct.ingv.it/ <https://urldefense.com/v3/__http://www.ct.ingv.it/__;!!IKRxdwAv5BmarQ!b59a6hvmu4DfAA8PId9kUYmBoaTg6jYslSeeDcd0QPrr1Fdw2HgH_luC2xjIz5S8BBahkgau2dmlPSD3WgL9ZLE-rg$> Lascar | Chile | 23.37°S, 67.73°W | Summit elev. 5592 m The Servicio Nacional de GeologÃa y MinerÃa (SERNAGEOMIN) reported increasing unrest at Láscar. Satellite images detected progressively increasing sulfur dioxide emissions since 6 February (188 tons per day) with an average of 1,191 tons per day (t/d) recorded on 20 February. Sulfur dioxide emissions measured with Differential Optical Absorption Spectroscopy (DOAS) instrumentation located at the Emú station, 6 km ESE, averaged 1,010 t/d on 22 February. Thermal anomalies occasionally detected in satellite data indicated increased temperatures on the crater floor during 6-23 February. Additionally, crater incandescence was visible in webcam images during 19 and 22-23 February. Seismicity during 19-24 February was characterized by a decrease in long-period earthquakes and an increase in signals indicating surficial activity such as landslides. The Alert Level remained at Yellow (the second lowest level on a four-color scale) and the public was warned to stay at least 1 km away from the crater. 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. Source: Servicio Nacional de GeologÃa y MinerÃa (SERNAGEOMIN) http://www.sernageomin.cl/ <https://urldefense.com/v3/__http://www.sernageomin.cl/__;!!IKRxdwAv5BmarQ!b59a6hvmu4DfAA8PId9kUYmBoaTg6jYslSeeDcd0QPrr1Fdw2HgH_luC2xjIz5S8BBahkgau2dmlPSD3WgLEBYSnLw$> Lewotobi | Indonesia | 8.542°S, 122.775°E | Summit elev. 1703 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that eruptive activity continued at Lewotobi Laki-laki. During 14-20 February the seismic network recorded decreasing seismicity, specifically there was a notable decrease in both deep and shallow volcanic earthquakes, though signals indicating emissions continued to fluctuate. Fumarolic plumes rose from cracks on the upper NW flank and eruptive events producing ash plumes were recorded on 17 February. The exclusion zone was reduced to a radius of 6 km in all directions from the center of Laki-laki. At 1200 on 20 February the Alert Level was lowered to 3 (on a scale of 1-4) and the exclusion zone was again reduced, to 5 km from the center of Laki-laki and 6 km in a semicircle counterclockwise from the NE to the SW. Several eruptive events per day during 21-22 and 24 February, and one event on 23 February, generated ash plumes that rose 0.4-2 km above the summit and drifted in different directions. Incandescence at the summit and reflected in the plume was visible in several of the webcam images posted with the reports. Geologic Summary. The Lewotobi edifice in eastern Flores Island is composed of the two adjacent Lewotobi Laki-laki and Lewotobi Perempuan stratovolcanoes (the "husband and wife"). Their summits are less than 2 km apart along a NW-SE line. The conical Laki-laki to the NW has been frequently active during the 19th and 20th centuries, while the taller and broader Perempuan has had observed eruptions in 1921 and 1935. Small lava domes have grown during the 20th century in both of the summit craters, which are open to the north. A prominent cone, Iliwokar, occurs on the E flank of Perampuan. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://vsi.esdm.go.id/ <https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!b59a6hvmu4DfAA8PId9kUYmBoaTg6jYslSeeDcd0QPrr1Fdw2HgH_luC2xjIz5S8BBahkgau2dmlPSD3WgL6Tm1vfA$> Lewotolok | Indonesia | 8.274°S, 123.508°E | Summit elev. 1431 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that an eruption at Lewotolok was ongoing during 19-25 February. Daily white-and-gray ash plumes rose as high as 300 m above the summit and drifted NW, E, and SE. Incandescence at the summit was visible in webcam images and in at least one of them (at 2201 on 19 February) incandescent material was being ejected above the summit. The Alert Level remained at 2 (on a scale of 1-4) and the public was warned to stay 2 km away from the vent and 2.5 km away on the S, SE, and W flanks. Geologic Summary. The Lewotolok (or Lewotolo) stratovolcano occupies the eastern end of an elongated peninsula extending north into the Flores Sea, connected to Lembata (formerly Lomblen) Island by a narrow isthmus. It is symmetrical when viewed from the north and east. A small cone with a 130-m-wide crater constructed at the SE side of a larger crater forms the volcano's high point. Many lava flows have reached the coastline. Eruptions recorded since 1660 have consisted of explosive activity from the summit crater. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://vsi.esdm.go.id/ <https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!b59a6hvmu4DfAA8PId9kUYmBoaTg6jYslSeeDcd0QPrr1Fdw2HgH_luC2xjIz5S8BBahkgau2dmlPSD3WgL6Tm1vfA$> Poas | Costa Rica | 10.2°N, 84.233°W | Summit elev. 2697 m The Observatorio Vulcanológico y Sismológico de Costa Rica-Universidad Nacional (OVSICORI-UNA) reported that eruptive activity at Poás continued at variable levels during 18-20 February. Several small phreatic eruptions from the central part of the crater lake ejected sediment and gas-and-steam plumes as high as 100 m above the surface of the water. Weather clouds obscured views on 21 February. Geologic Summary. The broad vegetated edifice of Poás, one of the most active volcanoes of Costa Rica, contains three craters along a N-S line. The frequently visited multi-hued summit crater lakes of the basaltic-to-dacitic volcano are easily accessible by vehicle from the nearby capital city of San José. A N-S-trending fissure cutting the complex stratovolcano extends to the lower N flank, where it has produced the Congo stratovolcano and several lake-filled maars. The southernmost of the two summit crater lakes, Botos, last erupted about 7,500 years ago. The more prominent geothermally heated northern lake, Laguna Caliente, is one of the world's most acidic natural lakes, with a pH of near zero. It has been the site of frequent phreatic and phreatomagmatic eruptions since an eruption was reported in 1828. Eruptions often include geyser-like ejections of crater-lake water. Source: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA) http://www.ovsicori.una.ac.cr/ <https://urldefense.com/v3/__http://www.ovsicori.una.ac.cr/__;!!IKRxdwAv5BmarQ!b59a6hvmu4DfAA8PId9kUYmBoaTg6jYslSeeDcd0QPrr1Fdw2HgH_luC2xjIz5S8BBahkgau2dmlPSD3WgKYWLufkw$> Telica | Nicaragua | 12.606°N, 86.84°W | Summit elev. 1036 m Based on webcam and satellite images, the Washington VAAC reported that on 19 and 22 February ash emissions at Telica rose as high as 1.5 km (5,000 ft) a.s.l. and drifted SW and W. Geologic Summary. Telica, one of Nicaragua's most active volcanoes, has erupted frequently since the beginning of the Spanish era. This volcano group consists of several interlocking cones and vents with a general NW alignment. Sixteenth-century eruptions were reported at symmetrical Santa Clara volcano at the SW end of the group. However, its eroded and breached crater has been covered by forests throughout historical time, and these eruptions may have originated from Telica, whose upper slopes in contrast are unvegetated. The steep-sided cone of Telica is truncated by a 700-m-wide double crater; the southern crater, the source of recent eruptions, is 120 m deep. El Liston, immediately E, has several nested craters. The fumaroles and boiling mudpots of Hervideros de San Jacinto, SE of Telica, form a prominent geothermal area frequented by tourists, and geothermal exploration has occurred nearby. Source: Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html <https://urldefense.com/v3/__http://www.ssd.noaa.gov/VAAC/messages.html__;!!IKRxdwAv5BmarQ!b59a6hvmu4DfAA8PId9kUYmBoaTg6jYslSeeDcd0QPrr1Fdw2HgH_luC2xjIz5S8BBahkgau2dmlPSD3WgJnmv7klg$> Ongoing Activity Ahyi | United States | 20.42°N, 145.03°E | Summit elev. -75 m Unrest at Ahyi Seamount continued during 13-21 February. A plume of discolored water in the vicinity of the seamount was identified in satellite images during 14-16 February, indicating possible submarine activity. No signals coming from the direction of Ahyi were identified in data from underwater pressure sensors near Wake Island (about 2,270 km E of Ahyi). 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 ocean surface ~18 km SE of the island of Farallon de Pajaros 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, 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://www.usgs.gov/ <https://urldefense.com/v3/__https://www.usgs.gov/__;!!IKRxdwAv5BmarQ!b59a6hvmu4DfAA8PId9kUYmBoaTg6jYslSeeDcd0QPrr1Fdw2HgH_luC2xjIz5S8BBahkgau2dmlPSD3WgIoyN0EUg$> Aira | Japan | 31.5772°N, 130.6589°E | Summit elev. 1117 m The Japan Meteorological Agency (JMA) reported ongoing eruptive activity at Minamidake Crater (Aira Calderaâ??s Sakurajima volcano) during 17-24 February. Nightly crater incandescence was visible in webcam images. Explosions at 0643 and 1944 on 21 February generated ash plumes that rose 1.4-1.6 km above the crater rim and drifted SE, and ejected large blocks 500-900 m from the vent. An ash plume from an eruptive event at 1510 on 21 February rose 1 km above the crater rim and drifted SE. An explosion at 0104 on 23 February generated an ash plume that rose 1.5 km above the crater rim and drifted SE. At 1924 on 24 February an explosion ejected blocks 500-700 m from the vent and generated an ash plume that rose 600 m above the crater rim and drifted S. The Alert Level remained at 3 (on a 5-level scale), and the public was warned to stay 1 km away from both craters. Geologic Summary. The Aira caldera in the northern half of Kagoshima Bay contains the post-caldera Sakurajima volcano, one of Japan's most active. Eruption of the voluminous Ito pyroclastic flow accompanied formation of the 17 x 23 km caldera about 22,000 years ago. The smaller Wakamiko caldera was formed during the early Holocene in the NE corner of the caldera, along with several post-caldera cones. The construction of Sakurajima began about 13,000 years ago on the southern rim and built an island that was joined to the Osumi Peninsula during the major explosive and effusive eruption of 1914. Activity at the Kitadake summit cone ended about 4,850 years ago, after which eruptions took place at Minamidake. Frequent eruptions since the 8th century have deposited ash on the city of Kagoshima, located across Kagoshima Bay only 8 km from the summit. The largest recorded eruption took place during 1471-76. Source: Japan Meteorological Agency (JMA) http://www.jma.go.jp/jma/ <https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!b59a6hvmu4DfAA8PId9kUYmBoaTg6jYslSeeDcd0QPrr1Fdw2HgH_luC2xjIz5S8BBahkgau2dmlPSD3WgI-Vhe8xg$> Dukono | Indonesia | 1.6992°N, 127.8783°E | Summit elev. 1273 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that the eruption at Dukono was ongoing during 19-25 February. White-and-gray ash plumes rose as high as 2 km above the crater rim and drifted in multiple directions during 19-22 and 24-25 February. White plumes rose 200-300 m above the crater rim and drifted SW, W, and NW on 23 February. Booming sounds were reported during 19 and 22-24 February. The Alert Level remained at Level 2 (on a scale of 1-4) and the public was warned to stay 4 km away from the Malupang Warirang Crater. Geologic Summary. Reports from this remote volcano in northernmost Halmahera are rare, but Dukono has been one of Indonesia's most active volcanoes. More-or-less continuous explosive eruptions, sometimes accompanied by lava flows, have occurred since 1933. During a major eruption in 1550 CE, a lava flow filled in the strait between Halmahera and the N-flank Gunung Mamuya cone. This complex volcano presents a broad, low profile with multiple summit peaks and overlapping craters. Malupang Wariang, 1 km SW of the summit crater complex, contains a 700 x 570 m crater that has also been active during historical time. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://vsi.esdm.go.id/ <https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!b59a6hvmu4DfAA8PId9kUYmBoaTg6jYslSeeDcd0QPrr1Fdw2HgH_luC2xjIz5S8BBahkgau2dmlPSD3WgL6Tm1vfA$> Great Sitkin | United States | 52.076°N, 176.13°W | Summit elev. 1740 m The Alaska Volcano Observatory (AVO) reported that slow lava effusion continued to feed a thick lava flow in Great Sitkinâ??s summit crater, confirmed by a 21 February radar image. The lava flow advanced along the NNE margin. Small daily earthquakes were detected by the seismic network. Typical minor steaming from the vent region was detected in a satellite image on 21 February and slightly elevated surface temperatures observed in satellite data during 23-25 February. Weather clouds sometimes obscured views of the volcano. The Volcano Alert Level remained at Watch (the third level on a four-level scale) and the Aviation Color Code remained at Orange (the third color on a four-color scale). Geologic Summary. The Great Sitkin volcano forms much of the northern side of Great Sitkin Island. A younger 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 older edifice and produced a submarine debris avalanche. Deposits from this and an even 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. Eruptions have been recorded since the late-19th century. Source: US Geological Survey Alaska Volcano Observatory (AVO) https://avo.alaska.edu/ <https://urldefense.com/v3/__https://avo.alaska.edu/__;!!IKRxdwAv5BmarQ!b59a6hvmu4DfAA8PId9kUYmBoaTg6jYslSeeDcd0QPrr1Fdw2HgH_luC2xjIz5S8BBahkgau2dmlPSD3WgI8k-aStQ$> Home Reef | Tonga | 18.992°S, 174.775°W | Summit elev. -10 m The Tonga Geological Services reported that increased thermal activity at Home Reef was identified in satellite images since 8 February with the latest signs of activity detected on 20 February. Satellite images from 8 February showed a larger crater that was about 78 m in diameter and about 50 m deep. The crater was had an estimated area of 4,350 square meters. Large blocks were scattered 65-75 m from the center of the crater, likely ejected during a recent eruptive event; the largest block was about 14 x 15 m. Small plumes rose from the vent that were ash-rich near the base and mostly comprised of gas and steam at higher levels. Satellite imagery on 20 February showed discolored water to the SW and a thermal anomaly over the vent. The Maritime Alert Level remained at Orange (the third level on a four-level scale), and mariners were advised to stay at least 2 nautical miles (3.7 km) away from the island. The Aviation Color Code remained at Yellow (the second level on a four-level scale), and the Alert Level for residents of Vavaâ??u and Haâ??apai remained at Green (the first level on a four-level scale). 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, large amounts of floating pumice, and an ephemeral 500 x 1,500 m island, with cliffs 30-50 m high that enclosed a water-filled crater. In 2006 an island-forming eruption produced widespread dacitic pumice rafts that drifted as far as Australia. Another island was built during a September-October 2022 eruption. Source: Tonga Geological Services, Government of Tonga https://www.facebook.com/tongageologicalservice <https://urldefense.com/v3/__https://www.facebook.com/tongageologicalservice__;!!IKRxdwAv5BmarQ!b59a6hvmu4DfAA8PId9kUYmBoaTg6jYslSeeDcd0QPrr1Fdw2HgH_luC2xjIz5S8BBahkgau2dmlPSD3WgK7ZTvd-w$> Ibu | Indonesia | 1.488°N, 127.63°E | Summit elev. 1325 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that the eruption at Ibu continued during 19-25 February. Multiple daily gray or white-and-gray ash plumes that were often dense rose as high as 1.5 km above the summit and drifted mainly in multiple directions. Incandescence at the summit was visible in some webcam images posted with the reports. The Alert Level remained at 3 (the second highest level on a four-level scale) and the public was advised to stay 4 km away from the active crater and 5 km away from the N crater wall opening. Geologic Summary. The truncated summit of Gunung Ibu stratovolcano along the NW coast of Halmahera Island has large nested summit craters. The inner crater, 1 km wide and 400 m deep, has contained several small crater lakes. The 1.2-km-wide outer crater is breached on the N, creating a steep-walled valley. A large cone grew ENE of the summit, and a smaller one to the WSW has fed a lava flow down the W flank. A group of maars is located below the N and W flanks. The first observed and recorded eruption was a small explosion from the summit crater in 1911. Eruptive activity began again in December 1998, producing a lava dome that eventually covered much of the floor of the inner summit crater along with ongoing explosive ash emissions. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://vsi.esdm.go.id/ <https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!b59a6hvmu4DfAA8PId9kUYmBoaTg6jYslSeeDcd0QPrr1Fdw2HgH_luC2xjIz5S8BBahkgau2dmlPSD3WgL6Tm1vfA$> Kanlaon | Philippines | 10.4096°N, 123.13°E | Summit elev. 2422 m The Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported continuing eruptive activity at Kanlaon during 18-24 February. The seismic network recorded 3-33 daily volcanic earthquakes. Average daily sulfur dioxide emissions ranged from 1,542 to 6,534 tonnes per day. Gas-and-steam emissions that were mainly diffuse rose as high as 150 m above the summit and drifted W and SW during 18-19 and 21-22 February; plumes occasionally contained ash on 19 and 22 February. On 22 February an ash emission that lasted about 12 minutes long generated plumes that rose 300 m and drifted SW. The Alert Level remained at 3 (on a scale of 0-5); the public was warned to stay 6 km away from the summit and pilots were warned not to fly close to the volcano. Geologic Summary. Kanlaon volcano (also spelled Canlaon) forms the highest point on the Philippine island of Negros. The massive andesitic stratovolcano is covered with fissure-controlled pyroclastic cones and craters, many of which are filled by lakes. The largest debris avalanche known in the Philippines traveled 33 km SW from Kanlaon. The summit contains a 2-km-wide, elongated northern caldera with a crater lake and a smaller but higher active vent, Lugud crater, to the south. Eruptions recorded since 1866 have typically consisted of phreatic explosions of small-to-moderate size that produce minor local ashfall. Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS) http://www.phivolcs.dost.gov.ph/ <https://urldefense.com/v3/__http://www.phivolcs.dost.gov.ph/__;!!IKRxdwAv5BmarQ!b59a6hvmu4DfAA8PId9kUYmBoaTg6jYslSeeDcd0QPrr1Fdw2HgH_luC2xjIz5S8BBahkgau2dmlPSD3WgKyxHhVYw$> Kilauea | United States | 19.421°N, 155.287°W | Summit elev. 1222 m The Hawaiian Volcano Observatory (HVO) reported that the eruption within Kilaueaâ??s Kaluapele summit caldera, from vents along the SW margin of Halemaâ??umaâ??u Crater, continued at variable levels during 19-25 February. Lava fountaining began at the N vent at 2022 on 19 February and by 2100 the fountains were 90-125 m high. During a visit the next morning field crews observed lava fountains rising 45-60 m high at 0645 and that lava flows had covered about 75 percent of the crater floor. Incandescence at the S vent was visible. Sulfur dioxide emission rates were estimated to be 10,000 tons per day (t/d) or higher based on emissions measured during earlier lava-fountaining episodes. Peleâ??s Hair was reported on surfaces throughout the summit area of Hawaiâ??i Volcanoes National Park and surrounding communities. Fountaining heights slowly declined and ceased at 0918 on 20 February, after about 13 hours of fountaining activity. Sulfur dioxide emission rates averaged 2,100 t/d at 1100. During 21-25 February spots of orange incandescence on the crater floor were visible at night as the erupted lava continued to cool. Incandescence at both vents was variable. The Volcano Alert Level remained at Watch (the third level on a four-level scale) and the Aviation Color Code remained at Orange (the third color on a four-color scale). Geologic Summary. 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://volcanoes.usgs.gov/observatories/hvo/ <https://urldefense.com/v3/__https://volcanoes.usgs.gov/observatories/hvo/__;!!IKRxdwAv5BmarQ!b59a6hvmu4DfAA8PId9kUYmBoaTg6jYslSeeDcd0QPrr1Fdw2HgH_luC2xjIz5S8BBahkgau2dmlPSD3WgIfms9NdQ$> Marapi | Indonesia | 0.38°S, 100.474°E | Summit elev. 2885 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that the seismic network at Marapi (on Sumatra) recorded an increase in volcanic earthquakes and tremors during early to mid-February. On 19 February white-and-gray ash plumes rose 200-700 m above the summit and drifted E. Webcam images at 0321 and 2056 showed incandesce at the summit. An eruptive event was recorded on 23 February, though no emissions were observed. On 24 February a dense gray ash plume rose 500 m above the summit and drifted E. The Alert Level remained at 2 (on a scale of 1-4) and the public was warned to stay 3 km away from the active 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) http://vsi.esdm.go.id/ <https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!b59a6hvmu4DfAA8PId9kUYmBoaTg6jYslSeeDcd0QPrr1Fdw2HgH_luC2xjIz5S8BBahkgau2dmlPSD3WgL6Tm1vfA$> Merapi | Indonesia | 7.54°S, 110.446°E | Summit elev. 2910 m The Balai Penyelidikan dan Pengembangan Teknologi Kebencanaan Geologi (BPPTKG) reported that the eruption at Merapi (on Java) continued during 14-20 February. Seismicity remained at high levels. The SW lava dome produced 64 lava avalanches that traveled as far as 1.9 km SW down the Bebeng drainage, 17 that traveled as far as 1.7 km SW down the Krasak drainage, and 57 that traveled as far as 1.9 km SW down the Sat/Putih drainage. Morphological changes to the SW lava dome resulting from continuing effusion and collapses of material. The volume of the SW dome had increased in size to an estimated 3,546,200 cubic meters based a 20 February drone survey. The hottest temperature was around 247.4 degrees Celsius, higher than the previous measurement. No significant morphological changes at the summit dome were visible and the highest temperature was around 228 degrees Celsius, similar to the previous measurement. 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) http://www.merapi.bgl.esdm.go.id/ <https://urldefense.com/v3/__http://www.merapi.bgl.esdm.go.id/__;!!IKRxdwAv5BmarQ!b59a6hvmu4DfAA8PId9kUYmBoaTg6jYslSeeDcd0QPrr1Fdw2HgH_luC2xjIz5S8BBahkgau2dmlPSD3WgL_HFz-9Q$> Nyamulagira | DR Congo | 1.408°S, 29.2°E | Summit elev. 3058 m Satellite images acquired on 20 and 25 February showed continuing activity at Nyamuragira. A thermal anomaly just NE of the central part of the summit crater was visible in the 20 February image, along with smaller thermal anomalies to the NE and SW. Thermal anomalies near the distal end of the lava flow on the WSW flank possibly indicated that it continued to advance; the flow was about 3.3 km long, measured from the W crater rim. Another anomaly was visible about 780 m W of the crater rim. Most of the summit crater and lava-flow field was obscured by weather clouds in the 25 February image, though the end of the active lava flow was visible and had advanced about 80 m. Geologic Summary. Africa's most active volcano, Nyamulagira (also known as Nyamuragira), is a massive high-potassium basaltic shield about 25 km N of Lake Kivu and 13 km NNW of the steep-sided Nyiragongo volcano. The summit is truncated by a small 2 x 2.3 km caldera that has walls up to about 100 m high. Documented eruptions have occurred within the summit caldera, as well as from the numerous flank fissures and cinder cones. A lava lake in the summit crater, active since at least 1921, drained in 1938, at the time of a major flank eruption. Recent lava flows extend down the flanks more than 30 km from the summit as far as Lake Kivu; extensive lava flows from this volcano have covered 1,500 km2 of the western branch of the East African Rift. Source: Copernicus https://www.copernicus.eu/en <https://urldefense.com/v3/__https://www.copernicus.eu/en__;!!IKRxdwAv5BmarQ!b59a6hvmu4DfAA8PId9kUYmBoaTg6jYslSeeDcd0QPrr1Fdw2HgH_luC2xjIz5S8BBahkgau2dmlPSD3WgJ1FOM9vQ$> Reventador | Ecuador | 0.077°S, 77.656°W | Summit elev. 3562 m The Instituto GeofÃsico-Escuela Politécnica Nacional (IG-EPN) reported that eruptive activity continued at Reventador during 18-25 February. Seismicity included 36-84 daily explosions, long-period earthquakes, harmonic tremor, and tremor associated with emissions, though the transmission of seismic and webcam data was sometimes interrupted, especially during 21-23 February. Weather conditions on most days were clear enough to observe ash-and-gas plumes in webcam and/or satellite images rising 300-1,100 m above the crater and drifting NW, WNW, W, and SW. Webcams almost nightly recorded multiple instances of incandescent material descending the flanks as far as 1 km below the crater rim. At 1245 on 22 February a small- to moderate-sized, secondary lahar descended the Marker River on the S flank. SecretarÃa de Gestión de Riesgos 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 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 left extensive deposits on the scarp slope. The largest recorded eruption took place in 2002, producing a 17-km-high eruption column, pyroclastic flows that traveled up to 8 km, and lava flows from summit and flank vents. Sources: Instituto GeofÃsico-Escuela Politécnica Nacional (IG-EPN) http://www.igepn.edu.ec/ <https://urldefense.com/v3/__http://www.igepn.edu.ec/__;!!IKRxdwAv5BmarQ!b59a6hvmu4DfAA8PId9kUYmBoaTg6jYslSeeDcd0QPrr1Fdw2HgH_luC2xjIz5S8BBahkgau2dmlPSD3WgLyf7RYrw$> ; SecretarÃa de Gestión de Riesgos (SGR) http://www.gestionderiesgos.gob.ec/ <https://urldefense.com/v3/__http://www.gestionderiesgos.gob.ec/__;!!IKRxdwAv5BmarQ!b59a6hvmu4DfAA8PId9kUYmBoaTg6jYslSeeDcd0QPrr1Fdw2HgH_luC2xjIz5S8BBahkgau2dmlPSD3WgLVGwHpLA$> Sangay | Ecuador | 2.005°S, 78.341°W | Summit elev. 5286 m The Instituto GeofÃsico-Escuela Politécnica Nacional (IG-EPN) reported that moderate levels of eruptive activity continued at Sangay during 18-25 February. The seismic network recorded 31-95 daily explosions, though the transmission of seismic data was sometimes interrupted. Weather clouds mostly obscured views during the week, but on 24 February gas-and-ash plumes were visible rising 100 m above the summit and drifting W. Incandescence at the crater was occasionally visible the second half of the week during dark hours. SecretarÃa de Gestión de Riesgos (SGR) maintained the Alert Level at Yellow (the second highest level on a four-color scale). Geologic Summary. The isolated Sangay volcano, located east of the Andean crest, is the southernmost of Ecuador's volcanoes and its most active. The steep-sided, glacier-covered, dominantly andesitic volcano grew within the open calderas of two previous edifices which were destroyed by collapse to the east, producing large debris avalanches that reached the Amazonian lowlands. The modern edifice dates back to at least 14,000 years ago. It towers above the tropical jungle on the east side; on the other sides flat plains of ash have been eroded by heavy rains into steep-walled canyons up to 600 m deep. The earliest report of an eruption was in 1628. Almost continuous eruptions were reported from 1728 until 1916, and again from 1934 to the present. The almost constant activity has caused frequent changes to the morphology of the summit crater complex. Sources: Instituto GeofÃsico-Escuela Politécnica Nacional (IG-EPN) http://www.igepn.edu.ec/ <https://urldefense.com/v3/__http://www.igepn.edu.ec/__;!!IKRxdwAv5BmarQ!b59a6hvmu4DfAA8PId9kUYmBoaTg6jYslSeeDcd0QPrr1Fdw2HgH_luC2xjIz5S8BBahkgau2dmlPSD3WgLyf7RYrw$> ; SecretarÃa de Gestión de Riesgos (SGR) http://www.gestionderiesgos.gob.ec/ <https://urldefense.com/v3/__http://www.gestionderiesgos.gob.ec/__;!!IKRxdwAv5BmarQ!b59a6hvmu4DfAA8PId9kUYmBoaTg6jYslSeeDcd0QPrr1Fdw2HgH_luC2xjIz5S8BBahkgau2dmlPSD3WgLVGwHpLA$> Santa Maria | Guatemala | 14.757°N, 91.552°W | Summit elev. 3745 m The Instituto Nacional de SismologÃa, VulcanologÃa, MeteorologÃa e HidrologÃa (INSIVUMEH) reported ongoing eruptive activity at Santa Mariaâ??s Santiaguito dome complex during 18-25 February with continuing lava extrusion at Caliente dome. Daily explosions, as many as seven per hour when reported, generated gas-and-ash plumes that rose as high as 1.2 km above the dome and drifted as far as 40 km W, SW, S, and SE. Effusion of blocky lava and collapses of material produced daily block avalanches that were sometimes heard several kilometers away; these mainly descended the SW and S flanks, but occasionally went SE. Collapsed material sometimes produced short pyroclastic flows. Incandescence was visible at the crater and upper part of the SW flank lava flow. During 19-20 February ashfall was reported in Las MarÃas (9.5 km S), Finca El Patrocinio (8 km SW), San Marcos (10 km SW), Loma Linda Palajunoj (7 km SW), and other nearby communities, and forecasted for areas downwind on most days. Geologic Summary. Symmetrical, forest-covered Santa MarÃa volcano is part of a chain of large stratovolcanoes that rise above the Pacific coastal plain of Guatemala. The sharp-topped, conical profile is cut on the SW flank by a 1.5-km-wide crater. The oval-shaped crater extends from just below the summit to the lower flank, and was formed during a catastrophic eruption in 1902. The renowned Plinian eruption of 1902 that devastated much of SW Guatemala followed a long repose period after construction of the large basaltic-andesite stratovolcano. The massive dacitic Santiaguito lava-dome complex has been growing at the base of the 1902 crater since 1922. Compound dome growth at Santiaguito has occurred episodically from four vents, with activity progressing E towards the most recent, Caliente. Dome growth has been accompanied by almost continuous minor explosions, with periodic lava extrusion, larger explosions, pyroclastic flows, and lahars. Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH) http://www.insivumeh.gob.gt/ <https://urldefense.com/v3/__http://www.insivumeh.gob.gt/__;!!IKRxdwAv5BmarQ!b59a6hvmu4DfAA8PId9kUYmBoaTg6jYslSeeDcd0QPrr1Fdw2HgH_luC2xjIz5S8BBahkgau2dmlPSD3WgIXExgfTg$> Semeru | Indonesia | 8.108°S, 112.922°E | Summit elev. 3657 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that eruptive activity continued at Semeru during 19-25 February with daily eruptive events recorded by the seismic network. Daily white-and-gray or gray ash plumes rose 300-1,000 m above the summit and drifted in multiple directions. The Alert Level remained at 2 (the second lowest level on a scale of 1-4). The public was warned to stay at least 5 km away from the summit in all directions, 13 km from the summit to the SE, 500 m from the banks of the Kobokan drainage as far as 17 km from the summit, and to avoid other drainages including the Bang, Kembar, and Sat, due to lahar, avalanche, and pyroclastic flow hazards. Geologic Summary. Semeru, the highest volcano on Java, and one of its most active, lies at the southern end of a volcanic massif extending north to the Tengger caldera. The steep-sided volcano, also referred to as Mahameru (Great Mountain), rises above coastal plains to the south. Gunung Semeru was constructed south of the overlapping Ajek-ajek and Jambangan calderas. A line of lake-filled maars was constructed along a N-S trend cutting through the summit, and cinder cones and lava domes occupy the eastern and NE flanks. Summit topography is complicated by the shifting of craters from NW to SE. Frequent 19th and 20th century eruptions were dominated by small-to-moderate explosions from the summit crater, with occasional lava flows and larger explosive eruptions accompanied by pyroclastic flows that have reached the lower flanks of the volcano. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://vsi.esdm.go.id/ <https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!b59a6hvmu4DfAA8PId9kUYmBoaTg6jYslSeeDcd0QPrr1Fdw2HgH_luC2xjIz5S8BBahkgau2dmlPSD3WgL6Tm1vfA$> Sheveluch | Russia | 56.653°N, 161.36°E | Summit elev. 3283 m The Kamchatkan Volcanic Eruption Response Team (KVERT) reported that lava extrusion may have continued at Sheveluchâ??s â??300 years of RASâ?? dome on the SW flank of Old Sheveluch and at the Young Sheveluch dome during 13-20 February. Thermal anomalies over the domes were identified in satellite images during 14, 16, and 18-20 February. The Aviation Color Code remained at Orange (the second highest level on a four-color scale). Dates are based on UTC times; specific events are in local time where noted. Geologic Summary. The high, isolated massif of Sheveluch volcano (also spelled Shiveluch) rises above the lowlands NNE of the Kliuchevskaya volcano group. The 1,300 km3 andesitic volcano is one of Kamchatka's largest and most active volcanic structures, with at least 60 large eruptions during the Holocene. The summit of roughly 65,000-year-old Stary Shiveluch is truncated by a broad 9-km-wide late-Pleistocene caldera breached to the south. Many lava domes occur on its outer flanks. The Molodoy Shiveluch lava dome complex was constructed during the Holocene within the large open caldera; Holocene lava dome extrusion also took place on the flanks of Stary Shiveluch. Widespread tephra layers from these eruptions have provided valuable time markers for dating volcanic events in Kamchatka. Frequent collapses of dome complexes, most recently in 1964, have produced debris avalanches whose deposits cover much of the floor of the breached caldera. Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php <https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!b59a6hvmu4DfAA8PId9kUYmBoaTg6jYslSeeDcd0QPrr1Fdw2HgH_luC2xjIz5S8BBahkgau2dmlPSD3WgJQ_eNxSQ$> Stromboli | Italy | 38.789°N, 15.213°E | Summit elev. 924 m The Sezione di Catania - Osservatorio Etneo (INGV) reported that eruptive activity continued at Stromboli during 17-23 February. Webcam images showed Strombolian activity at four vents in Area N within the upper part of the Sciara del Fuoco and from at least two vents in Area C-S (South-Central Crater) on the crater terrace. The vents in Area N continued to produce low- to medium-intensity explosions at a rate of 7-9 events per hour, ejecting lapilli and bombs less than 150 m above the vents. Low-intensity spattering continued at one of the vents. Explosions at the vents in Area C-S ejected tephra above the vent at a rate of 1-4 events per hour. The Alert Level remained at Yellow (the second lowest level on a four-level scale). 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. Sources: Sezione di Catania - Osservatorio Etneo (INGV) http://www.ct.ingv.it/ <https://urldefense.com/v3/__http://www.ct.ingv.it/__;!!IKRxdwAv5BmarQ!b59a6hvmu4DfAA8PId9kUYmBoaTg6jYslSeeDcd0QPrr1Fdw2HgH_luC2xjIz5S8BBahkgau2dmlPSD3WgL9ZLE-rg$> ; Dipartimento della Protezione Civile https://www.protezionecivile.gov.it/it/ <https://urldefense.com/v3/__https://www.protezionecivile.gov.it/it/__;!!IKRxdwAv5BmarQ!b59a6hvmu4DfAA8PId9kUYmBoaTg6jYslSeeDcd0QPrr1Fdw2HgH_luC2xjIz5S8BBahkgau2dmlPSD3WgJvZHvlkg$> Suwanosejima | Japan | 29.638°N, 129.714°E | Summit elev. 796 m The Japan Meteorological Agency (JMA) reported that eruptive activity at Suwanosejima's Ontake Crater continued during 19-25 February. Incandescence was observed nightly in webcam images. Explosions at 0219 on 19 February, at 1906 on 21 February, and at 0601 on 24 February generated ash plumes that rose 700-900 m above the crater rim and drifted SE and S. An eruptive event at 1748 on 22 February generated an ash plume that rose 1 km above the summit and drifted SE. The Alert Level remained at 2 (the second level on a five-level scale) and the public was warned to stay at least 1.5 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 active summit craters. The summit is truncated by a large breached crater extending to the sea on the E 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 covered 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 an open collapse scarp extending 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) http://www.jma.go.jp/jma/ <https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!b59a6hvmu4DfAA8PId9kUYmBoaTg6jYslSeeDcd0QPrr1Fdw2HgH_luC2xjIz5S8BBahkgau2dmlPSD3WgI-Vhe8xg$> Ubinas | Peru | 16.345°S, 70.8972°W | Summit elev. 5608 m The Instituto GeofÃsico del Perú (IGP) reported that a lahar carrying blocks descended the Volcánmayo drainage on the SE flank of Ubinas at 2052 on 23 February. The public was warned to stay away from the drainage and to avoid driving on the Querapi-Ubinas-Huarina highway. The Alert Level remained at Yellow (the second level on a four-color scale) and the public was warned to stay 2 km away from the crater. Geologic Summary. The truncated appearance of Ubinas, Perú's most active volcano, is a result of a 1.4-km-wide crater at the summit. It is the northernmost of three young volcanoes located along a regional structural lineament about 50 km behind the main volcanic front. The growth and destruction of Ubinas I was followed by construction of Ubinas II beginning in the mid-Pleistocene. The upper slopes of the andesitic-to-rhyolitic Ubinas II stratovolcano are composed primarily of andesitic and trachyandesitic lava flows and steepen to nearly 45°. The steep-walled, 150-m-deep summit crater contains an ash cone with a 500-m-wide funnel-shaped vent that is 200 m deep. Debris-avalanche deposits from the collapse of the SE flank about 3,700 years ago extend 10 km from the volcano. Widespread Plinian pumice-fall deposits include one from about 1,000 years ago. Holocene lava flows are visible on the flanks, but activity documented since the 16th century has consisted of intermittent minor-to-moderate explosive eruptions. Source: Instituto GeofÃsico del Perú (IGP) http://www.igp.gob.pe/ <https://urldefense.com/v3/__http://www.igp.gob.pe/__;!!IKRxdwAv5BmarQ!b59a6hvmu4DfAA8PId9kUYmBoaTg6jYslSeeDcd0QPrr1Fdw2HgH_luC2xjIz5S8BBahkgau2dmlPSD3WgIe8obkzA$> Whakaari/White Island | New Zealand | 37.52°S, 177.18°E | Summit elev. 294 m On 24 February GeoNet reported that large, white, steam-rich plumes from Whakaari/White Island were visible in the Whakatane and Te Kaha webcams during the past week. On several of those days sulfur dioxide emissions were detected in satellite data and sulfur odors were noted by residents along the coast. During 22-23 February those plumes also contained small amounts of ash as reported by the Wellington VAAC and visible as a faint haze from the coast. The activity was consistent with moderate to heightened levels of unrest, therefore the Volcanic Alert Level remained at 2 (on a scale of 0-5). At 1430 on 24 February the Aviation Color Code was raised to Orange (the second highest level on a four-color scale) due to the presence of ash in the emissions. GeoNet stated that the Alert Levels were reflective of the current level of activity, but there was uncertainty due to the current lack of consistent, usable, real-time monitoring data; GeoNet relies on remote cameras, satellite images, and occasional overflights to monitor Whakaari. 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 http://www.geonet.org.nz/ <https://urldefense.com/v3/__http://www.geonet.org.nz/__;!!IKRxdwAv5BmarQ!b59a6hvmu4DfAA8PId9kUYmBoaTg6jYslSeeDcd0QPrr1Fdw2HgH_luC2xjIz5S8BBahkgau2dmlPSD3WgJBUaaK4g$> 2-2-2-2-2-2-2-2-2-2-2-2-2 ============================================================== Volcano Listserv is a collaborative venture among Arizona State University (ASU), Portland State University (PSU), the Global Volcanism Program (GVP) of the Smithsonian Institution's National Museum of Natural History, and the International Association for Volcanology and Chemistry of the Earth's Interior (IAVCEI). 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