3-3-3-3-3-3-3-3-3-3-3-3-3 From: "Kuhn, Sally" <KUHNS@xxxxxx> Smithsonian / USGS Weekly Volcanic Activity Report 19-25 March 2025 Sally Sennert - Weekly Report Editor (kuhns@xxxxxx) Tricia Light - contributor (tlight@xxxxxxxx) URL: https://volcano.si.edu/reports_weekly.cfm <https://urldefense.com/v3/__https://volcano.si.edu/reports_weekly.cfm__;!!IKRxdwAv5BmarQ!czNBL4OAqFxFiec9k3yLKRQyE5JBnekRWK3Q984rO16x3iTmnwCbZBrda4BdY5J6H3pWxIp28UQFCIJeCXq_G1llrQ$> New Activity/Unrest: Lewotobi, Indonesia | Lewotolok, Indonesia | Poas, Costa Rica Ongoing Activity: Ahyi, United States | Aira, Japan | Bezymianny, Russia | Dukono, Indonesia | Etna, Italy | Great Sitkin, United States | Home Reef, Tonga | Ibu, Indonesia | Kanlaon, Philippines | Karymsky, Russia | Kilauea, United States | Marapi, Indonesia | Merapi, Indonesia | Nyamulagira, DR Congo | Popocatepetl, Mexico | Rincon de la Vieja, Costa Rica | Semeru, Indonesia | Sheveluch, Russia | Suwanosejima, Japan | 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 Lewotobi | Indonesia | 8.542°S, 122.775°E | Summit elev. 1703 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported increased activity at Lewotobi Laki-laki during mid-March, culminating in a more intense phase on 20 March. Visual observations during 8-15 March indicated that the average height of emissions was increasing with white-to-gray ash plumes rising as high as 2.5 km above the summit. Seismic signals indicating emissions slightly increased, harmonic tremor fluctuated, the number of deep volcanic earthquakes and low-frequency earthquakes slightly decreased, though there was a slight increase in the number of deep volcanic earthquakes on 13 March. No shallow volcanic earthquakes were detected. Crater incandescence was visible on 13 March. Activity significantly increased during 13-20 March. Daily gray ash plumes continued to rise as high as 2.5 km above the summit, though the average height of plumes had increased. Harmonic tremor continued to fluctuate and the number of low-frequency earthquakes slightly increased. A tornillo-type earthquake was detected on 16 March. The number of deep volcanic earthquakes increased significantly during 19-20 March totaling 205 compared to the average of 3-6 events per day. Shallow volcanic earthquakes began to be detected on 20 March indicating rising magma. Eruptive activity continued to intensify; in response PVMBG raised the Alert Level to 4 (on a scale of 1-4) at 2230 on 20 March and increased the exclusion zone to a radius of 7 km from the center of Laki-laki and 8 km in a semicircle clockwise from the SW to the NE. BNPB reported that residents were evacuated from several villages during 19-20 March including Pululera Village (8 km NW), Dulipali Village (6 km NNW), Padang Pasir (5 km NW), Nobo (5 km NE), Klatanlo (3 km NW), Hokeng Jaya (4 km NW), Boru (8 km WNW), and Nawakote. Incandescence at the summit and possibly low on the NW flank was visible in a webcam image starting at 2245 on 20 March. An explosion at 2256 was recorded by several monitoring stations in Flores and heard in areas as far as Maumere City (63 km WSW) and Larantuka (35 km NE). The corresponding seismic signals lasted 11 minutes and nine seconds. A gray-to-black ash plume rose 8 km above the summit and drifted SW and W. According to the Darwin VAAC an ash plume was identified in a satellite at 2340 drifting W at an altitude of 16.1 km (53,000 ft) a.s.l., or 14.5 km above the summit. Dense gray ash plumes rose 2.5 km and 700 m above the summit and drifted W and N and NE at 0010 and 0122 on 21 March, respectively, according to PVMBG. BNPB reported that tephra fell in several surrounding areas. By 0300 the VAAC noted that the plume had detached from the summit and continued to drifted W. Lower-level ash emissions, at 6.1 km (20,000 ft) a.s.l., 4.4 km above the summit, drifted SE. Ash plumes continued to be identified in satellite images during 0600-0900; ash at 3-6.1 km (10,000-20,000 ft) a.s.l., 1.3-4.4 km above the summit, drifted SE and ash at 12.2 km (40,000 ft) a.s.l., 10.5 km above the summit, drifted SWW. The high-level ash plume at 16.1 km a.s.l. continued to drift W but was beginning to be obscured by weather clouds by 1000. Eruptive events were recorded at 1413 on 21 March, at 1916 on 22 March, at 0445 on 23 March, and at 0222 on 25 March, though weather clouds and/or darkness obscured views. According to news reports and BNPB, two people suffered from burns but there were no fatalities during the 20-21 March eruption; around 4,000 people that had evacuated months earlier remained in temporary housing. News articles also noted that 16 international flights to and from the Ngurah Rai International Airport were cancelled, others were delayed, and some domestic flights were postponed. 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. Sources: 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!czNBL4OAqFxFiec9k3yLKRQyE5JBnekRWK3Q984rO16x3iTmnwCbZBrda4BdY5J6H3pWxIp28UQFCIJeCXpHgN3dpA$> ; Badan Nacional Penanggulangan Bencana (BNPB) http://www.bnpb.go.id/ <https://urldefense.com/v3/__http://www.bnpb.go.id/__;!!IKRxdwAv5BmarQ!czNBL4OAqFxFiec9k3yLKRQyE5JBnekRWK3Q984rO16x3iTmnwCbZBrda4BdY5J6H3pWxIp28UQFCIJeCXoDJupegg$> ; Darwin Volcanic Ash Advisory Centre (VAAC) http://www.bom.gov.au/aviation/volcanic-ash/darwin-va-advisory.shtml <https://urldefense.com/v3/__http://www.bom.gov.au/aviation/volcanic-ash/darwin-va-advisory.shtml__;!!IKRxdwAv5BmarQ!czNBL4OAqFxFiec9k3yLKRQyE5JBnekRWK3Q984rO16x3iTmnwCbZBrda4BdY5J6H3pWxIp28UQFCIJeCXpggn0m1Q$> ; Antara News https://kl.antaranews.com/berita/30793/bandara-ngurah-rai-7-penerbangan-batal-dampak-erupsi-gunung-lewotobi <https://urldefense.com/v3/__https://kl.antaranews.com/berita/30793/bandara-ngurah-rai-7-penerbangan-batal-dampak-erupsi-gunung-lewotobi__;!!IKRxdwAv5BmarQ!czNBL4OAqFxFiec9k3yLKRQyE5JBnekRWK3Q984rO16x3iTmnwCbZBrda4BdY5J6H3pWxIp28UQFCIJeCXr53Hw6hQ$> ; Antara News https://m.antaranews.com/amp/berita/4727569/bupati-flores-timur-pastikan-penanganan-korban-lewotobi-sesuai-skema <https://urldefense.com/v3/__https://m.antaranews.com/amp/berita/4727569/bupati-flores-timur-pastikan-penanganan-korban-lewotobi-sesuai-skema__;!!IKRxdwAv5BmarQ!czNBL4OAqFxFiec9k3yLKRQyE5JBnekRWK3Q984rO16x3iTmnwCbZBrda4BdY5J6H3pWxIp28UQFCIJeCXpQcumbOw$> ; Antara News https://www.antaranews.com/berita/4727569/bupati-flores-timur-pastikan-penanganan-korban-lewotobi-sesuai-skema <https://urldefense.com/v3/__https://www.antaranews.com/berita/4727569/bupati-flores-timur-pastikan-penanganan-korban-lewotobi-sesuai-skema__;!!IKRxdwAv5BmarQ!czNBL4OAqFxFiec9k3yLKRQyE5JBnekRWK3Q984rO16x3iTmnwCbZBrda4BdY5J6H3pWxIp28UQFCIJeCXoI50ThvA$> ; Antara News https://bali.antaranews.com/berita/373541/bandara-ngurah-rai-total-16-penerbangan-batal-akibat-erupsi <https://urldefense.com/v3/__https://bali.antaranews.com/berita/373541/bandara-ngurah-rai-total-16-penerbangan-batal-akibat-erupsi__;!!IKRxdwAv5BmarQ!czNBL4OAqFxFiec9k3yLKRQyE5JBnekRWK3Q984rO16x3iTmnwCbZBrda4BdY5J6H3pWxIp28UQFCIJeCXoUOe4hlA$> 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 March. White steam-and-gas plumes rose as high as 400 m above the summit and drifted NE, E, and SE on most days; weather conditions obscured views during 22-23 March. At 0639, 0718, and 0850 on 19 March ash plumes that were gray or gray-to-black rose 300-700 m above the summit and drifted E. At 0454 on 20 March a dense gray-to-black ash plume rose 700 m above the summit and drifted E, and at 1616 on 24 March a dense gray ash plume rose 100 m and drifted E. Another dense gray ash plume rose 300 m and drifted E at 0627 on 25 March. Incandescent material being ejected above the summit was visible in a webcam image from 0453 on 20 March. 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!czNBL4OAqFxFiec9k3yLKRQyE5JBnekRWK3Q984rO16x3iTmnwCbZBrda4BdY5J6H3pWxIp28UQFCIJeCXpHgN3dpA$> 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 an elevated level during 19-25 March. Significant inflation continued to be detected and gas-and-steam emissions were ongoing. Analysis of the ash revealed a significant amount, around 20 percent, of juvenile material. Sulfur dioxide emissions fluctuated at high levels, with averages ranging from 675-844 tons per day (t/d) during 19-20 March, based on MultiGAS station data. Sulfur dioxide emissions detected in satellite data were as high as 844 t/d on 20 March. Occasional phreatic eruptions were recorded by the seismic and acoustic network. Two small phreatic eruptions on 19 March ejected material 50-100 m high and another recorded at 1815 on 20 March produced a 200-m-high plume. A small phreatic eruption at Boca C on 23 March was followed by a period of small, very frequent events during 23-25 March; weather conditions obscured views of the crater. Video from 0747 on 25 March showed a phreatic eruption ejecting dark material above the vent and a steam plume drifting downwind. Ballistics were ejected onto the crater floor. The Alert Level remained at 3 (the second highest level on a four-level scale) and the Aviation Color Code remained at Orange (the second highest color on a four-color scale). 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!czNBL4OAqFxFiec9k3yLKRQyE5JBnekRWK3Q984rO16x3iTmnwCbZBrda4BdY5J6H3pWxIp28UQFCIJeCXrq-nmAtQ$> Ongoing Activity Ahyi | United States | 20.42°N, 145.03°E | Summit elev. -75 m Unrest at Ahyi Seamount continued during 14-21 March. A diffuse plume of discolored water in the vicinity of the seamount was identified in a satellite image on 15 March, indicating possible submarine activity. 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!czNBL4OAqFxFiec9k3yLKRQyE5JBnekRWK3Q984rO16x3iTmnwCbZBrda4BdY5J6H3pWxIp28UQFCIJeCXr_tOyh8g$> Aira | Japan | 31.5772°N, 130.6589°E | Summit elev. 1117 m The Japan Meteorological Agency (JMA) reported ongoing eruptive activity at Minamidake Crater (Aira Calderaâ??s Sakurajima volcano) during 17-24 March. Nightly crater incandescence was visible in webcam images. Very small eruptive events were periodically recorded during 17-21 March. An explosion at 0201 on 22 March generated an ash plume that rose 600 m above the crater rim and drifted SE. The explosion ejected large blocks 600-900 m from the vent. An eruptive event at 0555 on 23 March generated an ash plume that rose 1.8 km above the crater rim and drifted SE. The Alert Level remained at 3 (on a 5-level scale), and the public was warned to stay 2 km away from both the Minimadake and Showa craters. Geologic Summary. The Aira caldera in the northern half of Kagoshima Bay contains the post-caldera Sakurajima volcano, one of Japan's most active. Eruption of the voluminous Ito pyroclastic flow accompanied formation of the 17 x 23 km caldera about 22,000 years ago. The smaller Wakamiko caldera was formed during the early Holocene in the NE corner of the caldera, along with several post-caldera cones. The construction of Sakurajima began about 13,000 years ago on the southern rim and built an island that was joined to the Osumi Peninsula during the major explosive and effusive eruption of 1914. Activity at the Kitadake summit cone ended about 4,850 years ago, after which eruptions took place at Minamidake. Frequent eruptions since the 8th century have deposited ash on the city of Kagoshima, located across Kagoshima Bay only 8 km from the summit. The largest recorded eruption took place during 1471-76. Source: Japan Meteorological Agency (JMA) http://www.jma.go.jp/jma/ <https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!czNBL4OAqFxFiec9k3yLKRQyE5JBnekRWK3Q984rO16x3iTmnwCbZBrda4BdY5J6H3pWxIp28UQFCIJeCXoMcOJxFQ$> Bezymianny | Russia | 55.972°N, 160.595°E | Summit elev. 2882 m The Kamchatkan Volcanic Eruption Response Team (KVERT) reported that a strong thermal anomaly over Bezymianny was identified in satellite images during 13-20 March. According to the Institute of Volcanology and Seismology (IVS) of the Far Eastern Branch of the Russian Academy of Sciences (FEB RAS), incandescent debris avalanches descended the SE and/or E flanks and daily summit incandescence was visible during dark hours. Summit incandescence was less intense and debris avalanches were less frequent later in the week. Ash plumes generated from debris avalanches rose as high as 600 m above the summit and drifted in multiple directions. Weather conditions occasionally 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!czNBL4OAqFxFiec9k3yLKRQyE5JBnekRWK3Q984rO16x3iTmnwCbZBrda4BdY5J6H3pWxIp28UQFCIJeCXr9oZRNeA$> ; Institute of Volcanology and Seismology (IVS) of the Far Eastern Branch of the Russian Academy of Sciences (FEB RAS) http://www.kscnet.ru/ivs/ <https://urldefense.com/v3/__http://www.kscnet.ru/ivs/__;!!IKRxdwAv5BmarQ!czNBL4OAqFxFiec9k3yLKRQyE5JBnekRWK3Q984rO16x3iTmnwCbZBrda4BdY5J6H3pWxIp28UQFCIJeCXodafWRoQ$> 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 March. White-and-gray or gray ash plumes that were often dense rose as high as 1.1 km above the crater rim and drifted NW, W, E, and NE on all days except 23 March. Rumbling and banging sounds were sometimes accompanied by strong booms during 19 and 24-25 March. Ashfall was reported in Tobelo (15 km ENE) and surrounding areas during 24-25 March. 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!czNBL4OAqFxFiec9k3yLKRQyE5JBnekRWK3Q984rO16x3iTmnwCbZBrda4BdY5J6H3pWxIp28UQFCIJeCXpHgN3dpA$> Etna | Italy | 37.748°N, 14.999°E | Summit elev. 3357 m The Sezione di Catania - Osservatorio Etneo (INGV) reported continuing activity at Etna during 17-23 March. Weather clouds often obscured views of the summit area, though during a few clear periods gas emissions were observed rising from the summit craters and Strombolian activity was observed at SE Crater. Strombolian activity at various vents in SE Crater began around 2225 on 19 March. Explosions ejected material a few tens of meters above the crater rim with coarse material falling back into the crater. The intensity and frequency of the explosions gradually increased until about 1430 on 20 March and material was ejected onto the flanks of the cone. The activity gradually decreased and by 1745 explosions were no longer visible in webcam images. Ash emissions that quickly dispersed near the summit persisted for around another hour. Strombolian activity at SE Crater was visible at 1125 on 24 March when weather conditions allowed for views, though it was not clear enough to determine the intensity and frequency of the explosions. At around 1235 lava overflowed the crater rim and traveled a short distance down the S flank. Strombolian activity continued until about 2100 on 24 March and around the same time the lava flow appeared to be cooling. 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!czNBL4OAqFxFiec9k3yLKRQyE5JBnekRWK3Q984rO16x3iTmnwCbZBrda4BdY5J6H3pWxIp28UQFCIJeCXoNIHfoKA$> 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 flow in Great Sitkinâ??s summit crater during 19-25 March. Small daily earthquakes were detected by the seismic network. No unusual activity was visible in mostly cloudy webcam and satellite images for most of the week. Steaming from the vent region and slightly elevated surface temperatures were detected in satellite and webcam views of the volcano during 23-24 March. 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!czNBL4OAqFxFiec9k3yLKRQyE5JBnekRWK3Q984rO16x3iTmnwCbZBrda4BdY5J6H3pWxIp28UQFCIJeCXo62uiNLw$> Home Reef | Tonga | 18.992°S, 174.775°W | Summit elev. -10 m The Tonga Geological Services reported ongoing and consistent activity at Home Reef during 11-21 March. A lava dome just SW of the central part of the island was visible in an 11 March satellite image; this 80 m W-E, 100 m N-S feature had not changed in size since the previous view. Thermal anomalies were ongoing at least through 19 March and were at mostly low levels, though occasionally they were characterized as moderate. Infrasound data also indicated continuing minor eruptive activity. The Maritime Alert Level remained at Orange (the third level on a four-level scale), and mariners were advised to stay at least 2 nautical miles (3.7 km) away from the island. The Aviation Color Code remained at Yellow (the second level on a four-level scale), and the Alert Level for residents of Vavaâ??u and Haâ??apai remained at Green (the first level on a four-level scale). Geologic Summary. Home Reef, a submarine volcano midway between Metis Shoal and Late Island in the central Tonga islands, was first reported active in the mid-19th century, when an ephemeral island formed. An eruption in 1984 produced a 12-km-high eruption plume, large amounts of floating pumice, and an ephemeral 500 x 1,500 m island, with cliffs 30-50 m high that enclosed a water-filled crater. In 2006 an island-forming eruption produced widespread dacitic pumice rafts that drifted as far as Australia. Another island was built during a September-October 2022 eruption. Source: Tonga Geological Services, Government of Tonga https://www.facebook.com/tongageologicalservice <https://urldefense.com/v3/__https://www.facebook.com/tongageologicalservice__;!!IKRxdwAv5BmarQ!czNBL4OAqFxFiec9k3yLKRQyE5JBnekRWK3Q984rO16x3iTmnwCbZBrda4BdY5J6H3pWxIp28UQFCIJeCXowe2jAQw$> 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 12-18 March. Eruptive events were recorded daily though weather conditions sometimes obscured views. Dense gray ash plumes rose 300-700 m above the summit and drifted SW, NW, and E during 19-21 and 24 March. Incandescence at the summit was visible in a few 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!czNBL4OAqFxFiec9k3yLKRQyE5JBnekRWK3Q984rO16x3iTmnwCbZBrda4BdY5J6H3pWxIp28UQFCIJeCXpHgN3dpA$> Kanlaon | Philippines | 10.4096°N, 123.13°E | Summit elev. 2422 m The Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported continuing eruptive activity at Kanlaon during 18-24 March. The seismic network recorded 2-12 daily volcanic earthquakes. Average daily sulfur dioxide emissions ranged from 2,125 to 3,632 tonnes per day. Gas-and-steam emissions that occasionally contained ash rose as high as 200 m above the summit and drifted W and SW; weather conditions obscured views during 21-22 March. There were 1-2 periods of ash emissions on 18, 20, and 23 March that each lasted 6-26 minutes. According to the Tokyo VAAC ash plumes on 23 March were visible in satellite images drifting SW. The Alert Level remained at 3 (on a scale of 0-5); the public was warned to stay 6 km away from the summit and pilots were warned not to fly close to the volcano. Geologic Summary. Kanlaon volcano (also spelled Canlaon) forms the highest point on the Philippine island of Negros. The massive andesitic stratovolcano is covered with fissure-controlled pyroclastic cones and craters, many of which are filled by lakes. The largest debris avalanche known in the Philippines traveled 33 km SW from Kanlaon. The summit contains a 2-km-wide, elongated northern caldera with a crater lake and a smaller but higher active vent, Lugud crater, to the south. Eruptions recorded since 1866 have typically consisted of phreatic explosions of small-to-moderate size that produce minor local ashfall. Sources: Philippine Institute of Volcanology and Seismology (PHIVOLCS) http://www.phivolcs.dost.gov.ph/ <https://urldefense.com/v3/__http://www.phivolcs.dost.gov.ph/__;!!IKRxdwAv5BmarQ!czNBL4OAqFxFiec9k3yLKRQyE5JBnekRWK3Q984rO16x3iTmnwCbZBrda4BdY5J6H3pWxIp28UQFCIJeCXpjnnYbQQ$> ; Tokyo Volcanic Ash Advisory Center (VAAC) http://ds.data.jma.go.jp/svd/vaac/data/vaac_list.html <https://urldefense.com/v3/__http://ds.data.jma.go.jp/svd/vaac/data/vaac_list.html__;!!IKRxdwAv5BmarQ!czNBL4OAqFxFiec9k3yLKRQyE5JBnekRWK3Q984rO16x3iTmnwCbZBrda4BdY5J6H3pWxIp28UQFCIJeCXqve5aP1g$> Karymsky | Russia | 54.049°N, 159.443°E | Summit elev. 1513 m The Kamchatkan Volcanic Eruption Response Team (KVERT) reported moderate levels of activity at Karymsky during 13-20 March. Thermal anomalies over the volcano were identified in satellite images on 16 and 18 March; weather clouds obscured views on the other days. The Aviation Color Code remained at Orange (the third level on a four-color scale). Dates are based on UTC times; specific events are in local time where noted. Geologic Summary. Karymsky, the most active volcano of Kamchatka's eastern volcanic zone, is a symmetrical stratovolcano constructed within a 5-km-wide caldera that formed during the early Holocene. The caldera cuts the south side of the Pleistocene Dvor volcano and is located outside the north margin of the large mid-Pleistocene Polovinka caldera, which contains the smaller Akademia Nauk and Odnoboky calderas. Most seismicity preceding Karymsky eruptions originated beneath Akademia Nauk caldera, located immediately south. The caldera enclosing Karymsky formed about 7600-7700 radiocarbon years ago; construction of the stratovolcano began about 2000 years later. The latest eruptive period began about 500 years ago, following a 2300-year quiescence. Much of the cone is mantled by lava flows less than 200 years old. Historical eruptions have been vulcanian or vulcanian-strombolian with moderate explosive activity and occasional lava flows from the summit crater. Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php <https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!czNBL4OAqFxFiec9k3yLKRQyE5JBnekRWK3Q984rO16x3iTmnwCbZBrda4BdY5J6H3pWxIp28UQFCIJeCXr9oZRNeA$> 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 18-25 March. Occasional bursts of spatter rose from the N vent overnight during 18-19 March, with activity becoming more frequent in the morning. From 2358 on 18 March to 0514 on 19 March the S vent overflowed six times, sending lava flows up to 50 m across the crater floor. During 0602-0610 lava overflowed the S vent for a seventh time and was accompanied by large spatter bursts that could be seen over the top of the N vent cone in a webcam. None of the lava flows were active for more than 10 minutes. Spatter activity at both vents waned around 0700 and then increased at around 0920. Lava overflowed the N vent at 0926 and the S vent during 0950-1035. At the N vent periods of low domed fountains, as high as 10 m, alternated with â??drainbacksâ?? (2-3 m drops) of the 65 x 45 m lava pond that occurred every 5-10 minutes, with the interval decreasing over time. The dome fountains significantly increased in size at around 0200 on 20 March, rising 15-30 m. Fountains rose from the S vent at 0630, and within 20 minutes both vents were producing sustained fountains. By 0715 the fountains were rising 120-180 m and lava covered more than half the crater floor. Fountaining at the N vent ceased at 0746 while fountain heights at the S vent increased to 200 m. Fountaining at the S vent continued through the early afternoon, rising as high as 180 m. All activity ceased by 1349 and lava flows covered about three quarters of the crater floor. A maximum sulfur dioxide gas emission rate was approximately 50,000 tons per day (t/d) during the morning of 20 March. The rate had decreased to 1,500 t/d by 1700. The fountains produced tephra such as pumice and Pele's Hair; Peleâ??s Hair was reported on surfaces in areas within Hawaiâ??i Volcanoes National Park and surrounding communities. Spots of orange glow on the crater floor were visible at night as the erupted lava cooled. The vents degassed and were incandescent at night during 21-24 March. Activity at the vents resumed on 25 March. Eight cycles of small spatter fountaining at the N vent began at 0927, 0955, 1011, 1029, 1048, 1107, 1127, and 1145, with each cycle lasting 5-10 minutes. The ninth cycle occurred during 1204-1219 and produced lava flows that extended 50-100 m across the crater floor. Activity that began at the S vent around noon also sent lava flows onto the crater floor. Cyclic fountaining, 10-15 m high, at the N vent was visible during 1225-1239, 1247-1302, 1308-1323, 1329-1339, and 1346-1358. Lava covered about 5 percent of the crater floor by around 1400. 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!czNBL4OAqFxFiec9k3yLKRQyE5JBnekRWK3Q984rO16x3iTmnwCbZBrda4BdY5J6H3pWxIp28UQFCIJeCXroyOqoYw$> Marapi | Indonesia | 0.38°S, 100.474°E | Summit elev. 2885 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that eruptive activity at Marapi (on Sumatra) continued during 19-25 March. Daily white plumes generally rose as high as 250 m above the summit and drifted in multiple directions. At 0229 on 20 March a dense gray ash plume rose 1 km above the summit and drifted S. An eruptive event was recorded at 0842 on 22 March but not visually observed due to weather conditions. According to a news report the event produced a loud bang heard in several areas including Padang Panjang City (11 km SW), Koto Baru (15 km NNW), Sungai Pua Village (7 km NW), and Bukittinggi City (13 km NW). One resident in Bukittinggi City noted that loud bangs had been heard quite often over the previous few months. The Alert Level remained at 2 (on a scale of 1-4) and the public was warned to stay 3 km away from the active crater. Geologic Summary. Gunung Marapi, not to be confused with the better-known Merapi volcano on Java, is Sumatra's most active volcano. This massive complex stratovolcano rises 2,000 m above the Bukittinggi Plain in the Padang Highlands. A broad summit contains multiple partially overlapping summit craters constructed within the small 1.4-km-wide Bancah caldera. The summit craters are located along an ENE-WSW line, with volcanism migrating to the west. More than 50 eruptions, typically consisting of small-to-moderate explosive activity, have been recorded since the end of the 18th century; no lava flows outside the summit craters have been reported in historical time. Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://vsi.esdm.go.id/ <https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!czNBL4OAqFxFiec9k3yLKRQyE5JBnekRWK3Q984rO16x3iTmnwCbZBrda4BdY5J6H3pWxIp28UQFCIJeCXpHgN3dpA$> ; Antara News https://www.antaranews.com/berita/4729161/pga-kolom-abu-erupsi-gunung-marapi-tertutup-awan <https://urldefense.com/v3/__https://www.antaranews.com/berita/4729161/pga-kolom-abu-erupsi-gunung-marapi-tertutup-awan__;!!IKRxdwAv5BmarQ!czNBL4OAqFxFiec9k3yLKRQyE5JBnekRWK3Q984rO16x3iTmnwCbZBrda4BdY5J6H3pWxIp28UQFCIJeCXo7YbmN2g$> Merapi | Indonesia | 7.54°S, 110.446°E | Summit elev. 2910 m The Balai Penyelidikan dan Pengembangan Teknologi Kebencanaan Geologi (BPPTKG) reported that the eruption at Merapi (on Java) continued during 14-20 March. Seismicity remained at high levels. The SW lava dome produced 31 lava avalanches that traveled as far as 1.8 km SW down the Bebeng drainage, 29 that traveled as far as 1.8 km SW down the Krasak drainage, 29 that traveled as far as 1.9 km W down the Sat/Putih drainage, and one that descended the Boyong drainage on the S flank as far as 1.2 km. Two pyroclastic flows descended the Krasak drainage as far as 1.8 km. Slight morphological changes to the SW lava dome resulted from continuing effusion and collapses of material. The Alert Level remained at 3 (on a scale of 1-4), and the public was warned to stay 3-7 km away from the summit, based on location. Geologic Summary. Merapi, one of Indonesia's most active volcanoes, lies in one of the world's most densely populated areas and dominates the landscape immediately north of the major city of Yogyakarta. It is the youngest and southernmost of a volcanic chain extending NNW to Ungaran volcano. Growth of Old Merapi during the Pleistocene ended with major edifice collapse perhaps about 2,000 years ago, leaving a large arcuate scarp cutting the eroded older Batulawang volcano. Subsequent growth of the steep-sided Young Merapi edifice, its upper part unvegetated due to frequent activity, began SW of the earlier collapse scarp. Pyroclastic flows and lahars accompanying growth and collapse of the steep-sided active summit lava dome have devastated cultivated lands on the western-to-southern flanks and caused many fatalities. Source: Balai Penyelidikan dan Pengembangan Teknologi Kebencanaan Geologi (BPPTKG) http://www.merapi.bgl.esdm.go.id/ <https://urldefense.com/v3/__http://www.merapi.bgl.esdm.go.id/__;!!IKRxdwAv5BmarQ!czNBL4OAqFxFiec9k3yLKRQyE5JBnekRWK3Q984rO16x3iTmnwCbZBrda4BdY5J6H3pWxIp28UQFCIJeCXoEfXB9-A$> Nyamulagira | DR Congo | 1.408°S, 29.2°E | Summit elev. 3058 m Satellite images acquired on 17 and 22 March showed continuing activity at Nyamuragira. A bright thermal anomaly just NE of the central part of the summit crater was visible in both images, along with surrounding elevated temperatures on the E half of the crater floor, likely from lava flows. Although weather and volcanic gas plumes obscured most of the W flank, a small incandescent spot from an active lava flow on the upper W flank was visible in the 17 March image. 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!czNBL4OAqFxFiec9k3yLKRQyE5JBnekRWK3Q984rO16x3iTmnwCbZBrda4BdY5J6H3pWxIp28UQFCIJeCXojQC5sMg$> Popocatepetl | Mexico | 19.023°N, 98.622°W | Summit elev. 5393 m The Centro Nacional de Prevención de Desastres (CENAPRED) reported that eruptive activity continued at Popocatépetl during 18-25 March. The seismic network recorded 31-87 long-period events per day on most days, accompanied by steam-and-gas emissions. In addition, the seismic network also recorded daily low-amplitude tremor, characterized by harmonic and high-frequency signals, with periods lasting 11 minutes to as long as four hours and 33 minutes. According to the Washington VAAC an ash plume was visible in webcam and satellite images on 24 March rising 6.7 km (22,000 ft) a.s.l. (around 1.3 km above the summit) and drifting E. The ash had dissipated within about six hours. The Alert Level remained at Yellow, Phase Two (the middle level on a three-color scale) and the public was warned to stay 12 km away from the crater. 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. Sources: 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!czNBL4OAqFxFiec9k3yLKRQyE5JBnekRWK3Q984rO16x3iTmnwCbZBrda4BdY5J6H3pWxIp28UQFCIJeCXq3zadoKQ$> ; Centro Nacional de Prevencion de Desastres (CENAPRED) https://www.gob.mx/cenapred <https://urldefense.com/v3/__https://www.gob.mx/cenapred__;!!IKRxdwAv5BmarQ!czNBL4OAqFxFiec9k3yLKRQyE5JBnekRWK3Q984rO16x3iTmnwCbZBrda4BdY5J6H3pWxIp28UQFCIJeCXrqKby2Wg$> Rincon de la Vieja | Costa Rica | 10.83°N, 85.324°W | Summit elev. 1916 m The Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA) reported that occasional, small, phreatic eruptions at Rincón de la Vieja were recorded during 18-20 March in monitoring network data. Sulfur dioxide emissions averaged 311 tons per day on 18 March, which was significantly higher than averages during the previous few days. At 1815 on 20 March a phreatic eruption produced a gas-and-steam plume that rose 200 m. Geologic Summary. Rincón de la Vieja, the largest volcano in NW Costa Rica, is a remote volcanic complex in the Guanacaste Range. The volcano consists of an elongated, arcuate NW-SE-trending ridge constructed within the 15-km-wide early Pleistocene GuachipelÃn caldera, whose rim is exposed on the south side. Sometimes known as the "Colossus of Guanacaste," it has an estimated volume of 130 km3 and contains at least nine major eruptive centers. Activity has migrated to the SE, where the youngest-looking craters are located. The twin cone of Santa MarÃa volcano, the highest peak of the complex, is located at the eastern end of a smaller, 5-km-wide caldera and has a 500-m-wide crater. A Plinian eruption producing the 0.25 km3 RÃo Blanca tephra about 3,500 years ago was the last major magmatic eruption. All subsequent eruptions, including numerous historical eruptions possibly dating back to the 16th century, have been from the prominent active crater containing a 500-m-wide acid lake located ENE of Von Seebach crater. Source: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA) http://www.ovsicori.una.ac.cr/ <https://urldefense.com/v3/__http://www.ovsicori.una.ac.cr/__;!!IKRxdwAv5BmarQ!czNBL4OAqFxFiec9k3yLKRQyE5JBnekRWK3Q984rO16x3iTmnwCbZBrda4BdY5J6H3pWxIp28UQFCIJeCXrq-nmAtQ$> Semeru | Indonesia | 8.108°S, 112.922°E | Summit elev. 3657 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that activity continued at Semeru during 19-25 March, with multiple, daily eruptive events recorded by the seismic network. Dense gray or white-and-gray ash plumes rose 300-900 m above the summit and drifted N and NE during 19-21 March. 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!czNBL4OAqFxFiec9k3yLKRQyE5JBnekRWK3Q984rO16x3iTmnwCbZBrda4BdY5J6H3pWxIp28UQFCIJeCXpHgN3dpA$> Sheveluch | Russia | 56.653°N, 161.36°E | Summit elev. 3283 m The Kamchatkan Volcanic Eruption Response Team (KVERT) reported that lava extrusion may have continued at Sheveluchâ??s â??300 years of RASâ?? dome on the SW flank of Old Sheveluch and at the Young Sheveluch dome during 13-20 March. Daily thermal anomalies over the domes were identified in satellite images. The Aviation Color Code remained at Orange (the second highest level on a four-color scale). Dates are based on UTC times; specific events are in local time where noted. Geologic Summary. The high, isolated massif of Sheveluch volcano (also spelled Shiveluch) rises above the lowlands NNE of the Kliuchevskaya volcano group. The 1,300 km3 andesitic volcano is one of Kamchatka's largest and most active volcanic structures, with at least 60 large eruptions during the Holocene. The summit of roughly 65,000-year-old Stary Shiveluch is truncated by a broad 9-km-wide late-Pleistocene caldera breached to the south. Many lava domes occur on its outer flanks. The Molodoy Shiveluch lava dome complex was constructed during the Holocene within the large open caldera; Holocene lava dome extrusion also took place on the flanks of Stary Shiveluch. Widespread tephra layers from these eruptions have provided valuable time markers for dating volcanic events in Kamchatka. Frequent collapses of dome complexes, most recently in 1964, have produced debris avalanches whose deposits cover much of the floor of the breached caldera. Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/index_eng.php <https://urldefense.com/v3/__http://www.kscnet.ru/ivs/kvert/index_eng.php__;!!IKRxdwAv5BmarQ!czNBL4OAqFxFiec9k3yLKRQyE5JBnekRWK3Q984rO16x3iTmnwCbZBrda4BdY5J6H3pWxIp28UQFCIJeCXr9oZRNeA$> 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 17-24 March. Incandescence was observed nightly in webcam images. Eruptive activity generated emissions that rose 800 m above the crater rim and ejected blocks as far as 300 m. 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!czNBL4OAqFxFiec9k3yLKRQyE5JBnekRWK3Q984rO16x3iTmnwCbZBrda4BdY5J6H3pWxIp28UQFCIJeCXoMcOJxFQ$> Whakaari/White Island | New Zealand | 37.52°S, 177.18°E | Summit elev. 294 m On 25 March GeoNet reported that semi-continuous steam-and-gas plumes from Whakaari/White Island contained variable but minor amounts of ash during the previous few weeks. The plumes were visible in images from webcams (at Whakatane and Te Kaha) and occasionally detected in satellite data by the New Zealand Met Service. The ash sometimes created a hazy plume drifting downwind that could be seen from points along the mainland coast. During an overflight on 21 March scientists observed that the active event areas had slightly enlarged. They saw impact craters on the crater floor, up to 600 m from the vent, suggesting that occasional more explosive activity had recently occurred. Temperature measurements of the active vent were 360 degrees Celsius, up from 220 degrees measured in January. But well below the highs of over 580 degrees measured in August 2024. Sulfur dioxide emissions were not identified in satellite data. 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). The Aviation Color Code remained at 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 periodic 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!czNBL4OAqFxFiec9k3yLKRQyE5JBnekRWK3Q984rO16x3iTmnwCbZBrda4BdY5J6H3pWxIp28UQFCIJeCXqGWky8NA$> 3-3-3-3-3-3-3-3-3-3-3-3-3 ============================================================== 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). ASU - http://www.asu.edu/ PSU - http://pdx.edu/ GVP - https://volcano.si.edu/ IAVCEI - https://www.iavceivolcano.org/ To subscribe to the volcano list, send the message: subscribe volcano to: listserv@xxxxxxx, or write to: volcano-request@xxxxxxx To unsubscribe from the volcano list, send the message: signoff volcano to: listserv@xxxxxxx, or write to: volcano-request@xxxxxxx. To contribute to the volcano list, send your message to: volcano@xxxxxxx. Please do not send attachments. ============================================================== ------------------------------ End of Volcano Digest - 24 Mar 2025 to 26 Mar 2025 (#2025-26) *************************************************************
