4-4-4-4-4-4-4-4-4-4-4-4-4 From: "Kuhn, Sally" <KUHNS@xxxxxx> Smithsonian / USGS Weekly Volcanic Activity Report 5-11 March 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!cwqxtT0ni_2hCUXunLS6Pp8O05DtTecJxH6WjzpmeZ0O4rDpO4iqsGButwFmLlaV8BLM7h1lL96vPww1HJKq8Zz3kA$> New Activity/Unrest: Bezymianny, Russia | Etna, Italy | Fuego, Guatemala | Langila, Papua New Guinea | Poas, Costa Rica | Turrialba, Costa Rica Ongoing Activity: Ahyi, United States | Aira, Japan | Dukono, Indonesia | Great Sitkin, United States | Home Reef, Tonga | Ibu, Indonesia | Kanlaon, Philippines | Kilauea, United States | Lewotobi, Indonesia | Lewotolok, Indonesia | Marapi, Indonesia | Merapi, Indonesia | Nevado del Ruiz, Colombia | Semeru, Indonesia | Suwanosejima, Japan 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 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 28 February-6 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 flanks daily and summit incandescence was visible during dark hours. Ash plumes generated from debris avalanches rose as high as 2.2 km above the summit and drifted mainly E, NE, and NW. 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!cwqxtT0ni_2hCUXunLS6Pp8O05DtTecJxH6WjzpmeZ0O4rDpO4iqsGButwFmLlaV8BLM7h1lL96vPww1HJKRjlJWjg$> ; 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!cwqxtT0ni_2hCUXunLS6Pp8O05DtTecJxH6WjzpmeZ0O4rDpO4iqsGButwFmLlaV8BLM7h1lL96vPww1HJLiEaRy3w$> Etna | Italy | 37.748°N, 14.999°E | Summit elev. 3357 m The Sezione di Catania - Osservatorio Etneo (INGV) reported that lava effusion at the fissure on the upper S flank of Etnaâ??s Bocca Nuova Crater ceased on 2 March and began cooling. During 3-9 March gas emissions were observed rising from the summit craters, though weather clouds often obscured views. The Aviation Color Code was lowered to Yellow (the second lowest level on a four-color scale) at 1152 on 5 March and then to Green at 1839 that same day. Geologic Summary. Mount Etna, towering above Catania on the island of Sicily, has one of the world's longest documented records of volcanism, dating back to 1500 BCE. Historical lava flows of basaltic composition cover much of the surface of this massive volcano, whose edifice is the highest and most voluminous in Italy. The Mongibello stratovolcano, truncated by several small calderas, was constructed during the late Pleistocene and Holocene over an older shield volcano. The most prominent morphological feature of Etna is the Valle del Bove, a 5 x 10 km caldera open to the east. Two styles of eruptive activity typically occur, sometimes simultaneously. Persistent explosive eruptions, sometimes with minor lava emissions, take place from one or more summit craters. Flank vents, typically with higher effusion rates, are less frequently active and originate from fissures that open progressively downward from near the summit (usually accompanied by Strombolian eruptions at the upper end). Cinder cones are commonly constructed over the vents of lower-flank lava flows. Lava flows extend to the foot of the volcano on all sides and have reached the sea over a broad area on the SE flank. Source: Sezione di Catania - Osservatorio Etneo (INGV) http://www.ct.ingv.it/ <https://urldefense.com/v3/__http://www.ct.ingv.it/__;!!IKRxdwAv5BmarQ!cwqxtT0ni_2hCUXunLS6Pp8O05DtTecJxH6WjzpmeZ0O4rDpO4iqsGButwFmLlaV8BLM7h1lL96vPww1HJLY47HfqA$> Fuego | Guatemala | 14.473°N, 90.88°W | Summit elev. 3763 m The Instituto Nacional de SismologÃa, VulcanologÃa, MeteorologÃa e HidrologÃa (INSIVUMEH) reported that elevated eruptive activity at Fuego was characterized by explosions and ash plumes, incandescent material ejected above the summit, incandescent avalanches, and pyroclastic flows. The stronger activity began at around 0255 on 9 March with explosions detected in seismic and acoustic data and increasing thermal radiance at the summit detected in satellite data. Explosions ejected incandescent material onto the upper flanks on all directions and caused avalanches of incandescent material. Explosions and gas ejections were heard in areas several kilometers away. According to the Washington VAAC significant ash plumes rose about 1.1 km above the summit at 0350, but by 0930 the plumes were more sporadic and diffuse; the plumes drifted W and NW. INSIVUMEH noted that activity intensified in the early evening and became continuous. The VAAC reported that at 1620 ash plumes rose around 500 m above the summit and drifted W. At around 1800 air quality monitoring stations in Guatemala City recorded decreased quality conditions due to ash in the air, according to CONRED. The VAAC reported that at 2200 dense ash emissions rose 500 m and drifted 150 km SW while a second plume rose 1.1 km above the summit and drifted NW. Activity notably intensified again at 2100 on 9 March. Lava fountains rose 300 m above the summit, avalanches of incandescent blocks descended the flanks, and shockwaves from explosions rattled nearby houses and structures. Ash plumes rose 3.2 km above the summit and fanned out as far as 50 km SW, W, and NW. Continuous ashfall was reported in areas W and S. Just before 2330 pyroclastic flows descended the Seca (W) and Ceniza (SSW) drainages and about 25 minutes later pyroclastic flows descended the Las Lajas (SE) and El Jute (ESE) drainages. CONRED staff assisted 267 people from El Porvenir and 15 from Las Lajitas to an evacuation shelter in the Municipal Hall of San Juan Alotenango, Sacatepéquez. A section of the RN-14, the national route connecting Escuintla and Sacatepéquez, was temporarily closed as a preventative measure. Overnight during 9-10 March lava fountains rose 500 m high. Dense ash-and-gas plumes rose 6 km above the summit and drifted 100-120 km NW and E. Low-altitude plumes with ash remobilized from earlier pyroclastic flows drifted SW. On 10 March the Ministry of Education suspended classes in the municipalities of Alotenango, Sacatepéquez; Escuintla and Siquinalá in the department of Escuintla; and in San Pedro Yepocapa, Chimaltenango. Activity began to decrease and by 1130 on 10 March explosions were no longer continuous. Ash-and-gas plumes rose 1.1 km above the summit and drifted 100 km NW and SW. Minor ashfall continued to impact areas to the W and SW; ash remained suspended in the air and ashfall on crops was up to 1 mm thick. By 1230 the air quality monitoring station in Guatemala City recorded improved quality conditions due to less ash in the air. Activity continued to decline. INSIVUMEH issued a report at 1800 noting that activity had returned to â??baselineâ?? levels; seismicity was at â??normalâ?? levels and satellite data indicated that large amounts of ash were no longer suspended in the air. Thermal anomalies were also no longer detected in satellite data. Overnight during 10-11 March a few incandescent blocks in the crater were visible along with minor avalanches of incandescent material. Diffuse gas emissions rose form the crater. During 11-12 March gas emissions rose about 100 m above the summit and no incandescent explosions were observed. Geologic Summary. Volcán Fuego, one of Central America's most active volcanoes, is also one of three large stratovolcanoes overlooking Guatemala's former capital, Antigua. The scarp of an older edifice, Meseta, lies between Fuego and Acatenango to the north. Construction of Meseta dates back to about 230,000 years and continued until the late Pleistocene or early Holocene. Collapse of Meseta may have produced the massive Escuintla debris-avalanche deposit, which extends about 50 km onto the Pacific coastal plain. Growth of the modern Fuego volcano followed, continuing the southward migration of volcanism that began at the mostly andesitic Acatenango. Eruptions at Fuego have become more mafic with time, and most historical activity has produced basaltic rocks. Frequent vigorous historical eruptions have been recorded since the onset of the Spanish era in 1524, and have produced major ashfalls, along with occasional pyroclastic flows and lava flows. Sources: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH) http://www.insivumeh.gob.gt/ <https://urldefense.com/v3/__http://www.insivumeh.gob.gt/__;!!IKRxdwAv5BmarQ!cwqxtT0ni_2hCUXunLS6Pp8O05DtTecJxH6WjzpmeZ0O4rDpO4iqsGButwFmLlaV8BLM7h1lL96vPww1HJJ80QiD9w$> ; Coordinadora Nacional para la Reducción de Desastres (CONRED) http://conred.gob.gt/ <https://urldefense.com/v3/__http://conred.gob.gt/__;!!IKRxdwAv5BmarQ!cwqxtT0ni_2hCUXunLS6Pp8O05DtTecJxH6WjzpmeZ0O4rDpO4iqsGButwFmLlaV8BLM7h1lL96vPww1HJKS91k6Pg$> Langila | Papua New Guinea | 5.525°S, 148.42°E | Summit elev. 1330 m The Darwin VAAC reported that an ash plume from Langila was identified in a satellite image at 0700 on 6 March rising to 1.8 km (6,000 ft) a.s.l. and drifting SW. The ash had dissipated within two hours. Geologic Summary. Langila, one of the most active volcanoes of New Britain, consists of a group of four small overlapping composite basaltic-andesitic cones on the lower E flank of the extinct Talawe volcano in the Cape Gloucester area of NW New Britain. A rectangular, 2.5-km-long crater is breached widely to the SE; Langila was constructed NE of the breached crater of Talawe. An extensive lava field reaches the coast on the N and NE sides of Langila. Frequent mild-to-moderate explosive eruptions, sometimes accompanied by lava flows, have been recorded since the 19th century from three active craters at the summit. The youngest and smallest crater (no. 3 crater) was formed in 1960 and has a diameter of 150 m. Source: Darwin Volcanic Ash Advisory Centre (VAAC) 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!cwqxtT0ni_2hCUXunLS6Pp8O05DtTecJxH6WjzpmeZ0O4rDpO4iqsGButwFmLlaV8BLM7h1lL96vPww1HJKLOt90YQ$> 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 intensified during 1-2 March and continued at a high level through 11 March. Frequent phreatic eruptions during 4-7 March ejected material as high as 50 m above the crater floor. The phreatic eruptions were almost continuous at Boca C and sporadic and Boca A. Radial deformation and inflation was detected in and around the crater, and the rate of deformation was increasing. The lake level had dropped, and the water was separated into two small ponds. An analysis of monitoring data suggested that there were disturbances of the magmatic system at depth which increased the probability of dangerous eruptions within the Parque Nacional Volcán Poás within the next few days or weeks. At 1330 on 7 March the Alert Level was raised to 3 (the second highest level on a four-level scale) and the Aviation Color Code was raised to Orange (the second highest color on a four-color scale). Small frequent phreatic eruptions, mostly at Boca C, continued during 8-9 March. In a special report issued at 1000 on 9 March OVSICORI-UNA reported that two shock waves identified in infrasound data signified an eruptive event. Steam plumes rose several hundred meters and material was likely ejected as high as 200 m above the vent, though visual confirmation was obscured by the plumes. Phreatic eruptions at 1053, 1236, and 1821 on 9 March generated gas-and-steam plumes that rose as high as 1 km; the plumes obscured views of the crater. Sulfur dioxide emissions detected in satellite data averaged 538 tons per day. Notably, during the evening, eight volcano-tectonic events associated with rock fracturing were recorded in both seismic and infrasound data. Activity continued during 9-10 March mainly from Boca C and some from Boca A. The phreatic eruptions ejected material 200-400 m above the crater floor and generated steam-and-gas plumes that rose as high as 1 km. The ponds continued to shrink and the water had a high sediment content. Blocks up to 1 m in diameter were ejected from the vents onto the crater floor and sediments rich in native sulfur were deposited around the edges of the small ponds. Eruptive activity continued on 11 March at similar levels, moderate- to high-level tremor was recorded, and inflation continued. 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!cwqxtT0ni_2hCUXunLS6Pp8O05DtTecJxH6WjzpmeZ0O4rDpO4iqsGButwFmLlaV8BLM7h1lL96vPww1HJI5agvunA$> Turrialba | Costa Rica | 10.025°N, 83.767°W | Summit elev. 3340 m The Observatorio Vulcanológico y Sismológico de Costa Rica-Universidad Nacional (OVSICORI-UNA) reported that the seismic network at Turrialba recorded signals during 9-10 March that were likely related to small landslides of material within West Crater. Gas emissions remained at low levels. Geologic Summary. Turrialba, the easternmost of Costa Rica's Holocene volcanoes, is a large vegetated basaltic-to-dacitic stratovolcano located across a broad saddle NE of Irazú volcano overlooking the city of Cartago. The massive edifice covers an area of 500 km2. Three well-defined craters occur at the upper SW end of a broad 800 x 2200 m summit depression that is breached to the NE. Most activity originated from the summit vent complex, but two pyroclastic cones are located on the SW flank. Five major explosive eruptions have occurred during the past 3500 years. A series of explosive eruptions during the 19th century were sometimes accompanied by pyroclastic flows. Fumarolic activity continues at the central and SW summit craters. 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!cwqxtT0ni_2hCUXunLS6Pp8O05DtTecJxH6WjzpmeZ0O4rDpO4iqsGButwFmLlaV8BLM7h1lL96vPww1HJI5agvunA$> Ongoing Activity Ahyi | United States | 20.42°N, 145.03°E | Summit elev. -75 m Unrest at Ahyi Seamount continued during 28 February-7 March. A plume of discolored water in the vicinity of the seamount was identified in a satellite image on 3 March, indicating possible submarine activity. Weather clouds obscured views during the rest of the week. No signals coming from the direction of Ahyi were identified in data from underwater pressure sensors near Wake Island (about 2,270 km E of Ahyi). The Aviation Color Code remained at Yellow (the second lowest level on a four-color scale) and the Volcano Alert Level remained at Advisory (the second lowest level on a four-level scale). Geologic Summary. Ahyi seamount is a large conical submarine volcano that rises to within 75 m of the ocean surface ~18 km SE of the island of Farallon de Pajaros in the northern Marianas. Water discoloration has been observed there, and in 1979 the crew of a fishing boat felt shocks over the summit area, followed by upwelling of sulfur-bearing water. On 24-25 April 2001 an explosive eruption was detected seismically by a station on Rangiroa Atoll, Tuamotu Archipelago. The event was well constrained (+/- 15 km) at a location near the southern base of Ahyi. An eruption in April-May 2014 was detected by NOAA divers, hydroacoustic sensors, and seismic stations. Source: US Geological Survey https://www.usgs.gov/ <https://urldefense.com/v3/__https://www.usgs.gov/__;!!IKRxdwAv5BmarQ!cwqxtT0ni_2hCUXunLS6Pp8O05DtTecJxH6WjzpmeZ0O4rDpO4iqsGButwFmLlaV8BLM7h1lL96vPww1HJLDoRTouQ$> 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 3-10 March. Nightly crater incandescence was visible in webcam images. An explosion at 0523 on 4 March generated an ash plume that rose 1.5 km above the crater rim, drifted NE, and merged into weather clouds. The explosion ejected large blocks 600-900 m from the vent. Eruptive events at 0851 on 6 March, at 1640, 1704, 1808, and 2003 on 7 March, at 0031 on 8 March, and at 1525, 1645, and 1714 on 9 March generated ash plumes that rose 1-1.2 km above the crater rim and sometimes drifted NE or SE. Explosions at 1502 on 9 March and at 1124, 1604, and 2206 on 10 March produced ash plumes that rose as high as 1.3 km above the crate rim and drifted S and N. The explosion at 2206 on 10 March ejected blocks 600-900 m from the vent. 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!cwqxtT0ni_2hCUXunLS6Pp8O05DtTecJxH6WjzpmeZ0O4rDpO4iqsGButwFmLlaV8BLM7h1lL96vPww1HJLthbybNw$> Dukono | Indonesia | 1.6992°N, 127.8783°E | Summit elev. 1273 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that the eruption at Dukono was ongoing during 26 February-4 March. Daily white-and-gray or gray-to-black ash plumes that were often dense rose as high as 1.2 km above the crater rim and drifted NE, NW, W, and S. Booming sounds were reported during 6-7 March. An explosion on 9 March was heard as far as the Dukono observation post (11 km N). The Alert Level remained at Level 2 (on a scale of 1-4) and the public was warned to stay 4 km away from the Malupang Warirang Crater. Geologic Summary. Reports from this remote volcano in northernmost Halmahera are rare, but Dukono has been one of Indonesia's most active volcanoes. More-or-less continuous explosive eruptions, sometimes accompanied by lava flows, have occurred since 1933. During a major eruption in 1550 CE, a lava flow filled in the strait between Halmahera and the N-flank Gunung Mamuya cone. This complex volcano presents a broad, low profile with multiple summit peaks and overlapping craters. Malupang Wariang, 1 km SW of the summit crater complex, contains a 700 x 570 m crater that has also been active during historical time. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://vsi.esdm.go.id/ <https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!cwqxtT0ni_2hCUXunLS6Pp8O05DtTecJxH6WjzpmeZ0O4rDpO4iqsGButwFmLlaV8BLM7h1lL96vPww1HJJc1ZhZfQ$> 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 5-11 March, confirmed by a 6 March radar image. Small daily earthquakes were detected by the seismic network. Weather clouds often obscured satellite and webcam 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!cwqxtT0ni_2hCUXunLS6Pp8O05DtTecJxH6WjzpmeZ0O4rDpO4iqsGButwFmLlaV8BLM7h1lL96vPww1HJKZ9N_PwQ$> Home Reef | Tonga | 18.992°S, 174.775°W | Summit elev. -10 m The Tonga Geological Services reported that thermal activity at Home Reef had increased since 21 February with the last thermal anomaly detected on 4 March. Weather conditions sometimes prevented satellite observations during 21 February-7 March. Infrasound data was evidence of continuing minor eruptive activity. The Maritime Alert Level remained at Orange (the third level on a four-level scale), and mariners were advised to stay at least 2 nautical miles (3.7 km) away from the island. The Aviation Color Code remained at Yellow (the second level on a four-level scale), and the Alert Level for residents of Vavaâ??u and Haâ??apai remained at Green (the first level on a four-level scale). Geologic Summary. Home Reef, a submarine volcano midway between Metis Shoal and Late Island in the central Tonga islands, was first reported active in the mid-19th century, when an ephemeral island formed. An eruption in 1984 produced a 12-km-high eruption plume, large amounts of floating pumice, and an ephemeral 500 x 1,500 m island, with cliffs 30-50 m high that enclosed a water-filled crater. In 2006 an island-forming eruption produced widespread dacitic pumice rafts that drifted as far as Australia. Another island was built during a September-October 2022 eruption. Source: Tonga Geological Services, Government of Tonga https://www.facebook.com/tongageologicalservice <https://urldefense.com/v3/__https://www.facebook.com/tongageologicalservice__;!!IKRxdwAv5BmarQ!cwqxtT0ni_2hCUXunLS6Pp8O05DtTecJxH6WjzpmeZ0O4rDpO4iqsGButwFmLlaV8BLM7h1lL96vPww1HJKaPkmVFw$> 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 5-11 March. 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 NW, W, and SW. Minor 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!cwqxtT0ni_2hCUXunLS6Pp8O05DtTecJxH6WjzpmeZ0O4rDpO4iqsGButwFmLlaV8BLM7h1lL96vPww1HJJc1ZhZfQ$> Kanlaon | Philippines | 10.4096°N, 123.13°E | Summit elev. 2422 m The Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported continuing eruptive activity at Kanlaon during 4-11 March. The seismic network recorded 3-19 daily volcanic earthquakes, including 1-2 periods of volcanic tremor lasting from five minutes to three hours and two minutes during 6-7 and 9 March. Average daily sulfur dioxide emissions ranged from 1,712 to 3,144 tonnes per day. Gas-and-steam emissions that were often continuous and occasionally contained ash rose as high as 300 m above the summit and drifted NW, W, and SW. There were 1-2 periods of ash emissions lasting 1-15 minutes during 4-5, 7, and 9 March, and seven periods of ash emissions on 6 March lasting eight minutes to nearly three hours. The Alert Level remained at 3 (on a scale of 0-5); the public was warned to stay 6 km away from the summit and pilots were warned not to fly close to the volcano. Geologic Summary. Kanlaon volcano (also spelled Canlaon) forms the highest point on the Philippine island of Negros. The massive andesitic stratovolcano is covered with fissure-controlled pyroclastic cones and craters, many of which are filled by lakes. The largest debris avalanche known in the Philippines traveled 33 km SW from Kanlaon. The summit contains a 2-km-wide, elongated northern caldera with a crater lake and a smaller but higher active vent, Lugud crater, to the south. Eruptions recorded since 1866 have typically consisted of phreatic explosions of small-to-moderate size that produce minor local ashfall. Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS) http://www.phivolcs.dost.gov.ph/ <https://urldefense.com/v3/__http://www.phivolcs.dost.gov.ph/__;!!IKRxdwAv5BmarQ!cwqxtT0ni_2hCUXunLS6Pp8O05DtTecJxH6WjzpmeZ0O4rDpO4iqsGButwFmLlaV8BLM7h1lL96vPww1HJLStSHHnw$> 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 4-11 March. Lava fountaining and lava flow effusion from cones at both the N and S vents began around 0730 on 4 March and continued at variable levels through the day. Lava fountains at the N vent were rising over 100 m by 1430. At around the same time low dome fountains began rising from the S vent and lava flows advanced onto the crater floor. The fountains started to grow taller by 1500 and by 1520 they were 100-130 m tall, the same height as fountains at the N vent. Fountains at the S vent continued to rise and approached 180 m tall, while fountains at the N vent decreased in height. In addition to the activity at the N and S vents, small breakouts were visible on the rootless flows near the September 2023 vents on the down-dropped block in the E part of Halemaâ??umaâ??u. Fountaining at the N vent ceased at 2026. Fountains at the S vent dropped to 90-120 m and continued to be active overnight. The N vent produced occasional bursts of spatter. Sustained lava fountains at the S vent decreased to 30-60 m during 0300-0430 on 5 March. Fountaining at the S vent increased at around 0800, and the N vent briefly resumed fountaining and erupting lava flows during 0842-0911. Lava flows covered more than two thirds of the crater floor. Activity at both vents ceased by 1030. Sulfur dioxide emission averaged approximately 35,000 tonnes per day (t/d) during the period of high fountaining on the afternoon of 4 March, then decreased to 20,000 t/d during lower fountaining on the morning of 5 March, and to 1,800 t/d by the afternoon. The flows from the N and S vents were active during 5-6 March with ooze outs and small crustal overturns, but the activity had ceased by the morning of 7 March. Sulfur dioxide emission averaged 1,000 t/d on 7 March. Incandescence from both the N and S vents was visible during 8-10 March. At about 0130 on 10 March small, sporadic, spatter fountains at the N vent rose 5-10 m high and continued to intensify until 1835. Spattering was visible overnight. Lava flows emerged from the N vent at 0236 on 11 March and tall fountaining started 10 minutes later. By 0330 the fountains were 120-150 m tall and lava covered up to one-third of the crater floor. Lava flows unrelated to the activity at the N and S vents continued to spread out on the down-dropped block in the E part of the crater during 5-10 March and were possibly fed from by older stored lava from beneath the crater floor. 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!cwqxtT0ni_2hCUXunLS6Pp8O05DtTecJxH6WjzpmeZ0O4rDpO4iqsGButwFmLlaV8BLM7h1lL96vPww1HJJssG-aZg$> Lewotobi | Indonesia | 8.542°S, 122.775°E | Summit elev. 1703 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that eruptive activity continued at Lewotobi Laki-laki during 5-11 March. Eruptive events were detected on 5 and 7 March, though not confirmed visually; weather clouds sometimes prevented observations. Gray ash plumes that were sometimes dense rose as high as 2 km above the summit and drifted multiple directions during 8-11 March. Incandescence at the summit was occasionally visible in webcam images posted with the reports. The Alert Level remained at 3 (on a scale of 1-4) and the public was warned to stay 5 km away from the center of Laki-laki and 6 km in a semicircle clockwise from the SW to the NE. Geologic Summary. The Lewotobi edifice in eastern Flores Island is composed of the two adjacent Lewotobi Laki-laki and Lewotobi Perempuan stratovolcanoes (the "husband and wife"). Their summits are less than 2 km apart along a NW-SE line. The conical Laki-laki to the NW has been frequently active during the 19th and 20th centuries, while the taller and broader Perempuan has had observed eruptions in 1921 and 1935. Small lava domes have grown during the 20th century in both of the summit craters, which are open to the north. A prominent cone, Iliwokar, occurs on the E flank of Perampuan. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://vsi.esdm.go.id/ <https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!cwqxtT0ni_2hCUXunLS6Pp8O05DtTecJxH6WjzpmeZ0O4rDpO4iqsGButwFmLlaV8BLM7h1lL96vPww1HJJc1ZhZfQ$> 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 5-11 March. White-and-gray ash plumes that were sometimes dense rose as high as 600 m above the summit and drifted E and SE, W, and NW. Rumbling sounds were reported on 10 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!cwqxtT0ni_2hCUXunLS6Pp8O05DtTecJxH6WjzpmeZ0O4rDpO4iqsGButwFmLlaV8BLM7h1lL96vPww1HJJc1ZhZfQ$> Marapi | Indonesia | 0.38°S, 100.474°E | Summit elev. 2885 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that eruptive activity at Marapi continued during 5-11 March. At 0245 on 7 March a gray dense ash plume rose 1.2 km above the summit and drifted N. Almost two hours later, at 0431, a webcam image showed crater incandescence. An eruptive event at 1041 on 8 March was recorded by the seismic network but not visually observed. The Alert Level remained at 2 (on a scale of 1-4) and the public was warned to stay 3 km away from the active crater. Geologic Summary. Gunung Marapi, not to be confused with the better-known Merapi volcano on Java, is Sumatra's most active volcano. This massive complex stratovolcano rises 2,000 m above the Bukittinggi Plain in the Padang Highlands. A broad summit contains multiple partially overlapping summit craters constructed within the small 1.4-km-wide Bancah caldera. The summit craters are located along an ENE-WSW line, with volcanism migrating to the west. More than 50 eruptions, typically consisting of small-to-moderate explosive activity, have been recorded since the end of the 18th century; no lava flows outside the summit craters have been reported in historical time. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://vsi.esdm.go.id/ <https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!cwqxtT0ni_2hCUXunLS6Pp8O05DtTecJxH6WjzpmeZ0O4rDpO4iqsGButwFmLlaV8BLM7h1lL96vPww1HJJc1ZhZfQ$> 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 28 February-6 March. Seismicity was at higher levels that the previous week. The SW lava dome produced 57 lava avalanches that traveled as far as 2 km SW down the Bebeng drainage, 43 that traveled as far as 2 km SW down the Krasak drainage, and 34 that traveled as far as 2 km SW down the Sat/Putih drainage. Slight morphological changes to the SW lava dome resulting 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!cwqxtT0ni_2hCUXunLS6Pp8O05DtTecJxH6WjzpmeZ0O4rDpO4iqsGButwFmLlaV8BLM7h1lL96vPww1HJIjrmBeug$> Nevado del Ruiz | Colombia | 4.892°N, 75.324°W | Summit elev. 5279 m The Servicio Geológico Colombianoâ??s (SGC) Observatorio Vulcanológico y Sismológico de Manizales reported that eruptive activity at Nevado del Ruiz continued during 4-11 March. Seismic data indicated that events associated with fluid movement increased in both number and intensity compared to the previous week. Some of the seismic events were associated with pulsating ash emissions; webcam images confirmed these ash emissions, including some with higher-temperature ejecta. Gas-and-ash plumes rose as high as 1.1 km above the summit; at 0850 on 5 March a plume rose as high as 2.2 km above the summit as it drifted downwind. Notably, at 0100 on 11 March, a gas-and-ash emission was associated with a more intense thermal anomaly. Seismicity associated with rock fracturing increased in number but lower in magnitude compared to the previous week. The earthquakes were mainly located below Arenas Crater and the NE flank within 5 km, with depths of 2-6 km, and a fewer number occurred below the E, SE, and SW flanks. Low-energy thermal anomalies on the crater floor were identified in satellite data, though on 11 March the anomaly was characterized as moderate. Sulfur dioxide emissions detected in satellite data continued to be significant. The Alert Level remained at Yellow (the second level on a four-level scale), and the public was warned to stay out of the restricted areas around Arenas Crater, not to spend long periods of time on the Murillo-Cerro Gualà Road, and to avoid drainages in the high-threat zones. Geologic Summary. Nevado del Ruiz is a broad, glacier-covered volcano in central Colombia that covers more than 200 km2. Three major edifices, composed of andesitic and dacitic lavas and andesitic pyroclastics, have been constructed since the beginning of the Pleistocene. The modern cone consists of a broad cluster of lava domes built within the caldera of an older edifice. The 1-km-wide, 240-m-deep Arenas crater occupies the summit. The prominent La Olleta pyroclastic cone located on the SW flank may also have been active in historical time. Steep headwalls of massive landslides cut the flanks. Melting of its summit icecap during historical eruptions, which date back to the 16th century, has resulted in devastating lahars, including one in 1985 that was South America's deadliest eruption. Source: Servicio Geológico Colombiano (SGC) https://www2.sgc.gov.co/volcanes/index.html <https://urldefense.com/v3/__https://www2.sgc.gov.co/volcanes/index.html__;!!IKRxdwAv5BmarQ!cwqxtT0ni_2hCUXunLS6Pp8O05DtTecJxH6WjzpmeZ0O4rDpO4iqsGButwFmLlaV8BLM7h1lL96vPww1HJLhYQIFEw$> 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 26 February-4 March, with multiple, daily eruptive events recorded by the seismic network. Daily white-and-gray or gray ash plumes rose 200-1,300 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!cwqxtT0ni_2hCUXunLS6Pp8O05DtTecJxH6WjzpmeZ0O4rDpO4iqsGButwFmLlaV8BLM7h1lL96vPww1HJJc1ZhZfQ$> Suwanosejima | Japan | 29.638°N, 129.714°E | Summit elev. 796 m The Japan Meteorological Agency (JMA) reported that eruptive activity at Suwanosejima's Ontake Crater continued during 3-10 March. Incandescence was observed nightly in webcam images. Eruptive activity generated emissions that rose 800 m above the crater rim. No changes around the crater were observed during a 5 March aerial observation. The Alert Level remained at 2 (the second level on a five-level scale) and the public was warned to stay at least 1.5 km away from the crater. Geologic Summary. The 8-km-long island of Suwanosejima in the northern Ryukyu Islands consists of an andesitic stratovolcano with two active summit craters. The summit is truncated by a large breached crater extending to the sea on the E flank that was formed by edifice collapse. One of Japan's most frequently active volcanoes, it was in a state of intermittent Strombolian activity from Otake, the NE summit crater, between 1949 and 1996, after which periods of inactivity lengthened. The largest recorded eruption took place in 1813-14, when thick scoria deposits covered residential areas, and the SW crater produced two lava flows that reached the western coast. At the end of the eruption the summit of Otake collapsed, forming a large debris avalanche and creating an open collapse scarp extending to the eastern coast. The island remained uninhabited for about 70 years after the 1813-1814 eruption. Lava flows reached the eastern coast of the island in 1884. Only about 50 people live on the island. Source: Japan Meteorological Agency (JMA) http://www.jma.go.jp/jma/ <https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!cwqxtT0ni_2hCUXunLS6Pp8O05DtTecJxH6WjzpmeZ0O4rDpO4iqsGButwFmLlaV8BLM7h1lL96vPww1HJLthbybNw$> 4-4-4-4-4-4-4-4-4-4-4-4-4 ============================================================== 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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