3-3-3-3-3-3-3-3-3-3-3-3-3 From: "Kuhn, Sally" <KUHNS@xxxxxx> Smithsonian / USGS Weekly Volcanic Activity Report 28 May-3 June 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!bFm1LbFOs_VYB0ZRFbFc7qh_b9_SRbmpZCDqhDr8pZRgInMXpuYa69VstwwbV9c9cJ4yhVURHQ13Hw3gMoHcEawFYg$> New Activity/Unrest: Etna, Italy | Klyuchevskoy, Russia | Taal, Philippines Ongoing Activity: Ahyi, United States | Aira, Japan | Ambae, Vanuatu | Ambrym, Vanuatu | Dukono, Indonesia | Fuego, Guatemala | Gaua, Vanuatu | Great Sitkin, United States | Ibu, Indonesia | Kanlaon, Philippines | Karymsky, Russia | Kilauea, United States | Lewotobi, Indonesia | Lewotolok, Indonesia | Lopevi, Vanuatu | Marapi, Indonesia | Merapi, Indonesia | Poas, Costa Rica | Popocatepetl, Mexico | Rincon de la Vieja, Costa Rica | Santa Maria, Guatemala | Semeru, Indonesia | Sheveluch, Russia | Stromboli, Italy | Suwanosejima, Japan | Yasur, Vanuatu | Yellowstone, United States 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 Etna | Italy | 37.748°N, 14.999°E | Summit elev. 3357 m The Sezione di Catania - Osservatorio Etneo (INGV) reported that tremor amplitude at Etna began to increase starting at around 0000 on 2 June and reached high levels by 0250. Infrasound activity slightly increased at around 0230 and around 0350 Strombolian activity at the SE Crater was visible in webcam images. The Aviation Color Code was raised to Yellow (the second highest color on a four-color scale) at 0323, to Orange at 0402, and to Red at 0839. Ash emissions at this time were confined to the summit area, though Strombolian activity intensified through the morning and became almost continuous. Lava overflowed the E rim of the crater and produced a small lava flow towards the Valle del Bove. A larger flow traveled S. Infrasound activity was both frequent and intense. Lava fountaining began at SE Crater at around 1000 and both lava flows advanced; the flows branched and were 2 km long. Ash plumes rose above the summit and drifted W. Minor ashfall was reported in the Piano Vetore area (6 km SSW) prior to 1100. A fissure opened on the upper NE flank of SE Crater at around 1100 and produced a lava flow that advanced N, according to the Associazione Italiana di Vulcanologia ETS (AIV ETS). Emissions of gas, ash, and white-to-reddish-brown steam rose from that same area. The emissions progressively intensified for 20 minutes. INGV noted that at 1124 a pyroclastic flow was likely generated from a collapse of material at the N side of the SE Crater cone and traveled NE, reaching the N wall of the Valle del Leone (the upper part of the Valle del Bove). AIV ETS stated that the pyroclastic flow interacted explosively with buried snow and traveled 2 km in one minute. Ash rose along the pyroclastic flow to about 3 km above the summit and was visible across eastern Sicily. According to INGV fine reddish ash drifted WNW and fell in Cesarò (27 km WNW) and Bronte (15 km WNW). A lava flow from the base of the N flank of SE Crater advanced N. News article noted that many tourists were on the flanks and were seen running away from the pyroclastic flow; tourist visits to the volcano were halted. About 20 percent of flights into Catania were delayed. Strombolian activity decreased during the afternoon and at 1600 the Aviation Color Code was lowered to Orange. Minor ash emissions continued but dispersed near the summit area; the Aviation Color Code was lowered Yellow at 1656. Activity ceased and at 2011 the Aviation Color Code was lowered to Green. 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. Sources: Sezione di Catania - Osservatorio Etneo (INGV) http://www.ct.ingv.it/ <https://urldefense.com/v3/__http://www.ct.ingv.it/__;!!IKRxdwAv5BmarQ!bFm1LbFOs_VYB0ZRFbFc7qh_b9_SRbmpZCDqhDr8pZRgInMXpuYa69VstwwbV9c9cJ4yhVURHQ13Hw3gMoEXwOS6nA$> ; Toulouse Volcanic Ash Advisory Centre (VAAC) http://vaac.meteo.fr/ <https://urldefense.com/v3/__http://vaac.meteo.fr/__;!!IKRxdwAv5BmarQ!bFm1LbFOs_VYB0ZRFbFc7qh_b9_SRbmpZCDqhDr8pZRgInMXpuYa69VstwwbV9c9cJ4yhVURHQ13Hw3gMoE7WXfF8w$> ; National Public Radio (NPR) https://www.npr.org/2025/06/02/g-s1-70041/mount-etna-erupts-volcano-italy-sicily <https://urldefense.com/v3/__https://www.npr.org/2025/06/02/g-s1-70041/mount-etna-erupts-volcano-italy-sicily__;!!IKRxdwAv5BmarQ!bFm1LbFOs_VYB0ZRFbFc7qh_b9_SRbmpZCDqhDr8pZRgInMXpuYa69VstwwbV9c9cJ4yhVURHQ13Hw3gMoHVjtJBeg$> ; New York Times https://www.nytimes.com/2025/06/02/travel/mount-etna-volcano-eruption-sicily-italy.html <https://urldefense.com/v3/__https://www.nytimes.com/2025/06/02/travel/mount-etna-volcano-eruption-sicily-italy.html__;!!IKRxdwAv5BmarQ!bFm1LbFOs_VYB0ZRFbFc7qh_b9_SRbmpZCDqhDr8pZRgInMXpuYa69VstwwbV9c9cJ4yhVURHQ13Hw3gMoFV98SxBg$> ; Associazione Italiana di Vulcanologia ETS (AIV ETS) https://www.aivulc.it/ <https://urldefense.com/v3/__https://www.aivulc.it/__;!!IKRxdwAv5BmarQ!bFm1LbFOs_VYB0ZRFbFc7qh_b9_SRbmpZCDqhDr8pZRgInMXpuYa69VstwwbV9c9cJ4yhVURHQ13Hw3gMoGgYO5Kog$> Klyuchevskoy | Russia | 56.056°N, 160.642°E | Summit elev. 4754 m The Kamchatkan Volcanic Eruption Response Team (KVERT) reported that a daily bright thermal anomaly at Klyuchevskoy was identified in satellite images during 23-29 May. Explosions at 1945 on 28 May produced ash plumes that rose 6.5 km (21,300 ft) a.s.l., or about 1.7 km above the summit, and drifted 5 km SW. The ash plumes were identified in webcam images. The Aviation Color Code was raised to Orange (the second highest level on a four-color scale) at 2000. Dates are based on UTC times; specific events are in local time where noted. Geologic Summary. Klyuchevskoy is the highest and most active volcano on the Kamchatka Peninsula. Since its origin about 6,000 years ago, this symmetrical, basaltic stratovolcano has produced frequent moderate-volume explosive and effusive eruptions without major periods of inactivity. It rises above a saddle NE of Kamen volcano and lies SE of the broad Ushkovsky massif. More than 100 flank eruptions have occurred during approximately the past 3,000 years, with most lateral craters and cones occurring along radial fissures between the unconfined NE-to-SE flanks of the conical volcano between 500 and 3,600 m elevation. Eruptions recorded since the late 17th century have resulted in frequent changes to the morphology of the 700-m-wide summit crater. These eruptions over the past 400 years have originated primarily from the summit crater, but have also included numerous major explosive and effusive eruptions from flank craters. 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!bFm1LbFOs_VYB0ZRFbFc7qh_b9_SRbmpZCDqhDr8pZRgInMXpuYa69VstwwbV9c9cJ4yhVURHQ13Hw3gMoF513kmAw$> Taal | Philippines | 14.0106°N, 120.9975°E | Summit elev. 311 m The Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported continuing unrest at Taal during 27 May-3 June. There were 0-20 daily volcanic earthquakes and a few periods of tremor that lasted 1-10 minutes long during 27-30 May and on 2 June; no volcanic earthquakes were recorded during 31 May-1 June. Daily gas-and-steam emissions that were sometimes voluminous rose 900-1,500 m above the crater rim and drifted NW and NE. Hot fluids upwelling in the lake were periodically observed. Sulfur dioxide emissions averages were 1,351-6,289 tonnes per day on most days. A minor phreatic eruption lasting four minutes occurred on 29 May. The Alert Level remained at 1 (on a scale of 0-5); PHIVOLCS reminded the public that the entire Taal Volcano Island was a Permanent Danger Zone (PDZ) and recommended that the Main Crater and areas along the Daang Kastila fissure should remain prohibited. Geologic Summary. Taal is one of the most active volcanoes in the Philippines and has produced some powerful eruptions. The 15 x 20 km Talisay (Taal) caldera is largely filled by Lake Taal, whose 267 km2 surface lies only 3 m above sea level. The maximum depth of the lake is 160 m, with several submerged eruptive centers. The 5-km-wide Volcano Island in north-central Lake Taal is the location of all observed eruptions. The island is composed of coalescing small stratovolcanoes, tuff rings, and scoria cones. Powerful pyroclastic flows and surges have caused many fatalities. Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS) http://www.phivolcs.dost.gov.ph/ <https://urldefense.com/v3/__http://www.phivolcs.dost.gov.ph/__;!!IKRxdwAv5BmarQ!bFm1LbFOs_VYB0ZRFbFc7qh_b9_SRbmpZCDqhDr8pZRgInMXpuYa69VstwwbV9c9cJ4yhVURHQ13Hw3gMoFWVcaQiw$> Ongoing Activity Ahyi | United States | 20.42°N, 145.03°E | Summit elev. -75 m Unrest at Ahyi Seamount continued during 24-30 May. A small plume of discolored water in the vicinity of the seamount was identified in a satellite image on 28 May, indicating possible submarine activity. Possible infrasound signals coming from the direction of Ahyi were identified in data from underwater pressure sensors near Wake Island (about 2,270 km E) on 29 May. 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!bFm1LbFOs_VYB0ZRFbFc7qh_b9_SRbmpZCDqhDr8pZRgInMXpuYa69VstwwbV9c9cJ4yhVURHQ13Hw3gMoFg_es-Lg$> 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 28 May-2 June. Very small eruptive events were recorded during 26-28 May. Sulfur dioxide emissions measured during a field survey on 28 May were extremely high, averaging 3,500 tons per day. An explosion at 1537 on 29 May produced an ash plume that rose 1.5 km above the crater rim, going into weather clouds, and ejected large blocks 700 m from the rim. Nighttime crater incandescence was visible during 30 May-2 June. Explosions at 1727 and 2058 on 30 May and at 1610 on 1 June generated ash plumes that rose 3-3.5 km above the crater rim and drifted S and SE and ejected large blocks as far as 1.1 km from the crater rim. An explosion at 2341 on 2 June ejected large blocks as far as 1 km from the crater rim; details about any emissions were unknown. The Alert Level remained at 3 (on a 5-level scale), and the public was warned to be cautious within 2 km of 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!bFm1LbFOs_VYB0ZRFbFc7qh_b9_SRbmpZCDqhDr8pZRgInMXpuYa69VstwwbV9c9cJ4yhVURHQ13Hw3gMoHraaafBQ$> Ambae | Vanuatu | 15.389°S, 167.835°E | Summit elev. 1496 m On 28 May the Vanuatu Meteorology and Geohazards Department (VMGD) reported ongoing unrest at Ambae during the month of May. Steam and/or gas emissions from the active vents were visible in webcam images on 1 May. That same day a thermal anomaly was identified in a satellite image. Sulfur dioxide emissions were detected in satellite data during 1-4, 8-21, and 24-26 May. Seismic data also confirmed ongoing unrest. The Alert Level remained at 2 (on a scale of 0-5), and the public was warned to stay outside of the Danger Zone, defined as a 2-km radius around the active vents in Lake Voui, and away from drainages during heavy rains. Geologic Summary. The island of Ambae, also known as Aoba, is a massive 2,500 km3 basaltic shield that is the most voluminous volcano of the New Hebrides archipelago. A pronounced NE-SW-trending rift zone with numerous scoria cones gives the 16 x 38 km island an elongated form. A broad pyroclastic cone containing three crater lakes (Manaro Ngoru, Voui, and Manaro Lakua) is located at the summit within the youngest of at least two nested calderas, the largest of which is 6 km in diameter. That large central edifice is also called Manaro Voui or Lombenben volcano. Post-caldera explosive eruptions formed the summit craters about 360 years ago. A tuff cone was constructed within Lake Voui (or Vui) about 60 years later. The latest known flank eruption, about 300 years ago, destroyed the population of the Nduindui area near the western coast. Source: Vanuatu Meteorology and Geohazards Department (VMGD) http://www.geohazards.gov.vu/ <https://urldefense.com/v3/__http://www.geohazards.gov.vu/__;!!IKRxdwAv5BmarQ!bFm1LbFOs_VYB0ZRFbFc7qh_b9_SRbmpZCDqhDr8pZRgInMXpuYa69VstwwbV9c9cJ4yhVURHQ13Hw3gMoFog5VWmQ$> Ambrym | Vanuatu | 16.25°S, 168.12°E | Summit elev. 1334 m On 28 May the Vanuatu Meteorology and Geohazards Department (VMGD) reported ongoing unrest at Ambrym during the month of May. Webcam images recorded volcanic emissions rising from Benbow Crater on 9 May. Seismic data confirmed ongoing unrest. The Alert Level remained at 2 (on a scale of 0-5). VMGD warned the public to stay outside of Permanent Danger Zone A, defined as a 1-km radius around Benbow Crater and a 2-km radius around Marum Crater, and to stay 500 m away from the ground cracks created by the December 2018 eruption. Geologic Summary. Ambrym, a large basaltic volcano with a 12-km-wide caldera, is one of the most active volcanoes of the New Hebrides Arc. A thick, almost exclusively pyroclastic sequence, initially dacitic then basaltic, overlies lava flows of a pre-caldera shield volcano. The caldera was formed during a major Plinian eruption with dacitic pyroclastic flows about 1,900 years ago. Post-caldera eruptions, primarily from Marum and Benbow cones, have partially filled the caldera floor and produced lava flows that ponded on the floor or overflowed through gaps in the caldera rim. Post-caldera eruptions have also formed a series of scoria cones and maars along a fissure system oriented ENE-WSW. Eruptions have apparently occurred almost yearly during historical time from cones within the caldera or from flank vents. However, from 1850 to 1950, reporting was mostly limited to extra-caldera eruptions that would have affected local populations. Source: Vanuatu Meteorology and Geohazards Department (VMGD) http://www.geohazards.gov.vu/ <https://urldefense.com/v3/__http://www.geohazards.gov.vu/__;!!IKRxdwAv5BmarQ!bFm1LbFOs_VYB0ZRFbFc7qh_b9_SRbmpZCDqhDr8pZRgInMXpuYa69VstwwbV9c9cJ4yhVURHQ13Hw3gMoFog5VWmQ$> Dukono | Indonesia | 1.6992°N, 127.8783°E | Summit elev. 1273 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that eruptive activity at Dukono continued during 14-20 May. Daily white-and-gray or white, gray, and black gas-and-ash plumes rose 900-1,900 m above the summit and drifted NW, W, and S. The emissions were described as ongoing through the week. Residents 10-11 km away felt vibrations from the activity on 29 May and occasional banging sounds were heard at the same distances during 29-30 May. Faint rumbling was heard at the observation post, 11 km N, during 31 May-1 June. 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. The Dukono complex in northern Halmahera is on an edifice with a broad, low profile containing multiple peaks and overlapping craters. Almost 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 Gunung Mamuya cone, 10 km NE. Malupang Wariang, 1 km SW of the summit crater complex, contains a 700 x 570 m crater that has also had reported eruptions. 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!bFm1LbFOs_VYB0ZRFbFc7qh_b9_SRbmpZCDqhDr8pZRgInMXpuYa69VstwwbV9c9cJ4yhVURHQ13Hw3gMoGCfeCqbA$> Fuego | Guatemala | 14.4748°N, 90.8806°W | Summit elev. 3799 m The Instituto Nacional de SismologÃa, Vulcanologia, Meteorologia e HidrologÃa (INSIVUMEH) reported continued eruptive activity at Fuego during 27 May-3 June. Daily explosions were recorded by the seismic network at rates of 3-7 per hour when reported. The explosions generated daily gas-and-ash plumes that rose as high as 1.1 km above the summit and drifted as far as 30 km NW, W, and SW. Incandescent material was occasionally observed at night being ejected 100-150 m above the summit. Rumbling sounds and shock waves were occasionally reported. Explosions sometimes generated block avalanches that descended multiple flanks, sometimes reaching vegetated areas. Ashfall was reported in Panimache I and II (8 km SW), Morelia (10 km SW), Santa Sofia (12 km SW), El Porvenir (11 km SW), Finca la Asunción (12 km SW), and surrounding areas during 27-28 May and in areas downwind including Panimache I and II and Yepocapa (8 km WNW) during 1-2 June. 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 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. Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH) http://www.insivumeh.gob.gt/ <https://urldefense.com/v3/__http://www.insivumeh.gob.gt/__;!!IKRxdwAv5BmarQ!bFm1LbFOs_VYB0ZRFbFc7qh_b9_SRbmpZCDqhDr8pZRgInMXpuYa69VstwwbV9c9cJ4yhVURHQ13Hw3gMoEOKvDs8g$> Gaua | Vanuatu | 14.281°S, 167.514°E | Summit elev. 729 m On 28 May the Vanuatu Meteorology and Geohazards (VMGD) reported that unrest continued at Gaua. Steam and/or gas emissions from the vent were visible in satellite images during the month; sulfur dioxide emissions were identified in images on 19 and 24 May. A moderate-level thermal anomaly was identified in a satellite image on 17 May, indicative of increased surface temperatures. The Alert Level remained at 2 (on a scale of 0-5) and the public was warned to stay away from the main cone. Geologic Summary. The roughly 20-km-diameter Gaua Island, also known as Santa Maria, consists of a basaltic-to-andesitic stratovolcano with an 6 x 9 km summit caldera. Small vents near the caldera rim fed Pleistocene lava flows that reached the coast on several sides of the island; littoral cones were formed where these lava flows reached the ocean. Quiet collapse that formed the roughly 700-m-deep caldera was followed by extensive ash eruptions. The active Mount Garet (or Garat) cone in the SW part of the caldera has three pit craters across the summit area. Construction of Garet and other small cinder cones has left a crescent-shaped lake. The onset of eruptive activity from a vent high on the SE flank in 1962 ended a long period of dormancy. Source: Vanuatu Meteorology and Geohazards Department (VMGD) http://www.geohazards.gov.vu/ <https://urldefense.com/v3/__http://www.geohazards.gov.vu/__;!!IKRxdwAv5BmarQ!bFm1LbFOs_VYB0ZRFbFc7qh_b9_SRbmpZCDqhDr8pZRgInMXpuYa69VstwwbV9c9cJ4yhVURHQ13Hw3gMoFog5VWmQ$> 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 28 May-3 June. Small daily earthquakes were detected by the seismic network. Weather clouds often obscured views of the volcano, though weakly elevated surface temperatures consistent with lava effusion were identified in satellite images on 29 May and 2 June and minor steaming was visible in satellite images on 30 May and 2 June. A 3 June radar image confirmed growth to the SE. 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!bFm1LbFOs_VYB0ZRFbFc7qh_b9_SRbmpZCDqhDr8pZRgInMXpuYa69VstwwbV9c9cJ4yhVURHQ13Hw3gMoFKNso0wA$> 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 14-20 May. Daily gray or white-to-brown ash plumes rose as high as 1 km above the summit and drifted S, SW, NW, and NE. Nighttime crater incandescence was visible in some webcam images. 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!bFm1LbFOs_VYB0ZRFbFc7qh_b9_SRbmpZCDqhDr8pZRgInMXpuYa69VstwwbV9c9cJ4yhVURHQ13Hw3gMoGCfeCqbA$> Kanlaon | Philippines | 10.4096°N, 123.13°E | Summit elev. 2422 m The Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported continuing eruptive activity at Kanlaon during 27 May-3 June. The seismic network recorded 5-38 daily volcanic earthquakes. Daily sulfur dioxide emissions ranged from 300 to 1,844 tonnes per day. Gas-and-steam emissions of variable densities generally rose 75-750 m above the crater rim, though they reached 1.2 km on 2 June, and drifted SE, NE, NW, and SW. During 1338-1407 on 2 June a grayish ash plume rose 1.2 km above the summit and drifted W. The Alert Level remained at 3 (on a scale of 0-5); the public was warned to stay 6 km away from the summit and pilots were warned not to fly close to the volcano. Geologic Summary. Kanlaon volcano (also spelled Canlaon) forms the highest point on the Philippine island of Negros. The massive andesitic stratovolcano is covered with fissure-controlled pyroclastic cones and craters, many of which are filled by lakes. The largest debris avalanche known in the Philippines traveled 33 km SW from Kanlaon. The summit contains a 2-km-wide, elongated northern caldera with a crater lake and a smaller but higher active vent, Lugud crater, to the south. Eruptions recorded since 1866 have typically consisted of phreatic explosions of small-to-moderate size that produce minor local ashfall. Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS) http://www.phivolcs.dost.gov.ph/ <https://urldefense.com/v3/__http://www.phivolcs.dost.gov.ph/__;!!IKRxdwAv5BmarQ!bFm1LbFOs_VYB0ZRFbFc7qh_b9_SRbmpZCDqhDr8pZRgInMXpuYa69VstwwbV9c9cJ4yhVURHQ13Hw3gMoFWVcaQiw$> Karymsky | Russia | 54.049°N, 159.443°E | Summit elev. 1513 m The Kamchatkan Volcanic Eruption Response Team (KVERT) reported that moderate activity continued at Karymsky during 23-29 May. A thermal anomaly over the volcano was identified in satellite images during 22, 25, and 27-28 May; weather clouds obscured views on other days. The Aviation Color Code remained at Orange (the third level on a four-color scale). Dates are based on UTC; 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!bFm1LbFOs_VYB0ZRFbFc7qh_b9_SRbmpZCDqhDr8pZRgInMXpuYa69VstwwbV9c9cJ4yhVURHQ13Hw3gMoF513kmAw$> 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, characterized by episodic fountaining and intermittent spatter at two vents along the SW margin of Halemaâ??umaâ??u Crater, continued at variable levels during 28 May-3 June. Night incandescence and occasional spattering was visible from both the N and S vents during the week, though the incandescence was stronger at the N vent. Gas emissions rose from both vents. Strands of Peleâ??s hair were present throughout the summit area of Hawaiâ??i Volcanoes National Park and surrounding communities. 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!bFm1LbFOs_VYB0ZRFbFc7qh_b9_SRbmpZCDqhDr8pZRgInMXpuYa69VstwwbV9c9cJ4yhVURHQ13Hw3gMoE5zQsaoQ$> Lewotobi | Indonesia | 8.542°S, 122.775°E | Summit elev. 1703 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that daily white steam-and-gas plumes rose as high as 1 km above the summit of Lewotobi Laki-laki during 28 May-3 June. The Alert Level remained at 3 (on a scale of 1-4) and the public was warned to stay 6 km away from the center of Laki-laki. 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!bFm1LbFOs_VYB0ZRFbFc7qh_b9_SRbmpZCDqhDr8pZRgInMXpuYa69VstwwbV9c9cJ4yhVURHQ13Hw3gMoGCfeCqbA$> Lewotolok | Indonesia | 8.274°S, 123.508°E | Summit elev. 1431 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that an eruption at Lewotolok was ongoing during 28 May-3 June. Daily gray or white-to-gray ash plumes rose as high as 1 km above the summit of the cone and drifted NW and W. Clear nighttime webcam images showed incandescent material at the summit cone, being ejected above the summit cone, and on the upper S flank. The Alert Level remained at 2 (on a scale of 1-4) and the public was warned to stay 2 km away from the vent and 2.5 km away on the S, SE, and W flanks. Geologic Summary. The Lewotolok (or Lewotolo) stratovolcano occupies the eastern end of an elongated peninsula extending north into the Flores Sea, connected to Lembata (formerly Lomblen) Island by a narrow isthmus. It is symmetrical when viewed from the north and east. A small cone with a 130-m-wide crater constructed at the SE side of a larger crater forms the volcano's high point. Many lava flows have reached the coastline. Eruptions recorded since 1660 have consisted of explosive activity from the summit crater. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://vsi.esdm.go.id/ <https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!bFm1LbFOs_VYB0ZRFbFc7qh_b9_SRbmpZCDqhDr8pZRgInMXpuYa69VstwwbV9c9cJ4yhVURHQ13Hw3gMoGCfeCqbA$> Lopevi | Vanuatu | 16.507°S, 168.346°E | Summit elev. 1413 m On 28 May the Vanuatu Meteorology and Geohazards Department (VMGD) reported that during the month seismic data confirmed continuing unrest at Lopevi. Small fumarolic steam plumes were continuously emitted from the summit crater based on a webcam image from 1 May. Low-level thermal anomalies were identified in satellite images on 1 and 20 May, indicative of increased surface temperatures. The Alert Level remained at 2 (on a scale of 0-4). Geologic Summary. The small 7-km-wide conical island of Lopevi, known locally as Vanei Vollohulu, is one of Vanuatu's most active volcanoes. A small summit crater containing a cinder cone is breached to the NW and tops an older cone that is rimmed by the remnant of a larger crater. The basaltic-to-andesitic volcano has been active during historical time at both summit and flank vents, primarily along a NW-SE-trending fissure that cuts across the island, producing moderate explosive eruptions and lava flows that reached the coast. Historical eruptions at the 1413-m-high volcano date back to the mid-19th century. The island was evacuated following major eruptions in 1939 and 1960. The latter eruption, from a NW-flank fissure vent, produced a pyroclastic flow that swept to the sea and a lava flow that formed a new peninsula on the western coast. Source: Vanuatu Meteorology and Geohazards Department (VMGD) http://www.geohazards.gov.vu/ <https://urldefense.com/v3/__http://www.geohazards.gov.vu/__;!!IKRxdwAv5BmarQ!bFm1LbFOs_VYB0ZRFbFc7qh_b9_SRbmpZCDqhDr8pZRgInMXpuYa69VstwwbV9c9cJ4yhVURHQ13Hw3gMoFog5VWmQ$> Marapi | Indonesia | 0.38°S, 100.474°E | Summit elev. 2885 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that eruptive activity at Marapi (on Sumatra) continued during 28 May-3 June. White plumes rose 100-400 m above the summit and drifted in multiple directions on most days. An eruptive event at 2236 on 30 May was recorded by the seismic network, though a plume was not visible. White-and-gray plumes rose 150-300 m above the summit and drifted E and SE on 31 May. The Alert Level remained at 2 (on a scale of 1-4) and the public was warned to stay 3 km away from the active crater. Geologic Summary. Gunung Marapi, not to be confused with the better-known Merapi volcano on Java, is Sumatra's most active volcano. This massive complex stratovolcano rises 2,000 m above the Bukittinggi Plain in the Padang Highlands. A broad summit contains multiple partially overlapping summit craters constructed within the small 1.4-km-wide Bancah caldera. The summit craters are located along an ENE-WSW line, with volcanism migrating to the west. More than 50 eruptions, typically consisting of small-to-moderate explosive activity, have been recorded since the end of the 18th century; no lava flows outside the summit craters have been reported in historical time. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://vsi.esdm.go.id/ <https://urldefense.com/v3/__http://vsi.esdm.go.id/__;!!IKRxdwAv5BmarQ!bFm1LbFOs_VYB0ZRFbFc7qh_b9_SRbmpZCDqhDr8pZRgInMXpuYa69VstwwbV9c9cJ4yhVURHQ13Hw3gMoGCfeCqbA$> 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 23-29 May. Seismicity remained at high levels. The SW lava dome produced 30 lava avalanches that traveled as far as 1.8 km SW down the Bebeng drainage, 12 that traveled as far as 1.8 km SW down the Krasak drainage, and 33 that traveled as far as 2 km W down the Sat/Putih drainage. Small morphological changes to the SW lava dome resulted from continuing effusion and minor collapses. 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!bFm1LbFOs_VYB0ZRFbFc7qh_b9_SRbmpZCDqhDr8pZRgInMXpuYa69VstwwbV9c9cJ4yhVURHQ13Hw3gMoFh3UEVug$> 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 continuing gas-and-steam emissions at Poás during 28 May-3 June. Variable sulfur dioxide gas emissions were higher during the last week of May compared to the previous week, but not as high as peak emissions at the end of April. Incandescence continued to be visible and detected in infrared webcam views at Boca A vent. Minor inflation was detected on some days and no clear trend was apparent on others. At 1022 on 1 June a gas-and-steam plume with minor ash content rose 1 km and drifted W. Gas-and-steam emissions continued during 2-3 June; the plume was tinted blue due to a high concentration of sulfur dioxide gas. The volcanoâ??s Alert Level remained at 3 (the second highest level on a four-level 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!bFm1LbFOs_VYB0ZRFbFc7qh_b9_SRbmpZCDqhDr8pZRgInMXpuYa69VstwwbV9c9cJ4yhVURHQ13Hw3gMoHapRuG8w$> 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 27 May-3 June. The seismic network recorded 42-70 long-period events per day, accompanied by steam-and-gas emissions with occasional ash content. In addition, the seismic network recorded daily periods of tremor, sometimes characterized by harmonic and high-frequency signals, lasting from 41 minutes to three hours and 52 minutes. According to the Washington VAAC an ash plume was visible in webcam and satellite images at 1646 on 30 May rising 5.8 km (19,000 ft) a.s.l. (about 400 m above the crater rim) and drifting N. Steam-and-gas plumes with minor ash content were visible in webcam images on 2 June rising 5.8 km a.s.l. and drifting NW and SW. 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: Centro Nacional de Prevencion de Desastres (CENAPRED) https://www.gob.mx/cenapred <https://urldefense.com/v3/__https://www.gob.mx/cenapred__;!!IKRxdwAv5BmarQ!bFm1LbFOs_VYB0ZRFbFc7qh_b9_SRbmpZCDqhDr8pZRgInMXpuYa69VstwwbV9c9cJ4yhVURHQ13Hw3gMoHcapV27g$> ; Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html <https://urldefense.com/v3/__http://www.ssd.noaa.gov/VAAC/messages.html__;!!IKRxdwAv5BmarQ!bFm1LbFOs_VYB0ZRFbFc7qh_b9_SRbmpZCDqhDr8pZRgInMXpuYa69VstwwbV9c9cJ4yhVURHQ13Hw3gMoFVXKQPLg$> 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 28 May-3 June. At 1546 on 31 May an explosive event recorded by the seismic network produced a white plume that rose 3 km above crater rim and drifted W. Two additional brief (around 1 minute long) phreatic events were recorded at 0642 on 1 June and at 0205 on 2 June. The first event generated a white plume with no ash that rose 1.5 km and drifted W; the plume from the second event was not visible. Sulfur dioxide emissions peaked near 1,000 tonnes per day in association with each of the three events. 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!bFm1LbFOs_VYB0ZRFbFc7qh_b9_SRbmpZCDqhDr8pZRgInMXpuYa69VstwwbV9c9cJ4yhVURHQ13Hw3gMoHapRuG8w$> Santa Maria | Guatemala | 14.757°N, 91.552°W | Summit elev. 3745 m The Instituto Nacional de SismologÃa, VulcanologÃa, MeteorologÃa e HidrologÃa (INSIVUMEH) reported high levels of ongoing eruptive activity at Santa Mariaâ??s Santiaguito dome complex during 27 May-3 June with continuing lava extrusion at Caliente dome. Daily weak and moderate explosions, as many as three per hour when reported, generated gas-and-ash plumes that rose as high as 1 km above the dome and drifted as far as 40 km in various directions. Effusion of blocky lava and collapses of material produced block avalanches that descended multiple flanks; the collapsed material sometimes produced short pyroclastic flows that reached the base of Caliente cone. Incandescence was visible at Caliente dome and upper part of the SW flank lava flow. Ashfall was reported in areas downwind including San Marcos (10 km SW), Loma Linda (7 km W), Palajunoj (17 km SSW), Finca Monte Bello (6 km WSW), and Monte MarÃa during 27-31 May. Geologic Summary. Symmetrical, forest-covered Santa MarÃa volcano is part of a chain of large stratovolcanoes that rise above the Pacific coastal plain of Guatemala. The sharp-topped, conical profile is cut on the SW flank by a 1.5-km-wide crater. The oval-shaped crater extends from just below the summit to the lower flank, and was formed during a catastrophic eruption in 1902. The renowned Plinian eruption of 1902 that devastated much of SW Guatemala followed a long repose period after construction of the large basaltic andesite stratovolcano. The massive dacitic Santiaguito lava-dome complex has been growing at the base of the 1902 crater since 1922. Compound dome growth at Santiaguito has occurred episodically from four vents, with activity progressing E towards the most recent, Caliente. Dome growth has been accompanied by almost continuous minor explosions, with periodic lava extrusion, larger explosions, pyroclastic flows, and lahars. Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH) http://www.insivumeh.gob.gt/ <https://urldefense.com/v3/__http://www.insivumeh.gob.gt/__;!!IKRxdwAv5BmarQ!bFm1LbFOs_VYB0ZRFbFc7qh_b9_SRbmpZCDqhDr8pZRgInMXpuYa69VstwwbV9c9cJ4yhVURHQ13Hw3gMoEOKvDs8g$> 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 21-27 May, with often multiple daily eruptive events recorded by the seismic network. White-and-gray ash plumes rose 400-1,200 m above the summit and drifted in multiple directions; no plumes were visible on 31 May. The Alert Level remained at 2 (the second lowest level on a scale of 1-4). The public was warned to stay at least 3 km away from the summit in all directions, 8 km from the summit to the SE, 500 m from the banks of the Kobokan drainage as far as 13 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!bFm1LbFOs_VYB0ZRFbFc7qh_b9_SRbmpZCDqhDr8pZRgInMXpuYa69VstwwbV9c9cJ4yhVURHQ13Hw3gMoGCfeCqbA$> 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 23-29 May. Thermal anomalies over the domes were identified almost daily in satellite images; weather clouds sometimes obscured views. The Far Eastern Branch of the Russian Academy of Sciences (FEB RAS) reported that minor ash plumes rising as high as 3 km (10,000 ft) a.s.l. drifted NW, W, SW, and SE during 23, 25-26, and 28-29 May. The Aviation Color Code remained at Orange (the second highest level on a four-color scale). Dates are based on UTC; 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. 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!bFm1LbFOs_VYB0ZRFbFc7qh_b9_SRbmpZCDqhDr8pZRgInMXpuYa69VstwwbV9c9cJ4yhVURHQ13Hw3gMoF513kmAw$> ; 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!bFm1LbFOs_VYB0ZRFbFc7qh_b9_SRbmpZCDqhDr8pZRgInMXpuYa69VstwwbV9c9cJ4yhVURHQ13Hw3gMoHRQ2YkJQ$> Stromboli | Italy | 38.789°N, 15.213°E | Summit elev. 924 m The Sezione di Catania - Osservatorio Etneo (INGV) reported that eruptive activity continued at Stromboli during 26 May-1 June. Webcam images showed Strombolian activity at four vents in Area N within the upper part of the Sciara del Fuoco and from at least two vents in Area C-S (South-Central Crater) on the crater terrace. The vents in Area N continued to produce low- to medium-intensity explosions at a rate of 4-8 events per hour, ejecting lapilli and bombs less than 150 m above the vents. Low- to medium-intensity explosions at the vents in Area C-S ejected ash, bombs, and lapilli above the vent at a rate of 3-5 events per hour. The Alert Level remained at Yellow (the second lowest level on a four-level scale) according to the Dipartimento della Protezione Civile. Geologic Summary. Spectacular incandescent nighttime explosions at Stromboli have long attracted visitors to the "Lighthouse of the Mediterranean" in the NE Aeolian Islands. This volcano has lent its name to the frequent mild explosive activity that has characterized its eruptions throughout much of historical time. The small island is the emergent summit of a volcano that grew in two main eruptive cycles, the last of which formed the western portion of the island. The Neostromboli eruptive period took place between about 13,000 and 5,000 years ago. The active summit vents are located at the head of the Sciara del Fuoco, a prominent scarp that formed about 5,000 years ago due to a series of slope failures which extends to below sea level. The modern volcano has been constructed within this scarp, which funnels pyroclastic ejecta and lava flows to the NW. Essentially continuous mild Strombolian explosions, sometimes accompanied by lava flows, have been recorded for more than a millennium. Sources: Sezione di Catania - Osservatorio Etneo (INGV) http://www.ct.ingv.it/ <https://urldefense.com/v3/__http://www.ct.ingv.it/__;!!IKRxdwAv5BmarQ!bFm1LbFOs_VYB0ZRFbFc7qh_b9_SRbmpZCDqhDr8pZRgInMXpuYa69VstwwbV9c9cJ4yhVURHQ13Hw3gMoEXwOS6nA$> ; Dipartimento della Protezione Civile https://www.protezionecivile.gov.it/it/ <https://urldefense.com/v3/__https://www.protezionecivile.gov.it/it/__;!!IKRxdwAv5BmarQ!bFm1LbFOs_VYB0ZRFbFc7qh_b9_SRbmpZCDqhDr8pZRgInMXpuYa69VstwwbV9c9cJ4yhVURHQ13Hw3gMoGM3UA40A$> Suwanosejima | Japan | 29.638°N, 129.714°E | Summit elev. 796 m The Japan Meteorological Agency (JMA) reported that eruptive activity at Suwanosejima's Ontake Crater continued during 26 May-2 June. Incandescence was observed nightly in webcam images. No explosions were detected, though plumes from eruptive events rose 600 m above the crater rim. Ashfall was reported by the Suwanosejima Branch of the Toshima Village Office (3.5 km SSW). The Alert Level remained at 2 (the second level on a five-level scale) and the public was warned to be cautious within 1.5 km of the crater. Geologic Summary. The 8-km-long island of Suwanosejima in the northern Ryukyu Islands consists of an andesitic stratovolcano with two active summit craters. The summit is truncated by a large breached crater extending to the sea on the E flank that was formed by edifice collapse. One of Japan's most frequently active volcanoes, it was in a state of intermittent Strombolian activity from Otake, the NE summit crater, between 1949 and 1996, after which periods of inactivity lengthened. The largest recorded eruption took place in 1813-14, when thick scoria deposits covered residential areas, and the SW crater produced two lava flows that reached the western coast. At the end of the eruption the summit of Otake collapsed, forming a large debris avalanche and creating an open collapse scarp extending to the eastern coast. The island remained uninhabited for about 70 years after the 1813-1814 eruption. Lava flows reached the eastern coast of the island in 1884. Only about 50 people live on the island. Source: Japan Meteorological Agency (JMA) http://www.jma.go.jp/jma/ <https://urldefense.com/v3/__http://www.jma.go.jp/jma/__;!!IKRxdwAv5BmarQ!bFm1LbFOs_VYB0ZRFbFc7qh_b9_SRbmpZCDqhDr8pZRgInMXpuYa69VstwwbV9c9cJ4yhVURHQ13Hw3gMoHraaafBQ$> Yasur | Vanuatu | 19.532°S, 169.447°E | Summit elev. 361 m On 28 May the Vanuatu Meteorology and Geohazards Department (VMGD) reported that activity at Yasur continued at a level of â??major unrest,â?? as defined by the Alert Level 2 status (on a scale of 0-5). Satellite and webcam images indicated that explosions continued, producing emissions of gas, steam, and/or ash. Sulfur dioxide gas emissions were identified in satellite images during 3, 5-7, 10, 13-16, 18-24, and 26 May, and low-level thermal anomalies were identified during 3, 5, 7, 13-14, and 26 May. Seismic data confirmed continuing volcanic activity with explosions that were occasionally strong. The report warned that ejected material from explosions could fall in and around the crater. The public was reminded to not enter the restricted area within 600 m around the boundaries of the Permanent Exclusion Zone, defined by Danger Zone A on the hazard map. Geologic Summary. Yasur has exhibited essentially continuous Strombolian and Vulcanian activity at least since Captain Cook observed ash eruptions in 1774. This style of activity may have continued for the past 800 years. Located at the SE tip of Tanna Island in Vanuatu, this pyroclastic cone has a nearly circular, 400-m-wide summit crater. The active cone is largely contained within the small Yenkahe caldera, and is the youngest of a group of Holocene volcanic centers constructed over the down-dropped NE flank of the Pleistocene Tukosmeru volcano. The Yenkahe horst is located within the Siwi ring fracture, a 4-km-wide open feature associated with eruption of the andesitic Siwi pyroclastic sequence. Active tectonism along the Yenkahe horst accompanying eruptions has raised Port Resolution harbor more than 20 m during the past century. Source: Vanuatu Meteorology and Geohazards Department (VMGD) http://www.geohazards.gov.vu/ <https://urldefense.com/v3/__http://www.geohazards.gov.vu/__;!!IKRxdwAv5BmarQ!bFm1LbFOs_VYB0ZRFbFc7qh_b9_SRbmpZCDqhDr8pZRgInMXpuYa69VstwwbV9c9cJ4yhVURHQ13Hw3gMoFog5VWmQ$> Yellowstone | United States | 44.43°N, 110.67°W | Summit elev. 2805 m The Yellowstone Volcano Observatory (YVO) reported that a small hydrothermal explosion occurred at Black Diamond Pool, in Yellowstoneâ??s Biscuit Basin thermal area, at 2039 on 31 May. An analysis of the periodic webcam images (taken every 15 minutes) revealed changes at the pool that same evening; the nature and timing of the changes was not reported. The event was the first at Black Diamond Pool that had been captured on video since the hydrothermal explosion on 23 July 2024, though there was evidence from other monitoring data and eyewitnesses that sporadic eruptions had occurred several times since that event. The Volcano Alert Level remained at Normal (the lowest level on a four-level scale) and the Aviation Color Code remained at Green (the lowest color on a four-color scale). Geologic Summary. The Yellowstone Plateau volcanic field developed through three volcanic cycles spanning two million years that included some of the world's largest known eruptions. Eruption of the over 2,450 km3 Huckleberry Ridge Tuff about 2.1 million years ago created the more than 75-km-long Island Park caldera. The second cycle concluded with the eruption of the Mesa Falls Tuff around 1.3 million years ago, forming the 16-km-wide Henrys Fork caldera at the western end of the first caldera. Activity subsequently shifted to the present Yellowstone Plateau and culminated 640,000 years ago with the eruption of the over 1,000 km3 Lava Creek Tuff and the formation of the present 45 x 85 km caldera. Resurgent doming subsequently occurred at both the NE and SW sides of the caldera and voluminous (1000 km3) intracaldera rhyolitic lava flows were erupted between 150,000 and 70,000 years ago. No magmatic eruptions have occurred since the late Pleistocene, but large hydrothermal events took place near Yellowstone Lake during the Holocene. Yellowstone is presently the site of one of the world's largest hydrothermal systems, including Earth's largest concentration of geysers. Source: Yellowstone Volcano Observatory (YVO) https://www.usgs.gov/observatories/yvo <https://urldefense.com/v3/__https://www.usgs.gov/observatories/yvo__;!!IKRxdwAv5BmarQ!bFm1LbFOs_VYB0ZRFbFc7qh_b9_SRbmpZCDqhDr8pZRgInMXpuYa69VstwwbV9c9cJ4yhVURHQ13Hw3gMoGbMk7C5g$> 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). 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