The Weekly Volcanic Activity Report: May 28-June 3, 2026

New activity/unrest: Ivao Group, Russia | Titan Ridge, Papua New Guinea | Tokachidake, Japan.

New activity/unrest

Ivao Group, Russia

45.7593°N, 149.6762°E; Elev. 1,426 m

According to the Tokyo Volcanic Ash Advisory Center (VAAC) a possible eruption at the Ivao Group may have generated an ash plume that rose 2.7 km (9,000 ft) a.s.l. and drifted E at 2150 on 29 May. Any ash had dissipated by 0120 on 30 May.

Geological summary: The Ivao group of cones along the Krishtofovich Ridge of SW Urup Island contains several well-preserved cones of Holocene age. The first of a group of three young cones, at the NW end of the chain, is the Ivao cone. The SE-most cone bisects a glacial valley, forming Lake Ivao. The elongated central cone, Krutaya Mountain, is the youngest, and produced a viscous lava flow that traveled to the east.

Titan Ridge, Papua New Guinea

3.03°S, 147.78°E; Elev. -1,300 m

The Rabaul Volcano Observatory (RVO) reported that the eruption at Titan Ridge continued during 28 May-4 June. After a decrease in activity over a couple of days the number of hydroacoustic signals significantly increased during 28-29 May, signifying the resumption of semi-continuous activity. Weather clouds prevented satellite observations of the vent areas. Activity was ongoing during 29 May-2 June based on satellite views and hydroacoustic data. By 1 June a steam plume was rising from part of the NE vent area and drifting E and SE; there were no plumes rising from the vent area to the SW. A shallow plume of discolored water drifted as far as 8 km SE from the NE vent. Hot pumice associated with the plume of discolored water was seen floating within a few hundred meters of the vent area; resultant thermal anomalies were hotter than those previously detected. Pumice rafts from previous days were scattered around the Bismarck Sea. During 2-4 June the eruption plume rose as high as 5 km a.s.l. The steam-and-gas plume as well as a plume of discolored sea water drifted NW, N, E, and SE. The number of daily hydroacoustic signals declined on 3 June. Significant amounts of floating pumice, thick and extensive rafts, washed up on the shores of the Admiralty Islands.

Geological summary: SOFAR signals resembling those produced at known submarine eruptions were recorded in January 1972 in the central Bismarck Sea (Johnson et al., 1981). The source of the signals was at the junction of two segments of the N margin of the South Bismarck plate. The more easterly of these segments is a transform fault, whereas the more westerly is an area of oblique active seafloor spreading. The signals were detected by a seismic station on nearby Manus Island, as well as at hydrophone stations on Wake and Midway Islands in the central Pacific. During the eruption in 2026 the “Titan Ridge” name was proposed by local residents. The general story of the Titan (pronounced Tee-Tahn) people is that their island home got devastated and reduced to the Circular Reef (~40 km SSW) due to an uncertain natural phenomenon; they drifted for awhile before they settled, and most of the Titan villages are now mainly along the south coast of Manus Island.

Tokachidake, Japan

43.418°N, 142.686°E; Elev. 2,077 m

The Japan Meteorological Agency (JMA) reported increasing seismicity at Tokachidake. Fumarolic activity, including the volume of plumes and the rate of volcanic gas emissions at Crater 62-2, remained high. Seismicity began gradually increasing in April, with occasional temporary spikes in earthquake frequency; volcanic activity overall showed a slight upward trend. The number of volcanic earthquakes located at shallow depths beneath Crater 62-2 began to increase at around 0100 on 31 May and by 0900 on 1 June the network had recorded a preliminary total of 86 events. The Alert Level remained at 1 (on a 5-level scale).

Geological summary: Tokachidake volcano consists of a group of dominantly andesitic stratovolcanoes and lava domes arranged on a NE-SW line above a plateau of welded Pleistocene tuffs in central Hokkaido. Numerous explosion craters and cinder cones are located on the upper flanks of the small stratovolcanoes, with the youngest Holocene centers located at the NW end of the chain. Frequent historical eruptions, consisting mostly of mild-to-moderate phreatic explosions, have been recorded since the mid-19th century. Two larger eruptions occurred in 1926 and 1962. Partial cone collapse of the western flank during the 1926 eruption produced a disastrous debris avalanche and mudflow.

Ongoing activity

Aira, Japan

31.5772°N, 130.6589°E; Elev. 1,117 m

The Japan Meteorological Agency (JMA) reported ongoing eruptive activity at Minamidake Crater (Aira Caldera’s Sakurajima volcano) during 25 May-1 June. Very small eruptive events were detected during 25-29 May. Crater incandescence was visible in nighttime webcam images during 29 May-1 June. Eruptive events at 1917 on 29 May, at 0443, at 1954, and at 2223 on 30 May, and at 1510 on 31 May generated ash plumes that rose 1.1-1.3 km above the crater rim and drifted in multiple directions. 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.

Geological 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.

Ambae, Vanuatu

15.389°S, 167.835°E; Elev. 1,496 m

The Wellington Volcanic Ash Advisory Center (VAAC) reported that ash-and-gas plumes from Ambae were identified in satellite and/or webcam images and seen by local observers during 28-29 May and 3 June; plumes rose to 1.2-3 km (4,000-10,000 ft) a.s.l. and drifted SW, E, NW. The Alert Level remained at 3 (on a scale of 0-5), and the public was warned to stay outside of Danger Zone B, defined as a 3-km radius around the active vents in Lake Voui, and to stay away from drainages during heavy rains.

Geological 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.

Bur ni Telong, Indonesia

4.769°N, 96.821°E; Elev. 2,617 m

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported decreasing unrest at Bur ni Telong. Seismicity began fluctuating in March, but began to decline in mid-May. Notably, the average number of deep volcanic earthquakes per day dropped from 6 to 3. No emissions were visible rising from the crater. The Alert Level remained at 2 (on a scale of 1-4) based on visual instrumental observations, though the exclusion zone was decreased to a radius of 2 km.

Geological summary: The conical Bur ni Telong volcano was constructed at the southern base of the massive Bur ni Geureudong volcanic complex, one of the largest in northern Sumatra. The historically active volcano lies 4.5 km from the summit of Geureudong,and its summit crater has migrated to the ESE, leaving arcuate crater rims. Lava flows are exposed on the southern flank. Explosive eruptions were recorded during the 19th and 20th centuries.

Dukono, Indonesia

1.6992°N, 127.8783°E; Elev. 1,273 m

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that eruptive activity at Dukono continued during 28 May-3 June. Daily white-to-gray or gray-to-black plumes rose 200-1,300 m above the summit and drifted NE, E, and SE. Faint rumbling was heard at the Dukono observation post (11 km N) on 31 May. 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.

Geological 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.

Great Sitkin, United States

52.076°N, 176.13°W; Elev. 1,740 m

The Alaska Volcano Observatory (AVO) reported that slow lava effusion continued to feed a thick flow in Great Sitkin’s summit crater during 28 May-3 June. Radar data acquired on 29 May confirmed that slow growth was concentrated along the E margin. Minor seismicity was detected on most days. Weather clouds sometimes prevented webcam and satellite observations, though slightly elevated surface temperatures were visible in satellite images during 29 May-2 June. 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).

Geological 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.

Ibu, Indonesia

1.4941°N, 127.6324°E; Elev. 1,357 m

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that activity at Ibu continued during 28 May-3 June, with daily eruptive events recorded by the seismic network. Daily gray or white-to-gray ash plumes rose 300-800 m above the summit and drifted NE and NW. Incandescence at the summit was visible in some nighttime webcam images. The Alert Level remained at 2 (the second lowest level on a four-level scale) and the public was advised to stay 2 km away from the active crater and 3.5 km away from the N crater wall opening.

Geological 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.

Kanlaon, Philippines

10.4096°N, 123.13°E; Elev. 2,422 m

The Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported continuing eruptive activity at Kanlaon during 28 May-3 June. The seismic network recorded 7-24 daily volcanic earthquakes, including 0-12 daily periods of volcanic tremor lasting 3 minutes to six hours and 13 minutes each. Sulfur dioxide emissions ranged from 1,201 to 2,428 tonnes per day during 28-30 May. Volcanic emissions rose as high as 1.5 km above the summit and drifted SW, SE, and E; weather conditions obscured views on 31 May. During 28-30 May and 3 June there were 1-7 daily periods of ash emissions lasting as short as three minutes to as long as one hour and 51 minutes. Specifically, the webcam recorded grayish ash emissions at 0600 on 28 May rising 1.2 km above the crater rim and drifting SW. The Alert Level remained at 2 (on a scale of 0-5); the public was warned to stay out of the 4-km-radius Permanent Danger Zone (PDZ) and pilots were advised to avoid flying close to the summit.

Geological 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.

Kilauea, United States

19.421°N, 155.287°W; Elev. 1,222 m

The Hawaiian Volcano Observatory (HVO) reported that the eruption within Kilauea’s Kaluapele summit caldera, characterized by episodic fountaining, incandescence, and intermittent spatter from craters along the SW margin of Halema’uma’u Crater, continued at variable levels during 20-27 May. Nighttime incandescence was persistent at both the N and S vents during 27-30 May. Two brief small bursts of spatter at the N vent occurred on 27 May; spattering became sporadic by the evening of 28 May and more vigorous by 0751 on 31 May, building a small cone around the vent. A single spatter burst at the S vent occurred at 0347 on 29 May. Lava overflowed the S vent at 1741 on 30 May, prompting HVO to raise the Volcano Alert Level to Watch (the second highest level on a four-level scale) and the Aviation Color Code to Orange (the second highest color on a four-color scale) at 1749. There were 94 more overflows at the S vent through the morning of 1 June, produced by low dome fountains. Each overflow occurred every 15-30 minutes and lasted 5-10 minutes. The sluggish lava flows traveled short distances (a few hundred meters) from the vent.

A lava overflow occurred at the N vent at 0346 on 1 June. Low-level dome fountaining steadily escalating in vigor and height until it transitioned to sustained lava fountaining at 0440. The fountains grew to a maximum height of around 200 m at 0550. The lava fountain produced significant heat and ash, feeding an eruption plume that rose as high as 7.6 km (25,000 ft) a.s.l. based on radar data reported by the National Weather Service (NWS) and Washington Volcanic Ash Advisory Center. Initially, lower-level trade winds from the NE caused most tephra to be deposited in areas SW of Halema’uma’u. Parts of the plume at higher altitudes 3-6.1 km (10,000-20,000 ft) a.s.l. drifted N. Tephra fell at several locations around the rim of Kaluapele. At 0531 the NWS issued an ashfall advisory for the SE and NE parts of the island, including Hawai’i Volcanoes National Park. Pumice up to 2-5 cm in diameter fell at the Uekahuna overlook and Namakanipaio campground along with Highway 11 W to the 34-mile marker. Fine ash and Pele?s hair were deposited around the Kilauea Visitor Center and outside of the national park in communities to the NE, including Mauna Loa Estates, Ohia Estates, and Volcano village as well as to the W of the caldera between the 34- and 36-mile markers. Very sparse, fine ash was reported as far as Mountain View. A commercial pilot reported and ash-and-gas cloud off of Laupahoehoe. According to a news article, flights between Hilo and Honolulu were cancelled after ash fell on the runway.

After reaching the maximum height, the lava fountain gradually declined over a few hours and was 90 m tall by around 1237. Continuous fountaining ended after 9 hours at 1337, with gas jetting occurring during the last minute. The average effusion rate was 185 cubic meters per second; the highest peak was 320 cubic meters per second, occurring just before 0600. An estimated 7.3 million cubic meters of lava erupted and covered about 40 percent of the Halema’uma’u Crater floor. Gas jetting and spattering from the S vent was periodically visible during the fountaining episode at the N vent. At 1347 the Volcano Alert Level was lowered to Advisory and the Aviation Color Code was lowered to Yellow. During 1-2 June flames at the vents were periodically visible, as well as continuous incandescence throughout the night.

The current Halema’uma’u eruption now has the most fountaining episodes ever recorded for an eruption, with more than the 47 episodes of the Pu’u ‘O’o eruption. Though other eruptions have had additional episodes related to changes in vent activity and location, this count only applies to episodic fountains.

Geological 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.

Lewotolok, Indonesia

8.274°S, 123.508°E; Elev. 1,431 m

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported ongoing eruptive activity at Lewotolok during 28 May-3 June. Daily white plumes rose as high as 100 m above the summit and drifted in multiple directions. An eruptive event at 2317 on 28 May generated a white-and-gray plume that rose 100 m above the summit and drifted SE. A webcam image at 2318 that same day showed incandescent material on the cone’s flanks. On 30 May white-and-gray plumes rose up to 200 m above the summit. Incandescent material on the cone’s flanks was visible in a webcam image from 2318 later that day. Minor incandescence at the summit was visible in a webcam image from 2333 on 1 June. The Alert Level remained at 2 (on a scale of 1-4) and the public was warned to stay 2 km away from the summit.

Geological 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.

Marapi, Indonesia

0.38°S, 100.474°E; Elev. 2,885 m

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that eruptive activity at Marapi (on Sumatra) continued during 28 May-3 June. At 0842 on 30 May a dense gray ash plume rose to around 2 km above the summit and drifted NE. Eruptive events were recorded at 1956 on 2 June and at 0305 on 3 June but weather conditions prevented visual confirmation. 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.

Geological 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.

Mayon, Philippines

13.257°N, 123.685°E; Elev. 2,462 m

The Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported that the eruption at Mayon continued during 28 May-3 June, characterized by lava effusion, pyroclastic density currents (PDCs), incandescent rockfalls, ash-and-gas plumes, and occasional minor Strombolian activity. Emissions were visible daily rising as high as 1.5 km above the summit and drifting in various directions. Each day the seismic network recorded 223-364 rockfalls, 0-3 PDCs, and 7-35 volcanic earthquakes. The earthquake counts included 6-24 daily periods of volcanic tremor, each lasting between two minutes to two hours and 30 minutes. Daily measurements of sulfur dioxide emissions averaged 1,083-2,747 tonnes per day. The lava flows did not advance in the Mi-isi (S), Basud (E), and Bonga (SE) drainages, remaining 1.8, 3.8, and 3.2 km long, respectively.

The number of evacuees was similar to the previous week; by 1800 on 1 June a total of 3,975 people (1,088 families) were staying in 12 evacuation shelters, and an additional 137 people (40 families) were staying with friends or relatives, according to the Disaster Response Operations Monitoring and Information Center (DROMIC). The Alert Level remained at 3 (on a 0-5 scale) and residents were reminded to stay away from the 6-km-radius Permanent Danger Zone (PDZ). The PHIVOLCS recommended that civil aviation authorities advise pilots to avoid flying close to the summit.

Geological summary: Symmetrical Mayon, which rises above the Albay Gulf NW of Legazpi City, is the most active volcano of the Philippines. The steep upper slopes are capped by a small summit crater. Recorded eruptions date back to 1616 and range from Strombolian to basaltic Plinian, with cyclical activity beginning with basaltic eruptions, followed by longer term andesitic lava flows. Eruptions occur predominately from the central conduit and have also produced lava flows that travel far down the flanks. Pyroclastic flows and mudflows have commonly swept down many of the approximately 40 ravines radiating from the summit and have often damaged populated lowland areas. A violent eruption in 1814 killed more than 1,200 people and devastated several towns.

Merapi, Indonesia

7.54°S, 110.446°E; Elev. 2,910 m

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that the eruption at Merapi (on Java) continued during 28 May-3 June. Seismicity was less intense compared to the previous week. The SW lava dome produced 44 lava avalanches that traveled as far as 1.8 km SW down the Bebeng drainage. Morphological changes to the SW dome resulted from continuing effusion and collapses of material. The Alert Level remained at 3 (on a scale of 1-4) and the public was warned to stay 3-7 km away from the summit, based on location.

Geological 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 N of the major city of Yogyakarta. The steep-sided modern edifice, its upper part unvegetated due to frequent eruptive activity, was constructed to the SW of an arcuate scarp cutting the eroded older Batulawang volcano. Pyroclastic flows and lahars accompanying growth and collapse of the steep-sided active summit lava dome have devastated cultivated and inhabited lands on the western-to-southern flanks and caused many fatalities.

Nevado del Ruiz, Colombia

4.892°N, 75.324°W; Elev. 5,279 m

The Servicio Geológico Colombiano (SGC) reported that low-level eruptive activity at Nevado del Ruiz continued during 27 May-2 June. Seismic activity associated with rock fracturing increased in both the number of events and the seismic energy released compared to the previous week; these earthquakes were mainly located in the Arenas Crater and on the SW, WSW, NNE, and ESE flanks at depths of less than 7 km. The largest event, a M 2.3, was located on the ESE flank at 1129 on 27 May. Seismic signals indicating fluid movement decreased in both number and seismic energy released; several ash emissions associated with some of these signals were confirmed by webcam and satellite images. Sulfur dioxide emissions and the height of gas-and-steam emissions remained variable. Thermal anomalies on the crater floor were detected in satellite images. The Alert Level remained at Yellow (the second lowest level on a four-color scale).

Geological summary: Nevado del Ruiz is a broad, glacier-covered volcano 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 cluster of lava domes constructed within the summit caldera of an older edifice. The 1-km-wide, 240-m-deep Arenas crater occupies the summit. The prominent La Olleta pyroclastic cone 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.

Popocatepetl, Mexico

19.023°N, 98.622°W; Elev. 5,393 m

The Centro Nacional de Prevencion de Desastres (CENAPRED) reported that eruptive activity continued at Popocatépetl during 27 May-3 June. Each day there were 13-24 steam-and-gas emissions that sometimes contained minor amounts of ash and drifted mainly NW. The seismic network recorded periods of low-amplitude tremor lasting 14-40 minutes during 27-29 May and 1-2 June. Minor crater incandescence was visible overnight during 29-30 May. Two small explosions were recorded on 1 June, at 0254 and 0309. According to the Washington VAAC an ash plume from the second explosion rose 500 m above the summit to 5.8 km (19,000 ft) a.s.l. and drifted N. 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.

According to the Washington VAAC an ash plume was visible in webcam images at 0244 on 3 June rising 700 m above the summit to 6.1 km (20,000 ft) a.s.l. and drifting NW. The plume became less dense over time and ash was no longer identifiable in satellite images by 0851.

Geological summary: Popocatépetl, the second-highest volcano in North America and whose name means Smoking Mountain in the Aztec language, towers to the SE of Mexico City. The glacier-clad stratovolcano contains a 250-450 m deep crater. The current volcano was constructed to the S of the 17,000 year-old to 23,000 year-old Ventorrillo edifice following edifice failure. At least three previous major cone failures that each produced extensive debris avalanches covered broad areas S of the volcano. The modern volcano has been active since the mid-Holocene and has produced large eruptions, with pyroclastic flows and voluminous lahars, during the Holocene. Some eruptions were subplinian to plinian, causing pumice fall in areas near the volcano and ashfall as far away as the Valley of Mexico. The first Spanish records were from 1519; historical eruptions since then have included frequent small-to-moderate explosions, and periodic larger explosions. After an explosive eruption in 1920-22, the volcano was relatively quiet until unrest began in 1990. Small explosions first occurred in 1994 and have continued intermittently.

Purace, Colombia

2.3095°N, 76.3948°W; Elev. 4,650 m

The Servicio Geologico Colombiano (SGC) reported ongoing low-level eruptive activity at Puracé during 26 May-1 June. Seismic activity associated with rock fracturing processes was mainly located beneath Piocollo and Puracé volcanoes at depths of 1-3 km; the level of seismicity was similar to the previous week. A thermal anomaly continued to be detected in satellite images within the crater of Puracé and in the fumarolic field along its outer rim. Sulfur dioxide emissions rates were at high levels. The rate of deformation between Puracé, Piocollo, and Curiquinga volcanoes slightly increased. Continuous tremor levels associated with fluid movement and emissions increased, with signals located beneath both Puracé and Piocollo at depths less than 3 km. Gas-and-ash emissions rose as high as 2 km above the summit and drifted NW and W. Ashfall was reported in the rural communities of Hato Viejo (12 km WNW), Ambiró, Pululó, Tabío, Hispala (32 km NW), Chapío (9 km NW), Cristales, Cobaló (11 kmW), 20 de Julio, Anambío, Pisanrabo, San Juan, Río Negro (20 km SW), and the municipal seat of Coconuco (Puracé municipality) and from certain sectors of the city of Popayán. The Alert Level remained at Yellow (the second lowest level on a four-color scale).

Geological summary: Puracé in Colombia, one of the most active volcanoes of the Northern Andean Volcanic Zone, consists of an andesitic stratovolcano with a 500-m-wide summit crater situated 4 km NW of Los Coconucos volcanic chain. The complex includes five volcanic cones, including Puracé, and several monogenetic cones to the NE. Frequent small-to-moderate explosive eruptions have been reported since 1816 CE, with records of earlier eruptions from the 16th-19th centuries. The largest eruptions occurred in 1849, 1869, and 1885.

Sabancaya, Peru

15.787°S, 71.857°W; Elev. 5,960 m

The Instituto Geofísico del Perú (IGP) reported that the eruption at Sabancaya continued during 26 May-1 June. The seismic network recorded a daily average of 50 explosions. Gas-and-ash plumes rose as high as 2.6 km above the summit and drifted less than 10 km SE, S, SW, and W. Thermal anomalies over the lava dome in the summit crater were identified in satellite images, though weather clouds sometimes prevented views. Sulfur dioxide emissions averaged 700 tons per day. Slight inflation was detected near the Hualca Hualca (4 km N). The Alert Level remained at Orange (the third level on a four-color scale) and the public was warned to stay outside of a 12-km radius.

Geological summary: Sabancaya, located about 20 km S of the older Hualca Hualca stratovolcano and 5 km N of Ampato, consists of two edifices: an older andesitic stratovolcano with lava domes that forms the summit N, and a younger, Holocene cone to the S. The younger cone contains a 400-m-wide summit crater and numerous lava flows on the flanks. There are no recorded eruptions of the older edifice; eruptions at the younger cone have been recorded since 1750.

Semeru, Indonesia

8.108°S, 112.922°E; Elev. 3,657 m

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that activity continued at Semeru during 28 May-3 June, with daily eruptive events recorded by the seismic network. Daily white-to-gray or gray ash plumes rose 300-2,000 m above the summit and drifted in multiple directions. According to a news article a pyroclastic flow was detected at around 1122 on 28 May but not visually observed due to weather conditions. Incandescent material was descending the upper SE flank at 1904 on 29 May and generated a pyroclastic flow and an ash plume at 1910 based on PVMBG webcam images. The Alert Level remained at 3 (the second lowest level on a scale of 1-4) and the public was warned to stay at least 5 km away from the summit in all directions, 13 km from the summit on the SE flank along the Kobokan drainage, and 500 m from the banks of the Kobokan drainage as far as 17 km SE of the summit.

Geological 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.

Sheveluch, Russia

56.653°N, 161.36°E; Elev. 3,283 m

The Kamchatkan Volcanic Eruption Response Team (KVERT) reported that lava-dome extrusion at Sheveluch’s “300 years of RAS” dome on the SW flank of Old Sheveluch and at Young Sheveluch continued during 22-29 May. Daily thermal anomalies over the domes were identified in satellite images. The Aviation Color Code remained at Orange (the third level on a four-color scale). Dates are based on UTC times; specific events are in local time where noted.

Geological 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 volcano is one of Kamchatka’s largest and most active. The summit of approximately 65,000-year-old Old Sheveluch is truncated by a 9-km-wide late-Pleistocene caldera breached to the S. Many lava domes dot its outer flanks. The Molodoy Sheveluch lava-dome complex was constructed during the Holocene within the large horseshoe-shaped caldera; Holocene lava-dome extrusion also occurred on the flanks of Old Sheveluch. At least 60 large eruptions of Sheveluch have occurred during the Holocene, making it the most vigorous andesitic volcano of the Kuril-Kamchatka arc. Widespread tephra layers from these eruptions have provided valuable time markers for dating volcanic events in Kamchatka.

Stromboli, Italy

38.789°N, 15.213°E; Elev. 924 m

The Sezione di Catania – Osservatorio Etneo (INGV) reported that activity at Stromboli continued during 26 May-1 June. Webcam images showed Strombolian activity at three vents in Area N, within the upper part of the Sciara del Fuoco, and from one vent at Area C-S (South-Central Crater) on the crater terrace. In Area N, explosive activity had a frequency of 5-13 events per hour and produced low-to-medium intensity explosions. Emissions from the vents in Area N consisted of ash and lapilli. Spattering at Area N was occasionally intense during 31 May-1 June. Explosive activity at Area C-S averaged 1-7 events per hour; explosions ejected ash and coarse material, sometimes mixed, as high as 150 m above the vent. The Dipartimento della Protezione Civile stated that during 31 May-1 June there was a sudden increase in Strombolian explosions, with 85 events recorded during a 24-hour period.

Three episodes of lava overflow from the vents in Area N, beginning at 1344 on 31 May and at 0415 and 1654 on 1 June, produced lava flows that descended the Sciara del Fuoco to an elevation of 300-400 m above sea level. The first lava overflow was preceded by increasing and continuous spattering and more intense explosions. A large block in the upper part of the Sciara del Fuoco produced a landslide, detected by the seismic and infrasonic network, that formed a small pyroclastic density current (PDC). The PDC descended the slope, interacted with the first lava flow, and continued to the ocean surface. The seismic station (STRE) recorded a significant increase in activity that peaked during 0215-1105 on 1 June, with 800 events per hour. The Alert Level remained at Yellow (the second lowest level on a four-color scale).

Geological summary: Spectacular incandescent nighttime explosions at Stromboli have long attracted visitors to the “Lighthouse of the Mediterranean.” 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 active summit vents are located at the head of the Sciara del Fuoco, a prominent horseshoe-shaped scarp formed about 5,000 years ago due to edifice collapse, 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.

Telica, Nicaragua

12.606°N, 86.84°W; Elev. 1,036 m

The Washington Volcanic Ash Advisory Center (VAAC) reported that a period of ongoing ash emissions at Telica was visible in webcam images on 30 May rising to 1.5 km (5,000 ft) a.s.l. and drifting W and NW. Ash was not identified in satellite images, possibly due to weather clouds.

Geological summary: Telica, one of Nicaragua’s most active volcanoes, has erupted frequently since the beginning of the Spanish era. This volcano group consists of several interlocking cones and vents with a general NW alignment. Sixteenth-century eruptions were reported at symmetrical Santa Clara volcano at the SW end of the group. However, its eroded and breached crater has been covered by forests throughout historical time, and these eruptions may have originated from Telica, whose upper slopes in contrast are unvegetated. The steep-sided cone of Telica is truncated by a 700-m-wide double crater; the southern crater, the source of recent eruptions, is 120 m deep. El Liston, immediately E, has several nested craters. The fumaroles and boiling mudpots of Hervideros de San Jacinto, SE of Telica, form a prominent geothermal area frequented by tourists, and geothermal exploration has occurred nearby.

References:

¹ Smithsonian Institution / US Geological Survey Weekly Volcanic Activity Report – GVP – May 28-June 3, 2026 – Managing Editor: Sally Sennert

Teo Blašković

I'm a dedicated researcher, journalist, and editor at The Watchers. With over 20 years of experience in the media industry, I specialize in hard science news, focusing on extreme weather, seismic and volcanic activity, space weather, and astronomy, including near-Earth objects and planetary defense strategies. You can reach me at teo /at/ watchers.news.

Earth

Space

Space weather

Monitoring tools

watchers.LIVE

SWX

SAM

StormWall

Support, updates, and contact

Subscribe

Newsletter

Report an event

Feeds and contact