The Weekly Volcanic Activity Report: June 11-17, 2026

New activity/unrest: Bardarbunga, Iceland | Dempo, Indonesia | Etna, Italy | Nevados de Chillan, Chile | Titan Ridge, Papua New Guinea.

New activity/unrest

Bardarbunga, Iceland

64.633°N, 17.516°W; Elev. 2,000 m

The Icelandic Meteorological Office (IMO) reported that an intense seismic swarm began at Bárdarbunga on 13 June in the NW part of the caldera. A M 2.6 earthquake and an M 4.8 earthquake were recorded at 2010 and 2014, respectively; both events were located at depths of 2-4 km. The events were followed by several more earthquakes above M 3 and more than 180 smaller earthquakes by 0043 on 14 June. The Aviation Color Code (ACC) was raised to Yellow (the second lowest color on a four-color scale). The swarm began to decrease in intensity by 0300; by 0846 about 400 earthquakes in total had been detected. The seismic activity did not escalate; only 14 minor earthquakes with magnitudes of 0.9 or lower were detected from around mid-morning on 14 June to 1242 on 15 June with the activity characterized as at background. The ACC was lowered to Green. IMO noted that the last comparable swarm occurred in January 2025.

Geological summary: The large central volcano of Bárðarbunga lies beneath the NW part of the Vatnajökull icecap, NW of Grímsvötn volcano, and contains a subglacial 700-m-deep caldera. Related fissure systems include the Veidivötn and Trollagigar fissures, which extend about 100 km SW to near Torfajökull volcano and 50 km NE to near Askja volcano, respectively. Voluminous fissure eruptions, including one at Thjorsarhraun, which produced the largest known Holocene lava flow on Earth with a volume of more than 21 km3, have occurred throughout the Holocene into historical time from the Veidivötn fissure system. The last major eruption of Veidivötn, in 1477, also produced a large tephra deposit. The subglacial Loki-Fögrufjöll volcanic system to the SW is also part of the Bárðarbunga volcanic system and contains two subglacial ridges extending from the largely subglacial Hamarinn central volcano; the Loki ridge trends to the NE and the Fögrufjöll ridge to the SW. Jökulhlaups (glacier-outburst floods) from eruptions at Bárðarbunga potentially affect drainages in all directions.

Dempo, Indonesia

4.016°S, 103.121°E; Elev. 3,142 m

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that a phreatic eruption at Dempo was recorded at 0747 on 12 June which seismic data showed lasted just over a minute. A diffuse white plume rose 50 m above the crater rim and drifted NW. The Alert Level remained at 2 (on a scale of 1-4), and the public were reminded to stay 1 km away from the crater and as far as 2 km on the N flank.

Geological summary: Dempo is a stratovolcano that rises above the Pasumah Plain of SE Sumatra. The andesitic complex has two main peaks, Gunung Dempo and Gunung Marapi, constructed near the SE rim of a 3-km-wide amphitheater open to the north. The high point of the older Gunung Dempo crater rim is slightly lower, and lies at the SE end of the summit complex. The taller Marapi cone was constructed within the older crater. Remnants of seven craters are found at or near the summit, with volcanism migrating WNW over time. The active 750 x 1,100 m active crater cuts the NW side of the Marapi cone and contains a 400-m-wide lake at the far NW end. Eruptions recorded since 1817 have been small-to-moderate explosions that produced local ashfall.

Etna, Italy

37.748°N, 14.999°E; Elev. 3,357 m

The Sezione di Catania – Osservatorio Etneo (INGV) reported minor eruptive activity at Etna’s summit craters beginning on 14 June. A Volcano Observatory Notice to Aviation (VONA) was issued at 1135 on 14 June raising the Aviation Color Code (ACC) to Yellow (the second lowest color on a four-color scale) due to unrest above background levels. Diffuse ash emissions occurred on 15 June, prompting the INGV to raise the ACC to Orange. Ashfall did not occur beyond the summit area. Minor ash emissions continued at least through 17 June.

Geological 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.

Nevados de Chillan, Chile

36.868°S, 71.378°W; Elev. 3,180 m

The Servicio Nacional de Geología y Minería (SERNAGEOMIN), Servicio Nacional de Prevención y Respuesta ante Desastres (SENAPRED), and the Servicio Geológico Minero Argentino (SEGEMAR) reported ash plumes at Nevados de Chillán. Beginning at the end of February, the seismic network recorded a sustained increase in signals indicating fluid movement. A tremor signal at 0820 on 15 June was associated with an ash plume at Nicanor Crater that rose 120 m above the crater rim and a long-period signal at 0855 was associated with an ash plume that rose 80 m above the crater rim; both plumes drifted SE. At least three more ash emissions were recorded the same day, rising as high as 160 m above the crater rim and drifting SE. SERNAGEOMIN raised the Alert Level to Yellow (the second lowest level on a four-color scale) at 1818 and SENAPRED declared an “Early Preventive Alert” for Pinto and Coihueco. SEGEMAR also raised the Alert Level to Yellow (the second lowest level on a four-color scale).

Geological summary: The compound volcano of Nevados de Chillán is one of the most active of the Central Andes. Three late-Pleistocene to Holocene stratovolcanoes were constructed along a NNW-SSE line within three nested Pleistocene calderas, which produced ignimbrite sheets extending more than 100 km into the Central Depression of Chile. The dominantly andesitic Cerro Blanco (Volcán Nevado) stratovolcano is located at the NW end of the massif. Volcán Viejo (Volcán Chillán), which was the main active vent during the 17th-19th centuries, occupies the SE end. The Volcán Nuevo lava-dome complex formed during 1906-1945 on the NW flank of Viejo. The Volcán Arrau dome complex was then constructed on the SE side of Volcán Nuevo between 1973 and 1986, and eventually exceeded its height. Smaller domes or cones are present in the 5-km valley between the two major edifices.

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 4-9 June, though at a low level. The number of hydroacoustic signals per day decreased to the lowest levels detected since the eruption began. A small wispy steam plume was occasionally visible. A long plume of discolored water persisted; a 15 June satellite image showed a narrow plume of discolored water extending more than 100 km W of the eruption site. The activity produced a small amount of floating pumice and minor thermal anomalies. Significant amounts of floating pumice, forming thick and extensive rafts, continued to wash 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.

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 8-15 June. Explosions at 2141 on 8 June, and at both 1555 and 2139 on 11 June, generated ash plumes that rose 400-800 m above the summit and drifted SE and E with blocks ejected 500-700 m from the vent. Sulfur dioxide emissions were slightly above normal, averaging 1,400 tons per day on 12 June. Very small eruptive events and nighttime crater incandescence were recorded during 12-15 June. 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 Minamidake 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.

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 11-17 June. Daily white-to-gray ash plumes rose 300-1,400 m above the summit and drifted E, NE, and NW. 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 10-17 June. A satellite image acquired on 11 June confirmed that slow growth was concentrated along the E margin and that the dome continued to produce rockfalls. Seismicity was low with occasional small volcanic earthquakes and signals indicating the minor rockfalls. Weather clouds often prevented webcam and satellite observations, though slightly elevated surface temperatures were visible in satellite images during 12-14 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 11-17 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 in multiple directions. Incandescence at the summit was visible in 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 10-17 June. The seismic network recorded 0-19 daily volcanic earthquakes; during 12-17 June the counts included 2-15 daily periods of volcanic tremor lasting one minute to nearly four hours each. Sulfur dioxide emissions ranged from 979 to 2,293 tonnes per day. Daily volcanic emissions generally rose as high as 1 km above the summit and drifted mainly NW, W, and SW. There were 1-12 daily periods of ash emissions during 12-17 June, each lasting as short as one minute to as long as three hours and 41 minutes. Specifically, the webcam recorded grayish ash emissions at 0828 on 12 June, at 0704 on 13 June, and at 0858 and 1721 on 16 June rising 300-600 m above the crater rim and drifting NW, W, and SW. At least 20 emissions were recorded during 15-16 June. 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 10-17 June. Robust gas plumes rose from both the N and S vents during 11-13 June. Bright and continuous incandescence persisted at the S vent and flames likely caused by the ignition of volcanic gases escaping the vent were periodically observed. Incandescence at the N vent was continuous and intensified. Minor spatter at the S vent was observed during 12-13 June and there were 10 periods of jetting lasting 2-3 minutes each overnight during 13-14 June.

Low dome fountains, 3-5 m high, began at the N vent at 0410 on 14 June and produced a short lava flow. The flow stagnated and the lava drained back into the vent at 0430. HVO raised 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 0447. A second overflow at the N vent began at 0559 and ended at 0704. A total of eight short (less than 7 minutes each) lava overflows at the S vent occurred during 0634-0912. Dome fountaining at the N vent began at 0814 and steadily grew in vigor and height until it transitioned into a taller fountain at 0936. The fountain peaked at 210 m tall by 1030 and then gradually declined over the next few hours; the fountain was 10 m tall at 1615. The lava fountain produced significant heat and ash, feeding an eruption plume that rose as high as 5.5 km (18,000 ft) a.s.l. and drifted SW based on radar data and webcam images. HVO field crews drove Crater Rim Drive, Highway 11, and into surrounding communities at around 1530 without finding any significant ashfall; none was reported within Hawai’i Volcanoes National Park, except for very sparse amounts of Pele’s hairs deposited on parked cars near the Kilauea Military Camp. Fountaining stopped abruptly at 1705 after just under 7.5 hours of continuous fountaining at the N vent. The last 2-3 minutes was marked by gas jetting from the N vent. The average effusion rate was 200 cubic meters per second; the highest peak was 320 cubic meters per second, occurring during 1030-1100. An estimated 6.5 million cubic meters of lava erupted and covered 40-50 percent of the Halema’uma’u Crater floor. The S vent did not produce a fountain, but instead it periodically spattered or jetted, ejecting spatter no more than 50 m into the air. At 1716 the Volcano Alert Level was lowered to Advisory and the Aviation Color Code was lowered to Yellow. Bright glow and sometimes large flames at the S vent and intermittent glow at the N vent were visible during 15-17 June.

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.

Lewotobi, Indonesia

8.542°S, 122.775°E; Elev. 1,703 m

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that eruptive activity continued at Lewotobi Laki-Laki during 11-17 June. Multiple daily ash plumes rose 300-1,500 m above the summit and drifted E, N, NW, and W. Incandescence at the summit was visible in webcam images on a few of the days. The Alert Level remained at 3 (on a scale of 1-4), and the public was warned to stay 5 km away from the center of Laki-Laki.

Geological 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.

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 11-17 June. White plumes rose as high as 100 m above the summit on most or all days. White-and-gray plumes rose as high as 200 m above the summit during 12 and 16-17 June. Faint rumbling was heard at the observation post (6 km SW) on 13 and 17 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 11-17 June. An eruptive event at 0302 on 11 June generated a brown ash plume that rose about 2.4 km above the crater rim and drifted NE. 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 10-17 June, characterized by lava effusion, periodic pyroclastic density currents (PDCs), incandescent rockfalls, ash-and-gas plumes, and occasional minor Strombolian activity. Emissions were visible daily rising as high as 1.3 km above the summit and drifting mainly NW, W, and SW. Each day the seismic network recorded 191-362 rockfalls, 0-5 PDCs, and 8-24 volcanic earthquakes. The earthquake counts included 3-16 periods of volcanic tremor, each lasting between 1-60 minutes on most days; no periods of tremor were detected on 15 June. Daily measurements of sulfur dioxide emissions averaged 1,082-3,619 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 15 June a total of 3,978 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). 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 since 1616 CE range from Strombolian to basaltic Plinian, with cyclical activity beginning with basaltic eruptions, followed by longer periods of andesitic lava flows. Eruptions occur predominately from the central conduit and have also produced lava flows that travel far down the flanks. Pyroclastic density currents and mudflows have commonly swept down many of the approximately 40 ravines that radiate 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 11-17 June with occasional lava avalanches produced by the active lava dome on the upper SW flank. White plumes rose as high as 250 m above the summit on most days. There were nine lava avalanches that traveled as far as 2 km down the Sat/Putih and Krasak drainages on the W flank on 11 June and one that traveled 1.9 km down the Sat/Putih drainage on 12 June. One pyroclastic flow was detected by the seismic network on 12 June. There were 3-4 daily lava avalanches that descended the Krasak drainage as far as 2 km during 13-14 June and 5-9 daily lava avalanches that descended the Sat/Putih drainage as far as 1.9 km during 15-17 June. Two pyroclastic flows were observed traveling 2 km down the W flank on 16 June, though three were detected seismically. 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 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.

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 9-15 June. Seismic activity associated with rock fracturing processes and hybrid events were mainly located beneath Piocollo and Puracé volcanoes at depths of 1-3 km; the level of seismicity slightly increased compared 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 persisted. A slow rate of deformation was detected between Puracé, Piocollo, and Curiquinga volcanoes. Signals associated with fluid movement and emissions increased. The signals were located beneath Puracé at depths less than 3 km. Gas-and-ash emissions were more frequent during 10-12 June, prompting the release of a special bulletin. The plumes rose as high as 1.5 km above the summit and drifted NW and NE. Ashfall was reported in the rural communities of Hato Viejo (12 km WNW), Ambiró, Patico, Pululó, Chapío (9 km NW), Cristales, Campamento, 20 de Julio, Anambío, Loma Linda, 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 is an active andesitic volcano with a 600-m-diameter summit crater at the NW end of the Los Coconucos Volcanic Chain. This volcanic complex includes nine composite and five monogenetic volcanoes, extending from the Puracé crater more than 6 km SE to the summit of Pan de Azúcar stratovolcano. The dacitic massif which the complex is built on extends about 13 km NW-SE and 10 km NE-SW. Frequent small to moderate explosive eruptions reported since 1816 CE have modified the morphology of the summit crater, with the largest eruptions in 1849, 1869, and 1885.

Sabancaya, Peru

15.787°S, 71.857°W; Elev. 5,960 m

The Instituto Geofísico del Perú’s (IGP) Centro Vulcanológico Nacional (CENVUL) reported continuing eruptive activity at Sabancaya during 8-14 June. The seismic network detected 65 seismic events related to the movement of magmatic fluids and additional earthquakes indicating rock fracturing. Gas, steam, and ash plumes periodically rose as high as 2 km above the crater rim and drifted less than 10 km NE, E, and SE. Thermal anomalies on the crater floor were identified in satellite images and moderate sulfur dioxide emissions averaged 881 tons per day. 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 from the summit.

Geological summary: Sabancaya, located in the saddle NE of Ampato and SE of Hualca Hualca volcanoes, is the youngest of these volcanic centers and the only one to have erupted in historical time. The oldest of the three, Nevado Hualca Hualca, is of probable late-Pliocene to early Pleistocene age. The name Sabancaya (meaning “tongue of fire” in the Quechua language) first appeared in records in 1595 CE, suggesting activity prior to that date. Holocene activity has consisted of Plinian eruptions followed by emission of voluminous andesitic and dacitic lava flows, which form an extensive apron around the volcano on all sides but the south. Records of observed eruptions date back to 1750 CE.

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 11-17 June, with daily eruptive events recorded by the seismic network. Daily white-to-gray ash plumes rose 300-1,000 m above the summit and drifted in multiple directions. 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 continuing eruptive activity at the lava domes along the N crater floor of Young Sheveluch (on the SW flank of Old Sheveluch) during 11-17 June. A daily thermal anomaly was identified in satellite images. Ash plumes were identified in satellite images on 12 June drifting 30 km SW. Explosions at 1600 on 17 June produced ash plumes that rose as high as 10 km (32,800 ft) a.s.l. and drifted at least 300 km NE. The Aviation Color Code remained at Orange (the second highest level on a four-color scale).

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 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.

Stromboli, Italy

38.789°N, 15.213°E; Elev. 924 m

The Sezione di Catania – Osservatorio Etneo (INGV) reported that eruptive activity continued at Stromboli during 8-14 June. Webcam images showed Strombolian activity from five 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 (two in sector N1 and three in sector N2) continued to produce medium-intensity explosions, ejecting lapilli and bombs above the vents, during most of the week. An explosion at 0712 on 12 June was followed by three lower-intensity explosions that occurred within a few minutes. An eruption cloud was produced but quickly dispersed. The event ejected lapilli, bombs, and lava spatter onto the upper parts of the Sciara del Fuoco, some of which was channeled down the flank. Low-intensity explosions ejected tephra from two vents in Area C-S at a low rate; activity intensified to moderately high levels on 15 June. The Alert Level remained at Yellow (the second lowest level on a four-level scale) according to the Dipartimento della Protezione Civile.

Geological 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.

Suwanosejima, Japan

29.638°N, 129.714°E; Elev. 796 m

The Japan Meteorological Agency (JMA) reported that eruptive activity at Suwanosejima’s Ontake Crater continued during 5-12 June. Incandescence was observed nightly in webcam images. Eruptive events generated plumes that rose as high as 800 m above the crater rim. No explosions were recorded. 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.

Geological 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.

References:

¹ Smithsonian Institution / US Geological Survey Weekly Volcanic Activity Report – GVP – June 11-17, 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.

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