The Weekly Volcanic Activity Report: May 14-20, 2026

New activity/unrest

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 on 17 May rising to 1.8-3 km (6,000-10,000 ft) a.s.l. and drifting E and 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.

Bulusan, Philippines

12.769°N, 124.056°E; Elev. 1,535 m

The Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported increased seismicity at Bulusan in a 20 May advisory, with a total of 442 volcano-tectonic (VT) earthquakes recorded by the seismic network since 1600 on 18 May. The VT earthquakes were associated with rock fracturing, with 55 of the events located at depths less than 5 km beneath the edifice. Very weak to moderate degassing was observed from active vents when the volcano was visible; sulfur dioxide emissions were at low levels, averaging 121 tonnes per day based on the most recent measurement on 22 April. Continuous GPS monitoring indicated inflation of the N flank since June 2025 and the upper W flank since January 2026, interpreted as slow pressurization due to shallow hydrothermal or tectonic processes. The Alert Level remained at 1 (the second lowest level on a scale of 0-5). The public was reminded not to enter the 4-km-radius Permanent Danger Zone (PDZ) and to exercise vigilance within the 2-km Extended Danger Zone (EDZ) on the SE sector. Pilots were warned not to fly close to the summit because of the potential of ash plumes from phreatic eruptions.

Geological summary: Luzon’s southernmost volcano, Bulusan, was constructed along the rim of the 11-km-diameter dacitic-to-rhyolitic Irosin caldera, which was formed about 36,000 years ago. It lies at the SE end of the Bicol volcanic arc occupying the peninsula of the same name that forms the elongated SE tip of Luzon. A broad, flat moat is located below the topographically prominent SW rim of Irosin caldera; the NE rim is buried by the andesitic complex. Bulusan is flanked by several other large intracaldera lava domes and cones, including the prominent Mount Jormajan lava dome on the SW flank and Sharp Peak to the NE. The summit is unvegetated and contains a 300-m-wide, 50-m-deep crater. Three small craters are located on the SE flank. Many moderate explosive eruptions have been recorded since the mid-19th century.

Central Bismarck Sea, Papua New Guinea

3.03°S, 147.78°E; Elev. -1,300 m

The Rabaul Volcano Observatory (RVO) reported that the eruption in the Central Bismarck Sea that began at around 0115 on 8 May (based on regional infrasound data) continued during 13-20 May. During 13-14 May, plumes of steam and gas of variable densities and vigor rose from the eruption site and drifted to the W and NW; plumes of discolored water drifted from the site as well. By 15 May steam-and-gas plumes were identified in satellite imagery originating from two separate vent areas approximately 2.5 km apart; the eastern area was about 1.5 km in diameter, and the western area was about 500 m in diameter. A M 5.4 earthquake was recorded at around 1113 on 15 May. During 15-16 May, pumice rafts identified in satellite images were producing thermal anomalies at up to 2 km from the source, suggesting that the rafts were initially thick. A 5-km-long area of thermal anomalies seen on 16 May, trending roughly WSW-ENE, was visible along the base of plumes; part of the thermal signature may have been from initially hot floating pumice. Small signatures indicating possible ash were detected on 16 May, though they were likely due to pumice pieces rapidly decompressing and disintegrating at the surface. Weather clouds obscured satellite views during parts of 15-17 May, making interpretations of the activity challenging, though data confirmed that the eruption remained submarine over this interval. During 18-20 May the steam plumes were more diffuse during previous days and drifted W and NW. Weak winds contributed to the plume rising to 5.5 km above the ocean’s surface. Plumes of discolored water drifted W, SW, and NW. According to a news article local fisherman observed and photographed the steam plumes, noting that there were dead fish nearby, and observing that “[the eruption] sounds like thunder and the sea smells like metal burning.”

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.

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’s Malupang Warirang Crater remained high after the 8 May eruption. During 9-16 May an average of 52 eruptive events per day were recorded with ash plumes rising 400-4,300 m above the summit and drifting NW, W, and SW. At 1838 on 17 May a gray-to-black ash plume rose 5 km above the summit and drifted SW, W, and NW. Additional eruptive events that same day rose 400-3,000 m above the summit and drifted those same directions. Ash plumes decreased slightly on 18 May, rising to 3,800 m above the summit, to 3,000 m above the summit on 19 May, and to 1,500 m above the summit on 20 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.

Iya, Indonesia

8.891°S, 121.641°E; Elev. 618 m

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported an earthquake of magnitude 2.1 near Iya on 16 May 2026, followed by an increase in seismicity at Iya through 17 May. In general, white plumes rose as high as 200 m above the summit and drifted in multiple directions between 14-20 May. The Alert Level remains at level 2 (on a scale of 1-4) and the public was warned to stay 2 km away from the active crater.

Geological summary: Gunung Iya is the southernmost of a group of three volcanoes comprising a small peninsula south of the city of Ende on central Flores Island. The cones to the north, Rooja and Pui, appear to be slightly older and have not shown historical activity, although Pui has a youthful profile (a reported 1671 eruption of Pui was considered to have originated from Iya volcano). Iya, whose truncated southern side drops steeply to the sea, has had numerous moderate explosive eruptions during historical time.

Kikai, Japan

30.793°N, 130.305°E; Elev. 704 m

The Japan Meteorological Agency (JMA) reported that an eruption at Iodake Crater (at Satsuma Iwo-jima, a subaerial part of Kikai’s NW caldera rim) was recorded at 0207 on 17 May, the first since 29 December 2025. An ash-and-gas plume rose 400 m above the crater rim and drifted S. The report noted that volcanic earthquakes remained infrequent, and no notable changes detected before or after the eruption. No volcanic tremors were recorded. The Alert Level remained at 2 (on a 5-level scale), and residents were warned to be cautious within 500 m away from Iodake Crater.

Geological summary: Multiple eruption centers have exhibited recent activity at Kikai, a mostly submerged, 19-km-wide caldera near the northern end of the Ryukyu Islands south of Kyushu. It was the source of one of the world’s largest Holocene eruptions about 6,300 years ago when rhyolitic pyroclastic flows traveled across the sea for a total distance of 100 km to southern Kyushu, and ashfall reached the northern Japanese island of Hokkaido. The eruption devastated southern and central Kyushu, which remained uninhabited for several centuries. Post-caldera eruptions formed Iodake (or Iwo-dake) lava dome and Inamuradake scoria cone, as well as submarine lava domes. Recorded eruptions have occurred at or near Satsuma-Iojima (also known as Tokara-Iojima), a small 3 x 6 km island forming part of the NW caldera rim. Showa-Iojima lava dome (also known as Iojima-Shinto), a small island 2 km E of Satsuma-Iojima, was formed during submarine eruptions in 1934 and 1935. Mild-to-moderate explosive eruptions have occurred during the past few decades from Iodake, a rhyolitic lava dome at the eastern end of Satsuma-Iojima.

Taal, Philippines

14.0106°N, 120.9975°E; Elev. 311 m

The Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported eruptive activity at Taal during 14-21 May. The seismic network recorded 3-15 daily volcanic earthquakes; the counts included 2-14 periods of tremor, each lasting 1-28 minutes, during 17-18 May. Daily diffuse gas-and-steam emissions rose as high as 2,400 m above the crater rim and drifted primarily SW with some W, NW, and NE drift. A minor phreatic eruption began at 0016 on 17 May, lasted for three minutes, and produced plumes that rose 300 m. The Alert Level remained at 1 (on a scale of 0-5); PHIVOLCS reminded the public that the entire Taal Volcano Island (TVI) was a Permanent Danger Zone (PDZ) and recommended that the Main Crater and areas along the Daang Kastila fissure should remain prohibited. Pilots were warned to avoid flying over TVI.

Geological 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.

Ongoing activity

Awu, Indonesia

3.689°N, 125.447°E; Elev. 1,318 m

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that unrest activity increased at Awu. During 1-18 May, seismicity increased, with 24 deep volcanic earthquakes and 519 shallow volcanic earthquakes recorded over the period. White plumes rose 100-200 m above the lava dome. Shallow seismic swarms, each with 74 events, occurred on 4 May and 19 May (0000-1200). CVGHM/PVMBG raised the Alert Level to 3 (on a 4-level scale) at 1300 on 19 May 2026. The public was advised to stay at least 4 km from the crater center.

Geological summary: The massive Gunung Awu stratovolcano occupies the northern end of Great Sangihe Island, the largest of the Sangihe arc. Deep valleys that form passageways for lahars dissect the flanks of the volcano, which was constructed within a 4.5-km-wide caldera. Powerful explosive eruptions in 1711, 1812, 1856, 1892, and 1966 produced devastating pyroclastic flows and lahars that caused more than 8000 cumulative fatalities. Awu contained a summit crater lake that was 1 km wide and 172 m deep in 1922, but was largely ejected during the 1966 eruption.

Bezymianny, Russia

55.972°N, 160.595°E; Elev. 2,882 m

The Kamchatkan Volcanic Eruption Response Team (KVERT) reported increasing activity at Bezymianny and an explosive eruption during 13-20 May. On 13 May the Aviation Color Code was raised to Orange (the second highest level on a four-level scale) due to hot avalanches descending the flanks and an intensifying thermal anomaly identified in satellite images. A gas-and-steam plume containing ash drifted 80 km SW at an altitude of 4 km (13,100 ft) a.s.l. Satellite images on 16 May indicated that hot avalanches continued to be generated from lava dome collapses. Ash plumes from the collapses drifted 40 km SE at an altitude of 4.5 km (14,800 ft) a.s.l. Activity escalated later that day at 1630, and by 2050 a large eruption cloud was visible in satellite images rising to 6.5 km (21,300 ft) a.s.l. and slowly drifting SE. Explosions on 17 May generated ash plumes that rose as high as 5 km (16,400 ft) a.s.l. and drifted SE. An explosive eruption that began at 1820 on 18 May produced ash plumes that rose 10 km (32,800 ft) a.s.l. and drifted ESE. A pyroclastic flow descended the E flank. The Aviation Color Code was raised to Red a few hours later at 2102. Hot avalanches continued to descend the flanks on 19 May, but no ash explosions were recorded; at 0424 the Aviation Color Code was lowered to Orange. The ash plume from the day before had drifted 500 km WNW. Lava effusion continued through 20 May, accompanied by gas-and-steam emissions and small hot avalanches. Dates are reported in UTC; specific events are in local time where noted.

Geological summary: The modern Bezymianny, much smaller than its massive neighbors Kamen and Kliuchevskoi on the Kamchatka Peninsula, was formed about 4,700 years ago over a late-Pleistocene lava-dome complex and an edifice built about 11,000-7,000 years ago. Three periods of intensified activity have occurred during the past 3,000 years. The latest period, which was preceded by a 1,000-year quiescence, began with the dramatic 1955-56 eruption. This eruption, similar to that of St. Helens in 1980, produced a large open crater that was formed by collapse of the summit and an associated lateral blast. Subsequent episodic but ongoing lava-dome growth, accompanied by intermittent explosive activity and pyroclastic flows, has largely filled the 1956 crater.

Fuego, Guatemala

14.4748°N, 90.8806°W; Elev. 3,799 m

The Instituto Nacional de Sismología, Vulcanologia, Meteorologia e Hidrología (INSIVUMEH) reported that eruptive activity at Fuego continued during 14-21 May. Daily Strombolian explosions recorded by the seismic network, at rates of 5-12 per hour when reported, generated gas-and-ash plumes that rose as high as 1 km above the summit and drifted as far as 40 km W and SW. Rumbling sounds, shock waves, and/or sounds associated with gas emissions were reported daily. Explosions occasionally ejected incandescent material as high as 300 m above the summit. Incandescent block avalanches descended the Seca (W), Taniluyá (SSW), Ceniza (SSW), Las Lajas (SE), and Honda (E) drainages, sometimes reaching vegetated areas. Ashfall was reported in areas downwind, including Panimaché I and II (8 km SW), Yepocapa (8 km WNW), Morelia (10 km SW), El Porvenir (11 km SW), and La Rochela (7.5 km SSW). A weak to moderate lahar descended the Ceniza drainage on 17 May at 1840 that carried branches, tree trunks, and boulders ranging from 30 cm to 3 m in diameter. INSIVUMEH made recommendations to avoid being in or near ravines during rainfall on the volcano and noted that it is prohibited to approach the “La Meseta” and “El Camelión” areas near the summit.

Geological 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.

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 14-20 May. Small earthquakes and rockfalls associated with the activity were periodically detected in seismic data. Lava-dome growth and resulting rockfalls were concentrated at the E part of the flow based on radar data. Weather clouds often prevented webcam and satellite observations. 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 14-20 May, with daily eruptive events recorded by the seismic network and by visual observation. Daily gray ash plumes rose 200-1,000 m above the summit and drifted in multiple directions. Incandescence at the summit was visible in several 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 14-20 May. The seismic network recorded 6-31 daily volcanic earthquakes including 20 episodes of tremor ranging from 4 to 61 minutes. Sulfur dioxide emissions ranged from 142 to 1464 tonnes per day. Daily volcanic emissions rose up to 1,500 m above the summit and drifted primarily SW with some moving N and NE. There were ash emission events on 16 May (1), 17 May (6), 18 May (6), and 20 May (3), each lasting from 7 to 51 minutes. 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 14-20 May. On 14 May, nighttime incandescence was accompanied by lava overflows onto the crater floor and flames at the S vent along with glow and spatter bursts at the N vent. At 1458 on 14 May, low-level dome fountaining began at the N vent, steadily escalating in vigor and height until it transitioned to sustained lava fountaining at 1527. After the N vent became active, the S vent continued to overflow cyclically for several hours, diminishing to only spattering that persisted until 1715; thereafter, periodic gas jetting punctuated its progressive burial by N-vent tephra. The N vent lava fountain erupted continuously for 9 hours, growing steadily until reaching a maximum height of around 200 m by 1700. The fountain height gradually declined and was estimated at around 60 m high just before the episode ended at 0027 on 15 May. The last minute of fountaining was marked by strong gas jetting and large flames from both eruptive vents that continued after the eruption ended.

Lava fountains generated an eruption plume that rose 6 km above the ground level, dispersing tephra SW of Halema’uma’u and around the rim of Kaluapele (Kilauea caldera). At 1701, the National Weather Service issued an ashfall advisory for Hawai’i Volcanoes National Park and areas to the NE. Sparse reticulite up to 5 cm in size fell at both the Uekahuna and Keanakako’i overlooks, while fine ash and Pele’s hair were deposited outside Hawai’i Volcanoes National Park in communities to the NE, including Mauna Loa Estates, ‘Ohi’a Estates, Volcano village, and Royal Hawaiian Estates. At 0034 on 15 May, the Volcano Alert Level was lowered to Advisory (the second lowest level on a four-level scale) and the Aviation Color Code was lowered to Yellow (the second lowest color on a four-color scale), due to reduced ground and aviation hazards. From 15 through 20 May bright glow and occasional flames were visible from both eruptive vents, and sulfur dioxide gas emissions reached up to 5,000 tonnes/day. Lava flows on the Halema’uma’u Crater floor remained incandescent and spread toward the E. Low-level seismic tremor persisted and initially (from 15-18 May) included bursts of tremor every 1-10 minutes, interpreted to result from gas pistoning events. Summit inflation continued.

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.

Kusatsu-Shiranesan, Japan

36.618°N, 138.528°E; Elev. 2,165 m

The Japan Meteorological Agency (JMA) reported decreasing unrest at Kusatsu-Shiranesan’s Yugama crater. The report noted that volcanic tremors had not been detected after November 2025 and the chemistry of fumaroles also indicated decreased activity. Seismicity had remained low since March 2026 and deformation stagnated in April. JMA lowered the Alert Level for the complex to 1 (on a 5-level scale) at 1110 on 15 May. The public was advised to be diligent within 500 m of Yugama Crater.

Geological summary: The Kusatsu-Shiranesan complex, located immediately north of Asama volcano, consists of a series of overlapping pyroclastic cones and three crater lakes. The andesitic-to-dacitic volcano was formed in three eruptive stages beginning in the early to mid-Pleistocene. The Pleistocene Oshi pyroclastic flow produced extensive welded tuffs and non-welded pumice that covers much of the E, S, and SW flanks. The latest eruptive stage began about 14,000 years ago. Historical eruptions have consisted of phreatic explosions from the acidic crater lakes or their margins. Fumaroles and hot springs that dot the flanks have strongly acidified many rivers draining from the volcano. The crater was the site of active sulfur mining for many years during the 19th and 20th centuries.

Lewotobi, Indonesia

8.542°S, 122.775°E; Elev. 1,703 m

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that activity continued at Lewotobi Laki-Laki during 14-20 May. Non-harmonic tremor continued, but surface activity remained low; no eruptions or rockfalls were detected seismically. White steam-and-gas plumes rose as high as 200 m above the crater rim. 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 14-20 May. Daily white plumes rose as high as 50 m above the summit with up to 13 daily eruptive events recorded by the seismic network. Rumbling was reported on 15 May. 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 14-20 May. Gray plumes rose as high as 100 m above the summit on several days and drifted in multiple directions. On 16 May, a gray eruption plume rose to around 500 m above the summit and drifted to the SE. 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 14-20 May, characterized by lava effusion, pyroclastic density currents (PDCs), incandescent rockfalls, and ash-and-gas plumes. There were also short periods of lava fountaining during 13-15 May, and some minor Strombolian activity through 16 May. Emissions were visible almost daily, rising as high as 1.3 km above the summit and drifting W, WSW, SW, SSW, S, SE, ESE, and WNW. Each day the seismic network recorded 287-428 rockfalls, 2-14 PDCs, and 20-71 volcanic earthquakes. The earthquake counts included 15-39 daily periods of volcanic tremor, each lasting between one minute to two hours and seven minutes. Daily measurements of sulfur dioxide emissions averaged 197-1,771 tonnes per day. The lava flows did not advance in the Basud (E), and Bonga (SE) drainages, remaining 3.8 and 3.2 long, respectively. The flow in the Mi-isi (SW) drainage was 1.7 km long on 20 May, 100 m longer than previously reported.

The number of evacuees was relatively stable; by 1800 on 20 May a total of 3,984 people (1,089 families) were staying in 12 evacuation shelters, and an additional 89 people (27 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 of Merapi volcano (on Java) continued during 14-20 May with occasional avalanches from the active lava dome on the upper SW flank. White plumes rose as high as 400 m above the summit on most days and drifted in all directions. There were 2-32 daily lava avalanches that traveled as far as 2 km down drainages on the SW flank, which include the Bebeng, Sat/Putih, and Krasak. One pyroclastic flow was observed on 17 May. 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 direction around the volcano.

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.

Pico, Portugal

38.47°N, 28.4°W; Elev. 2,351 m

The Centro de Informação e Vigilância Sismovulcânica dos Açores (CIVISA) reported a renewal of low-magnitude seismic activity off the NW coast of Pico, in a NE-SW zone along the Faial-Pico channel, W of Madalena to N of Lagido, and encompassing the Cachorro Submarine Volcanic System. The earthquake depths ranged from 13 km deep to near surface. On 15 May the Volcanic Alert Level was raised to V1 (the second lowest level on an 8-level scale) for the Faial-Pico channel.

Geological summary: The conical Pico stratovolcano occupies the western end of Pico Island and is the highest volcano in the Azores. The dominantly basaltic edifice lies west of on an older linear volcano with numerous flank cones that forms most of the 46-km-long island. It was constructed over the Montanha volcanic complex on the eastern side of the island and is capped by a 500-m-wide summit crater that is overtopped by a small steep-sided cone. An eruption beginning in 1562 from the Sao Roque Piedade/Planalto da Achada fissure zone produced lava flows that reached the northern coast. Two fissures erupted on the NNW flank and SE flank of Pico volcano in 1718, with lavas reaching the north and south coasts. Lava flows from a fissure on the SE flank in 1720 reached the ocean.

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 12-18 May. Seismic activity associated with rock fracturing processes was mainly located beteen Piocollo and Puracé volcanoes at depths of 1-2 km, with magnitudes less than 1.6; the level of seismicity was similar to the previous week. Sulfur dioxide emissions from fissures in Curiquinga and Piocollo volcanoes, and a thermal anomaly, continued to be detected in satellite images. Continuous tremor levels associated with fluid movement and emissions through the crater of Puracé increased, with signals located beneath the Puracé and Piocollo at depths less than 3 km. Gas-and-ash emissions rose as high as 1 km above the summit and drifted predominantly NW. Ashfall was reported in the city of Coconuco, the rural communities of Cristales, 20 de Julio, and Río Negro (Puracé municipality), as well as from the northern sector of the city of Popayán. An ash emission was recorded in a webcam image from 2 km NW of Puracé at 0740 on 13 May. 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 11-17 May. The seismic network detected 38 seismic events related to the movement of magmatic fluids and additional earthquakes indicating rock fracturing. No explosions were recorded. Gas, steam, and ash plumes periodically rose as high as 2 km above the crater rim and drifted less than 10 km NE and E. Thermal anomalies at the bottom of the crater were identified in satellite images. 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.

Santa Maria, Guatemala

14.757°N, 91.552°W; Elev. 3,745 m

The Instituto Nacional de Sismología, Vulcanología, Meteorología e Hidrología (INSIVUMEH) reported ongoing eruptive activity at Santa Maria’s Santiaguito dome complex during 14-20 May. Incandescence on the Caliente dome was sometimes observed during dark hours. Daily explosions, 0-4 per hour when reported, generated gas-and-ash plumes that rose as high as 900 m above the dome and drifted W and SW. Block avalanches descended the flanks to the W, SW, and S, at a rate of 2-4 per hour when reported. Minor ashfall was reported in and around the Finca Monte Bello on 14 May, along with the upper part of the Finca El Faro (7 km S), La Florida (6 km S), San Marcos Palajunoj (7.5 km SW), and surrounding areas on 17 May.

Geological summary: Symmetrical, forest-covered Santa María 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.

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 14-20 May, with daily eruptive events recorded by the seismic network. White-to-gray or gray ash plumes rose 500-1,000 m above the summit and drifted in multiple directions during 14, 16-17, and 19-20 May; weather conditions obscured visual observations on the other days. 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 13-20 May. A thermal anomaly was identified in satellite images on most days; weather clouds occasionally obscured views. According to the Far Eastern Branch of the Russian Academy of Sciences (FEB RAS), incandescence at the dome and descending hot avalanches of material on the dome’s flank were occasionally visible. KVERT stated that on 17 May explosions generated ash plumes that rose to 6.5 km (21,300 ft) a.s.l. The ash plume drifted 250 km SE during 17-18 May. An ash plume 110 x 55 km, generated from explosions that began at 0820 on 20 May, drifted as far as 916 km to the SE. Explosions later that day at 1813 sent ash up to 4.5 km a.s.l., and plumes drifted 50 km SE. 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.

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.

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 8-15 May. Incandescence was observed nightly in webcam images. Eruptive events on 13 and 15 May produced eruption plumes that rose as high as 600 m above the crater rim. Ashfall was confirmed in areas within 5 km according to the Suwanosejima Branch Office in Toshima village (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.

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 – May 14-20, 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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