The Weekly Volcanic Activity Report: April 2-8, 2026
**New activity/unrest:** Dempo, Indonesia | Karangetang, Indonesia | Piton de la Fournaise, France | Slamet, Indonesia | Sorikmarapi, Indonesia | Taal, Philippines.
**Ongoing activity:** Aira, Japan | Ambae, Vanuatu | Dukono, Indonesia | Great Sitkin, United States | Home Reef, Tonga | Ibu, Indonesia | Kanlaon, Philippines | Kilauea, United States | Lewotolok, Indonesia | Marapi, Indonesia | Mayon, Philippines | Merapi, Indonesia | Sabancaya, Peru | Semeru, Indonesia | Sheveluch, Russia | Suwanosejima, Japan | Whakaari/White Island, New Zealand.
## New activity/unrest
### Dempo, Indonesia
**4.016°S, 103.121°E; summit elev. 3142 m**
The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that a phreatic eruption at Dempo was recorded at 0139 on 7 April and lasted nearly three minutes based on the seismic network. A dense gray ash plume rose around 2.5 km above the summit and drifted E. Minor amounts of ash fell within 4.7 km to the E. Global Navigation Satellite System (GNSS) data did not indicate significant changes during 23 March-6 April, though tiltmeter data from the Tugu Rimau Station showed an inflationary trend beginning on 2 April. 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.
### Karangetang, Indonesia
**2.781°N, 125.407°E; summit elev. 1797 m**
Eruptive activity at Karangetang continued on 8 April according to a news source. At around 1949 on 8 April incandescent material was ejected 25 m above the summit of Kawah Dua (North Crater) and fell in areas around the crater with some hot material descending the SW flank 300-400 m. The event was accompanied by a loud rumbling sound that could be heard in residential areas. The Alert Level remained at 2 (on a scale of 1-4) and the public was advised to stay 1.5 km away from both craters, with an extension to 2.5 km on the W and SW flanks of Main Crater (South Crater).
**Geological summary:** Karangetang (Api Siau) volcano lies at the northern end of the island of Siau, about 125 km NNE of the NE-most point of Sulawesi. The stratovolcano contains five summit craters along a N-S line. It is one of Indonesia’s most active volcanoes, with more than 40 eruptions recorded since 1675 and many additional small eruptions that were not documented (Neumann van Padang, 1951). Twentieth-century eruptions have included frequent explosive activity sometimes accompanied by pyroclastic flows and lahars. Lava dome growth has occurred in the summit craters; collapse of lava flow fronts have produced pyroclastic flows.
### Piton de la Fournaise, France
**21.244°S, 55.708°E; summit elev. 2632 m**
The Observatoire Volcanologique du Piton de la Fournaise (OVPF) reported that eruptive activity at Piton de la Fournaise continued for a few days during 1-8 April. Lava levels were high in the main cone on the lower SE flank of Dolomieu Crater during 1-2 April, resulting in recurring lava overflows associated with the upwelling of gas bubbles. Only the S flow was active. Lava was transported downslope through a series of lava tubes with small lava breakouts scattered across the S flow field in the Grandes Pentes area. Lava flow rates estimated from satellite data on 1 April had decreased since the day before and were below 8 cubic meters per second. At around 2125 on 1 April lava crossed the National Road 2 (RN2) at an area about 300 m S of previous crossings. The gas plumes at the ocean entry were diffuse, suggesting that little to no lava was reaching the ocean.
Seismicity was at a high level but the amplitude of tremor signals indicating lava at the surface and gas emissions abruptly decreased at 2220 on 2 April. Following the amplitude decrease, low-amplitude intermittent tremor indicative of gas pistoning emerged that was likely linked to brief periods of degassing. The eruption ceased at 0010 on 3 April. Beginning at around 2040 that same day low-amplitude continuous volcanic tremor began beneath the SSE flank in the same location as during eruptive phases. Though no lava at the surface was visible, the signal indicated the release of hot gases and the presence of magma at shallow depths. During the evening of 5 April an incandescent spot at the summit of the cone was visible but had disappeared by the next morning. It may have been the result of molten material at the surface or from a landslide from within the crater exposing a hot surface. Seismicity beneath the summit had decreased during 5-6 April with only six shallow volcano-tectonic earthquakes detected by the seismic network. Slight inflation was detected by the deformation network during 5-7 April. Overnight during 6-7 April an incandescent spot at the summit of the cone was once again visible. The Alert Level remained at 2.2 (on a 0-4 scale).
**Geological summary:** Piton de la Fournaise is a massive basaltic shield volcano on the French island of Réunion in the western Indian Ocean. Much of its more than 530,000-year history overlapped with eruptions of the deeply dissected Piton des Neiges shield volcano to the NW. Three scarps formed at about 250,000, 65,000, and less than 5,000 years ago by progressive eastward slumping, leaving large embayments open to the E and SE. Numerous pyroclastic cones are present on the floor of the scarps and their outer flanks. Most recorded eruptions have originated from the summit and flanks of Dolomieu, a 400-m-high lava shield that has grown within the youngest scarp, which is about 9 km wide and about 13 km from the western wall to the ocean on the E. More than 150 eruptions, most of which have produced fluid basaltic lava flows, have occurred since the 17th century. Eruptions in 1708, 1774, 1776, 1800, 1977, and 1986 originated from fissures outside the scarps.
### Slamet, Indonesia
**7.242°S, 109.208°E; summit elev. 3428 m**
The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported recent changes within Slamet’s crater and increased unrest. Beginning in May 2024 the seismic network detected an increase in the number of deep volcanic earthquakes followed by an increase in the number of shallow earthquakes and continuous tremor that persisting through the end of 2024. Seismic activity though March 2026 was dominated by low-frequency earthquakes with fluctuating intensity and continuous tremor, and no significant visual changes were observed. The earthquakes began to intensify on 22 March, with signals becoming more distinct, and then became more numerous on 27 March. Deformation data indicated magma migration to shallower depths.
Temperature changes in the crater were observed based on a comparison of thermal images. Analysis indicated temperatures of around 247 degrees Celsius on 13 September 2024, and during that year the hot areas were localized within the central part of the crater. Temperatures around 411 degrees Celsius were detected on 2 April 2026 and the distribution of hot areas expanded to include a circular pattern of hotter areas around the crater walls. This distribution suggested the development of a fracture system. On 3 April white plumes began continuously rising as high as 300 m above the crater rim. 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:** Slamet is one of Java’s most active volcanoes. It has a cluster of about three dozen cinder cones on its lower SE-NE flanks and a single cinder cone on the W flank. It is composed of two overlapping edifices, an older basaltic andesite to andesitic volcano on the west and a younger basaltic to basaltic andesite one on the east. Gunung Malang II cinder cone on the upper E flank on the younger edifice fed a lava flow that extends 6 km E. Four craters occur at the summit of Gunung Slamet, with activity migrating to the SW over time. Eruptions recorded since the 18th century have originated from a 150-m-deep, 450-m-wide, steep-walled crater at the western part of the summit and have consisted of explosive eruptions generally lasting a few days to a few weeks.
### Sorikmarapi, Indonesia
**0.6834°N, 99.5409°E; summit elev. 2145 m**
The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported increased seismicity at Sorikmarapi. Typical seismicity was characterized as fluctuating and dominated by deep volcanic earthquakes. In March the seismic network recorded a total of 213 deep volcanic (VA) earthquakes (averaging seven events per day), 62 local tectonic earthquakes (averaging two events per day), and one felt earthquake. Seismicity significantly increased on 2 April with a total of 115 VA earthquakes and four felt earthquakes (ranging from II to IV on the MMI scale). Seismicity remained high on 3 April and by 1800 there were a total of 49 VA earthquakes, one felt earthquake (IV on the MMI scale), and three local tectonic earthquakes. The increase in VA signals was interpreted to represent an upward migration of magma. At 2100 on 3 April the Alert Level was raised to 2 (on a scale of 1-4) and the public was warned to stay 1.5 km away from the main crater and to avoid entering Sibangor Tonga Crater, Sibangor Julu Crater, or any other craters located in the vicinity of Sorikmarapi due to potential toxic gas exposure.
**Geological summary:** Sorikmarapi is a forested stratovolcano with a 600-m-wide summit crater containing a lake and substantial sulfur deposits. A smaller upper SE flank crater (Danau Merah) also contains a crater lake; these two craters and a series of smaller explosion pits occur along a NW-SE line. Several solfatara fields are located on the E flank. Phreatic eruptions have occurred from summit and flank vents during the 19th and 20th centuries.
### Taal, Philippines
**14.0106°N, 120.9975°E; summit elev. 311 m**
The Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported eruptive activity at Taal during 1-8 April. The seismic network recorded 0-9 daily volcanic earthquakes, and during 2 and 4-6 April there were 1-11 periods of volcanic tremor, each lasting 1-3 minutes. Daily gas-and-steam emissions were diffuse, rising as high as 600 m above the crater rim and generally drifting SW and NW. A minor phreatic event occurred at 0308 on 6 April, lasted for two minutes based on seismic and webcam data, and produced a plume that rose 200 m above the lake’s surface. Sulfur dioxide emissions averaged 858 tonnes per day on 7 April. 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
### Aira, Japan
**31.5772°N, 130.6589°E; summit elev. 1117 m**
The Japan Meteorological Agency (JMA) reported ongoing eruptive activity at Minamidake Crater (Aira Caldera’s Sakurajima volcano) during 30 March-6 April. Nighttime crater incandescence was visible in webcam images and very small eruptive events were occasionally recorded. 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; summit elev. 1496 m**
The eruption at Ambae continued during 2-9 April based on reports from the Vanuatu Meteorology and Geohazards Department (VMGD) and the Wellington Volcanic Ash Advisory Center (VAAC). VMGD noted that though residents were no longer seeing tall eruptive plumes nor hearing explosions, seismic activity remained high with continuous volcanic tremor and volcanic-seismic events. High fluxes of sulfur dioxide emissions along with a low-level thermal anomaly were identified daily in satellite data. According to the VAAC low-level gas, steam, and ash plumes were visible in webcam and satellite images rising as high as 3 km (10,000 ft) a.s.l., or about 1.5 km above the summit, and drifting N during 5-6 April. Continuous low-level gas-and-steam emissions were visible in both photos and satellite images during 6-8 April. Summit glow was visible at night during 7-8 April. 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.
### Dukono, Indonesia
**1.6992°N, 127.8783°E; summit elev. 1273 m**
The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that eruptive activity at Dukono began increasing on 30 March and continued at a higher level through 8 April. After a decline in activity that began in August 2025, activity intensified on 30 March 2026 with 199 explosive events recorded by the seismic network. The explosions produced ash plumes that rose as high as 400 m above the crater rim. Explosions on 2 April generated white-and-gray ash plumes that rose 1-1.5 km above the crater rim and drifted SE. On 3 April dense gray ash plumes rose as high as 4 km above the crater rim and drifted NW. Daily white-to-gray ash plumes that were continuously emitted for periods of time rose 700-1,400 m above the crater rim and drifted in multiple directions during 4-8 April. 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; summit elev. 1740 m**
The Alaska Volcano Observatory (AVO) reported that slow lava effusion continued to feed a thick flow in Great Sitkin’s summit crater during 1-8 April, with growth concentrated on the SW part of the flow. The seismic network recorded occasional small volcanic earthquakes and seismic signals from small rockfalls within the crater. Elevated surface temperatures were observed in satellite views during 1-3 and 7-8 April. Weather clouds sometimes 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.
### Home Reef, Tonga
**18.992°S, 174.775°W; summit elev. -10 m**
The Tonga Geological Services reported that activity at Home Reef was low during 28 March-4 April and that no significant activity was detected. A previously observed 25-m-wide cinder cone over the main vent had been visible for about a week, but was no longer visible by 12 March; a 26 March satellite image confirmed that it had not reformed. Diffuse gas-and-ash plumes were visible drifting NW in a 31 March satellite image along with plumes of discolored water extending up to 10 km, mainly to the SE of the island. The size of the island was an estimated 2.8 square kilometers. The Aviation Color Code was lowered to Yellow (the second lowest level on a four-level scale, the Maritime Alert Level remained at Red (the highest level on a four-level scale) with advice to stay at least 2 nautical miles (3.7 km) from the island, and the Alert Level for residents of Vava’u and Ha’apai remained at Green (the first level on a four-level scale).
**Geological summary:** Home Reef, a submarine volcano midway between Metis Shoal and Late Island in the central Tonga islands, was first reported active in the mid-19th century, when an ephemeral island formed. An eruption in 1984 produced a 12-km-high eruption plume, large amounts of floating pumice, and an ephemeral 500 x 1,500 m island, with cliffs 30-50 m high that enclosed a water-filled crater. In 2006 an island-forming eruption produced widespread dacitic pumice rafts that drifted as far as Australia. Another island was built during a September-October 2022 eruption.
### Ibu, Indonesia
**1.4941°N, 127.6324°E; summit elev. 1357 m**
The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that activity at Ibu continued during 2-8 April, with daily eruptive events recorded by the seismic network. Gray or white-and-gray ash plumes rose 400-800 m above the summit and drifted SE, S, SW, and W. 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; summit elev. 2422 m**
The Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported continuing eruptive activity at Kanlaon during 1-8 April. The seismic network recorded 5-12 daily volcanic earthquakes during 1-4 and 7-8 April; on 5 April there were 49 volcanic earthquakes and three periods of tremor (40 minutes to one hour and 31 minutes long), followed on 6 April by 34 volcanic earthquakes and eight periods of tremor (5-46 minutes long). Three periods of tremor were detected during 7-8 April, each lasting 33-54 minutes. Sulfur dioxide emissions ranged from 730 to 2,470 tonnes per day. Emissions were visible daily that generally rose 300-1,200 m above the summit and drifted in different directions. Four periods of ash emissions occurred on 5 April that rose 350-1,200 m above the crater rim, at 1310 (lasting 40 minutes), at 1510 (lasting one hour and 36 minutes), and at 1709 (lasting one hour and 11 minutes). A fourth period of ash emissions occurred at 2222 and was eight minutes long according to a news source. Nine ash emissions occurred on 6 April with each lasting 1-46 minutes; one ash emission on 7 April lasted for one hour and 35 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; summit elev. 1222 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 2-8 April. Both the N and S vents produced daily gas plumes and incandescence at variable intensities. The S vent produced a brief period of spattering just after 1730 on 2 April. From around 0600 on 3 April to 0600 on 6 April the S vent produced around 50 lava overflows that were accompanied by small dome fountains (1-2 m high). Each overflow was followed by vigorous spattering after the lava drained back into the vent. Overnight during 6-7 April several periods of gas-related flaming were visible in webcam images. Heavy rain and resulting steam obscured views of the vents overnight during 7-8 April, though evidence of a new lava flow was visible at 0320 on 8 April and another brief overflow occurred at around 0630. Intermittent spattering and gas jetting at the S vent was also visible on 8 April. 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:** 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; summit elev. 1431 m**
The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported ongoing eruptive activity at Lewotolok during 2-6 April. Daily white plumes rose as high as 100 m above the summit and drifted W and NW. An active lava flow on the SE flank was about 200 m long. White-and-gray ash plumes rose around 200 m above the summit and drifted W and NW at 1802 on 2 April, at 0928 on 4 April, and at 1653 and 1936 on 6 April. A webcam image from 1936 on 6 April showed incandescent material being ejected above the summit and onto the flanks. 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; summit elev. 2885 m**
The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that eruptive activity at Marapi (on Sumatra) continued during 2-8 April. White plumes rose as high as 300 m above the summit on most days and drifted in multiple directions. Eruptive events were recorded at 0525 and at 0741 on 4 April and at 2146 on 5 April but not visually observed due to weather conditions. 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; summit elev. 2462 m**
The Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported that the eruption at Mayon continued during 2-8 April, characterized by lava effusion, pyroclastic density currents (PDCs), incandescent rockfalls, ash plumes, and occasional minor Strombolian activity. Emissions were visible daily, rising 400-1,000 m above the summit and drifting in different directions. Each day the seismic network recorded 217-356 rockfalls, 0-12 PDCs, and 32-159 volcanic earthquakes. There were 1-19 periods of volcanic tremor, each lasting from as short as one minute to around two and a half hours during 1-3 and 6-7 April. Daily measurements of sulfur dioxide emissions averaged 1,519-2,558 tonnes per day. The lava flows did not advance in the Mi-isi (S), Basud (E), and Bonga (SE) drainages, remaining 1.3, 3.8, and 3.2 km long, respectively. Minor Strombolian activity and short periods of lava fountaining were recorded daily. At around 2000 on 2 April a rockfall ignited vegetation on the lower S flank. The fire burned through the night but ceased by the next morning. A video posted on social media showed an ash plume rising from an area low on the E flank, possibly from a collapse at a lava flow.
The number of evacuees did not notably change; by 1800 on 7 April a total of 4,020 people (1,105 families) were staying in 12 evacuation shelters, and an additional 85 people (26 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; summit elev. 2910 m**
The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that the eruption at Merapi (on Java) continued during 2-8 April with occasional lava avalanches produced by the active lava dome on the upper SW flank. White plumes rose as high as 425 m above the summit on most days and drifted in different directions. There were 3-13 lava avalanches that traveled as far as 1.9 km down the Sat/Putih drainage (W flank), the Krasak drainage (W flank), the Bebeng drainage (SW flank), and the Boyong (S) drainage on most days; none were reported on 7 April. One pyroclastic flow traveled 1.1 km down the Boyong drainage on 2 April. Two pyroclastic flows were detected by the seismic network on 7 April, though only one was visually observed descending the Boyong drainage as far as 1.8 km. A pyroclastic flow traveled 1.1 km down the Sat/Putih drainage on 8 April. 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.
### Sabancaya, Peru
**15.787°S, 71.857°W; summit elev. 5960 m**
The Instituto Geofísico del Perú’s (IGP) Centro Vulcanológico Nacional (CENVUL) reported continuing eruptive activity at Sabancaya during 1-8 April. The seismic network detected 6-9 daily earthquakes indicating the movement of magma and gases. As many as five daily thermal anomalies were identified in satellite images. Gas, steam, and ash plumes rose 500-1,800 m above the summit and drifted in multiple directions during 1-4 and 6-7 April. Gas-and-steam emissions rose as high as 1.2 km above the summit and drifted in multiple directions on 5 and 8 April. 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; summit elev. 3657 m**
The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that activity continued at Semeru during 2-8 April, with daily eruptive events recorded by the seismic network. Daily white-to-gray and gray ash plumes were visible generally rising 300-1,200 m above the summit and drifting in multiple directions. Small pyroclastic flows were visible in webcam images at 0206 on 5 April and at 0651 on 6 April descending the SE flank; on 5 April a pyroclastic flow traveled 3.5 km SE and an associated ash plume rose 1 km above the summit. An eruptive event at 1730 on 7 April generated a dense gray ash plume that rose 2 km above the summit and drifted NE and E. A pyroclastic flow descended the SE flank to the base, traveling as far as 4.5 km from the summit. 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; summit elev. 3283 m**
The Kamchatkan Volcanic Eruption Response Team (KVERT) reported continuing eruptive activity at the active lava domes along the N crater floor of Young Sheveluch (on the SW flank of Old Sheveluch) during 1-7 April. Dome growth continued to occur along the N part of the main lava dome. A thermal anomaly was identified in satellite images each day of the week. Explosions generated ash plumes identified in satellite at 1409 on 2 April that rose 10.7-11 km (35,100-36,100 ft) a.s.l. and drifted 345 km NNE. At 2122 the Aviation Color Code (ACC) was raised to Red (the highest level on a four-color scale). The ash plumes drifted 563 km NE within the next hour and no additional ash plumes were recorded; at 2226 the ACC was lowered back to Orange. By 3 April ash plumes had drifted 890 km NE. Explosions produced tall ash plumes on 5 April. At 2300 satellite images showed ash plumes rising 10.2 km (33.500 ft) a.s.l. and drifting NE. The ACC was raised to Red at 2348. Explosive activity subsided and no new ash plumes were observed by 0459 on 6 April; the ACC was lowered back to Orange. The previous ash plume continued to be visible in satellite images drifting 300 km NE at altitudes of 8.5-9 km (27,900-29,500 ft) a.s.l. On 6 April ash plumes were visible in satellite images drifting 1.600 km NE. Later that day, at 2320, ash plumes were identified in satellite images rising 10 km (32,800 ft) a.s.l. and drifting 30 km N. At 0122 on 7 April the ACC was raised to Red but moved back to Orange at 0246 because no additional ash plumes were visible. 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; summit elev. 796 m**
The Japan Meteorological Agency (JMA) reported that eruptive activity at Suwanosejima’s Ontake Crater continued during 27 March-3 April. Incandescence was observed nightly in webcam images. Eruptive events produced plumes that rose as high as 1 km above the crater rim. Ashfall was confirmed in areas within 5 km. 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.
### Whakaari/White Island, New Zealand
**37.52°S, 177.18°E; summit elev. 294 m**
The GeoNet reported that no eruptive activity at Whakaari/White Island had been observed since 24 March and that during 1-7 April only diffuse steam plumes were seen rising above the island in webcam images. During an overflight on 4 April scientists observed a bright white plume rising from the active vent. There was no evidence of new ballistics or ashfall on the crater floor. The maximum vent temperature was 100 degrees Celsius, measured with a thermal camera. The Volcanic Alert Level remained at 2 (on a scale of 0-5) and the Aviation Color Code was lowered to Yellow (the second lowest level on a four-color scale) on 7 April.
**Geological summary:** The uninhabited Whakaari/White Island is the 2 x 2.4 km emergent summit of a 16 x 18 km submarine volcano in the Bay of Plenty about 50 km offshore of North Island. The island consists of two overlapping andesitic-to-dacitic stratovolcanoes. The SE side of the crater is open at sea level, with the recent activity centered about 1 km from the shore close to the rear crater wall. Volckner Rocks, sea stacks that are remnants of a lava dome, lie 5 km NW. Descriptions of volcanism since 1826 have included intermittent moderate phreatic, phreatomagmatic, and Strombolian eruptions; activity there also forms a prominent part of Maori legends. The formation of many new vents during the 19th and 20th centuries caused rapid changes in crater floor topography. Collapse of the crater wall in 1914 produced a debris avalanche that buried buildings and workers at a sulfur-mining project. Explosive activity in December 2019 took place while tourists were present, resulting in many fatalities. The official government name Whakaari/White Island is a combination of the full Maori name of Te Puia o Whakaari (“The Dramatic Volcano”) and White Island (referencing the constant steam plume) given by Captain James Cook in 1769.
References:
1 Smithsonian Institution / US Geological Survey Weekly Volcanic Activity Report – GVP – April 2-8, 2026 – Managing Editor: Sally Sennert
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##### 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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