The Weekly Volcanic Activity Report: March 19-25, 2026
**New activity/unrest:** Bulusan, Philippines | Lewotobi, Indonesia | Piton de la Fournaise, France | Whakaari/White Island, New Zealand.
**Ongoing activity:** Aira, Japan| Ambae, Vanuatu | Great Sitkin, United States | Home Reef, Tonga | Ibu, Indonesia | Kanlaon, Philippines | Kilauea, United States | Krasheninnikov, Russia | Lewotolok, Indonesia | Marapi, Indonesia | Mayon, Philippines | Merapi, Indonesia | Reventador, Ecuador | Sabancaya, Peru | Sangay, Ecuador | Semeru, Indonesia | Sheveluch, Russia | Stromboli, Italy | Suwanosejima, Japan | Karangetang, Indonesia | Katmai, United States | Turrialba, Costa Rica.
## New activity/unrest
### Bulusan, Philippines
**12.769°N, 124.056°E; summit elev. 1535 m**
The Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported that a period of low-level unrest with a sustained series of volcanic earthquakes continued at Bulusan. The seismic network detected 475 volcanic earthquakes during 15-22 March. The seismicity mostly consisted of weak volcano-tectonic earthquakes associated with rock fracturing at shallow depths. The signal characteristics were similar to the seismicity that had occurred prior to the June 2022 and April 2025 eruptions. Additionally, inflation of the W and SE flanks was detected in ground deformation data from continuous GPS and electronic tilt monitoring instruments during the last week of January and the first week of March. Weak-to-moderate gas emissions rose from active vents; sulfur dioxide emissions were below background levels on 17 March averaging 91 tonnes per day (t/d). At 1200 on 22 March PHIVOLCS raised the Alert Level to 1 (the second lowest level on a scale of 0-5). Seismicity continued with 19-55 daily volcanic earthquakes during 22-25 March. Sulfur dioxide emissions averaged 94 t/d on 23 March. The public was reminded not to enter the 4-km-radius Permanent Danger Zone (PDZ) and to be vigilant within the 2-km Extended Danger Zone (EDZ) on the SE flank. Pilots were warned not to fly close to the summit as ash from any sudden phreatic eruption could be hazardous to aircraft.
**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.
### Lewotobi, Indonesia
**8.542°S, 122.775°E; summit elev. 1703 m**
The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported periodic ash plumes at Lewotobi Laki-laki during 19-25 March. Daily white plumes rose as high as 200 m above the summit and drifted N and NE on most days. An eruptive event at 1436 on 19 March produced a dense gray ash plume that rose around 1 km above the summit and drifted NE and N. At 0946 on 23 March an eruptive event produced a dense gray ash plume that rose 400 m above the summit and drifted NE. Both events lasted under three minutes. The Alert Level remained at 2 (the second lowest level on a scale of 1-4) and the exclusion zone was a radius of 4 km 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.
### 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 the eruption at Piton de la Fournaise intensified during 18-25 March and then ended in the early evening on 25 March. The eruption was characterized by activity at the main cone on the lower SE flank of Dolomieu Crater, lava flows being transported though lava tubes E in two main branches, a N and S flow, and an active ocean entry. On 18 March the lava effusion rate, estimated using satellite data, increased with peak values of 16 cubic meters per second. That same day lava flows were active on the upper part of the N flow; the distal end of the N flow had stalled on 16 February, stopping at about 660 m elevation or about 2.6 km from the National Road 2 (RN2). Lava fountaining resumed at the main cone on 19 March with jets of lava rising tens of meters above the cone’s rim. The S flow continued to produce lava breakouts both above and below RN2, and both enlarged the platform at the ocean entry. OVPF scientists measured lava temperatures up to 1,130 degrees Celsius as it reached the ocean. Acidic plumes composed of sea water, steam, and volcanic gases rose at the points where lava contacted ocean water.
Tremor had significantly increased on 14 March and was accompanied by intermittent “gas pistoning.” A resurgence of summit seismicity occurred on 18 March, around the same time that deflation trends were becoming apparent in deformation data. The seismicity was interpreted as a readjustment of the stress field as the magma reservoir depressurized. The intermittent “gas pistoning” seismicity ended at around 0730 on 20 March and was followed by a slight decrease in tremor amplitude; more than 180 shallow volcano-tectonic earthquakes were recorded on 20 March and were mainly located beneath the SE rim of Dolomieu Crater.
A southern branch of the S flow advanced towards RN2 and one of the flows downslope of RN2 reached the ocean during 18-20 March. The active part of the N flow had advanced to 690 m elevation or 2.8 km from RN2 by 0910 on 20 March. Peak flow rates exceeded 30 cubic meters per second. Lava tubes had developed on the platform. Overnight during 20-21 March several branches of the S flow were no longer advancing, and the N flow was again inactive.
The platform at the ocean entry continued to build during 21-24 March, though less lava was reaching the platform, and mainly reaching the ocean through tubes. Small collapses occurred along the platform’s margins due to wave action, though by 24 March the platform extended the coastline by about 193 m and was at least 840 m wide along the pre-existing coastline. Lava flow rates declined and were estimated to be as high as 13 cubic meters per second during 22-23 March. Deflation signals distinctly slowed by 23 March and ceased at the summit by 24 March. Lava fountaining continued at the main cone and the cone filled with lava; during 22-24 March lava overflowed the crater rim multiple times. Tremor indicating lava effusion and gas flux decreased during 0500-0700 on 24 March and the amplitude dropped sharply at 0700. Seismicity below the summit was lower during 22-23 March then increased on 24 March but remained below levels detected during the peak of deflation. Tremor levels fluctuated during 24-25 March. The S flow ceased being active at around 1630 on 25 March. 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 caldera-sized 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 side. More than 150 eruptions, most of which have produced fluid basaltic lava flows, have occurred since the 17th century. Only six eruptions, in 1708, 1774, 1776, 1800, 1977, and 1986, have originated from fissures outside the scarps.
### Whakaari/White Island, New Zealand
**37.52°S, 177.18°E; summit elev. 294 m**
The GeoNet reported that a small eruption occurred at Whakaari/White Island at 1735 on 24 March. Images captured by the Whakatane and Te Kaha webcams, located along the Bay of Plenty coast, showed a dark gray ash plume rising about 1.3 km above the summit for about two minutes and drifting W. Though no additional activity was visible, the Volcanic Alert Level was raised to 3 (on a scale of 0-5) and the Aviation Color Code was raised to Orange (the second highest level on a four-color scale). GeoNet noted that passive steam emissions interspersed with minor eruptive activity had been occurring during the previous few weeks.
**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.
## 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 16-23 March. Nighttime crater incandescence was visible in webcam images. A very small eruptive event was recorded on 16 March. 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 19-24 March based on ash advisories from the Wellington Volcanic Ash Advisory Center (VAAC). According to the VAAC gas, steam, and ash plumes were visible in webcam and satellite images rising as high as 4.6 km (15,000 ft) a.s.l., or about 3 km above the summit, and drifting S on most days. The plumes were intermittent, occasionally obscured by weather clouds, and sometimes only plumes of gas and steam were identified. Sulfur dioxide emissions were detected on 21 March. 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.
### 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 18-25 March, particularly to the SW. Very low seismic activity was characterized by occasional small volcanic earthquakes and daily small rockfalls within the crater. Daily elevated surface temperatures were observed in satellite views. 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 continuing activity at Home Reef during 14-20 March. Emissions rising from the main vent were visible in a 17 March satellite image along with discolored water on the E side of the island. The Aviation Color Code remained at Orange (the second highest 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 19-25 March, with daily eruptive events recorded by the seismic network. Gray ash plumes rose 400-700 m above the summit and drifted SE on most days; emissions were not visible during 19-20 March due to weather conditions. 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 18-25 March. The seismic network recorded 5-18 daily volcanic earthquakes, though on 23 and 24 March there were a total of 67 and 63 volcanic earthquakes, respectively. In addition, there were 2-18 daily periods of volcanic tremor each lasting as short as six minutes to just over five hours during 20-24 March. Daily sulfur dioxide emissions ranged from 553 to 2,169 tonnes per day. Emissions were visible daily and generally rose 100-700 m above the summit and drifted SW, SSW, and E. Several daily periods of ash emissions were visible during 20-23 March, including two periods on 20 March lasting one hour and 38 minutes and one hour and 49 minutes, nine periods on 21 March lasting 20 minutes to just over three hours, three periods on 22 March lasting 18 minutes to an hour and a half, 12 periods on 23 March lasting as short as two minutes to just over seven hours, and 7 periods lasting six minutes to just under three hours. 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 18-25 March. Incandescence at the S vents was intermittently visible in webcam images on most nights. Both the N and S vents emitted steam-and-gas plumes, and abundant steam rose from cooling lava flows within Halema’uma’u Crater. Seismic tremor decreased overall, though tremor bursts persisted at intervals of 5-10 minutes. The bursts correlated with peak temperatures recorded by a thermal camera at the S vent, consistent with ongoing gas pistoning within the vent. 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.
### Krasheninnikov, Russia
**54.596°N, 160.27°E; summit elev. 1816 m**
The Kamchatkan Volcanic Eruption Response Team (KVERT) reported that lava flows at Krasheninnikov continued to effuse onto the ENE flanks of the Northern Cone during 18-25 March. A thermal anomaly was identified daily in satellite images on 21 March; weather clouds obscured views on the other days. The Aviation Color Code remained at Yellow (the second lowest level on a four-color scale). Dates and times are provided in Coordinated Universal Time (UTC); events are in local time only where specified.
**Geological summary:** The late Pleistocene to Holocene Krasheninnikov volcano is comprised of two overlapping stratovolcanoes within a 9 x 10 km Pleistocene caldera. Young lava flows from summit and flank vents descend both into the caldera and down its outer flanks, and older flows that covered much of the SE caldera rim extended downslope at least 7 km. Tephra deposits from the caldera-forming eruption directly overlie a 39,000 years before present (BP) tephra thought to be associated with the formation of Uzon caldera (Florenskii, 1988). The intra-caldera stratovolcanoes are situated along a NE-SW-trending fissure that has also produced zones of Holocene cinder cones extending 15-20 km beyond the caldera. Construction of the southern edifice began about 11,000 years BP and lasted for about 4,500 years; it has a summit crater about 800-900 m wide. The northern edifice was constructed during a cycle of similar length that began about 6,500 years ago; it has a summit crater about 1.5 km wide, within which is low cone with an 800-m-wide crater containing another small cone. An eruptive cycle during about 600-400 years BP (1350-1550 CE) produced the Pauk lava cone in the crater of the northern cone and the Yuzhny lava flow on SW flank outside the caldera, followed by the Molodoy flow from the upper SW flank (Ponomareva, 1987; Ponomareva and Tsyurupa, 1985; Ponomareva and Braitseva, 1990).
### 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 19-25 March. White plumes rose as high as 50 m above the summit and drifted NE and E on most days; emissions were not visible during 24-25 March. Strombolian ejections of incandescent material at the summit were visible in webcam images on 19, 22, and 25 March. 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 19-25 March. White plumes rose as high as 800 m above the summit on most days and drifted in multiple directions. Eruptive events were recorded at 1424 and at 1754 on 24 March 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 18-25 March, characterized by lava effusion and collapses at the summit dome, pyroclastic density currents (PDCs), incandescent rockfalls, ash plumes, active lava flows, and occasional minor Strombolian activity. Emissions were visible almost daily, rising as high as 1.5 km above the summit and drifting mainly NW, W, and SW; views were obscured on 18 March. The seismic network recorded 262-412 daily rockfalls, 4-19 daily PDCs, and 128-271 daily volcanic earthquakes. There were 1-12 periods of volcanic tremor, each lasting from as short as one minute to just over an hour during 19, 21-22, and 24 March. Daily measurements of sulfur dioxide emissions averaged 1,132-4,352 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.
The number of evacuees did not notably change; by 1800 on 25 March a total of 4,019 people (1,105 families) were staying in 12 evacuation shelters, and an additional 86 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; summit elev. 2910 m**
The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that the eruption at Merapi (on Java) continued during 19-25 March with occasional lava avalanches. White plumes rose as high as 150 m above the summit and drifted E on most days. There were 5-25 lava avalanches that traveled as far as 2 km down the Sat/Putih drainage (W flank), Bebeng drainage (SW flank), and Krasak drainage (W flank) almost daily; no avalanches were reported on 25 March. 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.
### Reventador, Ecuador
**0.077°S, 77.656°W; summit elev. 3562 m**
The Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN) reported that eruptive activity at Reventador continued at a high level during 18-25 March. Seismicity was unknown during most of the week due to technical issues at the monitoring stations; during 24-25 March the seismic network recorded 77 explosions, long-period earthquakes, harmonic tremor, and tremor associated with emissions. Ash-and-gas plumes were not visible in webcam images due to weather conditions, but on most days they were identified in satellite images rising 400-1,600 m above the crater rim and drifting in various directions. Thermal anomalies were also identified in satellite images on most days. Ashfall was reported during 21-22 and 24-25 March in areas downwind, including Gonzalo Díaz de Pineda parish (26 km SSW) and Cantón El Chaco (15 km S). The Secretaría de Gestión de Riesgos (SGR) maintained the Alert Level at Orange (the second highest level on a four-color scale).
**Geological summary:** Volcán El Reventador is the most frequently active of a chain of Ecuadorian volcanoes in the Cordillera Real, well east of the principal volcanic axis. The forested, dominantly andesitic stratovolcano has 4-km-wide avalanche scarp open to the E formed by edifice collapse. A young, unvegetated, cone rises from the amphitheater floor to a height comparable to the rim. It has been the source of numerous lava flows as well as explosive eruptions visible from Quito, about 90 km ESE. Frequent lahars in this region of heavy rainfall have left extensive deposits on the scarp slope. The largest recorded eruption took place in 2002, producing a 17-km-high eruption column, pyroclastic flows that traveled up to 8 km, and lava flows from summit and flank vents.
### 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 18-25 March. The seismic network detected 8-16 daily earthquakes indicating the movement of magma and gases. As many as four daily thermal anomalies were identified in satellite images. An explosion at 1512 on 19 March generated an ash plume that rose 2 km above the summit and drifted S, SW, and NW. Gas-and-steam emissions rose as high as 800 m above the summit and drifted in multiple directions during 19-20 March. Gas, steam, and ash plumes rose 300-1,000 m above the summit and drifted in multiple directions during 21-24 March. 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.
### Sangay, Ecuador
**2.005°S, 78.341°W; summit elev. 5286 m**
The Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN) reported that the eruption continued at Sangay during 18-25 March. The seismic network recorded 51-158 daily explosions. Ash-and-gas plumes reported daily or nearly daily rose 300-1,800 m above the crater rim and drifted in multiple directions. Each night incandescent material was visible descending the flanks, particularly to the NW, as far as 1.4 km. The Secretaría de Gestión de Riesgos (SGR) maintained the Alert Level at Yellow (the second highest level on a four-color scale).
**Geological summary:** The isolated Sangay volcano, located east of the Andean crest, is the southernmost of Ecuador’s volcanoes and its most active. The steep-sided, glacier-covered, dominantly andesitic volcano grew within the open calderas of two previous edifices which were destroyed by collapse to the east, producing large debris avalanches that reached the Amazonian lowlands. The modern edifice dates back to at least 14,000 years ago. It towers above the tropical jungle on the east side; on the other sides flat plains of ash have been eroded by heavy rains into steep-walled canyons up to 600 m deep. The earliest report of an eruption was in 1628. Almost continuous eruptions were reported from 1728 until 1916, and again from 1934 to the present. The almost constant activity has caused frequent changes to the morphology of the summit crater complex.
### 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 19-25 March, with daily eruptive events recorded by the seismic network. Daily white-to-gray and gray ash plumes were visible rising 400-1,000 m above the summit and drifting in multiple directions. At around 0528 on 20 March a dense ash plume rose 1 km and a pyroclastic flow traveled 3.5 km down the SE flank, according to a news article. A webcam image at 0215 on 21 March showed a pyroclastic flow descending the flank and incandescence at 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 19-25 March. A new dome lobe continued to grow along the N part of the main lava dome. A thermal anomaly was identified in satellite images on most days; weather clouds obscured views on 23 March. Explosions during 19-20 and 22 March generated ash plumes that rose 9.5-11.6 km (31,200-38,100 ft) a.s.l. and drifted 2,410 km E and NE and 100-400 km NW. 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.
### Stromboli, Italy
**38.789°N, 15.213°E; summit elev. 924 m**
The Sezione di Catania – Osservatorio Etneo (INGV) reported that eruptive activity continued at Stromboli during 16-22 March. 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 low- to medium-intensity explosions at a rate of 15-20 per hour, ejecting lapilli and bombs less than 150 m above the vents. Weak but continuous spattering occurred at N2 and was particularly intense during the evening of 18 March. Low- to medium-intensity explosions ejected tephra from two vents in Area C-S at a rate of 1-4 times per hour.
The S vent at N2 overflowed on 18 and 22 March. Weather clouds obscured views on 18 March, though at around 0155 large blocks of incandescent material began rolling down the upper part of the Sciara del Fuoco. Lava that descended the same drainage was cooling by 1200. An overflow around 0630 on 22 March produced another lava flow that reached the mid-to-upper part of the Sciara del Fuoco; it had stopped and was cooling by 0300 on 23 March. 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; summit elev. 796 m**
The Japan Meteorological Agency (JMA) reported that eruptive activity at Suwanosejima’s Ontake Crater continued during 13-20 March. Incandescence was observed nightly in webcam images. An eruptive event on 14 March produced a plume that rose 400 m above the crater rim. Rumbling was heard at 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.
### Karangetang, Indonesia
**2.781°N, 125.407°E; summit elev. 1797 m**
The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that 1900 on 12 March an incandescent avalanche from Karangetang’s North Crater traveled 1 km W down the Sumpihi River drainage. The Alert Level remained at 2 (on a scale of 1-4) and the public was advised to stay 1.5 km away from Kawah Dua (North Crater) and the Main Crater (South Crater) with an extension to 2.5 km along the W and SW flanks of Main 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.
### Katmai, United States
**58.279°N, 154.9533°W; summit elev. 2047 m**
The Anchorage Volcanic Ash Advisory Center (VAAC) reported that during 18-19 March strong winds in the vicinity of Katmai and the Valley of Ten Thousand Smokes dispersed unconsolidated ash up to 1.8 km (6,000 ft) a.s.l. to the SE. The ash was originally deposited during the Novarupta-Katmai eruption in 1912. The Volcano Alert Level remained at Normal (the lowest level on a four-level scale) and the Aviation Color Code remained at Green (the lowest level on a four-color scale).
**Geological summary:** Katmai was initially considered to be the source of the Valley of Ten Thousand Smokes ash flow in 1912. However, the 3 x 4 km caldera of 1912 is now known to have formed as a result of the voluminous eruption at nearby Novarupta volcano. The edifice had four NE-SW-trending summits, most of which were truncated by the 1912 collapse. Two or more large explosive eruptions took place during the late Pleistocene. Most of the two overlapping pre-1912 Katmai volcanoes are Pleistocene, but Holocene lava flows from a flank vent descend the SE flank of the SW edifice into the Katmai River canyon. The steep walled young caldera has a jagged rim that rises 500-1,000 m above the caldera floor and contains a deep lake. Lake waters have covered a small post-collapse lava dome (Horseshoe Island) that was seen on the caldera floor at the time of the initial ascent to the caldera rim in 1916.
### Turrialba, Costa Rica
**10.025°N, 83.767°W; summit elev. 3340 m**
The Observatorio Vulcanológico y Sismológico de Costa Rica-Universidad Nacional (OVSICORI-UNA) reported that the seismic and acoustic infrasound sensor network at Turrialba recorded a volcano-tectonic signal at 1203 on 22 March followed one minute later by a signal indicating a small collapse within West Crater. Parque Nacional Volcán Turrialba officials reported that they heard a loud rumble and detected a sulfur odor in the summit area.
**Geological summary:** Turrialba, the easternmost of Costa Rica’s Holocene volcanoes, is a large vegetated basaltic-to-dacitic stratovolcano located across a broad saddle NE of Irazú volcano overlooking the city of Cartago. The massive edifice covers an area of 500 km2. Three well-defined craters occur at the upper SW end of a broad 800 x 2200 m summit depression that is breached to the NE. Most activity originated from the summit vent complex, but two pyroclastic cones are located on the SW flank. Five major explosive eruptions have occurred during the past 3500 years. A series of explosive eruptions during the 19th century were sometimes accompanied by pyroclastic flows. Fumarolic activity continues at the central and SW summit craters.
References:
1 Smithsonian Institution / US Geological Survey Weekly Volcanic Activity Report – GVP – March 19-25, 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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