The Weekly Volcanic Activity Report: November 26-December 2, 2025

New activity/unrest

Barren Island, India

12.278°N, 93.858°E | Summit elev. 354 m

Eruptive activity continued at Barren Island during 28-29 November. The Darwin Volcanic Ash Advisory Centre (VAAC) reported that ash plumes were identified in satellite images rising 1.8-2.1 km (6,000-7,000 ft) a.s.l. and drifting SE, SW, and W. Weather clouds sometimes obscured views.

Geologic summary: Barren Island, a possession of India in the Andaman Sea about 135 km NE of Port Blair in the Andaman Islands, is the only historically active volcano along the N-S volcanic arc extending between Sumatra and Burma (Myanmar). It is the emergent summit of a volcano that rises from a depth of about 2250 m. The small, uninhabited 3-km-wide island contains a roughly 2-km-wide caldera with walls 250-350 m high. The caldera, which is open to the sea on the west, was created during a major explosive eruption in the late Pleistocene that produced pyroclastic-flow and -surge deposits. Historical eruptions have changed the morphology of the pyroclastic cone in the center of the caldera, and lava flows that fill much of the caldera floor have reached the sea along the western coast.

Bezymianny, Russia

55.972°N, 160.595°E | Summit elev. 2882 m

The Kamchatkan Volcanic Eruption Response Team (KVERT) reported that activity at Bezymianny gradually increased during 21-25 November and intensified during 26-27 November. The Far Eastern Branch of the Russian Academy of Sciences (FEB RAS) reported that during 21-25 November hot avalanches descended the SE flank, the lava dome was occasionally incandescent, and a thermal anomaly was identified in satellite images; weather clouds sometimes obscured views, especially on 23 November. KVERT reported that on 25 November ash plumes from hot avalanches drifted 54 km NE.

Activity escalated on 26 November. At 0220 explosions produced ash plumes that rose 7 km (23,000 ft) a.s.l. and drifted 150 km E. At 0335 explosions generated ash plumes that rose to 10 km (32,800 ft) a.s.l. and drifted E, prompting KVERT to raise the Aviation Color Code to Red (the highest level on a four-color scale). FEB RAS noted that pyroclastic flows traveled down the SE flank. An hour later satellite image captured an ash plume covering a 70 x 50 km area, rising to 11.4 km (37,400 ft) a.s.l. and drifting 70 km W. By 1119 explosions and ash emissions were no longer being detected so the Aviation Color Code was lowered to Orange. Effusive activity remained high with gas-and-steam emissions and hot avalanches of material descending the flanks. At 2130 satellite images showed two plumes, one 660 km long and the other 480 km long, each as up to 50 km wide at the leading edge, drifting NW and E. The farthest point of the ash plumes was 1,040 km from the summit. Effusion and hot avalanches continued during 26-27 November. Ash plumes rose 3-4 km a.s.l. and drifted 60 km E from 2130 on 26 November to 0200 on 27 November; by 0331 no new ash clouds were visible. At 2256 the Aviation Color Code was lowered to Yellow. Dates are reported in UTC; specific events are in local time where noted.

Geologic 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.

Erta Ale, Ethiopia

13.601°N, 40.666°E | Summit elev. 585 m

Satellite images captured Erta Ale and the surrounding region on 23 and 25 November, before and after the 23 November eruption at Hayli Gubbi. The 25 November image showed extensive ashfall across Erta Ale and a new collapsed area, in the northern caldera SE of the previously active pit craters, was about 685 m NNW-SSE and about 385 m ENE-WSW. White plumes rose from both the N and S pit craters in both images.

Geologic summary: The Erta Ale basaltic shield volcano in Ethiopia has a 50-km-wide edifice that rises more than 600 m from below sea level in the Danakil depression. The volcano includes a 0.7 x 1.6 km summit crater hosting steep-sided pit craters. Another larger 1.8 x 3.1 km wide depression elongated parallel to the trend of the Erta Ale range is located SE of the summit and is bounded by curvilinear fault scarps on the SE side. Basaltic lava flows from these fissures have poured into the caldera and locally overflowed its rim. The summit caldera usually also holds at least one long-term lava lake that has been active since at least 1967, and possibly since 1906. Recent fissure eruptions have occurred on the N flank.

Hayli Gubbi, Ethiopia

13.5111°N, 40.7161°E | Summit elev. 493 m

The first recorded explosive eruption at Hayli Gubbi was detected in satellite data at around 1130 on 23 November. Explosions produced a significant gas-and-ash plume that rose 10-15 km (32,800-50,000 ft) a.s.l. and drifted E and ENE over several countries, reaching China by the next day. A plume of pyroclastic material also traveled N about 130 km, spreading about 60 km laterally; it was unknown if the plume was related to a pyroclastic density current (PDC) or ash and gas drifting at a low altitude. Photos in news reports suggested that the eruption produced potentially far-reaching PDCs. According to a Centre for Observation and Modelling of Earthquakes, Volcanoes and Tectonics (COMET) uplift of a few centimeters at most was detected during 13-19 November.

Satellite images captured Hayli Gubbi, Erta Ale, and the region on 23 and 25 November, before and after the eruption. The 25 November image showed extensive ashfall to the NNW, NE, and E. The main crater was enlarged, expanding from around 330 to 390 m in diameter N-S and around 330 to 360 m in diameter E-W. Two new craters had formed. The first was located about 100 m ESE of the main crater and was about 255 m in diameter. The second new crater adjacent to S of the first new crater was smaller, about 110 m in diameter. A white plume was rising from the main crater.

News reports noted that although there were no deaths the ashfall contaminated water and food sources, covering grazing fields for livestock.

Geologic summary: Hayli Gubbi is the southernmost volcano of the Erta Ale Range. Recent tectonism has created a NW-SE graben across the summit, with a 380-m-diameter scoria cone at the summit and a 260-m-diameter crater displaying fumarolic activity. A sequence of fissure vents and lava fields extends 6 km NW to the southern caldera of Erta Ale. Additional dark flows that originated from the summit area cover the W and NE flanks, and SE before turning E at the base on the shield. More fissure vents extend ~3.5 km SSE within the graben to another small shield. From there, the line of vents continues, along with a lava field that spreads across the Afrera Plain, to a distance of 25 km from the summit crater. Barberi and Varet (1970) reported that those basaltic flow fronts covered sediments in the plain which Roubet et al. (1969) described as lacustrine limestones and diatomites deposited around 8,200 years BP above hyaloclastite formations. This places the eruption of the SE-most flows sometime within the last 8,000 years, but no additional information about how recent they might be is known; in appearance they are similar to very recent flows from the Erta Ale shield. On 15 July 2025 a dike intrusion that originated at the Erta Ale N caldera pit craters produced active fissure vents and lava flows within and on the S flanks of the south caldera; another set of fissure vents were active 4 km SE from the caldera rim, within 2 km of the Hayli Gubbi crater. A large explosive eruption on 23 November 2025 excavated the previous summit cone and created a second large crater (~200 m in diameter) in the summit area, and a third smaller crater.

Iliwerung, Indonesia

8.532°S, 123.573°E | Summit elev. 583 m

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported increased seismicity at Iliwerung during November, notably on 29 November. Deep volcanic earthquakes were occasionally recorded in 2025, notably there were 21 events on 1 January, 11 events on 6 September, and 47 events on 14 September. During 1-28 November the seismic network recorded seven deep volcanic earthquakes, 27 local tectonic earthquakes, 18 felt earthquakes, and 108 distant tectonic earthquakes. On 29 November there were 19 deep volcanic earthquakes, six local tectonic earthquakes, one felt earthquake, and four distant tectonic earthquakes. During 0000-1100 on 30 November the network recorded four deep volcanic earthquakes and 1one local tectonic earthquake. No activity was observed during 1-30 November at locations around the crater nor at submarine locations. The increased seismicity prompted PVMBG to raise the Alert Level to 2 (on a scale of 1-4) at 1200 on 30 November. The public was warned to stay 2 km away from the crater and to be cautious around the Bualan area.

Geologic summary: Constructed on the southern rim of the Lerek caldera, Iliwerung forms a prominent south-facing peninsula on Lembata (formerly Lomblen) Island. Craters and lava domes have formed along N-S and NW-SE lines on the complex volcano; activity has been observed at vents from the summit to the submarine SE flank. The summit lava dome was formed during an eruption in 1870. In 1948 the Iligripe lava dome grew on the E flank at 120 m elevation. Beginning in 1973-74, when three ephemeral islands were formed, submarine eruptions began on the lower ESE flank at a vent named Hobal; several other eruptions have since taken place at this vent.

Lewotobi, Indonesia

8.542°S, 122.775°E | Summit elev. 1703 m

In a special report posted on 3 December the Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) provided details about a lahar that impacted local villages near Lewotobi Laki-laki. The lahar descended the flanks and flowed into residential areas during 0517-0636. Weather conditions prevented views of the flanks, though rumbling could be heard within a radius of 3 km. Three houses in Dulipali Village (4 km NW) were severely damaged and one house in Klatanlo Village (4 km NW) was buried by 40 cm of lahar material. A collapsed utility pole in Dulipali resulted in power outages. The Maumere–Larantuka road was temporarily blocked by the lahar. The Alert Level remained at 4 (the highest level on a scale of 1-4) and the public was warned to stay 6 km away from the center of Laki-laki and 7 km in an area clockwise from NW to NE.

Geologic 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 unrest increased at Piton de la Fournaise during September and November. Deep seismicity with signals located at depths of 20 km, began in mid-September and continued in November. Inflation began to be detected in late November with Global Navigation Satellite System (GNSS) data indicating that the magmatic source was shallow and about 2.5 km below the summit. Seismicity increased on 22 November characterized by low-magnitude signals ~4-5 km deep beneath the N rim of Dolomieu Crater; a total of 26 deep volcano-tectonic earthquakes were recorded during 24-26 November. Several long-period (LP) events began to be detected on 24 November. During 26-30 November there was a notable increase in daily shallow volcano-tectonic events. The increase in seismicity was accompanied by increased sulfur dioxide emissions, though fluxes were low, close to the detection threshold. The hazard status of “Vigilance” (or a Yellow Alert) was initiated on 28 November and described as “a possible eruption in medium term (a few days or weeks) or presence of risks on the sector (rockfalls, increase of gas emissions, still hot lava flows)”.

Geologic 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.

Purace, Colombia

2.3095°N, 76.3948°W | Summit elev. 4650 m

The Servicio Geologico Colombiano (SGC) reported increased activity and gas-and-ash emissions at Puracé. Continuous volcanic tremor was recorded by the seismic network during 19-25 November. Seismic signals indicting rock fracturing occurred at similar levels compared to the week before with events located between the Puracé, Piocollo, and Curiquinga volcanoes at depths of 1-3 km. Sulfur dioxide emissions remained within the range recorded in previous weeks. Slow deformation between the Puracé, Piocollo, and Curiquinga volcanoes had continued since the eruptive episode at Curiquinga on 20 January. On 23 November the characteristics of seismic signals indicating fluid movement changed, with some signals accompanied by ash emissions identified by the monitoring network and observed by surrounding communities and SCG employees conducting fieldwork. The earthquakes were mainly located beneath the W flank at depths less than 1 km. At 0638 on 25 November a gas-and-ash plume rose 1.6 km above the summit and drifted SW. On 27 November ashfall was reported in various locations NW in the municipality of Puracé, specifically in rural areas including Cristales, Anambío (7 km NW), Alto Michabala, and Chapío, and to the W in the municipal seat of Coconuco (11 km WNW). Minor ashfall and strong sulfur odors during 0800-1000 on 29 November were reported by residents of the Río Negro village in the Paletará district (16 km SW), from the Mina de Azufre, Agua Hirviendo (10 km WNW), and Totoró road areas, and the N part of Popayán (28 km NW). Activity intensified during the morning of 30 November. The seismic network detected an increase in both the intensity and number of earthquakes associated with fluid movement. Several ash-and-gas plumes were observed rising as high as 1 km above the summit and drifting NW. At 0830 the Alert Level was raised to Orange (the second highest level on a four-color scale) and the public was warned to stay away from the crater. Unidad Nacional para la Gestión del Riesgo de Desastres (UNGRD) recommended that local authorities consider evacuating about 70 residents living in a high-threat sector.

On 1 December a resident of Pululó village (about 7 km SW) noted that the color of the San Francisco River had changed color and had a brown hue, possibly related to rain transporting ash into the river. Ashfall was noted in San Juan de Puracé area at around 1400. Later that day, at 2327 a tremor signal was associated with a gas-and-ash plume that rose 500 m above the summit and drifted SE. During 1-2 December seismicity remained elevated and was associated with continuous gas-and-steam emissions that drifted in various directions. Some of the emissions contained ash and rose around 500 m above the summit and drifted SE. During 1-2 December seismicity remained elevated and was associated with continuous gas-and-steam emissions that drifted in various directions. Some of the emissions contained ash and rose around 500 m above the summit, though weather conditions sometimes obscured views.

Geologic 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.

Semeru, Indonesia

8.108°S, 112.922°E | Summit elev. 3657 m

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that after the large 19 November pyroclastic density currents at Semeru small- to medium-scale eruptive activity continued and instrumental data indicated no new supply of magma at depth. During 20-29 November the seismic network recorded low levels volcanic earthquake activity, and no post-event deformation was seen in tiltmeter or GPS data. At 0900 on 29 November the Alert level was lowered to 3 (the second highest 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.

Multiple daily eruptive events were recorded during 26 November-2 December; sometimes weather conditions prevented visual confirmation. Daily white-and-gray ash plumes were visible rising 400-900 m above the summit and drifting SW and S. Incandescence at the summit on the upper SE flank was visible in several nighttime webcam images.

Geologic 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.

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 24 November-1 December with five eruptive events and two explosions. Nightly crater incandescence was visible in webcam images. Sulfur dioxide emissions were characterized as extremely high, averaging 4,500 tons per day on 25 November. An explosion at 2120 on 24 November ejected blocks 600-900 m from the vent; emission characteristics were unknown. At 0223 on 27 November an explosion generated an ash plume that rose 3 km above the summit and ejected blocks 300-500 m from the vent. By 0800 notable ashfall was reported in Kagoshima City (about 10 km W). Ash plumes from eruptive events at 0254 and at 1440 on 27 November, at 1332 on 28 November, and at 1631 on 30 November rose 1-1.4 km above the crater rim and drifted NE, E, and SE. 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.

Geologic 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 Vanuatu Meteorology and Geohazards Department (VMGD) reported ongoing unrest at Ambae during the month of November based on seismic and satellite data and webcam images. Sulfur dioxide emissions at variable rates were identified in satellite images during 1-3, 5-13, 15-17, and 19-24 November. Steam and/or gas emissions were visible in satellite and webcam observations during 3-4, 6-10, 12, 14, 18-19, and 23-25 November. A low-level thermal anomaly was also detected in satellite images during 3, 5-7, 10-12, and 25 November. According to the Wellington Volcanic Ash Advisory Center (VAAC) a low-level ash plume rose to 2.4 km (8,000 ft) a.s.l. and drifted NE on 1 and 3 December. The Alert Level remained at 2 (on a scale of 0-5), and the public was warned to stay outside of Danger Zone A, defined as a 2-km radius around the active vents in Lake Voui, and to stay away from drainages during heavy rains.

Geologic 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.

Ambrym, Vanuatu

16.25°S, 168.12°E | Summit elev. 1334 m

The Vanuatu Meteorology and Geohazards Department (VMGD) reported ongoing unrest at Ambrym during November. Small fumarolic plumes rose from both craters based on 2 November observations photos. A weak thermal anomaly was detected in satellite images during 3, 5-7, and 11 November. Seismic data confirmed ongoing unrest and was characterized by volcanic tremor and several volcano-seismic events. The Alert Level remained at 2 (on a scale of 0-5). VMGD warned the public to stay outside of Permanent Danger Zone A, defined as a 1-km radius around Benbow Crater and a 2-km radius around Marum Crater, and to stay 500 m away from the ground cracks created by the December 2018 eruption.

Geological summary: Ambrym is a large basaltic volcano with a 12-km-wide caldera formed during a major Plinian eruption with dacitic pyroclastic flows about 1,900 years ago. A thick, almost exclusively pyroclastic sequence, initially dacitic then basaltic, overlies lava flows of a pre-caldera shield volcano. Post-caldera eruptions, primarily from Marum and Benbow cones, have partially filled the caldera floor and produced lava flows that ponded on the floor or overflowed through gaps in the caldera rim. Post-caldera eruptions have also formed a series of scoria cones and maars along a fissure system oriented ENE-WSW. Eruptions have been frequently reported since 1774, though mostly limited to extra-caldera eruptions that would have affected local populations. Since 1950 observations of eruptive activity from cones within the caldera or from flank vents have occurred almost yearly.

Fuego, Guatemala

14.4748°N, 90.8806°W | Summit elev. 3799 m

The Instituto Nacional de Sismología, Vulcanologia, Meteorologia e Hidrología (INSIVUMEH) reported that eruptive activity at Fuego continued during 25 November-2 December. Daily Strombolian explosions recorded by the seismic network, at rates of 4-15 per hour, generated gas-and-ash plumes that rose as high as 1.1 km above the summit and drifted as far as 40 km NW, W, and SW. Occasional rumbling sounds, shock waves, and/or sounds associated with gas emissions were reported. Explosions occasionally ejected incandescent material as high as 200 m above the summit and showered the upper flanks with incandescent material. Daily incandescent avalanches of material descended the flanks, including the Las Lajas (SE), Seca (W), Taniluya (SSW), Trinidad (SSW), Santa Teresa (W), El Jute (ESE), Honda, and Ceniza (SSW) drainages, occasionally reaching vegetated areas. Ashfall was reported in areas downwind on most days including Panimache (8 km SW), Sangre de Cristo, Finca Palo Verde, El Porvenir (10 km S), Morelia (10 km SW), Santa Sofia (12 km SW), Los Yucales (12 km SW), and Yepocapa. The Coordinadora Nacional para la Reducción de Desastres (CONRED) reported that a tourist climbing near the crater on 30 November was injured and had to be carried down by companions and rescuers.

Geologic 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; 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 26 November-2 December. Satellite data indicated that both the SW and SE parts of the flow margins had advanced during the previous week. Seismicity was low. Weather clouds obscured satellite and webcam 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).

Geologic 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 | Summit elev. 1357 m

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that the eruption at Ibu continued during 26 November-2 December. Dense gray, gray-to-brown, or white-to-gray ash plumes rose 300-800 m above the summit and drifted NE, E, and SE on most days; weather conditions prevented visual confirmation on 2 December. Incandescence at the summit was visible in a few 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.

Geologic 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 24 November-2 December. The seismic network recorded 0-5 daily volcanic earthquakes. Gas-and-steam emissions of variable densities rose 75-600 m above the crater rim and drifted NW, SW, and SSW; weather clouds obscured views on 25 November. Daily sulfur dioxide emissions ranged from 523 to 2,667 tonnes per day. Two ash emissions, six and 31 minutes long, were recorded on 24 November. One of the ash plumes, observed at 0554, rose 75 m above the crater rim and drifted SW. The Alert Level remained at 2 (on a scale of 0-5); the public was warned to stay out of the 4-km-radius Permanent Danger Zone (PDZ) and pilots were advised to avoid flying close to the summit.

Geologic 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 25 November-2 December. Following several days of precursory overflows (76 total since 0930 on 21 November) and low dome fountaining, a sustained lava overflow at the N vent began at 1415 on 25 November and as followed by lava fountaining at 1430. Two sustained lava fountains rose as high as 180 m for 9.2 hours, erupting lava at a combined rate of 190 cubic meters per second. An estimated 6.3 million cubic meters of lava flows covered about 75 percent of the crater floor. The eruptive plume rose higher than 4.2 km (14,000 ft) a.s.l. Lava did not erupt from the S vent, though weak spattering and persistent flaming was visible. The N vent abruptly ceased erupting at 2339. During 26 November-2 December peaks in tremor were indicative of gas pistoning at depth within the vents. Incandescence at the S vent was visible during dark hours and incandescence at the N vent was visible during dark hours starting on 29 November. White gas emissions rose from the craters. Weak spattering at the N vent was visible overnight during 1-2 December. 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).

Geologic 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 the eruption at Krasheninnikov continued during 21-27 November. A daily large thermal anomaly over the volcano was identified in satellite images. The Northern Cone continued to effuse lava onto the E flank. The Aviation Color Code remained at Orange (the second highest level on a four-color scale). Dates and times are provided in Coordinated Universal Time (UTC); specific events are indicated in local time where specified.

Geologic 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).

Lopevi, Vanuatu

16.507°S, 168.346°E | Summit elev. 1413 m

The Vanuatu Meteorology and Geohazards Department (VMGD) reported continuing unrest at Lopevi during November. Seismicity was characterized by volcanic tremor and several volcano-seismic events. Small fumarolic steam plumes were continuously emitted from the summit crater during 3, 6-9, 13, 18, 20, and 24-25 November based on webcam images. Low-level thermal anomalies were identified in satellite images on 5, 7, and 10 November. The Alert Level remained at 2 (on a scale of 0-4).

Geologic summary: The small 7-km-wide conical island of Lopevi, known locally as Vanei Vollohulu, is one of Vanuatu’s most active volcanoes. A small summit crater containing a cinder cone is breached to the NW and tops an older cone that is rimmed by the remnant of a larger crater. The basaltic-to-andesitic volcano has been active during historical time at both summit and flank vents, primarily along a NW-SE-trending fissure that cuts across the island, producing moderate explosive eruptions and lava flows that reached the coast. Historical eruptions at the 1413-m-high volcano date back to the mid-19th century. The island was evacuated following major eruptions in 1939 and 1960. The latter eruption, from a NW-flank fissure vent, produced a pyroclastic flow that swept to the sea and a lava flow that formed a new peninsula on the western coast.

Manam, Papua New Guinea

4.08°S, 145.037°E | Summit elev. 1807 m

The Darwin Volcanic Ash Advisory Centre (VAAC) reported that an ash plume from Manam was identified in a satellite image at 1730 on 30 November drifting NW. Weather clouds obscured the area later that day and early on 1 December.

Geologic summary: The 10-km-wide island of Manam, lying 13 km off the northern coast of mainland Papua New Guinea, is one of the country’s most active volcanoes. Four large radial valleys extend from the unvegetated summit of the conical basaltic-andesitic stratovolcano to its lower flanks. These valleys channel lava flows and pyroclastic avalanches that have sometimes reached the coast. Five small satellitic centers are located near the island’s shoreline on the northern, southern, and western sides. Two summit craters are present; both are active, although most observed eruptions have originated from the southern crater, concentrating eruptive products during much of the past century into the SE valley. Frequent eruptions, typically of mild-to-moderate scale, have been recorded since 1616. Occasional larger eruptions have produced pyroclastic flows and lava flows that reached flat-lying coastal areas and entered the sea, sometimes impacting populated areas.

Marapi, Indonesia

0.38°S, 100.474°E; summit elev. 2885 m

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that an eruptive event at Marapi (on Sumatra) was recorded at 2234 on 2 December. Emissions were not observed. 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.

Geologic 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.

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 continued during 26 November-2 December. The seismic network recorded the descent of pyroclastic flows during 27-28 and 30 November. The SW lava dome produced nine lava avalanches that traveled as far as 1.9 km SW down the Bebeng drainage on 28 November, one that traveled 1.8 km down the Bebeng drainage on 30 November, 19 that traveled as far as 1.7 km SW down the Krasak drainage on 1 December, and six that traveled 2 km W down the Sat/Putih drainage. 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.

Geologic 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 that daily gas-and-steam plumes at Sabancaya rose 300-1,100 m above the crater rim and drifted less than 10 km in multiple directions during 25 November-2 December. One to two thermal anomalies on the summit crater floor were detected almost daily. The seismic network detected 7-11 daily signals indicating the movement of magma and gases. 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.

Geologic 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.

Sheveluch, Russia

56.653°N, 161.36°E | Summit elev. 3283 m

The Kamchatkan Volcanic Eruption Response Team (KVERT) reported continuing eruptive activity at Sheveluch’s “300 years of RAS” dome on the SW flank of Old Sheveluch and at the Young Sheveluch dome during 20-27 November. Thermal anomalies over the domes were identified in satellite images during 21-22 and 25-27 November; the volcano was obscured by weather clouds on the other days. Three explosions during 26-27 November generated ash plumes that rose around 5 km, 8.6 km, and 10 km a.s.l., respectively, and drifted 385 km NE. 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.

Geologic 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 24-30 November. Webcam images showed Strombolian activity at 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 16-21 events per hour, ejecting lapilli and bombs less than 150 m above the vents. Spattering at both sectors was visible, though the activity was more intense at N1 during 24, 26, and 28-29 November. Low- to medium-intensity explosions ejected tephra from two vents in Area C-S at a rate of 0-4 times per hour. A lava flow began to descend the Sciara del Fuoco at 0135 on 29 November extending about halfway down. The flow appeared to be cooling after a few hours. The Alert Level remained at Yellow (the second lowest level on a four-level scale) according to the Dipartimento della Protezione Civile.

Geologic 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 21-28 November. Incandescence was observed nightly in webcam images and ashfall was reported in Toshima Village (3.5 km SSW). At 0310 on 23 November an eruptive event produced an ash plume that rose 1.3 km above the crater rim and drifted N. 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.

Geologic 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.

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 23 November-2 December. The seismic network recorded 3-40 daily volcanic earthquakes along with periods of volcanic tremor lasting one minute long to days long. Daily gas-and-steam emissions with variable densities rose 600-1,800 m above the crater rim and drifted mainly SW, W, and NW. Sulfur dioxide emissions averaged 208 tonnes per day (t/d) on 27 November. One minor phreatomagmatic event occurred during 0948-0950 on 23 November and produced a grayish plume that rose 750 m above the crater rim and drifted SW. 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.

Geologic 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.

Whakaari/White Island, New Zealand

37.52°S, 177.18°E | Summit elev. 294 m

According to the Wellington Volcanic Ash Advisory Center (VAAC) low-level gas-and-steam emissions at Whakaari/White Island were detected during 24, 26, 28, and 30 November and sometimes contained ash. The plumes rose 900 m (3,000 ft) a.s.l. and drifted S and E based on pilot observations, satellite images, and webcam images.

Geologic 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.

Yasur, Vanuatu

19.532°S, 169.447°E | Summit elev. 361 m

The Vanuatu Meteorology and Geohazards Department (VMGD) reported that activity at Yasur continued at a level of “major unrest,” as defined by the Alert Level 2 status (on a scale of 0-5) during November. Activity was characterized by continuous explosions, voluminous and high emissions of gas, steam, and/or ash plumes, and nighttime incandescence. Sulfur dioxide gas emissions were at moderate-to-high levels and low-to-moderate power thermal anomalies were identified in satellite images. Seismic data confirmed continuing volcanic activity with explosions that were occasionally strong. The report warned that ejected material from explosions could fall in and around the crater. The public was reminded to not enter the restricted area within 600 m around the boundaries of the Permanent Exclusion Zone, defined by Danger Zone A on the hazard map.

Geologic summary: Yasur has exhibited essentially continuous Strombolian and Vulcanian activity at least since Captain Cook observed ash eruptions in 1774. This style of activity may have continued for the past 800 years. Located at the SE tip of Tanna Island in Vanuatu, this pyroclastic cone has a nearly circular, 400-m-wide summit crater. The active cone is largely contained within the small Yenkahe caldera, and is the youngest of a group of Holocene volcanic centers constructed over the down-dropped NE flank of the Pleistocene Tukosmeru volcano. The Yenkahe horst is located within the Siwi ring fracture, a 4-km-wide open feature associated with eruption of the andesitic Siwi pyroclastic sequence. Active tectonism along the Yenkahe horst accompanying eruptions has raised Port Resolution harbor more than 20 m during the past century.

References:

¹ Smithsonian Institution / US Geological Survey Weekly Volcanic Activity Report – GVP – November 26 – December 2, 2025 – 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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