Aira (Japan) | 30 July-5 August 2025 | Continuing ActivityCite this Report

The Japan Meteorological Agency (JMA) reported ongoing eruptive activity at Minamidake Crater (Aira Caldera’s Sakurajima volcano) during 28 July-4 August. Three explosions occurred at the Minamidake crater 28-30 July, with ash plumes rising up to 1 km (3,300 ft) above the crater rim. On 2 August at 2006, an explosion produced an ash plume that rose 1.1 km (3,600 ft) above the rim. Very small eruptive events occasionally occurred during 3-4 August. 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.

Source: Japan Meteorological Agency (JMA)

Ambae (Vanuatu) | 30 July-5 August 2025 | Continuing ActivityCite this Report

The Vanuatu Meteorology and Geohazards Department (VMGD) reported ongoing unrest at Ambae during the month of July based on seismic and satellite data. Satellite imagery and webcam observations from 13, 17, 26, and 28-29 July showed continuous steam and/or gas emissions. Sulfur dioxide emissions were recorded in satellite images acquired on 1-3, 5-7, 9-16, 18-19, 22-24, 27-28, and 30 July. A low-level thermal anomaly was also detected in satellite images from 10, 23, and 28 July. 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.

Source: Vanuatu Meteorology and Geohazards Department (VMGD)

Ambrym (Vanuatu) | 30 July-5 August 2025 | Continuing ActivityCite this Report

The Vanuatu Meteorology and Geohazards Department (VMGD) reported ongoing unrest at Ambrym during the month of July. Field observations and webcam images from 11 and 14 July confirmed continuous degassing at Marum crater. Low-level thermal anomalies were detected in satellite imagery from 14 and 27 July. Seismic data further confirmed ongoing unrest. The Alert Level remained at 2 (on a scale of 0-5). VMGD warned the public to stay outside the Permanent Exclusion Zone, which includes a 1-km radius around Benbow Crater, and Danger Zone A, a 2-km radius around Marum Crater (including Maben-Mbwelesu, Niri-Mbwelesu, and Mbwelesu), and to stay 500 m away from the ground cracks created by the December 2018 eruption.

Source: Vanuatu Meteorology and Geohazards Department (VMGD)

Dukono (Indonesia) | 30 July-5 August 2025 | Continuing ActivityCite this Report

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that eruptive activity at Dukono continued during 30 July-5 August. White-and-gray gas-and-ash plumes rose 100-700 m above the summit and drifted in multiple directions on most days. The number of seismically recorded explosions varied from 9 to 174 per day, with the highest value recorded on 2 August. The Alert Level remained at Level 2 (on a scale of 1-4) and the public was warned to stay 4 km away from the Malupang Warirang Crater.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

Etna (Italy) | 30 July-5 August 2025 | Continuing ActivityCite this Report

The Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Etneo (INGV-OE), reported that eruptive activity continued at Etna’s summit craters during 28 July-3 August. The activity primarily involved variable-rate degassing, except at the SE crater, where low-level explosive activity generated ash emissions that were deposited throughout the summit area.

Source: Sezione di Catania - Osservatorio Etneo (INGV)

Fuego (Guatemala) | 30 July-5 August 2025 | Continuing ActivityCite this Report

The Instituto Nacional de Sismología, Vulcanologia, Meteorología e Hidrología (INSIVUMEH) reported that eruptive activity at Fuego continued during 30 July-5 August. A fumarole was visible on those days with white emissions rising 100 m above the crater and drifting W. Pulses of gas and ash were visible during 30 July and 1-2 August. Weak incandescence at the summit was occasionally observed in overnight webcam images.

Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)

Gaua (Vanuatu) | 30 July-5 August 2025 | Continuing ActivityCite this Report

The Vanuatu Meteorology and Geohazards Department (VMGD) reported that unrest continued at Gaua during the month of July. Satellite images taken on 2-4, 7, and 9 July showed continuous steam and/or gas emissions from the vent. Sulfur dioxide emissions were detected in satellite images from 28 July. Additionally, a low-level thermal anomaly was recorded in satellite images from 7 and 11 July. The alert level remained at 2 (on a scale of 0-5), and the public was warned to stay away from the main cone.

Source: Vanuatu Meteorology and Geohazards Department (VMGD)

Great Sitkin (United States) | 30 July-5 August 2025 | Continuing ActivityCite this Report

The Alaska Volcano Observatory (AVO) reported that slow lava effusion continued to feed a thick flow in Great Sitkin’s summit crater during 30 July-5 August. Low-level seismicity continued with occasional small earthquakes and rockfall signals detected. On 1 August elevated surface temperatures were observed in satellite data, with occasional steam emissions seen in clear views. High-resolution satellite views showed minor advancement of the SW lava lobe over the past week, as well as ongoing minor inflation of the S portion of the lava dome. Clouds obscured all satellite and webcam views on 2-5 August. 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).

Source: US Geological Survey Alaska Volcano Observatory (AVO)

Home Reef (Tonga) | 30 July-5 August 2025 | Continuing ActivityCite this Report

The Tonga Geological Services reported no signs of activity at Home Reef during 19 July-2 August. A thermal anomaly was last detected on 11 July, and both discolored water and sulfur deposits around the crater were last seen on 16 July. The Aviation Color Code remained at Yellow (the second lowest level on a four-level scale, the Maritime Alert Level remained at Orange (the third 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).

Source: Tonga Geological Services, Government of Tonga

Ibu (Indonesia) | 30 July-5 August 2025 | Continuing ActivityCite this Report

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that the eruption at Ibu continued during 30 July-5 August. Daily dense gray or white-to-gray ash plumes rose 300-900 m above the summit and drifted N, NW, and W. Between 109 and 137 daily explosions were noted. Crater incandescence was visible in nighttime webcam images. The Alert Level remained at 2 (the second highest 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.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

Karymsky (Russia) | 30 July-5 August 2025 | Continuing ActivityCite this Report

The Kamchatkan Volcanic Eruption Response Team (KVERT) reported that moderate steam-and-gas activity continued at Karymsky during 31 July-6 August. A weak thermal anomaly over the volcano was observed in satellite images during 2-5 August. The volcano was quiet or obscured by clouds on the other days of the week. The Aviation Color Code remained at Yellow (the second 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.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

Kirishimayama (Japan) | 30 July-5 August 2025 | Continuing ActivityCite this Report

The Japan Meteorological Agency (JMA) reported that eruptive activity continued at Shinmoedake (Shinmoe peak, a stratovolcano of the Kirishimayama volcano group) during 28 July-4 August. The number of volcanic earthquakes with epicenters directly beneath Shinmoedake had been fluctuating since late October 2024; volcanic tremor was occasionally detected. Eruptive activity occurred intermittently with grayish white plumes rising as high as 1.2 km above the crater rim. A field survey conducted at the foot of the mountain on 28 July found sulfur dioxide emissions of 600 tons per day, compared to 1,600 tons per day on 15 July. The Alert Level remained at 3 (on a 5-level scale) and the public was warned to exercise caution within 3 km from Shinmoedake Crater.

Source: Japan Meteorological Agency (JMA)

Lewotolok (Indonesia) | 30 July-5 August 2025 | Continuing ActivityCite this Report

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that an eruption at Lewotolok was ongoing during 30 July-5 August. White-to-gray or gray ash plumes typically rose 200-400 m above the summit of the cone and drifted in multiple directions. Clear nighttime webcam images showed incandescent material being ejected above the cone. Between 50 and 181 daily explosions were recorded over the week-long period. The Alert Level remained at 3 (on a scale of 1-4) and the public was warned to stay 3 km away from the summit.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

Marapi (Indonesia) | 30 July-5 August 2025 | Continuing ActivityCite this Report

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that eruptive activity at Marapi (on Sumatra) continued during 30 July-5 August. There were two explosions on 31 July, at 0100 and 0741. Only the 0741 event was observed, with a plume that rose 400 m above the summit and dispersed to the N. Another eruption was detected seismically on 2 August at 1233 but was not witnessed due to cloudy weather. 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.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

Merapi (Indonesia) | 30 July-5 August 2025 | Continuing ActivityCite this Report

The Balai Penyelidikan dan Pengembangan Teknologi Kebencanaan Geologi (BPPTKG) reported that the eruption at Merapi (on Java) continued during 25-31 July. During that 19 avalanches were observed descending into the upper reaches of the Krasak River and reaching as far as 2 km from the summit. There were six avalanches in the upper reaches of the Bebeng River that traveled as far as 1.9 km. Fifty avalanches descended into the upper Sat/Putih River, extending a maximum of 2 km. Based on analysis of aerial photos from 17 July, the volume of the SW lava dome and the central dome were 4,011,000 cubic meters and 2,368,900 cubic meters, respectively. Small morphological changes to the SW lava dome resulted from continuing effusion and minor collapses. 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.

Source: Balai Penyelidikan dan Pengembangan Teknologi Kebencanaan Geologi (BPPTKG)

Poas (Costa Rica) | 30 July-5 August 2025 | Continuing ActivityCite this Report

The Observatorio Vulcanológico y Sismológico de Costa Rica-Universidad Nacional (OVSICORI-UNA) reported continuing gas-and-steam emissions with occasional minor amounts of ash at Poás during 30 July-5 August. Strong incandescence at Boca A vent was observed. Sulfur dioxide emissions remained high and were between 250 and 1,000 tons per day during the week. The volcanic Alert Level remained at 2 (the second lowest level on a four-level scale) and the Aviation Color Code remained at Yellow (the second lowest color on a four-color scale).

Sources: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA), Comisión Nacional de Prevención de Riesgos y Atención de Emergencias (CNE)

Santa Maria (Guatemala) | 30 July-5 August 2025 | Continuing ActivityCite this Report

The Instituto Nacional de Sismología, Vulcanología, Meteorología e Hidrología (INSIVUMEH) reported strong eruptive activity continuing at Santa Maria’s Santiaguito dome complex during 30 July-5 August, including lava extrusion at Caliente dome. Daily explosions, 1-2 per hour when reported, generated gas-and-ash plumes that rose as high as 1 km above the dome and drifted W. Effusion of blocky lava and collapses of previous deposits produced block avalanches that descended multiple flanks; the collapsed material sometimes produced pyroclastic flows that reached the base of the volcano. Incandescence was visible at Caliente dome mostly during dark hours. Minor ashfall was reported in communities to the S and SW during 1 and 3-5 August.

Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)

Semeru (Indonesia) | 30 July-5 August 2025 | Continuing ActivityCite this Report

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that activity continued at Semeru during 30 July-5 August, with between 39 and 51 daily eruptive events recorded by the seismic network. Eruptive plumes rose between 400 and 900 m above the summit and generally traveled to the S and SW. The Alert Level remained at 2 (the second lowest level on a scale of 1-4). The public was warned to stay at least 3 km away from the summit in all directions, 8 km from the summit to the SE, 500 m from the banks of the Kobokan drainage as far as 13 km from the summit, and to avoid other drainages including the Bang, Kembar, and Sat, due to lahar, avalanche, and pyroclastic flow hazards.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

Sheveluch (Russia) | 30 July-5 August 2025 | Continuing ActivityCite this Report

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 31 July-6 August. Thermal anomalies were identified over the domes in satellite images from 30-31 July and 2 August. The volcano was obscured by clouds during the other days of the week. 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.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

Suwanosejima (Japan) | 30 July-5 August 2025 | Continuing ActivityCite this Report

The Japan Meteorological Agency (JMA) reported that eruptive activity at Suwanosejima's Ontake Crater continued during 28 July-4 August. Eruption plumes rose up to 500 m above the crater rim and no explosions were detected. 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.

Source: Japan Meteorological Agency (JMA)

Telica (Nicaragua) | 30 July-5 August 2025 | Continuing ActivityCite this Report

The Washington Volcanic Ash Advisory Center (VAAC) reported that during 3-4 August ash plumes from Telica were identified in satellite and/or webcam images at 1.5 km (5,000 ft) a.s.l. drifting SW. A plume with possible ash was visible in webcam images drifting SW on 3 August.

Source: Washington Volcanic Ash Advisory Center (VAAC)

Yasur (Vanuatu) | 30 July-5 August 2025 | Continuing ActivityCite this Report

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 July. Satellite and webcam images from 1, 3-17, 20-23, 25-26, and 28-31 July showed that explosive activity continued, producing gas, steam, and/or ash emissions. Sulfur dioxide emissions were detected in satellite images from 2-14 and 17-30 July. Low-to-moderate thermal anomalies were observed in satellite images on 5, 11-13, 15, 21, 24-25, and 27-29 July. Seismic data confirmed ongoing volcanic activity, with explosions that were occasionally strong. The public was advised to maintain a minimum distance of 600 m from the eruptive vents, designated as Danger Zone A on the Yasur Caldera Safety Map.

Source: Vanuatu Meteorology and Geohazards Department (VMGD)