The Weekly Volcanic Activity Report is a cooperative project between the Smithsonian's Global Volcanism Program and the US Geological Survey's Volcano Hazards Program. Updated by 2300 UTC every Wednesday, these notices are preliminary and subject to change as events are studied in more detail. This is not a comprehensive list of eruptions during the week, but rather a summary of activity that meet selected criteria. Carefully reviewed, detailed reports are published in the Bulletin of the Global Volcanism Network.

The Instituto Nacional de Sismología, Vulcanología, Meteorología e Hidrología (INSIVUMEH) reported that after the elevated eruptive activity at Fuego during 9-10 March, low-level unrest persisted through 18 March. Gas-and-steam plumes that were mostly diffuse rose as high as 700 m above the summit and drifted in multiple directions. Incandescence at the crater was sometimes visible during dark hours likely from blocks emplaced during the eruption.

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

The Darwin Volcanic Ash Advisory Centre (VAAC) reported that an ash plume from Langila rose to 3 km (10,000 ft) a.s.l. at 1530 on 13 March and drifted S based on a pilot report; weather clouds obscured satellite views. A satellite image at 2210 indicated that the ash had dissipated.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)

The Servicio Nacional de Geología y Minería (SERNAGEOMIN) reported continuing unrest at Láscar. A thermal anomaly in the crater detected on 16 March was the most intense anomaly recorded in the previous month. Other satellite data continued to show three zones of elevated temperatures in the crater. Whitish gas emissions persisted. The seismic network recorded a decrease of long-period earthquakes beginning in early February. The Alert Level remained at Yellow (the second lowest level on a four-color scale) and the public was warned to stay at least 1 km away from the crater.

Source: Servicio Nacional de Geología y Minería (SERNAGEOMIN)

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that an eruption at Lewotolok was ongoing during 12-18 March. Daily white steam-and-gas plumes rose as high as 500 m above the summit and drifted in multiple directions. At 0700 on 14 March a white-and-gray ash plume rose about 400 m above the summit and drifted NW. At 1515 and 1559 on 15 March gray ash plumes rose 500 and 600 m above the summit and drifted NW and NE, respectively. Seismicity significantly increased during 16-17 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 vent and 2.5 km away on the S, SE, and W flanks.

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

The Darwin Volcanic Ash Advisory Centre (VAAC) reported that an ash plume from Manam was identified in a satellite image at 1230 on 15 March drifting NNW. The plume had dissipated by 1510.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)

The Observatorio Vulcanológico y Sismológico de Costa Rica-Universidad Nacional (OVSICORI-UNA) reported that eruptive activity at Poás continued at an elevated level through 18 March. Four significant phreatic eruptions were recorded on 9 March that ejected material as high as 300 m above the lake?s surface and produced a steam-and-gas plume that rose 1 km. The monitoring network did not record eruptive events during 11-12 March. Sulfur dioxide emissions fluctuated; emissions detected in satellite data averaged 344 tons per day (t/d) on 11 March and 472 t/d on 12 March and relatively high concentrations were measured by a gas sensor located at the Visitor Observation Deck on 12 March. Residents in Grecia (16 km SW), Sarchí (18 km SW), and San Gertrudis (13 km SSW) reported a sulfur odor and minor ashfall. A small phreatic eruption occurred at 0536 on 13 March, though continuous and voluminous emissions of steam and gas obscured views of the event. A sequence of small phreatic events was recorded during 1800-2000, culminating in a moderate phreatic eruption at 2000. A plume containing significant amounts of sulfur dioxide, hydrogen sulfide, and tephra drifted NW as far as the SW part of Nicaragua. Sulfur dioxide emissions detected in satellite data averaged 844 t/d. At 2300 instruments located at the visitor building of the Parque Nacional Volcán Poás recorded extreme levels of sulfur dioxide gas and particulates in the air; these conditions lasted until around 0300 on 14 March. During 0140-0200 on 14 March a gas monitoring station in San Isidro de Coronado measured high levels of sulfur dioxide gas from a plume that drifted S and E of the Valle Central. Residents of Heredia (28 km SE), Alajuela (21 km S), and San José (33 km SE) reported sulfur odors, minor ashfall, and adverse health effects like respiratory discomfort for both residents and animals. Gas-and-steam emissions continued from both Boca A and Boca C through 18 March. The Alert Level remained at 3 (the second highest level on a four-level scale) and the Aviation Color Code remained at Orange (the second highest color on a four-color scale).

Source: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that a dense gray ash plume rose around 1.5 km above Raung?s summit crater rim and drifted W and NW at 0659 on 13 March. The Alert Level remained at 2 (on a scale of 1-4) and the public was warned to stay 3 km away from the summit crater.

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

The Observatorio Vulcanológico y Sismológico de Costa Rica-Universidad Nacional (OVSICORI-UNA) reported that a small landslide in Turrialba?s West Crater produced a small ash plume at 1545 on 14 March.

Source: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)

Unrest at Ahyi Seamount continued during 7-14 March. A few hydroacoustic detections coming from the direction of Ahyi were identified in data from underwater pressure sensors near Wake Island (about 2,270 km E of Ahyi). Weather clouds obscured satellite views of the seamount. The Aviation Color Code remained at Yellow (the second lowest level on a four-color scale) and the Volcano Alert Level remained at Advisory (the second lowest level on a four-level scale).

Source: US Geological Survey

The Japan Meteorological Agency (JMA) reported ongoing eruptive activity at Minamidake Crater (Aira Caldera?s Sakurajima volcano) during 10-17 March. Nightly crater incandescence was visible in webcam images during 10-14 March. An explosion at 1706 on 11 March generated an ash plume that rose 600 m straight up above the crater rim and merged into weather clouds. The explosion ejected large blocks 600-900 m from the vent. An eruptive event at 2027 on 13 March generated an ash plume that rose 1.2 km above the crater rim and drifted SW. An eruptive event at 1757 on 16 March generated an ash plume that rose 2.2 km above the crater rim. The Alert Level remained at 3 (on a 5-level scale), and the public was warned to stay 1 km away from both the Minimadake and Showa craters.

Source: Japan Meteorological Agency (JMA)

The Kamchatkan Volcanic Eruption Response Team (KVERT) reported that a strong thermal anomaly over Bezymianny was identified in satellite images during 6-13 March. According to the Institute of Volcanology and Seismology (IVS) of the Far Eastern Branch of the Russian Academy of Sciences (FEB RAS), incandescent debris avalanches descended the SE and/or E flanks and daily summit incandescence was visible during dark hours. The summit incandescence and debris avalanches were intense mid-week. Ash plumes generated from debris avalanches rose as high as 1.1 km above the summit and drifted mainly E, NE, and SE. Weather conditions occasionally obscured webcam and satellite views. The Aviation Color Code remained at Orange (the second highest level on a four-color scale). Dates are reported in UTC; specific events are in local time where noted.

Sources: Institute of Volcanology and Seismology (IVS) of the Far Eastern Branch of the Russian Academy of Sciences (FEB RAS),Kamchatkan Volcanic Eruption Response Team (KVERT)

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that activity at Dukono was high during 2025. The monitoring network recorded a range of 60-394 daily eruptive events (227 events/day average), with ash-and-gas plumes rising 200-2,500 m above the summit. Rumbling and booming sounds were reported during 12-13 March. Daily gas-and-ash plumes during 12-18 March generally rose up to 2.5 km above the summit and drifted NW, W, and SW. Plumes on 16 March rose higher; at 1346 and at 1442 dense gray ash plumes rose 3-3.1 km above the crater rim that drifted W and NW. 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)