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 Thursday, 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 Alaska Volcano Observatory (AVO) reported that a small explosion originating at Korovin?s summit crater lake within the Atka volcanic complex was detected in seismic and infrasound data at 0559 on 24 June. AVO noted that brief explosive events at Korovin were not uncommon and may occur without precursory unrest. 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 color on a four-color scale).

Source: US Geological Survey Alaska Volcano Observatory (AVO)

The Sezione di Catania - Osservatorio Etneo (INGV) reported eruptive activity at Etna?s summit craters during May-June. Intra-crater explosive activity at the Northeast Crater (NEC) began in late May and continued through June. The activity was characterized by intense, continuous degassing, nighttime incandescence from the crater, and the occasional ejection of incandescent material that fell back into the crater. Bocca Nuova Crater produced episodic, diffuse ash emissions that rapidly dispersed during 14-15 June. Activity at Voragine Crater (VOR) was notable in June. A minor collapse of a pit crater on the upper E flank of VOR occurred on 9 June. Sporadic brownish-gray ash emissions began rising from the pit crater during the morning of 10 June. INGV staff conducted a field survey on 21 June and used a drone to inspect the crater. They observed that a fracture system that had formed on the E flank between August 2025 and January 2026 had propagated to the NE and SE. Based on the survey they determined that an area on the E flank, about ~82,250 square meters in size, had moved about 3 m downslope to the SE. They also noted new fracture zones and pit craters. By the morning of 26 June the NE part of the fracture system had further extended downslope in an area near cones that had formed in 2014. At around noon that same day INGV staff observed a lava flow effusing from the terminal part of the fracture, located at about 3,030 m elevation, in the upper sector of Valle del Leone (upper Valle del Bove), and descending around 30 m. The Dipartimento della Protezione Civile raised the Alert Level to Yellow (the second lowest level on a four-level scale) at 1930. Overnight during 26-27 June weak, irregular Strombolian activity occurred at the pit crater on the upper E flank of VOR. A field survey was conducted on 27 June and drone video showed that effusion at the vent was continuing; the lava flow was around 650 m long with the distal end having advanced to around 2,780 m elevation. Intense gas emissions rose from VOR. During a field inspection two days later, on 29 June, INGV staff reported that the terminus of the lava flow had reached an area between 2,750 and 2,700 m elevation. Webcams began recording intermittent Strombolian activity of varying intensity at the pit crater later that day at around 2150.

Sources: Dipartimento della Protezione Civile,Sezione di Catania - Osservatorio Etneo (INGV)

According to the Toulouse Volcanic Ash Advisory Center (VAAC) an eruption at Heard was detected in satellite data at 0000 on 24 June and had ended by 0805 on 25 June. The Darwin VAAC reported that at 0600 on 24 June an ash plume was identified in a satellite image rising to 11 km (36,000 ft) a.s.l. and drifting NE. The plume was continuously emitted for a few hours, decreasing in altitude to 9.8 km (32,000 ft) a.s.l. by 0620 and to 9.1 km (30,000 ft) a.s.l. by 0920. The ash plume had detached from the volcano by 1020. At 1120 a new ash plume was identified in a satellite image rising to 9.1 km a.s.l. and drifting NE. The first plume continued to drift NE. The second plume was continuously emitted for most of the day. By 2100 the first plume has dissipated and was no longer identifiable in satellite data and the second plume had risen to 11 km a.s.l. and was drifting E. Satellite images at 0000 and 0600 on 25 June showed possible ash plumes rising to 11 km and drifting E, but by 0730 all ash had dissipated.

Sources: Darwin Volcanic Ash Advisory Centre (VAAC),Toulouse Volcanic Ash Advisory Centre (VAAC)

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that seismicity indicating emissions at Krakatau intensified on 26 June. A gray plume with minor ash content drifted WNW. According to the Darwin Volcanic Ash Advisory Centre (VAAC) analysis of satellite images the ash plume was continuous during 1200-1520 on 26 June, rose as high as 1.5 km (5,000 ft) a.s.l., and drifted WSW. A diffuse ash plume was visible in a satellite image at 1300 on 27 June rising to 1.5 km a.s.l. and drifting W. According to PVMBG white, gray, and black or brown-and-black plumes rose 200 m and drifted in various directions during 27 June-1 July. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to stay 2 km away from the active crater.

Sources: Darwin Volcanic Ash Advisory Centre (VAAC),Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

The Servicio Nacional de Geología y Minería (SERNAGEOMIN) reported that at 1100 on 26 June an ash plume at Nevados de Chillán rose around 380 m above the crater rim and drifted SE. The Alert Level remained at Yellow (the second lowest level on a four-color scale) and the Sistema y Servicio Nacional de Prevención y Repuesta Ante Desastres (SENAPRED) maintained an ?Early Preventive Alert? for Pinto and Coihueco. The Servicio Geológico Minero Argentino (SEGEMAR) also maintained an Alert Level to Yellow (the second lowest level on a four-color scale).

Sources: Servicio Geológico Minero Argentino (SEGEMAR),Servicio Nacional de Geología y Minería (SERNAGEOMIN),Sistema y Servicio Nacional de Prevención y Repuesta Ante Desastres (SENAPRED)

The Japan Meteorological Agency (JMA) reported ongoing eruptive activity at Minamidake Crater (Aira Caldera?s Sakurajima volcano) during 22-29 June. Very small eruptive events were detected on 22 and 29 June. No crater incandescence was visible during the week. 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)

The Wellington Volcanic Ash Advisory Center (VAAC) reported that an ash-and-gas plume from Ambae was identified in satellite images on 28 June rising to 2.7 km (9,000 ft) a.s.l. and drifting NW. 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.

Sources: Vanuatu Meteorology and Geohazards Department (VMGD),Wellington Volcanic Ash Advisory Center (VAAC)

The Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported increased seismicity at Bulusan in a special advisory noting that a total of 290 volcano-tectonic (VT) earthquakes were recorded by the seismic network during 0000-2130 on 27 June. The VT earthquakes were associated with rock fracturing, with 127 of the events located at shallow depths of less than 5 km beneath the edifice. Very weak to moderate degassing was observed from active vents when the volcano was visible; sulfur dioxide emissions were at low levels, averaging 138 tonnes per day based on the most recent measurement on 26 June. The seismicity was interpreted as being due to shallow hydrothermal or tectonic processes. Total numbers of volcanic earthquakes per day were 321 on 27 June, 163 on 28 June, and 145 on 29 June. The Alert Level remained at 1 (the second lowest level on a scale of 0-5). The public was reminded not to enter the 4-km-radius Permanent Danger Zone (PDZ) and to exercise vigilance within the 2-km Extended Danger Zone (EDZ) on the SE sector. Pilots were warned not to fly close to the summit because of the potential of ash plumes from phreatic eruptions.

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that eruptive activity at Dukono continued during 25 June-1 July. White-to-gray ash plumes rose 500-800 m above the summit and drifted SW, NW, and E. 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)

The Alaska Volcano Observatory (AVO) reported that slow lava effusion continued to feed a thick flow in Great Sitkin?s summit crater during 25 June-1 July. Seismicity was low and small rockfalls were occasionally detected. Webcam images were often obscured by weather clouds, though steaming at the summit area was visible during 24-25 June. Slightly elevated surface temperatures were visible in satellite images during 27-28 June. 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)

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that activity at Ibu continued during 25 June-1 July, with daily eruptive events recorded by the seismic network. Daily gray or white-to-gray ash plumes rose 200-800 m above the summit and drifted in multiple directions. Incandescence at the summit was visible in some 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.

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

The Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported continuing eruptive activity at Kanlaon during 24 June-1 July. The seismic network recorded 4-35 daily volcanic earthquakes. Sulfur dioxide emissions ranged from 944 to 3,762 tonnes per day. Volcanic emissions generally rose as high as 400 m above the summit and drifted NE, E, SE, and S; plumes rose as high as 2 km and drifted NE, E, ESE, and S on 26 June. Four periods of ash emissions were recorded on 1 July, each lasting 17-57 minutes long. Two of the events were recorded by webcams; at 1014 a grayish ash plume rose 700 m above the crater rim and drifted SW and during 1341-1438 grayish ash plumes rose as high as 750 m above the crater rim and drifted NNW. 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.

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)