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 Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported that the eruption at Mayon continued during 29 April-6 May, with a notable pyroclastic density current (PDC) from collapse events on 2 May. The activity in general was characterized by lava effusion, pyroclastic density currents (PDCs), incandescent rockfalls, ash-and-gas plumes, and occasional minor Strombolian activity. Emissions were visible daily, rising as high as 1 km above the summit and drifting mainly SW, W, and WNW. Each day the seismic network recorded 221-411 rockfalls, 0-4 PDCs, and 5-45 volcanic earthquakes. The earthquake counts included 4-25 daily periods of volcanic tremor, each lasting between one minute to just over one hour. Sulfur dioxide emissions averaged 1,586-2,087 tonnes per day. The lava flows did not advance in the Basud (E) and Bonga (SE) drainages, remaining 3.8 and 3.2 km long, respectively. Minor Strombolian activity and short periods of lava fountaining were recorded during 29 April-2 May. Two long sequences of PDCs from collapses occurred in the Mi-isi drainage on the SW flank on 2 May. The first sequence began at 1628 and lasted 39 minutes, followed by a more intense sequence with more frequent and larger PDCs that began at 1709 and lasted 95 minutes. Dense weather clouds obscured the upper half of the volcano. Most of the stations in the seismic network recorded broadband tremor, a volcanic earthquake signal that typically accompanies large-volume lava flow effusion and associated lava collapses; no explosions were recorded. The first sequence was characterized as at least seven small-volume PDCs that traveled 2-3 km and produced brownish-gray convecting ash clouds. The second sequence consisted of at least 22 PDC events, including some of the largest in the 2026 eruption so far. By 1730 more voluminous PDCs were observed descending the Mi-isi drainage as far as 4 km. These were followed by a rapid succession of PDCs that traveled more than 5 km down the flanks and generated darker ash clouds that drifted W; a PDC recorded at 1750 was the most voluminous and reached the greatest distance. Photos posted on social media showed an enormous dark ash cloud, that had accumulated from multiple PDCs, rising 5 km above the length of the deposits; after the cloud detached from the PDC it continued to move downslope as an ash curtain. Ashfall occurred across a narrow swath W of the volcano. Analysis of photos and drone images after this activity on 2 May showed that two short lava flows and part of a longer lava flow were gone, and the upper 2 km of the Mi-isi drainage was described as a deep gully. PDC deposits had filled in and spilled over the banks of the Mi-isi-Binaan channel about 4.8 km down from the summit, at around 400 m elevation, forming a deposit several meters higher than the channel banks with a lobate sloping terminus. On 3 May the Office of Civil Defense (OCD) reported that the barangays (neighborhoods) in Guinobatan, Camalig, and Ligao City (Albay) were most impacted by ashfall which lasted for about three hours. Residents reported low to no visibility in some areas due to ash in the air, and that the ashfall impacted crops, animals, and farmlands. The main roads were cleared by local authorities and firefighters by 3 May, and residents had begun clearing ash from their homes and vehicles. The OCD and other organizations distributed N95 masks, hygiene packs and necessities, food, and bottled water for communities where water sources may had been contaminated by ashfall. PHIVOLCS noted that as of 4 May there were four cities/municipalities and 109 barangays that had experienced ashfall, based on reports collected from local government officials, Disaster Risk Reduction (DRR) partners, and the PHIVOLCS Quick Response Team (QRT). In 21 barangays of Ligao City there was either trace amounts of ashfall or observable ashfall, reported as far as in Maonon (40 km SW). In Camalig ashfall was moderate to heavy in 17 barangays with the thickest deposit, 15 mm, observed in Tumpa (7 km SW); residents in barangay Ligban (10 km SSW) observed only minor ashfall. In Guinobatan ashfall was observed in 23 barangays, ranging from minimal to heavy. Residents of Doña Tomasa (7 km WSW), San Rafael (11 km SW), Muladbucad Pequeño (7 km W), and Travesia (10 km SW) reported periods of zero visibility. Residents in 53 barangays of Oas reported observable ashfall. Smaller-volume PDCs from collapses in the Mi-isi drainage periodically continued through the rest of the week. The most significant of these occurred during 0719-0726 on 5 May, traveling 3 km down the Mi-isi drainage and producing ash plumes that rose 1.9 km above the summit. New lava flows were active in the Mi-isi drainage and filled up the gully during 4-6 May. According to the Disaster Response Operations Monitoring and Information Center (DROMIC) report the number of residents that went to evacuation shelters increased after the 2 May event. By 1800 on 30 April a total of 4,022 people (1,105 families) were staying in 12 evacuation shelters and by 1800 on 3 May the numbers increased to 5,459 people (1,444 families) staying in 14 shelters; those numbers dropped to 4,905 people (1,362 families) during 4-5 May and two shelters were no longer in use. The number of individuals and families staying with friends or relatives did not change. The ongoing eruption continued to affect tens of thousands of people across the Albay province; by 1800 on 6 May the DROMIC report stated that a total of 286,939 people (70,150 families) across 160 barangays in Region V had been impacted by volcanic activity at Mayon. 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.

Sources: Disaster Response Operations Monitoring and Information Center (DROMIC),Philippine Institute of Volcanology and Seismology (PHIVOLCS) ,Philippine News Agency (PNA)

The Japan Meteorological Agency (JMA) reported ongoing eruptive activity at Minamidake Crater (Aira Caldera?s Sakurajima volcano) during 27 April-4 May. Very small eruptive events were periodically detected. Crater incandescence was visible in nighttime webcam images during 1-4 May. 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)

On 1 May the Vanuatu Meteorology and Geohazards Department (VMGD) reported that the eruption at Ambae was ongoing and characterized as minor. Seismicity remained at high levels with the detection of continuous volcanic tremor and volcanic-seismic events. Sulfur dioxide emissions were detected in satellite images on 30 April and thermal anomalies with variable intensities were identified in satellite images on 1 May. Photos from 1300 on 1 May showed emissions of steam, gas, and ash rising high above the crater rim. Continuous summit incandescence was also visible in photos. According to the Wellington Volcanic Ash Advisory Center (VAAC) a small ash plume rose 3 km (10,000 ft) a.s.l. and drifted NW on 6 May. 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 Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that seismicity at Awu had increased. The seismic network recorded a total of 74 earthquakes on 4 May, many of which were shallow volcanic earthquakes. During 0000-1200 on 5 May the network recorded 15 shallow volcanic earthquakes and two deep volcanic earthquakes. Low-frequency earthquakes associated with fluid movement had not been detected, and diffuse white plumes were rising at most 200 m above the lava dome. The Alert Level remained at 2 (on a scale of 1-4) and the public was warned to stay 3 km away from the crater?s center.

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

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that eruptive activity at Dukono continued during 30 April-6 May. Daily white-and-gray ash plumes rose 400-2,000 m above the summit and drifted in multiple directions. 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 29 April-6 May. Lava-dome growth and rockfalls were concentrated on the E and S parts of the flow. The rockfalls were recorded daily by the seismic network. Weather clouds often prevented webcam and satellite observations, though elevated surface temperatures were periodically visible in satellite images and steaming at the dome was visible during 5-6 May. 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 30 April-6 May, with daily eruptive events recorded by the seismic network. Daily gray or white-to-gray ash plumes rose 300-800 m above the summit and drifted NE, E, and SE. 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.

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 30 April-6 May. The seismic network recorded 7-54 daily volcanic earthquakes, including 2-15 daily periods of tremor lasting three minutes to nearly two hours. Sulfur dioxide emissions ranged from 1,154 to 2,098 tonnes per day. Emissions were visible daily that generally rose 300-1,800 m above the summit and drifted in multiple directions. There were 2-11 daily periods of ash emissions, each lasting for three minutes to nearly three hours. Notably, at 1723 on 24 April, at 0832 on 25 April, and at 1830 on 26 April ash plumes visible in webcam images rose 800 m, 300 m, and 1,200 m above the summit, respectively, and drifted W and 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.

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)

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 29 April-6 May. Consistent incandescence at the S vent and variable incandescence at the N vent was visible in webcam images overnight during 29 April-6 May. Occasional flaming or bursts of large flames caused by the ignition of volcanic gases escaping both vents were also visible. Lava began overflowing the N vent at around 0138 on 4 May, prompting HVO to raise the Volcano Alert Level to Watch (the second highest level on a four-level scale) and the Aviation Color Code to Orange (the second highest color on a four-color scale). Over the next roughly 19 hours there were 23 additional overflows at the N vent and 21 lava overflows at the S vent. Advancing lava flows covered about half of the crater floor. Low lava-dome fountaining at the N vent began at 0817 on 5 May. The fountain intensified and steadily grew taller, reaching a peak height of 200 m during 1000-1030. An eruption plume rose as high as 6 km (20,000 ft) a.s.l. based on radar data reported by the National Weather Service and the Washington Volcanic Ash Advisory Center. The plume drifted N and NW, causing tephra fall outside of the closed area of Hawai?i Volcanoes National Park along the N rim of the caldera on Highway 11 between mile markers 30 and 34 and in adjacent communities. Tephra as large as 15 cm in diameter fell on Highway 11, and fine ash and Pele?s hair were reported as far away as Mountain View. The fountain height gradually decreased to 50 m before stopping at 1722 after nine hours of continuous fountaining. At 1724 the Volcano Alert Level was lowered to Advisory and the Aviation Color Code was lowered to Yellow due to reduced ground and aviation hazards. The average effusion rate was 140 cubic meters per second; the highest peak was just over 240 cubic meters per second, occurring at around 0950. An estimated 4.6 million cubic meters of lava erupted and covered about 60 percent of the Halema?uma?u Crater floor. The S vent had one short-lived dome fountain and overflow after the onset of N vent fountaining and subsequently had periodic gas jetting and flames.

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that daily white plumes at Lewotobi Laki-laki rose as high as 200 m above the summit and drifted mainly N, W, and SW. In a special report on 4 May PVMBG noted that seismicity had increased significantly over the previous week. The number of deep volcanic earthquakes began to increase in late April and continued to rise in May, reaching 21-32 events per day; the previous rate was 5-10 events per day. Six larger deep volcanic earthquakes were recorded in May and were located beneath the N flank. Other seismic signals, particularly non-harmonic tremors, continued at a high rate, though the frequency of the events showed a decreasing trend. Low-frequency events were stable. Tiltmeter data from stations on both the N and E flanks indicated inflation on the N to NW flank and relative stability or possibly slight deflation on the E flank. The surge in the number of deep volcanic earthquakes and deformation suggested that the deeper magmatic system had reactivated. 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.

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

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported ongoing eruptive activity at Lewotolok during 29 April-6 May. Daily white plumes rose as high as 200 m above the summit and drifted SW, W, and NW. On 4 April white-and-gray plumes rose 50-200 m above the summit and drifted W and NW. Incandescence at the summit was visible in a webcam image at 1855 on 30 April and at 1906 on 5 May. 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.

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

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that eruptive activity at Marapi (on Sumatra) continued during 30 April-6 May. White plumes rose as high as 500 m above the summit on most days (no emissions were visible on 1 May) and drifted in multiple directions. On 4 May gray plumes rose to around 200 m above the summit and drifted NE. Eruptive events were recorded at 1634 on 5 May and at both 0341 and 0343 on 6 May by the seismic network, but were not visually observed due to darkness and/or 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.

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