The Vanuatu Meteorology and Geo-Hazards Department (VMGD) reported that a new eruption at Ambrym likely started on 19 September. An intense thermal anomaly and high sulfur dioxide emissions were identified in satellite data; a volcanic cloud was visible in a satellite image at 0600. Ground-based observers reported dark gray ash-and-gas plumes rising from Marum Crater and rumbling sounds coming from the crater. Minor ashfall was reported in areas downwind, including in communities to the W, NW, and NNE. Summit incandescence was reported by residents at around 2000. The eruption continued on 20 September. Ash-and-gas plumes were visible in satellite data at 0350 and lava effusion within the crater was detected at 1009. Residents continued to hear rumbling and observe crater incandescence. 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 (including Maben-Mbwelesu, Niri-Mbwelesu, and Mbwelesu craters).

Source: Vanuatu Meteorology and Geohazards Department (VMGD)

The Kamchatkan Volcanic Eruption Response Team (KVERT) reported that an explosive eruption at Chikurachki likely began at 1830 on 20 September based on satellite data and advisories issued by the Tokyo Volcanic Ash Advisory Center (VAAC). Ash plumes rose as high as 3 km (10,000 ft) a.s.l. and drifted 140 km NE and E. Explosions continued intermittently through the next day. The VAAC noted that during 20-21 September ash plumes rose to 2.7-4.6 km (9,000-15,000 ft) a.s.l. and drifted NE and E. At 1226 on 21 September the Aviation Color Code was raised to Orange (the second highest level on a four-color scale).

Sources: Kamchatkan Volcanic Eruption Response Team (KVERT), Tokyo Volcanic Ash Advisory Center (VAAC)

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported decreasing activity at Krakatau after a large eruption in early September. A continuous eruption during 4-6 September produced lava fountains, widespread ashfall, and lava flows that advanced NW, W, and SW. Some Strombolian explosions were detected after the period of continuous activity ended, but activity generally declined over the following two weeks and deformation data indicated deflation. According to a news article, one of the three crew members from the missing boat with five journalists was found deceased. The Alert Level was lowered to 2 (on a scale of 1-4) at 1830 on 21 September and the public was advised to stay 2 km away from summit.

Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM), Antara News

The Servicio Nacional de Geología y Minería (SERNAGEOMIN) and the Servicio Geológico Minero Argentino (SEGEMAR) reported that at around 1410 on 18 September a dense ash plume rose 380 m above Nevados de Chillán’s summit and drifted SSE. On 22 September SERNAGEOMIN reported that seismicity indicated eruptive activity; weather conditions prevented views of the summit, though tephra deposits on the flanks were visible. A long-period earthquake associated with fluid movement was recorded on 23 September, but weather conditions again prevented visual observations of the summit. The Alert Level remained at Yellow (the second lowest level on a four-color scale) and the public was warned that an eruption may impact areas within 1 km of the active crater. The Sistema y Servicio Nacional de Prevención y Repuesta Ante Desastres (SENAPRED) maintained an “Early Preventive Alert” for Pinto and Coihueco.

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

The Japan Meteorological Agency (JMA) reported that volcanic activity at Tokachidake continued to intensify. Inflation at relatively shallow depths began to be detected in March. Beginning in April there was an increase in sulfur dioxide emissions, a higher frequency of diffuse volcanic emissions and crater glow observed in monitoring cameras, and slightly elevated seismic activity near and around 62-2 Crater. Starting in May volcanic plumes became more frequent and emissions at the Furikozawa fumarole group rose higher. Subsequently, very small-scale eruptions occurred near the 62-2 Crater on 22 July, 5 August, and 6 August. Additionally, there was an increase in large-amplitude volcanic earthquakes originating near the edifice; two occurred on 12 September, bringing the total count over the preceding 30 days to five. At 0930 on 12 September the Alert Level was raised to 3 (on a scale of 1-5) and the public was warned to be cautious within a 3 km radius.

Source: Japan Meteorological Agency (JMA)

The Japan Meteorological Agency (JMA) reported ongoing eruptive activity at Minamidake Crater (Aira Caldera’s Sakurajima volcano) during 14-21 September. Crater incandescence was visible in nighttime webcam images during 14-18 September. Volcanologists conducted a field survey on 15 September and measured high sulfur dioxide emissions, averaging 2,600 tons per day. A total of 32 eruptive events during the week produced ash plumes that rose as high as 2.5 km above the crater and ejected large blocks 600 m from the vent. The Alert Level remained at 3 (on a 5-level scale), and the public was warned to be cautious within 1 km of both the Minimadake and Showa craters.

Source: Japan Meteorological Agency (JMA)

The Sezione di Catania - Osservatorio Etneo (INGV) reported that eruptive activity at Etna’s summit craters during 14-20 September was characterized by gas emissions and periodic minor ash emissions at Northeast Crater and Bocca Nuova Crater, and Strombolian activity at Bocca Nuova. Nearly continuous ash emissions at Northeast Crater were visible during 14-15 September and again during the day on 16 September. The BN1 vent in Bocca Nuova Crater produced Strombolian activity during 15-16 September. Continuous ash emissions rose from the same vent starting on the afternoon of 16 September and stopping at dawn on 18 September. Sporadic diffuse ash emissions at both Northeast and Bocca Nuova craters were visible during 19-20 September. The volcano Alert Level remained at Yellow (the second lowest level on a four-level scale) according to the Dipartimento della Protezione Civile.

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

The Alaska Volcano Observatory (AVO) reported that slow lava effusion continued to feed a thick flow in Great Sitkin’s summit crater during 16-23 September based on webcam and satellite images. Minor earthquakes consistent with the growth of the lava dome and occasional rockfalls were detected by the seismic network. Weather clouds obscured webcam and satellite views during most of the week; though slightly elevated surface temperatures were identified in satellite data during 16-17 September. 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 17-23 September, with daily eruptive events recorded by the seismic network. Gray or white-and-gray ash plumes rose 200-800 m above the summit and drifted in multiple directions. Incandescence at the summit and on the flanks 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 16-22 September. The seismic network recorded 3-24 daily volcanic earthquakes. Sulfur dioxide emissions ranged from 636 to 3,042 tonnes per day. Volcanic emissions generally rose as high as 700 m above the summit and drifted in various directions; plumes rose 1.2 km above the summit and drifted S on 22 September. One ash emission was visible in webcam images at 2351 on 19 September rising 300 m above the summit and drifting NNW. The emission lasted for just over two hours. 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 Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that the eruption at Karangetang’s North Crater (Kawah Dua) continued during 17-23 September. Daily white plumes rose as high as 50 m above the summit and drifted in various directions. Incandescence at the North Crater and from lava flows and/or incandescent avalanches on the flanks was visible in some webcam images throughout the week. Rumbling sounds were recorded daily. The Alert Level remained at 2 (on a scale of 1-4) and the public was advised to stay 1.5 km away from both craters, with an extension to 2.5 km on the NW and SW flanks of North Crater.

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

The Hawaiian Volcano Observatory (HVO) reported that the eruption within Kīlauea’s Kaluapele summit caldera, characterized by incandescence, intermittent spatter, and lava flows from craters and vents along the SW and W margins of Halemaʻumaʻu Crater, continued at variable levels during 16-23 September. During 14-16 September five new vents opened N of the older vent complex (with N, W, and S vents), on and near the NW wall of Halemaʻumaʻu Crater, and produced small lava flows. Intermittent bursts of spatter continued to build a small cone around the N vent, which reached 11-12 m tall by 14 September, and sporadic spatter bursts were also observed from the S and W vents. At around 1700 on 16 September a sixth vent opened to the N of the previous vent cluster; activity at all six vents stopped by 2030. Spattering at the older N, W, and S vents stopped during 1900-2100. Occasional incandescence and flames were observed in webcams images from the N, W, and S vents during 17-23 September, and minor intermittent spatter was variable at all three vents during 20-22 September. A very small, spatter-fed lava flow traveled 5-10 m from the N vent cone between 1923-1924 on 21 September. Lava vigorously overflowed the N vent during about 2210-2234 on 22 September, followed by another overflow at 2344. The Volcano Alert Level remained at Watch (the second highest level on a four-level scale) and the Aviation Color Code at Orange (the second highest color on a four-color scale).

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)

The Darwin Volcanic Ash Advisory Centre (VAAC) reported that an ash plume from Langila rose 2.4 km (8,000 ft) a.s.l. and drifted SW on 17 September based on satellite images.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported continuing eruptive activity at Lewotolok during 17-23 September. Gray or white-to-gray ash plumes rose 100-800 m above the summit and drifted NW and W nearly daily; white plumes rose 100 m above the summit on 23 September. Incandescent material was occasionally ejected onto the flanks and rumbling was sometimes heard. A lava flow on the SE flank that was 400 m long on 20 September had advanced 100 m by the next day. Several webcam images showed incandescent material being ejected above the summit and onto the flanks. The Alert Level remained at 2 (on a scale of 1-4). The public was warned to stay 2 km away from the summit with an extension to 3 km on the S and SE flanks.

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

The Washington Volcanic Ash Advisory Center (VAAC) reported that on 19 September a diffuse ash plume from Masaya was visible in satellite and webcam images rising to 1.2 km (4,000 ft) a.s.l. and drifting over 12 km SW.

Source: Washington Volcanic Ash Advisory Center (VAAC)

The Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported ongoing ash emissions and unrest at Mayon during 17-23 September. The seismic network recorded 7-23 daily volcanic earthquakes; one tremor (1-4 minutes long) was recorded on both 18 and 19 September, and one rockfall was detected on both 18 and 20 September. Sulfur dioxide emissions generally averaged 310-1,600 tonnes per day. Daily emissions rose 300-1,000 m above the crater and drifted in different directions. Minor Strombolian activity was observed on 18 September. That same day two visible ash plumes lasted 35 and 46 seconds; the emission at 0844 rose 300 m above the summit and drifted NNE. Three ash emissions, each lasting 1-2 minutes, were recorded on 19 September; one at 1653 with a gray appearance rose 600 m above the summit and drifted NE. A one-minute ash emission occurred on 21 September. The Alert Level remained at 2 (on a 0-5 scale) and the public was 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.

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that the eruption at Merapi (on Java) continued during 17-23 September with lava avalanches produced by the active lava dome on the upper SW flank. The seismic network recorded up to 12 lava avalanches per day that traveled as far as 2 km down the Sat/Putih and Krasak drainages on the SW flank and the Boyong drainage on the S flank. 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: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

The Centro Nacional de Prevención de Desastres (CENAPRED) reported that eruptive activity was low at Popocatépetl during 16-23 September. The seismic network recorded 8-120 long-period events per day, accompanied by steam-and-gas emissions; the emissions contained small amounts of ash during 20-23 September and drifted SSW and W. During 20-21 September the seismic network also detected 55 minutes of low-amplitude tremor and a 229-minute sequence of emissions. Four volcano-tectonic earthquakes were recorded during 21-22 September. According to the Washington Volcanic Ash Advisory Center (VAAC) ash plumes were visible in webcam and/or satellite images on 19 and 21 September rising 6.1-6.7 km (20,000-22,000 ft) a.s.l. (as high as 1.3 km above the summit) and drifted S. The Alert Level remained at Yellow, Phase Two (the middle level on a three-color scale) and the public was warned to stay 12 km away from the crater.

Sources: Centro Nacional de Prevencion de Desastres (CENAPRED), Washington Volcanic Ash Advisory Center (VAAC)

The Servicio Geologico Colombiano (SGC) reported intensifying eruptive activity at Puracé during 16-23 September. Signals associated with fluid movement, mainly long-period (LP) events, dominated the seismicity and were located beneath Puracé volcano at depths less than 1 km. Seismic activity associated with rock fracturing (volcano-tectonic earthquakes) continued to be recorded, but a majority of signals were located in an area 13-18 km NE of Puracé at depths of 6-12 km. Sulfur dioxide flux gradually decreased, though it remained above average baseline levels, and soil carbon dioxide concentrations rose throughout the reporting period. Slow ground deformation persisted in an area between the Puracé, Piocollo, and Curiquinga volcanoes. Low-energy thermal anomalies were detected some days on the crater floor. On most days a few ash emissions were detected by the seismic network and/or observed in webcam images. Notably, three ash emissions were detected but not visually observed during 16-17 September and two ash emissions during 20-21 September rose as high as 550 m above the summit. Three ash emissions rose as high as 1.2 km above the summit during 21-22 September and caused ashfall in Cobaló and Coconuco. The Alert Level remained at Orange (the second highest level on a four-color scale).

Source: Servicio Geológico Colombiano (SGC)

The Instituto Geofísico del Perú’s (IGP) Centro Vulcanológico Nacional (CENVUL) reported continuing eruptive activity at Sabancaya during 14-20 September. The seismic network detected 63 seismic events associated with the movement of magmatic fluids, along with earthquakes indicating internal rock fracturing; no volcanic explosions occurred during the period. Gas, steam, and ash emissions periodically rose as high as 1.7 km above the summit and drifted less than 10 km SE. Moderate sulfur dioxide (SO₂) emissions averaged 937 tons per day, and 13 thermal anomalies (each 4 MW or less) associated with the lava dome were identified. 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.

Source: Instituto Geofísico del Perú (IGP)

The Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN) reported that volcanic activity at Sangay increased during 19-21 September and remained elevated, after months of low activity. An ash emission seen in satellite and webcam images rose 1.2 km above the crater rim and drifted W on 16 September. A thermal anomaly was identified in satellite images on 17 September. A sustained increase in sulfur dioxide (SO₂) emissions began on 19 September; emissions peaked at around 78 and 256 tonnes per day (t/d) on 19 and 20 September, respectively. SO₂ emissions rose to 1,213 t/d on 21 September, which was the highest recorded value in 2026. Both the number and amplitude of detected infrasound signals increased at 1900 on 20 September. During 19-21 September gas-and-ash plumes rose as high as 3 km above the crater rim and drifted less than 100 km mainly W and SW, though plumes drifted N and NW late on 20 September. Minor ashfall was reported in Columbe (44 km WNW), Guarguallá Chico (25 km NW), and Riobamba (51 km NW), Chimborazo province. The ejection of incandescent material onto the upper flanks was observed during dark hours. Ash plumes rose as high as 3 km above the summit and drifted NW, WSW, and SW during 22-23 September. The Secretaría de Gestión de Riesgos (SGR) maintained the Alert Level at Yellow (the second highest level on a four-color scale).

Sources: Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN), Secretaría de Gestión de Riesgos (SGR)

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that activity continued at Semeru during 17-23 September, with daily eruptive events recorded by the seismic network. White-and-gray ash plumes rose 200-1,000 m above the summit and drifted NE and E on most days; no emissions were visible on 19 September. The Alert Level remained at 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 Jonggring Saloko Crater 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.

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

The Kamchatkan Volcanic Eruption Response Team (KVERT) reported continuing lava effusion and explosive activity at the lava domes along the N crater floor of Young Sheveluch (on the SW flank of Old Sheveluch) during 16-23 September. A thermal anomaly was identified in satellite images on a few of the days; weather clouds occasionally obscured views. Explosions at 2240 on 17 September generated ash plumes that rose 4-5.5 km (13,100-18,000 ft) a.s.l. and drifted 45 km E. 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.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)