KVERT reported that the eruption at Alaid was ongoing during 14-20 October. An intense thermal anomaly was identified in satellite images during 13-16 and 20 October; weather clouds obscured views on the other days. Explosive activity during 13-16 October generated ash plumes that rose as high as 6.5 km (21,300 ft) a.s.l. and drifted 360 km E and SE. The Aviation Color Code remained at Orange (the second highest level on a four-color scale). Dates are based on UTC times; specific events are in local time where noted.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

Activity at Bezymianny increased during 22-23 October characterized by incandescence at the summit, sometimes strong fumarolic activity, and an increasing temperature of a thermal anomaly identified in satellite images. KVERT raised the Aviation Color Code to Orange (the second highest level on a four-color scale). A strong explosive phase commenced and by 2340 local time on 23 October satellite images showed ash plumes rising to 10 km (32,800 ft) a.s.l. and drifting 10 km ENE. The Aviation Color Code was raised to Red. By 1005 local time on 24 October the phase was over, and the Aviation Color Code was lowered to Orange. Satellite images showed gas-and-steam plumes drifting NE and an intense thermal anomaly. The ash plumes from the day before had drifted as far as 1,915 km NE. At 2028 local time on 25 October KVERT lowered the Aviation Color Code to Yellow and noted that the intense thermal anomaly persisted. Dates are based on UTC times; specific events are in local time where noted.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

IG reported minor eruptive activity at Cotopaxi. A low-amplitude tremor signal recorded by the seismic network from 1950 on 21 October to 0040 on 22 October was associated with gas-and-ash emissions. The emissions were not visible due to darkness and weather conditions, but minor ashfall and a sulfur odor was reported by mountaineers in the Refugio José Rivas, 2 km N of the summit crater; the mountaineers evacuated. The Washington VAAC reported that during 2150-2200 on 21 October ash plumes rose to 7.6-8.5 (25,000-28,000 ft) a.s.l. and drifted NE based on information from IG and the Guayaquil MWO, satellite images, and webcam views. The ash had dissipated by 0410 on 22 October. A second ash plume was identified in webcam and satellite images rising to 7 km (23,000 ft) a.s.l. and drifting W at 0700 on 22 October. Ash was no longer visible by 1250. IG noted that following the end of the tremor signal seismicity declined and plumes of gas-and-steam rose as high as 1 km above the summit and drifted W. Based on the reports from IG the Servicio Nacional de Gestión de Riesgos y Emergencias (SNGRE) raised the Alert Level to Yellow (the second lowest level on a four-color scale) on 22 October.

Weather conditions at the volcano improved on 23 October and a layer of dark gray ash on the volcano, deposited the previous two days, became visible. Based on seismic data and media reports, small secondary lahars generated from the melted glacier beneath the ash deposit, were recorded during 1115-1300 and traveled short distances down the flanks. Weather clouds frequently prevented views of the volcano during 24-25 October, though steam emissions rising 200 m above the summit and drifting W were visible during a break in the cloud cover the morning of 25 October.

Sources: Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN), Servicio Nacional de Gestión de Riesgos y Emergencias (SNGRE)

PVMBG reported that white-and-brown or gray plumes from Kerinci rose as high as 750 m above the summit and drifted NE and NW during 18-24 October. The Aviation Color Code was raised to Orange (the second highest level on a four-color scale). The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to remain outside of the 3-km exclusion zone.

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

The Darwin VAAC reported that on 20 October an ash plume from Langila rose 2.7 km (9,000 ft) a.s.l. and drifted NW. The plume had dissipated within 5 hours.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)

HVO reported continuing unrest at Mauna Loa during 19-25 October. The seismic network detected 10-46 daily small-magnitude (below M 3) earthquakes 3-5 km beneath Mokuʻāweoweo caldera and 6-8 km beneath the upper NW flank of Mauna Loa. Data from Global Positioning System (GPS) instruments at the summit and flanks showed continuing inflation, though data from tiltmeters at the summit did not show significant surface deformation over the past week. A M 3.1 earthquake was recorded at 2035 on 23 October at a depth of 4 km beneath Mokuʻāweoweo caldera. The Volcano Alert Level remained at Advisory (the second lowest level on a four-level scale) and the Aviation Color Code remained at Yellow (the second lowest level on a four-color scale).

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)

CENAPRED reported that there were 27-62 steam-and-gas emissions, sometimes containing minor amounts of ash, rising from Popocatépetl each day during 19-25 October. Weather clouds often prevented visual observations of activity. The seismic network recorded daily periods of tremor lasting from 16 minutes to 10 hours and 35 minutes. One or two daily volcano-tectonic earthquakes were recorded. During 20-23 October daily periods of low-amplitude, high-frequency events varied between two hours and 19 minutes to five hours, and periods of harmonic tremor lasted from 11 minutes to five hours and 35 minutes. A small explosion was recorded at 0039 on 25 October. According to a news article a small new lava dome, about 60 m in diameter, had been growing on the crater floor since 7 October. The Alert Level remained at Yellow, Phase Two (the middle level on a three-color scale).

Sources: Centro Nacional de Prevencion de Desastres (CENAPRED), Tribuna Noticias

PHIVOLCS reported continuing unrest at Taal during 18-25 October. Daily white steam emissions rose as high as 3 km above the lake and drifted NE, NW, and SW. Upwelling gasses and hot fluids in the lake were periodically visible. Sulfur dioxide emissions averaged 6,702 tonnes per day on 20 October. The seismic network recorded 0-6 daily volcanic earthquakes and a few periods of volcanic tremor during 20-23 October. Webcam images showed increased activity during 21-22 October with 29 small phreatomagmatic bursts from a vent on the NE part of the lake, each lasting 1-5 minutes long. Some of the events produced 200-m-tall steam-rich plumes and very, short, dark ash plumes that immediately collapsed back into the water. Not all events generated detectable signals in the seismic and infrasound records. Ash plumes rose to 600 m (2,000 ft) a.s.l. on 21 October and drifted W according to the Tokyo VAAC. Two small phreatomagmatic bursts, each lasting 6-7 minutes long were recorded during 22-23 October. Sulfur dioxide emissions averaged 1,403 tonnes per day on 24 October. Ground deformation measurements continued to show slight inflation in the western half of the caldera and deflation in the eastern half. The Alert Level remained at 1 (on a scale of 0-5), and PHIVOLCS reminded the public that the entire Taal Volcano Island was a Permanent Danger Zone (PDZ).

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)

On 25 October SERNAGEOMIN reported that activity at Villarrica had been gradually increasing. Both the number and amplitude of long-period earthquakes increased during the month, and further increased the last week. Continuous tremor increased slightly. Webcams showed persistent gas emissions rising 460 m above the crater rim, and ash plumes drifting downwind on 2 and 23 October. Sulfur dioxide emissions averaged 535 (plus or minus 115) tonnes per day, peaking at 1,273 tonnes per day on 13 October. These values were within normal levels and were lower than in September. Crater incandescence increased in both frequency and intensity, consistent with reports from POVI and other collaborators, and likely indicated periodic Strombolian activity. On 14 October satellite images showed the active lava lake covering an area of 36 square meters in the E part of the crater floor. A partial collapse (less than 300 square meters) of the inner SSW crater rim was also evident.

POVI reported that lava fountaining and Strombolian explosions were visible in webcam images at 1917 on 18 October. The most intense thermal anomaly over the crater since September 2019 was detected in satellite images on 23 October, and crater incandescence was visible in webcam images. That same day tourists described seeing splashes of lava ejected from a depth of 80 m and hearing loud degassing sounds. Deposits of ejected tephra were visible around the crater rim and on the upper flanks on 24 October, and intense crater incandescence was visible in images on 25 October. The Alert Level remained at Green, the lowest level on a four-color scale.

Sources: Servicio Nacional de Geología y Minería (SERNAGEOMIN), Proyecto Observación Villarrica Internet (POVI)

JMA reported that four eruptive events and seven explosions at Minamidake Crater (at Aira Caldera’s Sakurajima volcano) were recorded during 17-24 October. Volcanic plumes rose as high as 2.4 km above the crater rim and large blocks were ejected as far as 1.3 km from the vent. Incandescence at the crater was visible nightly. The Alert Level remained at 3 (on a 5-level scale), and residents were warned to stay 2 km away from the crater.

Source: Japan Meteorological Agency (JMA)

KVERT reported that moderate activity at Ebeko was ongoing. According to volcanologists in Severo-Kurilsk (Paramushir Island, about 7 km E) explosions during 13-16 and 18 October generated ash plumes that rose to 4 km (13,100 ft) a.s.l. and drifted SE. Ashfall was reported in Severo-Kurilsk on 13 October and a thermal anomaly was identified in satellite images during 15-16 October. The Aviation Color Code remained at Orange (the second highest level on a four-color scale). Dates are based on UTC times; specific events are in local time where noted.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

AVO reported that slow lava effusion continued at Great Sitkin during 19-25 October along with low levels of seismicity. Slightly elevated surface temperatures were identified in satellite images during 21-22 October. The Volcano Alert Level remained at Watch (the second highest level on a four-level scale) and the Aviation Color Code remained at Orange (the second highest level on a four-color scale).

Source: US Geological Survey Alaska Volcano Observatory (AVO)

The Tonga Geological Services reported that the eruption at Home Reef that began on 10 September was over. Satellite-based measurements showed that the island had not changed in size since 28 September, remaining at 268 m N-S, 283 m E-W, and 15-18 m high. A thermal anomaly was last observed on 17 October. On 22 October the Aviation Color Code was lowered to Green (the lowest level on a four-color scale) and the warning to mariners was lifted, though the public was prohibited from landing on the island.

Source: Tonga Geological Services, Government of Tonga

HVO reported that lava continued to effuse from a vent in the lower W wall of Kīlauea's Halemaʻumaʻu Crater during 19-25 October entering the lava lake and flowing onto the crater floor. The active part of the lake remained at a steady level all week. The Aviation Color Code and the Volcano Alert Level remained at Orange and Watch, respectively.

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)

PVMBG reported that multiple ash plumes were visible rising from Anak Krakatau during 24-25 October. Webcam views showed that at 1757 on 24 October a dense black ash plume rose about 150 m above the summit, and at 2111 a dense gray-to-black ash plume rose 150 m and drifted E. Dense gray-to-black ash plumes were visible on 25 October at 0727, 0956, and 1711 rising 150-200 m above the summit and drifting NE. An eruptive event was recorded at 1845 by the seismic network; a webcam photo showed incandescent material being ejected above the crater rim. The Alert Level remained at 3 (on a scale of 1-4), and the public was warned to stay at least 5 km away from the crater.

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

PVMBG reported that the eruption at Lewotolok continued during 18-25 October. Daily white emissions rose as high as 600 m above the summit and drifted in multiple directions. During 22-23 October white-and-gray plumes rose as high as 500 m and drifted W. 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 crater and 4 km away from the crater on the SE flank.

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

BPPTKG reported that the eruption at Merapi continued during 14-20 October and seismicity remained at high levels. The SW lava dome produced as many as five minor lava avalanches that traveled up to 1.8 km down the Bebeng drainage on the SW flank. No significant morphological changes to the central and SW lava domes were evident in drone photographs. 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)

AVO reported that a minor eruption at a vent on Pavlof’s upper E flank was ongoing during 18-25 October and nearly continuous seismic tremor was recorded. Multiple daily explosions were detected in seismic and infrasound data. Sequences of small explosions during 18-20 October were accompanied by incandescence near the summit in webcam views. Webcam images from the afternoon of 20 October showed a new dark flow of lava and debris extending about a third of the way down the E flank. Elevated surface temperatures were identified in satellite images on almost all days. The Volcano Alert Level remained at Watch (the second highest level on a four-level scale) and the Aviation Color Code remained at Orange (the second highest level on a four-color scale).

Source: US Geological Survey Alaska Volcano Observatory (AVO)

IG described the ongoing eruption at Reventador as moderate during 18-25 October. Daily seismicity was characterized by 9-45 explosions, 2-67 long-period earthquakes, 4-25 signals that indicated emissions, and during 20-25 October there were 2-6 periods of harmonic tremor. Gas, steam, and ash plumes, observed almost daily with webcams or reported by the Washington VAAC, rose as high as 1.3 km above the summit and drifted SW, W, and NW. Weather clouds sometimes prevented visual observations. Crater incandescence was occasionally visible and the lava flow on the NE flank was active. Sulfur dioxide emissions averaged 52-83 tons per day during 19-23 October.

Source: Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN)

IG reported a high level of activity at Sangay during 18-25 October. Daily seismic counts ranges were 230-734 explosions, 39-86 tremor events indicating emissions, and 1-2 lahar events; 10-23 long-period events were recorded during 22-23 October. Daily ash-and-gas plumes were identified in IG webcam images and/or visible in satellite images according to the Washington VAAC. Plumes generally rose as high as 2.1 km above the volcano and drifted NW, W, and SW. Almost daily thermal anomalies were identified in satellite images, though weather clouds sometimes prevented views. Sulfur dioxide emissions averaged 363-1,716 tons per day during 18-25 October. Incandescence at the summit and from a new lava flow on the SE flank was visible during 18-19 October; incandescence from lava-flow activity continued to be periodically visible the rest of the week. Servicio Nacional de Gestión de Riesgos y Emergencias lowered the Alert Level to Yellow (on a four-color scale) during 20-21 October.

Source: Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN)

PVMBG reported that the eruption at Semeru continued during 19-24 October. Eruptive events at 0454 and 0633 on 20 October, 0451 on 21 October, 0634 on 23 October, and 0554 on 24 October produced ash plumes that rose 500 m above the summit and drifted mainly S and W. The Alert Level remained at 3 (on a scale of 1-4). The public was warned to stay at least 5 km away from the summit, and 500 m from Kobokan drainages within 17 km of the summit, along with other drainages originating on Semeru, 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)

KVERT reported that the ongoing eruption at Sheveluch was characterized by explosions, hot avalanches, and lava-dome extrusion during 14-20 October. A daily thermal anomaly was identified in satellite images. The Aviation Color Code remained at Orange (the second highest level on a four-color scale). Dates are based on UTC times; specific events are in local time where noted.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 17-24 October. Crater incandescence was visible nightly. A total of 119 explosions during 17-21 October produced eruption plumes that rose as high as 2 km above the crater rim and ejected blocks as far as 800 m from the vent. Occasional rumbling noises and ashfall were reported in Toshima village (3.5 km SSW). Only one explosion was reported during 21-24 October. Plumes rose as high as 1.5 km and blocks were ejected as far as 200 m from the vent. Ashfall was reported in Toshima village. The Alert Level remained at 3 (on a 5-level scale), and residents were warned to stay 2 km away from the crater.

Source: Japan Meteorological Agency (JMA)

On 26 October GeoNet reported continuing unrest at Whakaari/White Island characterized by persistent gas-and-steam emissions and intermittent, minor, passive ash emissions during the previous two weeks. Sulfur dioxide gas emissions were low, averaging around 217 tonnes per day when measured during an overflight on 7 October. During an observation overflight on 19 October scientists saw gas-and-steam plumes rising from several vents on the NW and W sides of the lake. The temperature of the emissions was 145 degrees Celsius, slightly less than the 165 degrees measured on 5 October. The Aviation Color Code was remained at Yellow (the second lowest level on a four-color scale) and the Volcanic Alert Level remained at 2 (on a scale of 0-5).

Source: GeoNet