Signs of unrest at Ahyi Seamount have been observed in satellite and remote geophysical data, starting in mid-October. Hydroacoustic signals continued to be observed but had declined in the previous few weeks. Discolored water over the seamount was first visible on 18 November and persisted, possibly from either degassing or an eruption. On 29 November the Aviation Color Code was raised to Yellow (the second lowest level on a four-color scale) and the Volcano Alert Level was raised to Advisory (the second lowest level on a four-level scale).

Source: US Geological Survey

On 22 November IG concluded that the minor ash emissions recorded at Cotopaxi on 21 October were due to magma in the volcano’s conduit, though not from new magma entering the system after the 2015 eruption. An average of one seismic event per day was recorded based on long-term seismic rates. In the months prior to the 21 October event, the rate had gradually increased to 1.5 events per day, though after the ash emission the rate fell back to one event per day. Most of the seismicity was located beneath the summit. Minor deformation was recorded during August-November, but it could not be conclusively linked to the eruptive activity. Sulfur dioxide emissions increased in October and gas-emission analysis indicated a magmatic origin. Nearly continuous emissions of gas-and-steam had been rising from the main crater since 21 October, as high as 2 km above the rim. The heights of emissions averaged 200 m and were as high as 800 m in 2021.

At 1848 on 25 November the seismic network recorded a tremor signal associated with a gas emission that drifted NNW. At approximately 0310 on 26 November a new episode of tremor was associated with a gas-and-ash emissions that lasted for several hours. The plume drifted 85 km NNW, passing over Quito (55 km N), and caused ashfall in El Pedregal (60 km N), Tambillo (32 km NNW), Guamaní (42 km NNW), Amaguaña (33 km NNW), Chillogallo (44 km NNW), Quitumbe (41 km NNW), Solanda (46 km NNW), Lloa (48 km NNW), Conocoto (41 km N), Mercado Mayorista (45 km NNW), Villaflora (47 km NNW), and Rumipamba (55 km N). Moderate levels of seismic tremor were recorded until about 1050. Servicio Nacional de Gestión de Riesgos y Emergencias (SNGRE) maintained the Alert Level at Yellow (the second lowest level on a four-color scale).

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

INGV reported that at about 1800 on 27 November a vent opened at the NE base of Etna’s SE Crater, at 2,800 m elevation, and produced a lava flow. The flow slowly advanced a few hundred meters towards the Valle del Leone. Tremor levels at the time the vent opened showed no variations from the average trend recorded during the previous week, and no notable changes were identified in deformation data. Effusive activity continued through 30 November, with additional small lava flows emplacing over the first one. For a period of about an hour, beginning at 1700 on 29 November, tremor amplitude increased and then peaked; the amplitude fluctuated between medium and high values for a few hours afterwards. The source of the tremor was in an area between the SE Crater and Bocca Nuova Crater, at elevations of 2,000-2,600 m.

Source: Sezione di Catania - Osservatorio Etneo (INGV)

On 24 November KVERT reported that the Strombolian eruption that had begun at Klyuchevskoy on 16 November was ongoing. Lava fountaining at the summit was visible and a thermal anomaly over the summit was identified in satellite images during 17-20 and 24 November. The Aviation Color Code remained at Yellow (the second lowest level on a four-color scale).

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

An eruption at Mauna Loa began at about 2330 on 27 November in Mokuʻāweoweo, the summit caldera, prompting HVO to raise the Aviation Color Code to Red (the highest level on a four-color scale) and the Volcano Alert Level to Warning (the highest level on a four-level scale). A thermal anomaly and a plume of sulfur dioxide gas were identified in satellite images at the onset of the eruption, according to NOAA’s National Environmental Satellite, Data, and Information Service (NESDIS). Hawai‘i Volcanoes National Park closed the summit area to visitors. Lava erupted from a fissure in the caldera and by 0127 on 28 November lava had overflowed the caldera walls. During an overflight at about 0630 scientists confirmed that the eruption had moved from the summit to the Northeast Rift Zone, where three fissures opened at a high elevation. The fissures fed several lava flows that traveled N and NE; the flows were active in the “saddle” area between Mauna Loa and Mauna Kea and were not threatening any populated areas. Lava fountains along the fissures were as tall as 30-60 m, though most were only a few meters tall. Lava flows from fissures 1 and 2 traveled downslope and stalled about 18 km from the Saddle Road; the two fissures were inactive by 1330. Sulfur dioxide emissions were approximately 250,000 tonnes per day.

Fissure 3, at the lowest elevation of the NE fissures, issued the longest lava flows. Lava flows crossed the Mauna Loa Weather Observatory Road at about 2000 on 28 November; by 0700 on 29 November the flow front was about 10 km from the Saddle Road. Lava fountains at Fissure 3 were 25 m high in the morning on 29 November but had grown to 40-50 m tall in the afternoon. Fissure 4, downslope of Fissure 3, opened at about 1930 and produced lava fountains that rose 5-10 m high. There was no activity in the summit caldera, nor along the Southwest Rift Zone. Gas plumes from the activity drifted N.

Sources: US Geological Survey Hawaiian Volcano Observatory (HVO), National Environmental Satellite, Data, and Information Service (NESDIS)

MARN reported that the eruption at San Miguel continued during 23-28 November. Daily phreatic explosions produced gas, steam, and ash emissions that generally rose around 500 m above the crater rim. There were a total of 188 events recorded by 28 November, with a daily average of 13. The explosions were more energetic mid-week; explosions at 1302 and 1642 on 26 November and 0718 and 0802 on 27 November ejected hot rocks onto the flanks and produced eruption plumes that rose as high as 1.1 km above the summit. A cow was killed by hot ballistics during the morning of 27 November, according to a news article. El Director General de Protección Civil issued a Green Alert for the municipalities of Chinameca, San Rafael Oriente, and San Jorge, and warned the public to stay 3 km away from the volcano. The notice recommended that those living within a 3-6 km radius should identify evacuation routes and to take preparation measures as guided by the Sistema Nacional de Protección Civil.

Sulfur dioxide emissions generally averaged 283 tons per day during 26-27 November, below the baseline of 300 tons per day. Specific measurements during explosive events revealed that the emissions were sometimes as high as 1,200 tons per day. MARN warned the public to stay 2 km away from the volcano, and for those living within a 2-5 km radius to identify evacuation routes and to take preparation measures as guided by the Sistema Nacional de Protección Civil.

Sources: Ministerio de Medio Ambiente y Recursos Naturales (MARN), ASAP Televisión, Protección Civil de El Salvador

JMA reported ongoing eruptive activity at Minamidake Crater (at Aira Caldera’s Sakurajima volcano) and nighttime crater incandescence during 21-28 November. Sulfur dioxide emissions were 700 tons per day on 21 November. An explosion on 21 November produced an ash plume that rose as high as 2.2 km above the crater rim and ejected large blocks as far as 500 m from the vent. Small eruptive events were recorded during 25-28 November. 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 lowered the Aviation Color Code for Alaid to Green (the lowest level on a four-color scale) on 24 November noting that activity had been gradually decreasing since the last ash plume was recorded on 26 October. The temperature of the thermal anomaly began decreasing on 29 October and reached background levels by 20 November. At 1025 on 26 November (local time) ash plumes from explosions were visible in satellite images drifting 38 km SE at altitudes of 4.5-4.7 km 14,800-15,400 ft) a.s.l. The Aviation Color Code was raised to Orange. Explosions continued through the day; by 1521 (local time) ash plumes were rising to 3.5 km (11,500 ft) a.s.l. and ash plumes had drifted as far as 220 km SE. Dates are based on UTC times; specific events are in local time where noted.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

KVERT reported that a thermal anomaly over Ebeko was identified in satellite images on 20 November. Weather clouds prevented views of the volcano on the other days during 17-24 November. 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 23-29 November and the flow field continued to grow. Elevated surface temperatures were identified in satellite images during 27-29 November. 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)

PVMBG reported that white steam-and-gas plumes rose as high as 150 m above Kerinci’s summit and drifted NE during 25-26 November. Gray plumes of variable densities rose 100-500 m above the summit and drifted NE, E, and NW. At 0830 on 27 November a gray ash plume rose about 400 m above the summit and drifted E. The Aviation Color Code remained at 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)

HVO reported that lava continued to effuse from a vent in the lower W wall of Kīlauea's Halemaʻumaʻu Crater during 23-29 November entering the lava lake and flowing onto the crater floor. The active part of the lake remained at a steady level all week. 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 Hawaiian Volcano Observatory (HVO)

BPPTKG reported that the eruption at Merapi continued during 18-24 November and seismicity remained at high levels. The SW lava dome produced 13 lava avalanches that traveled as far as 1.6 km down the SW flank (upstream in the Kali Bebeng drainage). No significant morphological changes to the central and SW lava domes were evident. According to the Darwin VAAC an ash plume rose to 4.6 km (15,000 ft) a.s.l. and drifted SW on 25 November. 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.

Sources: Balai Penyelidikan dan Pengembangan Teknologi Kebencanaan Geologi (BPPTKG), Darwin Volcanic Ash Advisory Centre (VAAC)

AVO reported that a minor eruption at a vent on Pavlof’s upper E flank was ongoing during 23-29 November and nearly continuous seismic tremor was recorded. Vent incandescence was visible in webcam images on most days, suggesting ongoing lava effusion. Elevated surface temperatures were occasionally identified in satellite images. Minor ash emissions were observed in webcam images during 26-27 November. A seismic signal at 1748 on 28 November indicated a flowage event. Webcam images from 29 November confirmed that a flowage event had occurred, and a resulting gas cloud possibly containing ash rose as high as 6.1 km (20,000 ft) a.s.l. 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)

OVSICORI-UNA reported continuing eruptive activity at Rincón de la Vieja characterized by occasional small phreatic explosions; five were recorded during 19-25 November. A notable variability in sulfur dioxide emissions was first observed on 18 November and continued through the week, with a peak measurement as high as 1,500 tons per day. A phreatic explosion at 1432 on 25 November produced a steam-rich plume that rose 2 km and drifted SW.

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

IG reported a high level of activity at Sangay during 22-29 November, which included daily explosions, volcanic tremor, and gas-and-steam emissions. The daily count of explosions ranged from 920-1,320, though seismic data transmission was sometimes interrupted. Daily ash-and-gas plumes were identified in either or both IG webcam images and satellite images according to the Washington VAAC. Plumes rose as high as 2.1 km above the volcano and drifted in various directions. Sulfur dioxide emissions were measured daily and ranged from 491.2 tons per day to 3,693.5 tons per day. During 22-29 November crater incandescence was visible at night and early mornings. Pyroclastic flows descended the flanks during 24-29 November. Lava flows, incandescent blocks, and incandescent material descended the SE flank during 25-29 November.

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

PVMBG reported that the eruption at Semeru continued during 23-29 November. Daily explosions at the summit produced ash plumes that varied in color and density, which generally rose 500-700 m above the summit and drifted in various directions. A dense gray ash plume at 0002 on 23 November rose 700 m and drifted SE and S, at 0507 and 0540 on 24 November white-to-gray and dense gray ash plumes, respectively, rose 500 m and drifted N, at 0702 on 25 November a dense gray ash plume rose 500 m and drifted NE, at 0444 on 26 November an ash plume rose 700 m and drifted S, at 0552 on 27 November a white-to-gray ash plume rose 500 m and drifted S, at 0556 on 28 November a dense gray ash plume rose 500 m and drifted N, that same day at 0611 a dense gray ash plume rose possibly higher than 1 km, and at 0509 on 29 November a white-and-gray ash plume rose 600 m and drifted N. 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)

On 23 November AVO lowered the Aviation Color Code for Semisopochnoi to Yellow (the second lowest level on a four-color scale) and the Volcano Alert Level to Advisory (the second lowest level on a four-level scale) noting that no ash emissions or explosive activity had been detected since 7 November. Seismicity had decreased, though remained at elevated levels. Steam emissions from the active vent in the N crater of Mount Cerberus persisted.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

KVERT reported that the ongoing eruption at Sheveluch during 17-24 November was generally characterized by explosions, hot avalanches, lava-dome extrusion, and strong fumarolic activity. A daily thermal anomaly was identified in satellite images. Collapses generated hot avalanches and ash plumes that drifted 80 km E during 17-18 and 20 November. 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)

INGV reported that during 21-27 November activity at Stromboli was characterized by ongoing explosions at three vents in Area N (North Crater area) and two vents in Area C-S (South-Central Crater area); weather conditions prevented visual confirmation of activity during 21-23 November. Low-intensity explosions from the N1 vent (Area N) ejected course material (bombs and lapilli) less than 80 m high at a rate of 3-7 explosions per hour. Spattering and occasional low-intensity explosive activity was visible at the N2 vent (Area N). Explosions from at least two vents in S2 (Area C-S) ejected ash and coarse material over 250 m above the vent at a rate of 6 events per hour.

Source: Sezione di Catania - Osservatorio Etneo (INGV)

JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 21-28 November and crater incandescence was visible nightly. Eruption plumes rose as high as 1.3 km above the crater rim and blocks were ejected as far as 300 m from the vent. Ashfall was occasionally reported in Toshima village (3.5 km SSW). 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)

POVI reported minor gas-and-steam emissions at Villarrica on 24 November; one circular emission (“vortex ring”) was also visible. During an overflight on 25 November, SERNAGEOMIN scientists observed the small cone on the crater floor with an incandescent lava lake at its center. The lake temperature was 1,043 degrees Celsius. The Alert Level remained at Yellow (the second lowest level on a four-color scale) and the public was warned that material could be ejected within 500 m of the crater. ONEMI remained the Alert Level Yellow (the middle level on a three-color scale) for the municipalities of Villarrica, Pucón (16 km N), Curarrehue, and the commune of Panguipulli.

Sources: Proyecto Observación Villarrica Internet (POVI), Servicio Nacional de Geología y Minería (SERNAGEOMIN), Oficina Nacional de Emergencia-Ministerio del Interior (ONEMI)

On 24 November Vanuatu Meteorology and Geohazards Department (VMGD) reported that activity at Yasur continued at a high level of “major unrest,” as defined by the Alert Level 2 status (the middle level on a scale of 0-4). Recent observations confirmed continuing low-to-moderate explosions that ejected bombs within the crater and produced ash, gas, and steam emissions. The public was reminded to not enter the restricted area within 600 m around the cone, defined by Danger Zone A on the hazard map.

Source: Vanuatu Meteorology and Geohazards Department (VMGD)