Signs of unrest at Ahyi Seamount continued. Plumes of discolored water extending as far as 19 km from the summit area were identified in satellite images during 23-26 January. Weather clouds obscured or mostly obscured views during the rest of the week. No volcanic activity was identified in data from underwater pressure sensors near Wake Island (about 2,270 km E of Ahyi). The Aviation Color Code remained at Yellow (the second lowest level on a four-color scale) and the Volcano Alert Level remained at Advisory (the second lowest level on a four-level scale).

Source: US Geological Survey

PVMBG reported that the eruption at Lewotobi’s Laki-laki volcano had decreased during 23-29 January based on visual and instrumental data. The lava flow on the NE flank continued to advance, reaching a length of 4 km, though the rate of advancement had slowed by 23 January, possibly due to gentler topography, a decrease in the effusion rate, or a combination of both. A total of 11 pyroclastic flows were detected and traveled 1-2 km N, NNE, and NE, though average distances were closer to 1 km. Eruption plume heights decreased from an average of 1.5 km above the summit to 500 m. The seismic network recorded a total of 388 lava avalanches that traveled as far as 1.5 km N and NE. Sulfur dioxide emissions significantly decreased, and deformation data indicated deflation. Analysis of deep volcanic earthquakes and low-frequency earthquakes both indicated a decrease in the supply of magma to the surface. At 1200 on 29 January the Alert Level was lowered to 3 (the second highest level on a scale of 1-4) and the public was warned to stay outside of the exclusion zone, defined as a 4-km radius around Laki-laki Crater, 5 km to the NNE, and 6 km on the NE flanks.

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

OVSICORI-UNA reported that at 0546 on 25 January a small phreatic eruption at Poás produced a steam plume that rose more than 500 m high and drifted W. The event produced the tallest plume recorded since 30 September 2019. According to the Comisión Nacional de Prevención de Riesgos y Atención de Emergencias (CNE) the event resulted in the restriction of the number of people that can be on the viewing platform to 56 at a time and visitors were required to wear hardhats. At 1437 on 26 January a more significant phreatic eruption ejected material 300 m above the lake’s surface and produced a gas-and-steam plume that rose 700 m high. During 26-27 January near constant degassing manifested as bubbling in the lake was observed.

Sources: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA), Comisión Nacional de Prevención de Riesgos y Atención de Emergencias (CNE)

JMA reported ongoing eruptive activity at Minamidake Crater (Aira Caldera’s Sakurajima volcano) during 22-29 January with nighttime crater incandescence. An eruptive event at 0014 on 27 January produced an ash plume that rose 1.1 km above the crater rim and drifted S. The Alert Level remained at 3 (on a 5-level scale), and the public was warned to stay 2 km away from both craters.

Source: Japan Meteorological Agency (JMA)

In a special advisory, PHIVOLCS reported increased seismicity at Bulusan, characterized by a total of 126 volcanic-tectonic earthquakes recorded by the seismic network during 0000-2145 on 28 January. The events had magnitudes of 0.3-2.2 and were located at depths of 1-9 km beneath the N and NW flanks. Weak-to-moderate gas emissions rose from the summit crater and active vents, which drifted SW and NW. The Alert Level remained at 1 (the second level on a scale of 0-5) and PHIVOLCS reminded the public not to enter the 4-km-radius Permanent Danger Zone (PDZ) and to be vigilant within the 2-km Extended Danger Zone (EDZ) on the SE flank.

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)

PVMBG reported that the eruption at Dukono was ongoing during 24-30 January. Gray-and-white ash plumes rose 100-1,500 m above the summit and drifted S on 25 and 29 January; emissions were not observed on the other days. The Alert Level remained at Level 2 (on a scale of 1-4), and the public was warned to remain outside of the 2-km exclusion zone.

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

KVERT reported that moderate explosive activity was ongoing at Ebeko during 18-25 January. According to volcanologists in Severo-Kurilsk (Paramushir Island, about 7 km E), explosions during 21-22 January generated ash plumes that rose as high as 3 km (10,000 ft) a.s.l and drifted NE and W. The Aviation Color Code remained at Orange (the third level on a four-color scale). Dates are UTC; specific events are in local time where noted.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

Instituto Geofísico del Perú (IGP) reported that lahars descended the SE flanks at El Misti at 1448 on 23 January and at 1642 on 25 January. The report noted that possible areas of impact included the Andamayo and Agua Salada river drainages in the Chiguata District. The public was warned to stay away from the drainages and roads on the SE flank.

Source: Instituto Geofísico del Perú (IGP)

During 13-23 January lava flows emerged from vents in Erta Ale’s S pit crater and traveled about 500 m S, 200 m NW, and 250 m SSW based on satellite images. Visitors to the volcano took photographs and video of low lava fountaining at a cone and advancing pāhoehoe flows. Activity increased notably during the morning of 27 January.

Sources: Copernicus, Il Mondo dei Terremoti, Aventure et Volcans

INSIVUMEH reported that eruptive activity continued at Fuego during 23-31 January. Explosions were recorded daily, averaging 2-9 per hour on most days when counts were reported; daily reports were not available on 29 and 30 January. The explosions generated gas-and-ash plumes that rose as high as 1.2 km above the crater rim and drifted as far as 30 km in multiple directions. Explosions caused frequent block avalanches that descended various drainages including the Ceniza (SSW), Seca (W), Taniluyá (SW), and Las Lajas (SE) and reached vegetated areas. The explosions also ejected incandescent material 100-400 m above the summit on most of the days. Ashfall was reported during 25-26 and 27-28 January in areas downwind including Yepocapa (12 km SW), Panimache I and II (8 km SW), Morelia (9 km SW), Santa Sofía (12 km SW), Finca Asuncion (12 km SW), La Rochela (8 km SSW), Finca Ceilán (9 km S), and San Andrés. Ashfall was forecasted to fall in communities to the N, NW, SW, and S on the other days. Weak rumbling sounds and shock waves were frequently reported.

Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)

AVO reported that the eruption of lava at Great Sitkin’s summit lava dome continued during 24-30 January, confirmed by satellite data acquired during the week. Effusion was concentrated at the center of the dome with minimal advancement at the margins of the flow. The center of the dome uplifted and caused radial cracks; a new lobe of lava extruded from the northernmost crack and traveled 180 m NW of the vent by 24 January. Weakly elevated surface temperatures were identified in satellite data during 24-26 January. Cloudy weather sometimes prevented satellite views of the volcano. Local webcams and seismic data communications that were offline due to a storm-related power failure came back online on 28 January; infrequent, small volcanic earthquakes were detected during 29-30 January. The Volcano Alert Level remained at Watch (the third highest level on a four-level scale) and the Aviation Color Code remained at Orange (the third highest color on a four-color scale).

Source: US Geological Survey Alaska Volcano Observatory (AVO)

PVMBG reported that the eruption at Lewotolok continued during 24-30 January. White gas-and-steam plumes rose 50-100 m above the summit and drifted NE, E, and SE on 27 and 29 January. White-and-gray plumes rose 50-200 m above the summit and drifted SE on 28 January. Emissions were not visible on the other days. The Alert Level remained at 2 (on a scale of 1-4) and the public was warned to stay at least 2 km away from the summit crater.

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

PVMBG reported that eruptive activity at Marapi (on Sumatra) was ongoing during 24-30 January. White-and-gray ash plumes rose 300 m above the summit and drifted N and NE on 25 January. White gas-and-steam plumes rose 150-250 m above the summit and drifted in multiple directions during 28-30 January. Emissions were not observed on the other days. The Alert Level remained at 3 (on a scale of 1-4), and the public was warned to stay 4.5 km away from the active crater.

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

BPPTKG reported that the eruption at Merapi (on Java) continued during 19-25 January. Seismicity remained at high levels. The SW lava dome produced a total of 47 lava avalanches that traveled as far as 1.5 km SW down the upper part of the Bebeng drainage. A total of 19 pyroclastic flows descended the Bebeng drainage as far as 3 km. The pyroclastic flows removed material from the upper parts of the Bebeng and Krasak drainages. According to news articles, minor ashfall was reported in Jelok Village (40 km S) at around 0845 on 21 January. An eruptive event with pyroclastic flows at 1355 that same day produced an ash plume that rose 1 km above the summit and caused ashfall in areas within 17 km SE, E, and NE, though some of the villages were located at greater distances. Minor amounts of ash fell in areas downwind, including Kemalang (15 km SE), Klaten (32 km SE), Selo Districts, Musuk, Boyolali (17 km E), Cepogo (4 km NE), Musuk (11 km ESE), Tamansari, Boyolali Kota, Teras (22 km E), Mojosongo (45 km E), and Sambi (28 ENE) at around 1430. The ash was washed away quickly due to rain. BPPTKG noted that morphological changes to the SW lava dome identified in webcam images were due to continuing collapses of material. 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), Antara News, Antara News

Servicio Geológico Colombiano’s (SGC) Observatorio Vulcanológico y Sismológico de Manizales reported that eruptive activity at Nevado del Ruiz continued at low levels during 23-29 January. Seismic events indicating rock fracturing increased in number, though the intensity of the signals was similar to the previous week. These events were mainly located in areas up to 6 km to the NE and SSE of Arenas Crater, and at depths of 1-7 km. The largest event, a M 1.3, occurred at 2105 on 24 January and was located about 1 km SSE of the crater and at a depth of 3 km. Seismicity associated with gas-and-ash emissions remained at similar numbers as the previous week but were less intense. Gas-and-ash emissions drifted NW and N and rose to a maximum height of 1.8 km above the summit, recorded on both 25 and 29 January. Sulfur dioxide emissions varied but decreased overall. The Alert Level remained at Yellow, Level III (the second level on a four-level scale), and the public was warned to stay out of the restricted areas around Arenas Crater.

Source: Servicio Geológico Colombiano (SGC)

Instituto Geofísico del Perú (IGP) reported that the eruption at Sabancaya continued at moderate levels during 22-28 January with a daily average of 47 explosions. Gas-and-ash plumes rose as high as 2 km above the summit and drifted less than 10 km NW and W. Thermal anomalies over the lava dome in the summit crater were identified in satellite data. Slight inflation was detected near the Hualca Hualca sector (4 km N). The Alert Level remained at Orange (the third level on a four-color scale) and the public were warned to stay outside of a 12 km radius.

Source: Instituto Geofísico del Perú (IGP)

INSIVUMEH reported that eruptive activity continued at Santa Maria’s Santiaguito lava dome complex during 23-31 January with a lava extrusion at the Caliente dome. Daily reports were not available on 29 and 30 January. Incandescence from the dome was visible during most nights and early mornings. Explosions occurring at a rate of 1-6 per hour on most days generated gas-and-ash plumes that rose 600-900 m above the dome and drifted mainly NW, W, and SW. The explosions produced block avalanches on the dome’s W, SW, S, and E flanks and generated occasional, short-range pyroclastic flows that predominantly descended the W, SW, and S flanks. Block avalanches were visible from the margins of the upper part of the lava flow on the SW flank. Ashfall occurred in Loma Linda (7 km W) and San Marcos Palajunoj (8 km SW) during 25-26 January.

Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)

KVERT reported that the eruption at Sheveluch continued during 18-25 January. A thermal anomaly was identified in satellite images during 20-25 January; weather clouds obscured views on the other days. The Aviation Color Code remained at Orange (the third 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 22-29 January. A total of 15 explosions were recorded during the week, with 1-4 occurring each day. Ash plumes rose as high as 1 km above the crater rim and drifted SE and E, and large blocks were ejected as far as 400 m from the vent. Crater incandescence was observed in webcam images nightly and rumbling was occasionally heard in Toshima village (3.5 km SSW). The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1 km away from the crater.

Source: Japan Meteorological Agency (JMA)

Instituto Geofísico del Perú (IGP) reported that lahars descended the Volcánmayo drainage on the SE flank at Ubinas at 1910 on 23 January, at 2015 on 25 January, and at 1540 on 27 January. The report noted that the lahars traveled towards the Ubinas River and could possibly impact the Districts of Ubinas, Matalaque, and population centers. The public was warned to stay away from the drainage and to avoid driving on the Querapi-Ubinas-Huarina highway. Daily gas-and-steam plumes rose 100-500 m above the summit and drifted in multiple directions during 24-30 January.

Source: Instituto Geofísico del Perú (IGP)