A brief seismic swarm at Grímsvötn was recorded by the seismic network beginning at 1600 on 4 January, prompting Icelandic Meteorological Office (IMO) to raise the Aviation Color Code to Yellow (the second level on a four-color scale). The swarm consisted of seven earthquakes with magnitudes above 1, which was considered unusual. Since the beginning of December there had been evidence of water drainage from the lake; the earthquakes may have been related to the drainage, but it was not confirmed. Activity did not escalate on 5 January and only one M 0.6 earthquake was detected. The Aviation Color Code was lowered to Green. The report noted that seismic activity at the volcano had been above background levels during the previous four months.

Source: Icelandic Meteorological Office (IMO)

AVO reported that unrest at Kanaga continued during 3-9 January; no new eruptive activity was evident in satellite and webcam images. Small daily earthquakes were detected until 2 January when a storm-related power failure took local monitoring data offline. Satellite radar images showed that large NW-SE-trending fractures intersecting the summit crater had likely formed around the time of the 18 December explosive event. The Volcano Alert Level remained at Advisory (the second level on a four-level scale) and the Aviation Color Code remained at Yellow (the second color on a four-color scale).

Source: US Geological Survey Alaska Volcano Observatory (AVO)

PVMBG reported that the eruption at Lewotobi’s Laki-laki volcano from a fissure on the upper NNW flank and from a vent on the upper SSE flank was ongoing during 3-9 January. White plumes rose 300-1,000 m above the summit and drifted SW and W during 3-5 December. During the rest of the week white-and-gray or gray-to-brown ash plumes rose 1-1.5 km above the summit and drifted NW, N, and NE. The ash plumes were sometimes dense.

Masks had been distributed in Hokeng Jaya, Pululera, Klatanlo, and Nawakote in the district of Wulanggitan and the village of Dulempari in the district of Bura after the eruption began in late December and residents were encouraged to wear them when outside to minimize ash inhalation. On 1 January as many as 1,185 residents of Boru Village and 328 residents in the Konga Village area self-evacuated to several other locations including relatives’ homes and evacuation posts. Ash fell in several areas in the Wulanggitan and Bura districts. Badan Penanggulangan Bencana Daerah (BPBD) East Flores Regency mobilized and provided residents with essentials including mobile kitchens, food, tents, and cleaned ash off roadways. By 4 January a total of 3,898 people had evacuated. The Frans Xavier Seda Airport in Sikka District closed on 1 January due to thick ash deposits on the runways; it remained closed as of 9 January.

Activity intensified during the evening of 9 January. Incandescent material was ejected from the summit and lava flows from the NNW-flank fissure descended the NW flank. At 2300 the Alert Level was raised to 4 (on a scale of 1-4) and the public was warned to stay 4 km away from the Perempuan and Laki-laki craters and an additional 5 km from the NNW flanks of Laki-laki.

Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM), Badan Nacional Penanggulangan Bencana (BNPB), Badan Penanggulangan Bencana Daerah Provinsi Jawa Timur (East Java BPBD), Directorate General Of Civil Aviation, Ministry Of Transportation Republic Of Indonesia

PVMBG reported that eruptive activity at Marapi (on Sumatra) was ongoing at Verbeek Crater during 3-9 January. White plumes rose 300-350 m above the summit and drifted S and SW on 4 January. White-and-gray ash plumes rose 150-600 m above the summit and drifted S, SW, N, and NE during 5-8 January.

PVMBG reevaluated instrumental data and visual observations at Marapi and concluded that activity was continuing at high levels; at 1800 on 9 January they raised the Alert Level to 3 (on a scale of 1-4) and warned the public to stay 4.5 km away from Verbeek Crater. They noted that ongoing high seismicity and increasing numbers of low-frequency and deep volcanic earthquakes indicated that magma continued to be supplied at depth. Incandescence at the crater and the ejection of incandescent material after the 3 December eruption indicated that the eruption style had change from phreatic to magmatic; sulfur dioxide emissions measured from satellite were at high levels.

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

JMA reported ongoing activity at Minamidake Crater (Aira Caldera’s Sakurajima volcano) during 1-8 January with incandescence at the crater observed nightly. Small eruptive events were occasionally recorded during the week. 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)

PVMBG reported that the eruption at Dukono was ongoing during 3-9 January. Gray-and-white ash plumes rose as high as 4 km above the summit and drifted SW on 3 January. White-and-gray ash plumes rose 100-1,900 m above the summit and drifted W and SW during 4 and 6-8 January. 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 28 December 2023-4 January 2024. According to volcanologists in Severo-Kurilsk (Paramushir Island, about 7 km E), explosions during 30-31 December generated ash plumes that rose as high as 3.5 km (11,500 ft) a.s.l and drifted SE. 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)

Although there was no eruptive activity reported at Gamalama, in a 4 January press release PVMBG noted that the number of daily deep volcanic earthquakes had significantly increased. The seismic network recorded a total of 45 deep volcanic earthquakes during 0000-0600 on 4 January; an average of 2-3 events per day had been recorded since January 2023. Diffuse white plumes only rose as high as 120 m above the summit during the previous month whereas typically they can rise as high as 300 m. PVMBG noted that the most likely hazard would be a phreatic event that could ejected material within the 1.5-km radius, though ash may be carried farther by wind. The Alert Level remained at 2 (on a scale of 1-4); visitors and residents were warned not to approach the crater within a 1.5-km radius.

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

AVO reported that a radar image of Great Sitkin showed continuing growth of a thick flow in the summit crater with expansion to the E; effusion likely continued during 3-9 January. Radial cracks around the central vent widened and pushed material 15 m N. Weather clouds often obscured views of the volcano. Seismicity was low, though beginning during 2-4 January web cameras and seismic data were offline due to a power failure. 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)

PVMBG reported that during 1-31 December diffuse white plumes rose as high as 80 m above Iya’s summit. During most of that period seismicity was at normal levels and characterized by both deep and shallow volcanic earthquakes. A total of 55 deep volcanic earthquakes were recorded during the month with 12 of them recorded during 30-31 December, signifying a significant increase during that period. The Alert Level was remained at 1 (on a scale of 1-4), and the public was warned to limit activity near the active crater area.

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

PVMBG reported that the eruption at Lewotolok continued during 3-9 January. White-and-gray ash plumes rose 300-350 m above the summit and drifted NW on 3 and 6 January. White steam-and-gas plumes rose 400-500 m above the summit and drifted NW on the other days. Incandescent lava was occasionally ejected about the vent. 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)

BPPTKG reported that the eruption at Merapi (on Java) continued during 29 December 2023-4 January 2024. The SW lava dome produced a total of 83 lava avalanches that descended the S and SW flanks; six traveled S as far as 1.4 km down the upper part of the Boyong drainage and the other 77 traveled SW as far as 2 km down the upper part of the Bebeng drainage. Two pyroclastic flows descended the Bebeng, traveling as far as 1.8 km. 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.

Source: Balai Penyelidikan dan Pengembangan Teknologi Kebencanaan Geologi (BPPTKG)

Servicio Geológico Colombiano’s (SGC) Observatorio Vulcanológico y Sismológico de Manizales reported that eruptive activity at Nevado del Ruiz continued at moderate levels during 2-8 January. Seismic events indicating rock fracturing increased in both number an intensity. These events were located in areas up to 4 km in various directions from Arenas Crater at depths of 1-7 km. The seismic activity was most notable on 3 and 5 January; the largest earthquake, a M 3.9, was recorded at 1103 on 3 January and felt by officials of the Parque Nacional Natural Los Nevados, SGC personnel in the field, and residents in Manizales (27 km NW). Seismicity associated with ash-and-gas emissions decreased in both size and number. The maximum height of the ash-and-gas emissions was 1.8 km above the summit, recorded on 6 January. Emissions during the week drifted NW, W, and SW, causing ashfall near the volcano and occasionally in Manizales. 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)

Observatorio Vulcanológico y Sismológico de Popayán, Servicio Geologico Colombiano (SGC) reported increased unrest at Puracé on 5 January. A sudden increase in carbon dioxide emissions was detected during the morning and decreased through the day; increased gas emissions were visible in webcam images during the afternoon. Seismicity increased at 1450 and continued at high levels at least through 1715, the time the report was issued. The earthquake signals indicated fluid movement, had low magnitudes, and were located less than 2 km below the summit. The Alert Level remained at Yellow (the second level on a four-color scale).

Source: Servicio Geológico Colombiano (SGC)

IG-EPN reported that a moderate eruption at Reventador was ongoing during 2-9 January. Seismicity was characterized by 37-58 daily explosions, long-period earthquakes, harmonic tremor, and tremor associated with emissions. Several ash-and-gas plumes rose as high as 1.3 km above the crater rim and drifted S, SW, W, and NW, though cloudy conditions often prevented views. Crater incandescence was occasionally visible during both overnight and morning hours; incandescent material was ejected 200-300 m above the crater and avalanches of incandescent material descended the flanks as far as 600 m from the summit during 6-9 January. A small lahar was recorded on 6 January. Secretaría de Gestión de Riesgos maintained the Alert Level at Orange (the second highest level on a four-color scale).

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

Instituto Geofísico del Perú (IGP) reported that the eruption at Sabancaya continued at moderate levels during 3-7 January with a daily average of 61 explosions. Gas-and-ash plumes rose as high as 1.7 km above the summit and drifted less than 10 km NW, W, and SW. 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)

IG-EPN reported a high level of eruptive activity at Sangay during 1-9 January, with seismic stations recording 173-583 daily explosions. Ash-and-gas plumes were visible, in both webcam and satellite images, rising as high as 1.5 km above the crater rim and drifting SW during 1-5 January. Webcam images showed incandescence at the summit vent and incandescent material descending the SE flank as far as 1.8 km from the crater. Beginning at 1536 on 6 January a series of explosions and ash emissions were visible in webcam images with ash-and-gas plumes rising 3 km above the summit and drifting NW. The activity continued into the late afternoon and intensified; ash plumes rose as high as 8 km above the summit and drifted W, NW, and N. Ashfall was reported in several towns downwind, including San Antonio, Pancún, Cebadas (35 km WNW), Gualiñag, Guargallá Chico, Guamote (40 km WNW), Pungalá (25 km NW), and Chunchi (73 km SW) in the province of Chimborazo, Chillanes (80 km W) in the province of Bolívar, Montalvo (106 km WNW), Babahoyo (135 km WNW), Ventanas, Pueblo Viejo (141 km NW), Vinces (165 km WNW), and Baba (152 km WNW) in the province of El Oro, and Palestina (185 km WNW) in the province of Guayas. Several pyroclastic flows descended the SE drainage during 6-7 January. Ash-and-gas plumes rose 400-800 m above the summit during 7-8 January. During the morning of 8 January, a pyroclastic flow descended the SE drainage and minor ashfall was reported in the Guamote-Chimborazo canton. Cloudy weather prevented views during 8-9 January, though crater incandescence was observed overnight. Secretaría de Gestión de Riesgos maintained the Alert Level at Yellow (the second highest level on a four-color scale).

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

PVMBG reported that eruptive activity continued at Semeru during 3-9 January. Daily white-and-gray ash plumes that were sometimes dense rose 400-1,200 m above the summit and drifted S, SW, and W. The Alert Level remained at 3 (third highest on a scale of 1-4). The public was warned to stay at least 5 km away from the summit in all directions, 13 km from the summit to the SE, 500 m from the banks of the Kobokan drainage as far as 17 km from the summit, and to avoid other drainages 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 eruption at Sheveluch continued during 28 December 2023-4 January 2024 with a daily thermal anomaly identified in satellite images. 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 1-8 January. No explosions were detected, though large blocks were ejected as far as 400 m from the vent. Ash plumes rose 1-2 km above the crater rim during 1-2, 6, and 8 January and drifted in multiple directions. Ash emissions were continuous during 0157-0620 and 0834-2235 on 2 January. 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)

Rabaul Volcano Observatory (RVO) reported that activity at Ulawun was low during 6 December 2023-9 January 2024. During periods of good visibility white steam plumes of variable densities were seen rising from the summit crater. On 19 December visibility was poor, though during a brief clear period, observers noted brown-tinged steam plumes. On 31 December residents of Noau Village photographed dense brown ash plumes rising a few hundred meters above the summit and drifting W, and a small pyroclastic flow descending the NNE flank. The Alert Level remained at Stage 1 (on the four-level scale).

Source: Rabaul Volcano Observatory (RVO)