Volcanos

Roundup of Global Volcanic Activity - Ongoing Activity for the week 4 January - 10 January 2023

Ahyi - Mariana Islands (USA) : Unrest continued to be detected at Ahyi Seamount during 4-10 January. Daily signals possibly indicating explosions were detected by hydrophone sensors on Wake Island (2,270 km E of Ahyi), though a data outage began at 0118 on 8 January. No activity was visible in mostly cloudy satellite images, though a plume of discolored water originating from the summit region of the seamount was seen in partly cloudy satellite images on 8 January.

Aira - Kyushu (Japan) : JMA reported ongoing eruptive activity at Minamidake Crater (at Aira Caldera’s Sakurajima volcano) during 2-9 January. Crater incandescence was visible nightly. Sulfur dioxide emissions were slightly elevated at 1,000 tons per day on 4 January. One explosion on 3 January and two explosions on 8 January were recorded by the seismic network. Eruption plumes rose as high as 2.4 km above the crater rim and blocks were ejected as far as 1.1 km from the vent.

Cleveland - Chuginadak Island (USA) : Signs of unrest has declined over the previous several months. Elevated surface temperatures in the summit crater were occasionally identified in satellite images but at a reduced frequency and strength. The last eruptive activity was a short-lived explosion on the evening of 1 June 2020, and sulfur dioxide emissions were last detected on 29 July 2022.

Cotopaxi - Ecuador : IG reported that the low-level eruption at Cotopaxi continued during 3-11 January, characterized by daily steam-and-gas emissions often with low ash content. Plumes of gas, steam, and minor ash content rose as high as 1.7 km above the crater rim and drifted NW, W, SW, and E, based on webcam views, satellite images, and information from the Guayaquil Meteorological Office. Minor ashfall was reported in the sectors of Colcas, San Ramon, and San Agustin de Callo (18 km WSW).

Ebeko - Paramushir Island (Russia) : KVERT reported that moderate activity at Ebeko was ongoing during 29 December 2022-5 January 2023. According to volcanologists in Severo-Kurilsk (Paramushir Island, about 7 km E) explosions during 31 December and 1-5 January generated ash plumes that rose as high as 4 km (13,100 ft) a.s.l. and drifted NE and E. A thermal anomaly was identified in satellite images during 3-4 January and an ash cloud drifted 12 km NE on 4 January.

Etna - Sicily (Italy) : INGV reported that the vents at the NE base of Etna’s SE Crater, in the Valle del Leone at about 2,800 m elevation, continued to feed lava flows during 2-8 January. The active flow field consisted of overlapping lava flows that expanded into the Valle del Leone and the Valle del Bove and hornitos. By 7 January the longest active lava flow had descended to 2,170 m elevation, and the area of the flow field was an estimated 0.63 square kilometers. Gas emissions rose from the summit craters, mainly at Bocca Nuova.

Fuego - South-Central Guatemala : INSIVUMEH reported that 2-8 explosions per hour were recorded at Fuego during 3-10 January, generating ash plumes that rose more than 1.2 km above the crater rim and drifted as far as 30 km in various directions. Daily ashfall was noted in areas downwind including Morelia (9 km SW), Panimaché I and II (8 km SW), Santa Sofía (12 km SW), El Porvenir (8 km ENE), Los Yucales (12 km SW), Sangre de Cristo (8 km WSW), El Porvenir (8 km ENE), San Pedro Yepocapa (8 km NW), and Finca Palo Verde. The avalanches occasionally resuspended ash deposits that rose 100 m and drifted W and SW. Daily shock waves rattled structures in communities around the volcano. Daily block avalanches descended the Ceniza (SSW), Seca (W), Trinidad (S), Taniluyá (SW), Honda, Las Lajas (SE), El Jute (ESE), and Trinity drainages, sometimes reaching vegetated areas. Strombolian explosions ejected incandescent material as high as 300 m above the summit almost daily.

Great Sitkin - Andreanof Islands (USA) : AVO reported that slow lava effusion likely continued at Great Sitkin during 4-10 January, though weather clouds often obscured satellite and webcam views. A few small daily earthquakes were detected during 6-10 January and slightly elevated surface temperatures were identified in satellite images during 7-10 January.

Kerinci - Central Sumatra : The eruption at Kerinci was ongoing during 4-8 January with brown, brown-to-gray, or white-and-brown ash plumes rising as high as 200 m above the crater rim and drifting NE and E.

Krakatau - Sunda Strait : PVMBG reported that the eruption at Anak Krakatau continued. A dense gray ash plume was seen at 1410 on 4 January rising 100 m above the summit and drifting E, followed at 1509 by a dense gray-to-black ash plume to 3 km above summit that also drifted E. Another event at 0013 on 5 January sent a dense gray ash plume 750 m above the summit that drifted NE. Although weather sometimes prevented visual observations during 6-9 January, white plumes of variable intensities rose as high as 200 m from the summit and drifted mainly NE and E.

Merapi - Central Java : BPPTKG reported that the eruption at Merapi continued during 30 December 2022-5 January 2023 and seismicity remained at high levels. The SW lava dome produced eight lava avalanches that traveled as far as 1.5 km down the SW flank (upstream in the Kali Bebeng drainage). One pyroclastic flow descended 900 m SW. No significant morphological changes to the central and SW lava domes were evident in webcam images.

Nevado del Ruiz - Colombia : Servicio Geológico Colombiano’s (SGC) reported that at 0706 on 6 January an ash cloud rose from Nevado del Ruiz and drifted NE, causing ashfall in Villahermosa (27 km NE). The ash emission occurred simultaneously with a seismic signal indicated moving fluids within the volcano’s conduit.

Nevados de Chillan - Central Chile : On 10 January SERNAGEOMIN lowered the Alert Level for Nevados de Chillán to Green, the lowest level on a four-color scale. No activity at the surface had been observed since mid-October 2022; other data reflected ongoing internal processes, though recently the activity had been lower and gradually returning to background levels.

Santa Maria - Southwestern Guatemala : INSIVUMEH reported that the eruption at Santa María’s Santiaguito lava-dome complex continued during 3-10 January. Effusion from Caliente cone fed lava flows that descended the San Isidro and El Tambor drainages on the W and SW flanks. Occasional block avalanches from the dome, and from both the ends and sides of the flows, descended the S, SW, and W flanks. The avalanches sometimes generated minor ash plumes that rose along their paths. Almost daily explosions produced gas-and-steam plumes with minor amounts of ash that rose as high as 800 m above the complex and sometimes drifted 5-8 km SW. Ashfall was reported in Las Marías (10 km S) and El Viejo Palmar (11 km S) during 8-9 January.

Semeru - Eastern Java : PVMBG reported that the eruption at Semeru continued during 3-10 January; weather clouds prevented visual observations during 4-6 January. At 0503 on 7 January a white-to-gray ash plume rose 400 m above the summit and drifted N. Ash plumes of variable densities generally rose 200-400 m above the summit and drifted N and NE on 8 January. At 0819 a white-to-brown ash plume rose 500 m and drifted N and NE. A webcam image posted on social media showed an incandescent lava flow extending 500 m from the summit crater on the SE flank. On 9 January at 0652 a white-to-brown ash plume rose 200 m and drifted N and NE. On 10 January white-and-gray ash plumes rose as high as 300 m and drifted N and NE. 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.

Sheveluch - Central Kamchatka (Russia) : KVERT reported that the ongoing eruption at Sheveluch during 29 December 2022-5 January 2023 was generally characterized by explosions, hot avalanches, lava-dome extrusion, and strong fumarolic activity. A daily thermal anomaly was identified in satellite images, and ash plumes from lava-dome collapses drifted 175 km E, NE, W, and SW during 30-31 December and 4-5 January.

Stromboli - Aeolian Islands (Italy) : INGV reported that both explosive and effusive activity at Stromboli occurred during 2-8 January at four vents in Area N, within the upper part of the Sciara del Fuoco, and at one vent in the Area C-S (South-Central Crater area) in the crater terrace area. The explosions were variable in intensity and ejected coarse material (bombs and lapilli) 80-150 m at a rate of 3-10 explosions per hour. Intense spattering from all four vents occurred during the week. Explosive activity at the Central-South area (CS) ejected fine-to-coarse material as high as 250 m above the vent at a rate of 1-4 explosions per hour. At 2136 on 2 January lava overflowed vents in the N2 area, after a period of intense spattering. The lava flowed part way down the Sciara del Fuoco, likely channeled in the ravine that had formed in October, out of view from webcams. The flow was well-fed for a couple of hours but then effusion slowed or stopped, and it began to cool. The same activity occurred again, with a lava overflow occurring at 0224 on 4 January, traveling about the same distance, and cooling within a few hours.

Suwanosejima - Ryukyu Islands (Japan) : JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 2-9 January. No explosions were recorded, though eruption plumes rose as high as 1.3 km above the crater rim. During 2-6 January blocks were ejected as far as 200 m from the vent and ashfall was occasionally reported in Toshima village (3.5 km SSW).

Villarrica - Central Chile : SERNAGEOMIN reported that activity at Villarrica had increased in recent weeks, with explosions ejecting material almost as far as 480 m, near the extent of the 500 m exclusion zone in place around the crater. On 6 January the exclusion zone was increased to 1 km as a preventative measure.