Volcano World

JMA reported that the amplitude of volcanic tremor signals at Asosan increased at around 1200 on 30 January and then increased again around 1220 and remained high. At 1330 JMA raised the Alert Level to 2 (on a scale of 1-5) and warned the public to stay at least 1 km away from the crater. White plumes were visible rising 300 m above the crater rim.

Source: Japan Meteorological Agency (JMA)

KVERT reported that an explosive eruption at Chikurachki likely began at 0630 on 29 January. Ash plumes rose to as high as 3 km (10,000 ft) a.s.l. and drifted 75 km SE based on satellite data. The Aviation Color Code was raised to Orange (the second highest level on a four-color scale). At 1406 and 1720 ash plumes were identified in satellite images rising to 4.3 km (14,000 ft) a.s.l. and drifting 70 km E. Ash plumes had dissipated by 2320.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

The Wellington VAAC reported that a low-level plume of ash and sulfur dioxide from a new eruption at Epi was identified in satellite data at 0730 on 31 January. According to the Vanuatu Meteorology and Geo-Hazards Department (VMGD) residents saw steaming at the ocean?s surface in the area over the vents at around 0748, and phreatic explosions that ejected steam and tephra 100 m above the water. The Alert Level was raised to 1 (on a scale of 0-5) and the public was warned to stay 10 km away from the East Epi submarine volcano. Observers reportedly saw a growing cone from ongoing ash emissions. The VAAC noted that the eruption was short-lived and had ceased by 1548; the ash had dissipated. Three submarine cones, Epi A, Epi B, and Epi C, and smaller cones and craters, are located 10-16 km NNE from the summit of Epi Island and are aligned along the N rim of an inferred caldera. Epi B is the shallowest of the seamounts and has been historically active, most recently in February 2004. A March 2004 bathymetric survey revealed that Epi B was about 300 m tall, with a diameter of about 1.8 km at the base. The summit crater was about 150 m in diameter and the crater floor was at a depth of 90 m. The highest point was on the NW rim of the summit crater, at a depth of 34 m.

Sources: Vanuatu Meteorology and Geo-Hazards Department (VMGD),Wellington Volcanic Ash Advisory Center (VAAC)

Small thermal anomalies in both of Erta Ale?s N and S pit craters were identified in satellite images on 23 January. On 28 January the anomaly in the N pit crater was large and intense.

Source: Sentinel Hub

SERNAGEOMIN reported increased seismicity at Lscar on 26 January with long-period (LP) events indicating fluid movement at shallower depths. The Alert Level was raised to Yellow (the second lowest level on a four-color scale) and SENAPRED warned the public to stay at least 3 km away from the crater. ONEMI declared an Alert Level Yellow (the middle level on a three-color scale) for San Pedro de Atacama (70 km NW). A seismic signal at 2259 corresponded to the ejection of incandescent material and the emission of a plume that likely contained tephra and rose almost 1.9 km and drifted NW. The intensity of LP events significantly increased at 2300 on 27 January and remained at anomalous levels. A series of four LP events were recorded at 0015, 0032, 0043, and 0052 on 28 January and corresponding emissions rose 380 m above the crater rim and drifted NW. An M 3.2 volcano-tectonic earthquake was recorded at 0115 and felt by residents. LP earthquakes continued to be detected, along with tremor and volcano-tectonic events to a lesser extent. Minor crater incandescence was visible and gas plumes rose as high as 760 m. At 0430 the Alert Level was raised to Orange and the restricted zone was increased to 5 km. Elevated levels of seismicity continued to be detected during 28-30 January. Whitish-gray gas plumes possibly containing tephra rose to low heights and minor crater incandescence was occasionally observed. On 31 January SERNAGEOMIN stated that a satellite image from the day before showed a dome-like feature on the crater floor that was 81 m by 93 m in dimension and covered an area of about 5,332 square meters. The exclusion zone was increased to 10 km.

Sources: Oficina Nacional de Emergencia-Ministerio del Interior (ONEMI) ,Servicio Nacional de Geologa y Minera (SERNAGEOMIN)

According to JMA an area of pale yellow-green discolored water with a diameter of about 100 m was visible about 65 km SSE of Myojinsho on 26 January, based on an overflight conducted by the Japan Coast Guard. An eruption warning was issued to mariners. Discolored water was last observed in March 2017.

Sources: Japan Coast Guard,Japan Meteorological Agency (JMA)

The Japan Coast Guard reported that during an overflight of Nishinoshima on 25 January scientists observed intermittent activity and small, blackish-gray plumes rising 900 m from the central part of the crater. The fumarolic zone on the E flank and base of the cone had expanded and emissions had intensified. Dark brown discolored water was visible all around the volcanic island.

Source: Japan Coast Guard

Unrest at Ahyi Seamount continued during 24-31 January. Pressure sensors on Wake Island, 2,270 km E of Ahyi Seamount, detected a possible explosion signal on 25 January. Plumes of discolored water were identified in satellite images during 27-31 January. 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

JMA reported ongoing eruptive activity at Minamidake Crater (at Aira Caldera?s Sakurajima volcano) during 23-30 January and crater incandescence was visible nightly. Two explosions were recorded on 24 January, though weather clouds prevented visual confirmation. Sulfur dioxide emissions were high at 2,800 tons per day on 26 January. An explosion at 2342 on 28 January produced an ash plume that rose 2.2 km above the crater rim and ejected large blocks as far as 700 m from the crater. 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)

IG reported that the eruption at Cotopaxi continued during 24-31 January, characterized by almost daily gas-and-steam and ash emissions; inclement weather conditions prevented views of the volcano on 29 January. During 24-25 January steam-and-gas plumes rose to the crater level and drifted W. During 26-27 January gas-and-ash plumes rose less than 1 km above the crater rim and drifted SW and W. Minor ashfall was reported in San Agustn de Callo (18 km WSW), Lima Villacs, Mulal, Barrancas, Ticatiln and Caspi (20 km WSW), and San Ramon (127 km W). Steam-and-gas emissions rose 600 m and drifted S on 28 January. A significant increase in the size and density of ash emissions was evident in satellite images at 0820 on 30 January. The plumes rose as high as 2.5 km above the crater rim and drifted SW, S, and SE. Minor amounts of ash fell in Mulal and Latacunga (18 km WSW). Ash plumes rose as high as 1.7 km and drifted S and SE on 31 January. Servicio Nacional de Gestin de Riesgos y Emergencias (SNGRE) maintained the Alert Level at Yellow (the second lowest level on a four-color scale).

Source: Instituto Geofsico-Escuela Politcnica Nacional (IG)