Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the Week 26 February 2020 – 3 March 2020

Aira | Kyushu (Japan) : JMA reported that during 25 February-2 March there were six explosions and three non-explosive eruptive events detected by the Minamidake Crater (at Aira Caldera’s Sakurajima volcano) seismic network. Ash plumes rose as high as 2.6 km above the crater rim and material was ejected 600-1,300 m away from the crater. Crater incandescence was visible every night. The Alert Level remained at 3 (on a 5-level scale).

Asosan | Kyushu (Japan) : JMA reported that eruptive activity at Asosan was recorded during 25 February-2 March. Gray-to-white ash plumes rose 700 m above the crater rim and caused ashfall in areas downwind. The sulfur dioxide emission rate was high, ranging from 1,500 to 4,900 tons per day. The Alert Level remained at 2 (on a scale of 1-5).

Dukono | Halmahera (Indonesia) : Based on satellite and wind model data, the Darwin VAAC reported that during 26-29 February and 1 March ash plumes from Dukono rose to 2.1 km (7,000 ft) a.s.l. and drifted S, SW, and W. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to remain outside of the 2-km exclusion zone.

Ebeko | Paramushir Island (Russia) : Volcanologists in Severo-Kurilsk (Paramushir Island), about 7 km E of Ebeko, observed explosions on 21, 25, and 27 February that sent ash plumes up to 2.9 km (9,500 ft) a.s.l. Ash plumes drifted S, SE, and NE; ashfall was reported in Severo-Kurilsk on 22 February. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Ibu | Halmahera (Indonesia) : The Darwin VAAC reported that on 27 February an ash plume from Ibu rose to 2.1 km (7,000 ft) a.s.l. and drifted SW based on satellite images and weather models. 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 active crater, and 3.5 km away on the N side.

Karangetang | Siau Island (Indonesia) : PVMBG reported that during 24 February-1 March lava continued to effuse from Karangetang’s Main Crater (S), traveling as far as 1.8 km down the Nanitu, Pangi, and Sense drainages on the SW and W flanks. Sometimes dense white plumes rose 150 m above the summit; foggy weather occasionally prevented observations. Incandescence from both summit craters was visible at night. The Alert Level remained at 2 (on a scale of 1-4).

Kerinci | Indonesia : PVMBG reported that at 0600 on 1 March and 0742 on 2 March brown ash emissions rose 400-500 m above Kerinci’s summit and drifted SSW and NE, respectively. 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.

Klyuchevskoy | Central Kamchatka (Russia) : KVERT reported that Strombolian activity at Klyuchevskoy was visible during 21-28 February, and a strong thermal anomaly was identified in satellite images those same days. A gas-and-steam plume containing some ash drifted 120 km E on 23 February. The Aviation colour Code remained at Orange.

Nishinoshima | Japan : The Japan Coast Guard (JCG) presented InSAR results from 17 November 2019 to 28 February 2020 showing growth of Nishinoshima’s central cone alomg with changes to the island’s surface and expansion of the coastline from lava flows. During an overflight on 17 February observers noted continuous activity from the central vent, including a diffuse ash plume rising about 600 m. Ejected material landed near the cone’s base. Lava flowed into the sea at the N and E coasts, causing a rising steam plume. Discoloured water had been seen on 4 February in an area 9 km S of the island but was not apparent during the overflight possibly due to weather conditions. The marine exclusion zone was defined as a radius of about 2.6 km from the island.

Pavlof | United States : AVO reported that seismic activity at Pavlof had decreased during the past several weeks, and no eruptive activity or summit emissions had been observed since minor steaming in late February. AVO lowered the Volcano Alert Level to Normal and the Aviation colour Code to Green on 3 March.

Ruapehu | North Island (New Zealand) : GeoNet reported that a period of increased seismicity was detected at Ruapehu during 22-23 February. The series of volcanic earthquakes began with the largest event, a M 1.3, which was followed by smaller events. The data showed that the seismicity originated from a source 3 km below the summit. The amplitude of the volcanic tremor declined during 24-28 February and then again increased around 29 February-1 March. In response to the 22-23 February sequence, volcanologists collected lake water samples and measured gas emissions the week after. The temperature of the lake water suggested slow heating from 24 to 30 degrees Celsius. They observed upwelling of gray sediment and sulfur slicks on the surface of the water. Carbon dioxide and sulfur gas emissions had increased since last measured on 7 February. GeoNet noted that gas-flux and the increased seismicity remained within the normal ranges for Ruapehu; the Volcanic Alert Level remained at 1 (minor volcanic unrest) and the Aviation colour Code remained at Green.

Sabancaya | Peru : Instituto Geofísico del Perú (IGP) reported that a daily average of 18 low- to medium-intensity explosions occurred at Sabancaya during 24 February-1 March. Gas-and-ash plumes rose as high as 2 km above the summit and drifted W, SW, and S. There was one thermal anomaly identified in satellite data, originating from the lava dome in the summit crater. On 26, 27, and 28 February at 1552, 1420, and 1300, respectively, lahars descended the Huayuray-Pinchollo drainage on the N flank. The lahars were small to moderate in size and blocked the Chivay-Cabanaconde road in the district of Cabanaconde. The Alert Level remained at Orange (the second highest level on a four-colour scale) and the public were warned to stay outside of a 12-km radius.

Semisopochnoi | United States : No signs of eruptive activity at Semisopochnoi were detected in infrasound and satellite data over the previous several weeks, prompting AVO to lower the Aviation colour Code to Yellow and the Volcano Alert Level to Advisory on 26 February. A robust steam plume rose from the main vent that same day. Short bursts of tremor and earthquakes persisted during 26 February-3 March.

Sheveluch | Central Kamchatka (Russia) : KVERT reported that a thermal anomaly over Sheveluch was identified in satellite images during 21-28 February. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Suwanosejima | Ryukyu Islands (Japan) : JMA reported that during 21-28 February incandescence from Suwanosejima’s Ontake Crater was visible nightly. Occasional eruptive events and two explosions were recorded; ash plumes rose as high as 1.2 km above the crater rim. Blocks were ejected onto the flanks during 23-24 February. The Alert Level remained at 2 (on a 5-level scale).

Taal | Luzon (Philippines) : PHIVOLCS reported that during 26 February-2 March steam plumes rose 50-300 m above the vent and drifted SW and NE. According to the Disaster Response Operations Monitoring and Information Center (DROMIC) there were a total of 4,314 people in 12 evacuation centers, and an additional 132,931 people were staying at other locations as of 3 March. The Alert Level remained at 2 (on a scale of 0-5) and PHIVOLCS recommended no entry onto Volcano Island, the area defined as the Permanent Danger Zone.

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