Volcanos

Roundup of Global Volcanic Activity – New Activity for the Week 20 January 2021 – 26 January 2021

Merapi – Central Java (Indonesia) : BPPTKG reported that the “2021 lava dome” continued to grow just below Merapi’s SW rim during 15-21 January, producing a total of 282 incandescent lava avalanches that traveled as far as 1 km down the Krasak and Boyong river drainages on the SW flank. Pyroclastic flows were recorded 19 times and descended the SW flanks as far as 1.8 km. A comparison of photos taken on 14 and 21 January showed that the morphological changes in the summit area were attributed to the emergence of new lava domes. The 2021 dome volume was an estimated 104,000 cubic meters on 21 January, with a growth rate of about 8,600 cubic meters per day. Deformation continued, though at a lower rate; Electronic Distance Measurement (EDM) data showed a distance shortening between points in the NW at a rate of 0.8 cm per day. Seismic activity was lower than the previous week. According to news articles ashfall was reported in several villages in the Musuk, Tamansari, and Kemalang districts on 19 January. The Alert Level remained at 3 (on a scale of 1-4), and the public were warned to stay 5 km away from the summit.

Raung – Eastern Java (Indonesia) : A brown-gray ash plume from Raung rose 100-400 m above the crater rim and drifted E at 0520 on 21 January, prompting PVMBG to raise the Alert Level to 2 (on a scale of 1-4). Gray plumes rose 200-600 m above the crater rim and drifted E on the next day. White-and-gray plumes rose 200-500 m on 23 January and drifted WSW, and crater incandescence was visible in webcam images. During 24-25 January ash plumes rose 500 m and drifted E and S, and Strombolian activity was visible.

Sarychev Peak – Matua Island (Russia) : KVERT reported that lava began to effuse from a vent in Sarychev Peak’s summit crater 10 January, and by 20 January it had traveled about 400 m down the N flank. A gas-and-steam plume drifted 36 km NE on 12 January. A thermal anomaly was visible during 15 and 18-21 January. The Aviation colour Code remained at Yellow (the second lowest level on a four-colour scale).

Soufriere St. Vincent – St. Vincent : University of the West Indies Seismic Research Centre (UWI-SRC) and National Emergency Management Organisation (NEMO) reported that the lava dome in Soufrière St. Vincent’s main crater continued to grow during 20-26 January. Gas-and-steam plumes were often visible from Belmont Observatory, on Richmond Peak, about 6 km SSW of the crater. Another seismic station and a webcam became operational, and additional instrumentation was prepped. Weather conditions sometimes prevented visual observations of the crater, though observations on 22 and 25 January confirmed that the previously-identified area of burnt vegetation had expanded, including towards the top of the E crater rim. During a monitoring visit on 24 January scientists took video and still photos of the dome and installed both a camera and an EDM reflector on the S crater wall. The Alert Level remained at Orange (the second highest level on a four-colour scale).

Suwanosejima – Ryukyu Islands (Japan) : JMA reported that incandescence at Suwanosejima’s Ontake Crater was occasionally visible at night during 15-22 January. Intermittent explosions produced ash plumes that rose as high as 2.5 km above the crater rim and ejected bombs 400 m away from the crater. Ashfall was reported in Toshima village (4 km SSW). The Alert Level remained at 2 (on a 5-level scale).

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