Volcanos

Roundup of Global Volcanic Activity – New Activity for the Week 13 January 2021 – 19 January 2021

Kilauea – Hawaiian Islands (USA) : HVO reported that low lava fountains from a vent on a cone on the inner NW wall of Kilauea’s Halema`uma`u Crater fed flows that traveled down a channel into a perched lava lake during 13-19 January. The western half of the lake deepened from 198 m to 202 m while the stagnant eastern half remained a few meters lower. The lake was perched 1-2 m above the rim. On 13 January a small portion of the cone collapsed, causing a second vent to open adjacent to the main vent and effuse lava for less than 20 minutes. The islands remained stationary in the E part of the lake; the dimensions of the largest island remained unchanged. The sulfur dioxide emission rate was 4,700 tons/day on 14 January.

Langila – New Britain (Papua New Guinea) : Based on analyses of satellite imagery and wind model data, the Darwin VAAC reported that on 13 January an ash plume from Langila produced an ash plume that rose to 3 km (10,000 ft) a.s.l. and drifted WSW.

Merapi – Central Java (Indonesia) : BPPTKG reported that the “2021 lava dome” continued to emerge just below Merapi’s SW rim during 8-14 January, producing a total of 128 incandescent lava avalanches that traveled as far as 900 m down the Krasak River drainage on the SW flank. A comparison of photos taken on 7 and 14 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 46,766 cubic meters on 14 January, with a growth rate of about 8,500 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 6 cm per day. Seismic activity significantly decreased compared to the previous week. At around 0400 on 16 January a pyroclastic flow descended 1.5 km down the Krasak drainage and produced an ash plume that rose 500 m. A pyroclastic flow was visible in webcam images around 1700 on 16 January, though somewhat obscured due to weather clouds, and traveled an estimated 1 km. From 1800 on 16 January to 0600 on 17 January there were a total of 56 incandescent lava avalanches that went a maximum distance of 1.5 km SW. During the first six hours of 18 January six incandescent avalanches descended 600 m SW. At 0543 a pyroclastic flow traveled about 1 km down the Krasak drainage and produced an ash plume that rose 50 m above the summit and drifted SE. 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.

Pelee – Martinique (France) : L’Observatoire Volcanologique et Sismologique de Martinique (OVSM) reported that seismicity at Pelée remained at significant levels during 8-15 January, though had slightly decreased compared to the previous week. The seismic network recorded at least 22 high-frequency, volcano-tectonic earthquakes with magnitudes less than 1, located at shallow depths between 600 and 1,000 m above sea level. Two low-frequency, long-period earthquakes were also noted. The Alert Level remained at Yellow (the second lowest level on a four-color scale).

Sarychev Peak – Matua Island (Russia) : KVERT reported that a thermal anomaly over Sarychev Peak was identified during 7-10 and 12-13 January. A gas-and-steam plume drifted 40 km NE on 12 January. The Aviation Color Code was raised to Yellow (the second lowest level on a four-color scale) on 10 January.

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 13-19 January. Observations on 14 January revealed that the dome was growing taller as well as expanding to the E and W. During an overflight on 15 January scientists saw extensive vegetation damage on the E, S, and W inner crater walls; damage previously noted along the upper part of the SW crater rim had expanded downslope. The dome dimensions were estimated to be 340 m long, 160 m wide, and 90 m high. Scientists visited the dome on 16 January and collected rock samples from the W part of the dome. They recorded temperatures around 590 degrees Celsius from the expanding dome front. Gas emissions were most notable from a small circular depression at the top of the dome. At night during 15-17 January residents to the W saw incandescence emanating from the crater, a phenomenon likely to be more frequent as the dome grows higher. Gas emissions were visible in the afternoon of 17 January rising from the top of the dome as well as from areas of contact between the new and old domes. An area of burnt vegetation extended from the dome along the W part of the crater floor. By the end of the week both new seismic and continuous GPS monitoring stations had been installed and were transmitting data, bring the total number of dedicated seismic stations to five. The Alert Level remained at Orange (the second highest level on a four-color scale).

Suwanosejima – Ryukyu Islands (Japan) : JMA reported that incandescence at Suwanosejima’s Ontake Crater was visible nightly during 11-15 January. Intermittent explosions produced ash plumes that rose as high as 1.4 km above the crater rim and ejected bombs 400 m away from the crater. The Alert Level was lowered to 2 (on a 5-level scale) on 14 January; JMA noted that no large bombs were ejected more than 1 km from the crater beginning on 29 December 2020.

from WordPress https://ift.tt/3iwj2vM