Volcanos

Roundup of Global Volcanic Activity – New Activity for the Week 17 February 2021 – 23 February 2021

Etna – Sicily (Italy) : INGV reported that a series of paroxysmal events separated by relative calm periods at Etna began on 16 February and continued at least through 23 February. The first episode began late on 16 February, characterized by gradually increasing Strombolian activity at the E vents of the Southeast Crater (SEC). Overflows of lava from the crater at 1805 caused a partial collapse of the cone and a pyroclastic flow that traveled 1.5 km along the W wall of the Valle de Bove. Lava fountains afterwards rose 500-600 m high. An eruptive plume rose several kilometers and drifted S, causing ashfall in areas as far as Syracuse, 60-80 km SSE. Lava flows advanced into the Valle de Bove and the Valle del Leone, and produced explosions in areas where they interacted with snow cover. Activity ended around 1900.

Klyuchevskoy – Central Kamchatka (Russia) : KVERT reported that during 1100-1150 on 18 February a new vent opened on Klyuchevskoy’s lower NW flank, near Erman glacier at elevations of 2,500-2,700 m, based on satellite images. Snowfall in the area of Klyuchi during 18-19 February inhibited webcam views. Bright incandescence was visible in webcam images beginning at 0323 on 21 February, likely indicating an advancing lava flow. On 23 February the Kamchatka Volcanological Station team reported that lava was flowing from two vents and bombs were being ejected 50 m high. A lahar along the Krutenkaya River was visible in an area 7 km E of Klyuchi Village (30 km NNE). Bright incandescence over the two flank vents was identified in satellite and video images on 24 February. KVERT raised the Aviation colour Code to Orange (the second highest level on a four-colour scale).

Krysuvik – Iceland : IMO raised the Aviation colour Code for Krýsuvík to Yellow on 24 February based on recent increased seismicity. Intense seismic activity had been detected for the previous few days and since midnight through the generation of the report at 1107 more than 500 earthquakes had been recorded. At 1005 a M 5.7 earthquake occurred 5 km W of Krýsuvík and at 1027 a M 4.2 was located in Nupshlidarhals, less than 1 km NW of Krýsuvík. The seismic unrest was unusual for the area in the context of the unrest in the Reykjanes peninsula that began in January 2020.

Laguna del Maule – Central Chile-Argentina border : SERNAGEOMIN reported that during 1-16 February the seismic network at Laguna del Maule recorded a total of 533 volcano-tectonic earthquakes. Two earthquake swarms were recorded during 15-16 February; the largest events were local magnitude 3.1, and were located 9.1 and 8.8 km SW of the lake at a depth of 1.9 km. The epicenters were near the area producing anomalous carbon dioxide emissions. Swarms were recorded in June and December 2020, and January and February 2021, with the largest events occurring during the most recent swarm. The highest rate of inflation during the previous 30 days was 2.3 cm/month, recorded at a station closest to the center of deformation. The highest horizontal displacement was an estimated 1.4 cm/month from a station just SW of the center. InSAR data mostly showed agreement in the magnitude and distribution of the ground-based deformation data. Overall, the deformation rates were higher than maximum averages. On 22 February the Alert Level was raised to Yellow, the second lowest level on a four-colour scale. ONEMI declared a Yellow Alert for San Clemente and recommended restricted access within a radius of 2 km from the center of elevated carbon dioxide emissions.

Pacaya – Guatemala : INSIVUMEH reported that seismicity at Pacaya increased around 0900 on 18 February. Incandescent material was ejected 200 m above Mackenney Crater and explosions produced gas-and-ash plumes that rose 450 m and drifted mostly NE and S. An active lava flow on the SSW flank was 1.1 km long and generated hot block avalanches from the flow front. A lava flow emerged on the SW flank on 19 February. During 19-20 February periods of increased activity lasted 3-5 hours; moderate-to-loud explosions were accompanied by rumbling and sounds resembling trains. Ballistics were ejected 300- 500 m from the crater and ash plumes rose as high as 450 m and drifted SW. Ashfall was reported in areas downwind including El Rodeo and El Patrocinio. A lava flow on the S flank was 800 m long and produced incandescent blocks from the flow front that descended 500 m.

Raung – Eastern Java (Indonesia) : PVMBG reported that daily gray and sometimes black ash plumes rose 200-1,200 m above Raung’s summit during 17-23 February. Ash plumes were sometimes dense and drifted mainly N, NE, E, and S. 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.

Sarychev Peak-Matua Island (Russia) : SVERT noted that thermal anomalies over Sarychev Peak were identified in satellite images during 9-10 and 12-14 February. KVERT reported on 19 February that the effusive eruption was over, though lava continued to advance in the summit crater and a thermal anomaly remained visible. KVERT lowered the Aviation colour Code to Green (the lowest level on a four-colour scale).

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