Volcanos

Roundup of Global Volcanic Activity – New Activity for the Week 3 March 2021 – 9 March 2021

Etna – Sicily (Italy) : INGV reported continuing episodes of lava fountaining at Etna’s Southeast Crater (SEC) on 2, 4, and 7 March. Weak Strombolian activity began at SEC at 1145 on 2 March, then intensified at 1234 and produced an ash plume. Lava fountaining began at 1324. Ash plumes rose to 9 km above the summit and drifted S, causing lapilli to fall in Nicolosi (16 km S), Aci San Antonio (18 km SE), Pedara (15 km SSE), and Catania (29 km SSE). Lava fountaining ceased at 1550, ending the eighth episode.

Krysuvik – Iceland : IMO reported that seismicity in the area between the Krýsuvík and Reykjanes-Svartsengi volcanic systems remained elevated during 4-10 March. GPS and InSAR data indicated that the intrusion was ongoing, with magma moving slowly SW along a fault between Keilir and Fagradalsfjall at depths of 2-6 km. Seismicity fluctuated during 6-7 March but continued to be elevated; the largest event was a M 5.1 on 7 March. The geophysical and satellite data on 8 March suggested that magma movement had decelerated over the past week, and was possibly as shallow as 1 km. A burst of seismicity was recorded around 0520 on 9 March, concentrated at the S end of the intrusion in an area that was most likely source of the magma. On 10 March IMO stated that more than 34,000 earthquakes had been detected during the past two weeks, a total larger than all of 2020 which was characterized as an unusually high year for seismicity. The Aviation Color Code for Krýsuvík remained at Orange.

Pacaya – Guatemala : INSIVUMEH and CONRED reported that during 2-6 March strong Strombolian explosions at Pacaya’s Mackenney Crater produced ash plumes that rose as high as 1 km above the summit and drifted W, SW, and S. Tephra fell in areas downwind including El Patrocinio (5 km W), El Rodeo (4 km WSW), San Francisco de Sales (5 km N), El Cedro (9 km NNW), Calderas (3 km N), and Las Jazmines (5 km W), and in the municipalities of Palín (10 km WNW) and Escuintla (22 km SW). Periods of lava fountaining were visible, and incandescent material was ejected 300-1,000 m high. Three lava flows were active and all had several branches; one traveled SSW, one traveled S, and one on the SE flank was 800-1,200 m long. During 6-8 March strong explosions ejected material as high as 500 m and produced dense ash plumes that rose up to 1 km. Lava flows continued to be active, sometimes producing block avalanches from the ends. On 8 March the S-flank flow was about 850 m long and continued to generated block avalanches. Strong explosions during 8-9 March ejected ballistics 300-500 m away from the crater. Dense ash plumes rose up to 1.5 km and drifted 30 km SW and S. The lava flow on the S flank was 900 m long and shed blocks from the end.

Pinatubo – Luzon (Philippines) : PHIVOLCS raised the Alert Level for Pinatubo to 1 (on a scale of 0-5) on 4 March noting elevated seismicity with a total of 1,722 earthquakes recorded in two swarms since 20 January. The first swarm was recorded during 20-26 January and was comprised of local M 1-2.5 events that occurred along the Sacobia Lineament fault at depths of 15-28 km. A more persistent swarm followed; it was comprised of local M 0.5-2.8 events at depths of 10-35 km along another fault system, with a few shallower earthquakes occurring at both ends of the swarm. Carbon dioxide flux at Pinatubo Crater lake was 378 tonnes per day in February, within background ranges that topped 1,000 tonnes per day during the last decade. Minor temperature increases were recorded at fumarolic vents.

Sinabung – Indonesia : PVMBG reported that the eruption at Sinabung continued during 3-9 March. According to the Darwin VAAC an ash plume was identified in satellite images rising to 3 km (10,000 ft) a.s.l. (or 600 m above the summit) and drifting NW on 5 March. The observatory noted that avalanches of material traveled 500 m down the SE flank during 6-7 March, and an ash plume rose 1 km and drifted NW at 1910 on 7 March. The Alert Level remained at 3 (on a scale of 1-4), with a general exclusion zone of 3 km and extensions to 5 km in the SE sector and 4 km in the NE sector.

Taal – Luzon (Philippines) : PHIVOLCS raised the Alert Level for Taal to 2 (on a scale of 0-5) on 9 March based on increased activity recorded since 13 February. During 8-9 March the seismic network recorded a total of 28 volcanic tremor events, four low-frequency volcanic earthquakes, and one hybrid event at depths of less than 1.5 km. These events added to the totals of 866 volcanic tremor events and 141 low-frequency volcanic earthquakes recorded during 13 February-9 March. Overall, seismicity over the past month indicated increased magmatic and hydrothermal activity at shallow depths beneath Taal Volcano Island (TVI).

Klyuchevskoy – Central Kamchatka (Russia) : KVERT reported that the eruption from vents on Klyuchevskoy’s lower NW flank continued during 26 February-5 March. A large, bright thermal anomaly over the vents was identified daily in satellite images. IVS FEB RAS volcanologists visited the field site on 2 March during good weather conditions. They estimated that the cinder cone was 54 m high and 101 m wide at the base. Lava effused from the cone and traveled downslope, melting ice and snow that formed muddy streams. The Aviation Color Code remained at Orange (the second highest level on a four-color scale).

Veniaminof – United States : AVO reported that elevated sulfur dioxide gas emissions at Veniaminof were first detected on 1 March and elevated surface temperatures were identified in satellite images sometime during 2-3 March. At 0513 on 4 March infrasound sensors recorded a small explosion, prompting AVO to raise the Volcano Alert Level to Watch and the Aviation Color Code to Orange. A low-level ash plume, to less than 3 km (10,000 ft) a.s.l., was visible in satellite and webcam images drifting SSE and minor ash deposits around the volcano were visible. Small emissions continued at least through 1048 that day. Sulfur dioxide emissions were visible in a webcam image on 5 March. Numerous small explosions were recorded during 6-7 March; some of them were heard and felt by residents in Perryville (35 km SE). Elevated surface temperatures were identified in satellite images, suggesting lava near or at the surface. During times of clear weather low-level gas-and-ash plumes were visible in satellite and webcam data and observed by pilots. The plumes mainly stayed below 3 km (10,000 ft) a.s.l., but at times went as high as 4.6 km (15,000 ft) a.s.l., and drifted 150 km NE.

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