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.

The ninth episode began at the SEC as weak Strombolian at 0120 on 4 March. Ash emissions were visible at 0200 but dispersed quickly. Strombolian activity at Voragine (VOR) was also visible with ejected material rising above the crater rim. Lava fountaining began at SEC at 0320, but by 0515 the activity had decreased. Lava flows that advanced towards the Valle de Bove were fed by spattering and a new vent that opened at the E base of the SEC. Strombolian activity at VOR changed to 300-m-tall lava fountaining at 0850. Ash plumes rose 11 km above the summit and caused lapilli to fall in Fiumefreddo (19 km ENE), Linguaglossa (17 km NE), and the area of Reggio Calabria.

The tenth episode began with Strombolian explosions at SEC and minor lava effusion at the new vent at the E base of SEC during the first hour on 7 March. Strombolian activity intensified at 0430; an eruption plume rose 5 km above the summit and drifted E. Lava overflowed the SEC onto the E flank and expanded into the Valle de Bove, reaching an elevation of 2,800 m by 0450. Strombolian activity again intensified beginning at 0520 and the lava flow advanced to 2,700 m elevation. Lava fountaining started at 0720 and ended at 0810. An eruption plume rose 10 km and drifted E. Ash and lapilli fell in Milo (11 km ESE), Fornazzo (10 km ESE), Trepunti (17 km ESE), Giarre (17 km ESE), Macchia di Giarre (16 km ESE), Mascali (18 km E), Riposto (19 km ESE), and Torre Archirafi (20 km ESE). Strombolian activity resumed at 1050 and was over by 1500.

Strombolian activity at SEC returned at 1914 on 9 March. Lava overflowed the crater at 2013 and advanced towards the Valle de Bove. Strombolian activity increased at 2100 and ash emissions drifted NE. The lava flow reached 2,900 m elevation.

Source: Sezione di Catania - Osservatorio Etneo (INGV)

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.

Source: Icelandic Meteorological Office (IMO)

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).

Sources: Kamchatkan Volcanic Eruption Response Team (KVERT), Kamchatka Volcanological Station

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.

Sources: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH), Coordinadora Nacional para la Reducción de Desastres (CONRED)

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.

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)

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.

Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM), Darwin Volcanic Ash Advisory Centre (VAAC)

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).

Over the past month minor deformation centered at a source beneath the SE part of TVI was evident in monitoring data, including integrated real-time ground tilt and continuous GPS, daily Electronic Distance Measurement (EDM) monitoring, and InSAR. The data also showed slow and steady inflation across the Taal region after the 2020 eruption. Geochemical data collected from Taal’s Main Crater lake indicated a continuous acidification of the water from pH 2.79 to 1.59 between January 2020 and mid-February 2021. Microgravity data was consistent with magma migration. PHIVOLCS strongly recommended no entry onto the island, and access to the Main Crater and Daang Kastila fissure (along the walking trail) was strictly prohibited.

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)

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.

On 7 March satellite images revealed that the emissions originated from a small cone in the summit caldera. Additionally, lava was likely effusing under the intra-caldera glacier in an area on the flank about 1 km E of the cone’s summit. This area produced incandescence and strongly elevated surface temperatures, as well as a small steam plume and meltwater. During 8-9 March satellite images showed a small, steam-rich plume drifting about 10 km NE at 4.6 km (15,000 ft) a.s.l.

Source: US Geological Survey Alaska Volcano Observatory (AVO)