Volcanos

Roundup of Global Volcanic Activity – New Activity for the Week 6 January 2021 – 12 January 2021

Kilauea – Hawaiian Islands (USA) : HVO reported that lava effusion from vents on a cone on the inner NW wall of Kilauea’s Halema`uma`u Crater continued to feed a growing perched lava lake during 6-12 January. Lava flowed through a crusted channel into the lake during most of the week. A dome fountain of upwelled lava at the partially submerged inlet was 5 m tall early on 6 January. Dome fountaining had weakened early on 7 January, giving way to spattering at the top of the vent and the formation of a second cone. Dome fountaining was possibly visible again on 8 January. The lake was perched at least 1-2 m above its narrow edges, though late on 10 January the stagnant, eastern part of the lake had subsided and was 3-4 m shallower. Overall the lake had deepened just 2 m by 11 January, reaching 196 m, and the lake volume was estimated at more than 27 million cubic meters. An island of cooler, solidified lava and the 11 smaller islands were relatively stationary in the E part of the lake. The dimensions of the largest island remained unchanged (250 m long and 135 m wide), though on 8 January the W end was 9 m above the lake’s surface and the high point was 23 m above the lake, suggesting that the island was rising. Sulfur dioxide emissions were 2,700 and 2,300 tonnes/day on 7 and 10 January, respectively.

Langila – New Britain (Papua New Guinea) : Based on analyses of satellite imagery and wind model data, the Darwin VAAC reported that on 9 January a short-lived eruption at Langila produced an ash plume that rose 4.9 km (16,000 ft) a.s.l. and drifted W.

Merapi – Central Java (Indonesia) : BPPTKG reported that a new lava dome, first observed on 4 January, continued to emerge just below Merapi’s SW rim during 5-12 January. Incandescent avalanches were observed 19 times during 4-7 January with material traveling as far as 800 m down the Krasak River drainage on the SW flank. At 0802 on 7 January a block-and-ash flow traveled down the upper part of the Krasak; the total distance was not observable due to weather clouds, though the seismic data suggested it was small and was not more than 1 km in length. The event also produced a 200-m-high ash plume. Similar events were recorded that same day at 1250, 1315, and 1402. Deformation continued; electronic Distance Measurement (EDM) data continued to measure a distance shortening between points in the NW at a rate of 15 cm per day. On 7 January BNPB noted that 1,342 residents were housed in evacuation centers. 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.

Martinique (France) – L’Observatoire Volcanologique et Sismologique de Martinique (OVSM) reported that seismicity related to volcanism has typically remained low at Pelée since 1980, when monitoring instrumentation was first installed, with a few dozen earthquakes recorded per year. Swarms were recorded in 1980, 1985-1986, 2007, and 2014, though the latter two swarms were associated with tectonic events. Volcanic seismicity appeared in April 2019 centered 4-5 km below the summit and deeper (more than 10 km below sea level). In addition, tremor-type signals were recorded during 8-9 November 2020, possibly signifying a reactivation of the hydrothermal system. The seismic data recorded since April 2019 represented an increase above baseline levels recorded during 1 January 2015 to April 2019. As a result of this activity OVSM raised the Alert Level to Yellow (the second lowest level on a four-color scale) on 4 December 2020. Seismicity remained above background levels during 18 December 2020-1 January 2021, with at least 14 volcano-tectonic earthquakes detected with magnitudes less than or equal to 1. Scientists did not observe fumarolic activity during an overflight on 29 December 2020. The number of high-frequency, volcano-tectonic earthquakes (M 1 or less) totaled 65 during 1-8 January. A significant number (249) of long-period earthquakes in a volcanic tremor-type signal were distributed over two periods, 0000-0200 on 3 January and between 2100 on 3 January and 0200 on 4 January. Two isolated, low-frequency, long-period signals were also recorded. The data suggested ongoing perturbation of the hydrothermal system.

Sarychev Peak – Matua Island (Russia) : KVERT raised the Aviation Color Code to Yellow (the second lowest level on a four-color scale) for Sarychev Peak on 10 January, noting that the temperature of a thermal anomaly was 79.8 degrees Celsius above background temperatures, possibly indicating lava in the crater.

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 that first formed on 27 December continued to grow during 6-12 January. Observations were made during a field visit on 5 January, during a helicopter overflight on 6 January, and based on 9 January drone video. During that time the dome grew and expanded to the W, produced small, hot rockfalls, had a blocky appearance, and continued to emit gasses and steam. Gas-and-steam plumes were also visible from Belmont Observatory. 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 4-11 January. Two explosions on 5 January produced ash plumes that rose 1.2 km above the crater rim and ejected bombs 400 m away from the crater. Two explosions during 9-10 January generated ash plumes that rose 1 km and again ejected bombs 400 m away. The Alert Level remained at 3 (on a 5-level scale).

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