Roundup of Global Volcanic Activity – New Activity for the week 29 December 2021 – 4 January 2022
Ambae – Vanuatu : The Vanuatu Meteorology and Geo-Hazards Department (VMGD) stated that ash-and-gas plumes from Ambae had recently become more noticeable and that residents had reported minor ashfall on roofs and crops. Webcam images showed ash plumes drifting ENE at 1730 and 1830 on 2 January. At 0600 on 3 January an ash-and-steam plume rose 5 km, though only the lower portion of the plume contained ash. At 0730 that same day an ash plume rose almost 1.6 km. The Alert Level remained at 2 (on a scale of 0-5) and the public was warned to stay outside of the Danger Zone defined as a 2-km radius around the active vents in Lake Voui and away from drainages during heavy rains.
Hunga Tonga-Hunga Ha’apai – Tonga Islands : The eruption at Hunga Tonga-Hunga Ha’apai continued intermittently during 29 December 2021 to 4 January 2022, though by 3 January activity had significantly decreased. Several surges of Surtseyan activity, with some periods lasting as long as 30 minutes, occurred during 28-29 December; gas, steam, and ash plumes rose at least to 12.2 km (40,000 ft) a.s.l. and drifted N, though the maximum altitude of the ash-rich portion of the plume was lower. Ashfall was local to areas around the island. Discolored water and rafts of pumice were visible in areas around the island on 30 December, and had been observed since the beginning of the eruption. Steam-and-gas plumes were visible throughout the day, interspersed with occasional tephra ejections. The plumes rose as high as 12 km (39,400 ft) a.s.l. and drifted NNE. During the morning of 31 December intermittent plumes of ash, steam, and gas rose to 3 km (10,000 ft) a.s.l. according to the Wellington VAAC, though the steam-and-gas portion of the plume rose as high as 18 km (59,000 ft) a.s.l. as stated by the Tonga Meteorological Services. The Met Services also noted that ash was no longer visible in the emissions starting around noon. Steam-and-gas plumes were occasional visible in satellite data during 1-2 January. A small ash plume rose 6-7 km (19,700-23,000 ft) a.s.l. during 2220-2230 on 2 January and drifted 10 m NE, dropping in altitude along the way. A cyclone that passed through the area during 3-4 January obscured views of the volcano.
Karangetang – Siau Island (Indonesia) : PVMBG reported that incandescence from Karangetang’s N crater was periodically visible during 31 December 2021 to 4 January 2022. Bluish-white emissions drifted S on 2 January. White-and-gray plumes rose as high as 200 m during 2-3 January.
Krysuvik-Trolladyngja – Iceland : Icelandic Meteorological Office (IMO) reported that the earthquake swarm at the Krýsuvík-Trölladyngja volcanic system was ongoing with more than 19,000 earthquakes recorded during 21-28 December. Earthquakes M 4 or above totaled 14. The number and size of the earthquakes progressively decreased during 29 December 2021 to 3 January 2022; 200 events were recorded during 0000-1535 on 3 January. The seismicity was located along the same dyke system that fed the recent eruption at Geldingadalir.
Nyiragongo – DR Congo : OVG reported that voluminous gas plumes were visible rising from Nyiragongo and crater incandescence was visible during 3-5 January. Lava fountaining and collapses at active vents on the crater floor were observed along with a growing lava lake. Rumbling was sometimes audible.
Piton de la Fournaise – Reunion Island (France) : OVPF reported that the eruption at Piton de la Fournaise continued during 29 December 2021 to 4 January 2022. Weather clouds often obscured views of the vent, though visual observations were made daily. Low lava fountaining, with material rarely rising just above the crater rim, was visible on 29 December. A small mound with a vent that had grown at the base of the main cone was producing gas emissions, and lava advanced through a tube. Lava fountaining was slightly more intense during 30 December 2021 to 3 January 2022, with lava more frequently rising above the crater rim. Several breakouts of lava from the tube were noted downstream of the vent. The lava effusion rate was an estimated 2.3-9 meters per second, with peak rates of 21 meters per second, based on satellite data. Activity at the main cone decreased during 3-4 January. Lava flows within the first 100 m from the cone were an estimated 15 m thick. The flow field continued to widen but had not significantly lengthened.
Semeru – Eastern Java (Indonesia) : PVMBG reported that the eruption at Semeru continued during 29 December 2021 to 4 January 2022. Crater incandescence was visible during the nights of 31 December-4 January. At 0431 on 31 December a pyroclastic flow was generated from the end of the lava flow and an ash plume that rose 2 km above the summit drifted N. A pyroclastic flow descended the Kobokan drainage a maximum distance of 5 km SE on 1 January. Gray-and-white ash plumes rose as high as 800 m above the summit during 3-4 January and drifted in multiple directions. A pyroclastic flow traveled 5 km SE. The Alert Level remained at 3 (on a scale of 1-4). The public was warned to stay at least 500 m away from Kobokan drainages within 17 km of the summit, and other drainages originating on Semeru including the Bang, Kembar, and Sat, due to lahar, avalanche, and pyroclastic flow hazards.