Roundup of Global Volcanic Activity – New Activity for the Week 18 August – 24 August 2021
Chirinkotan – Kuril Islands (Russia) : SVERT and KVERT reported that moderate eruptive activity continued at Chirinkotan during 14-23 August, characterized by explosions and ash plumes that rose to 2.5-4.5 km (4,900-9,800 ft) a.s.l. and drifted as far as 125 km S, E, SE, and SW. At 1110 on 18 August an explosion produced an ash plume, 20 x 27 km in size, that rose to 2-3 km (6,600-9,800 ft) a.s.l. and drifted 7 km NE and as far as 100 km SE. An explosion at 0935 on 23 August rose to 1.5-2.5 km (4,900-8,200 ft) a.s.l. and drifted 8 km SW and later, as far as 126 km W. The Tokyo VAAC reported ash plumes to 2.7-4.9 km (9,000-16,000 ft) a.s.l. that drifted S, NE, and SW during 18 and 23 August. .
Fukutoku-Oka-no-Ba – Volcano Islands (Japan) : The Japan Coast Guard reported that the eruption at Fukutoku-Oka-no-Ba continued during 16-22 August. Gas-and-steam emissions continued to be observed from the center of the island on 16 August. The pumice raft that was first identified on 15 August had expanded to about 100 km to the WNW and was about 13 km wide. Brown discoloration was visible surrounding the new island, which had a variable shape but a consistent diameter of 1 km by 16 August. A local fisherman in the Ogasawara Islands who was fishing in South Iwo Jima (5 km NNE) posted photos and videos on 17, 20, and 22 August that showed strong white gas-and-steam plumes rising above the volcano. On 20 August lightning was visible within the gas-and-steam plume. On 22 August the plume was observed during 0430-0630.
Kilauea – Hawaiian Islands (USA) : HVO reported that a swarm of earthquakes beneath the S part of Kilauea that began at 1630 on 23 August continued into the early morning of 24 August. The earthquake swarm increased in intensity at 0130 and was accompanied by an increase in the rate of ground deformation to the W of the swarm, as recorded by the Sandhill tiltmeter. This possibly indicated that there was magma movement 1-2 km beneath the S part of the caldera. Over 140 earthquakes were recorded during 24 August, the largest of which was an Mw 3.3; a majority of them were less than Mw 1. Small earthquakes continued at a rate of at least 10 earthquakes per hour through 24 August.
Krysuvik-Trolladyngja – Iceland : The fissure eruption in the W part of the Krýsuvík-Trölladyngja volcanic system, close to Fagradalsfjall on the Reykjanes Peninsula, continued during 18-24 August, though weather often obscured the view of the vents. During 18-19 August new lava flows were observed overflowing the SW and NE crater rims and traveling S, E, and SE in the Geldingadalur and Meradalir valleys. Gas-and-steam plumes often accompanied these flows. On 20 August a large collapse from the inner crater rim was observed in video images (Langihryggur camera), generating some ash emissions. Lava flows traveled toward the Nàtthagi valley during 21-24 August, based on webcam data. Video taken during 21-22 August showed some lava fountaining and flows overflowing the sides of the main cone, accompanied by white gas-and-steam emissions.
Pavlof – United States : AVO reported that occasional small explosions and elevated seismicity at Pavlof were detected in geophysical data during 18-19 August; clouds often obscured the view of the volcano. Observations from webcams and pilots indicated minor low-level ash emissions during 18-19 August. Weakly elevated surface temperatures were frequently detected during 18-22 August in the active vent based on satellite and webcam data.
Whakaari/White Island – North Island (New Zealand) : GeoNet maintained the Volcanic Alert Level at 2 and the Aviation Color Code at Yellow for Whakaari/White Island. A volcanic earthquake was recorded at 1900 on 19 August that continued for ten minutes; other seismic activity has been minor. Webcam images showed some incandescence during the night, which suggested that temperatures in the vent area were likely 500-600°C. On 22 August at 0740 a period of minor ash emissions was observed from the active vent area that lasted for two minutes, based on webcam images. Low levels of ground deformation around the active vent and lake area were identified in satellite radar data.