Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the Week 25 August – 31 August 2021

Dukono – Halmahera (Indonesia) : The Darwin VAAC reported that during 24 and 26-27 August white-and-gray ash plumes from Dukono rose 2.3 km (7,000 ft) a.s.l. and drifted W, SW, and S.

Ebeko – Paramushir Island (Russia) : According to volcanologists in Severo-Kurilsk (Paramushir Island), about 7 km E of Ebeko, explosions during 20-21 and 24-25 August produced ash plumes that rose as high as 4.6 km (15,100 ft) a.s.l. and drifted SE. A thermal anomaly was identified in satellite images during 20 and 23-25 August.

Etna – Sicily (Italy) : INGV reported that activity at Etna was concentrated at the Southeast Crater (SEC) during 23-29 August. Gas emissions rose from Bocca Nuova crater. A series of explosions at SEC that began at 1530 on 27 August and continued through the next morning produced ash puffs. Strombolian activity began in the early afternoon of 29 August and within an hour, lava fountains were visible rising up to 400 m above the vent. Ash emissions rose a few hundred meters. The activity varied in intensity and during intense periods, ash plumes rose up to 10 km above the summit. Ash and lapilli fell in areas to the E, including in Fornazzo, Milo, San Alfio, and Giarre. Lava flows from the SEC traveled SW and one from the E base traveled E toward the Valle del Bove.

Great Sitkin – Andreanof Islands (USA) : AVO reported that the lava dome at Great Sitkin continued to grow, reaching 880 m in diameter by 25 August and 1,090 m during 28-29 August. Elevated surface temperatures and small earthquakes were detected during 25-31 August, consistent with the growing dome.

Kadovar – Papua New Guinea : Based on satellite and wind model data, the Darwin VAAC reported that on 27 and 30 August ash plumes from Kadovar rose to altitudes of 1.2-1.5 km (4,000-5,000 ft) a.s.l. and drifted W and WNW.

Karymsky – Eastern Kamchatka (Russia) : KVERT reported that during 20-27 August daily gas-and-ash plumes from Karymsky were identified in satellite images drifting 94 km NE, E, and SE. Daily thermal anomalies were also visible. The Tokyo VAAC noted that during 25-27 August ash plumes rose to 3-4.6 (10,000-14,000 ft) a.s.l. and drifted E and NE.

Katmai – United States : AVO reported that on 28 August strong winds in the vicinity of Katmai and the Valley of Ten Thousand Smokes picked up unconsolidated ash and drifted SE towards Kodiak Island at an altitude up to 1.8 km (6,000 ft) a.s.l. The ash was originally deposited during the Novarupta eruption in 1912.

Lewotolok – Lembata Island (Indonesia) : PVMBG reported that the eruption at Lewotolok continued during 25-30 August. White, gray, and sometimes black plumes rose as high as 1.2 km above the summit and drifted W and NW.

Merapi – Central Java (Indonesia) : BPPTKG reported that of Merapi’s two lava domes, the dome just below the SW rim was more active than the dome in the summit crater during 20-26 August. The SW dome grew and shed material down the flanks, increasing in height by just 3 m overall. On 25 August the volume of the SW dome was estimated at 1.4 million cubic meters and the summit lava dome was stable at an estimated 2.831 million cubic meters. A total of two pyroclastic flows descended the SW flank as far as 2 km; as many as 211 lava avalanches traveled a maximum of 2 km SW. Based on satellite images the Darwin VAAC noted that during 28-29 August ash plumes rose to 3-3.7 km (10,000-12,000 ft) a.s.l. and drifted SW, W, and NW.

Nevado del Ruiz – Colombia : Servicio Geológico Colombiano’s (SGC) Observatorio Vulcanológico y Sismológico de Manizales reported that during 25-31 August seismicity at Nevado del Ruiz had generally decreased compared to the previous week. Deformation data indicated minor changes. Gas-and-steam emissions were sometimes visible in satellite data and webcam images rising as high as 1.2 km above the summit and drifting NW and W. These emissions sometimes contained ash; on 26 August an ash emission rose 490 m and drifted WNW.

Rincon de la Vieja – Costa Rica : OVSICORI-UNA reported that small eruptive events at Rincón de la Vieja were recorded at 1915, 2049, and 2053 on 26 August, though weather conditions prevented visual confirmation of emissions. A one-minute-long phreatic eruption was recorded at 1446 on 27 or 28 August and produced an eruption plume that rose 1 km above the crater rim.

Sabancaya – Peru : Instituto Geofísico del Perú (IGP) reported a daily average of 36 explosions at Sabancaya during 23-30 August. Gas-and-ash plumes rose as high as 3.5 km above the summit and drifted S, SW, N, and NE. Ten thermal anomalies originating from the lava dome in the summit crater were identified in satellite data. Minor inflation continued to be detected near Hualca Hualca (4 km N).

Semeru – Eastern Java (Indonesia) : PVMBG reported that at 0718 on 26 August an ash plume from Semeru rose 500 m above the summit and drifted SW.

Sheveluch – Central Kamchatka (Russia) : KVERT reported that the lava dome at Sheveluch continued to grow and produced hot lava avalanches during 20-27 August. A daily bright thermal anomaly was identified in satellite images and gas-and-steam plumes containing some ash drifted 307 km NE, E, and SE. At 1100 on 29 August an ash plume 14×15 km in dimension drifted 30 km W at altitudes of 2.5-3 km (8,200-10,000 ft) a.s.l. On 28 August the Kamchatka Branch of Geophysical Services (KBGS; Russian Academy of Sciences) posted photos of the incandescent dome and avalanches, noting that small landslides and hot avalanches periodically traveled down the S and SE flanks of the dome. Larger landslides were observed 2-4 times per night.

Sinabung – Indonesia : PVMBG reported that on most days during 25-31 August white gas-and-steam plumes from Sinabung rose as high as 500 m above the summit and drifted in multiple directions. Lava avalanches traveled 700 m down the flanks on 25 August.

Stromboli – Aeolian Islands (Italy) : INGV reported that during 23-29 August activity at Stromboli was characterized by ongoing explosive activity from three vents in Area N (North Crater area) and six vents in Area C-S (South-Central Crater area). Explosions from the N1 vent (Area N) ejected lapilli and bombs 80 m high, and produced minor ash emissions. Explosions at N2 vents (Area N) averaged 4-5 events per hour and ejected material 80 m high. Explosions from the S1 and S2 vents in Area C-S were sporadic and occurred at a rate of 5-12 per hour; coarse material was ejected 120 m high. Gas emissions rose from the C vent.

Suwanosejima – Ryukyu Islands (Japan) : JMA reported that 15 explosions at Suwanosejima’s Ontake Crater produced eruption plumes that rose as high as 3.2 km above the crater rim during 20-27 August. Large volcanic bombs were ejected 300 m from the crater. Crater incandescence was visible nightly and ashfall was often reported in Toshima village (4 km SSW); a large amount of ash fell in the village on 26 August. At 1231 on 28 August an eruption produced an ash plume that rose 4.8 km above the crater.

Yasur – Vanuatu : On 26 August the Vanuatu Meteorology and Geo-Hazards Department (VMGD) reported that seismic data and recent visual observations at confirmed ongoing explosions and gas-and-ash emissions. The Alert Level remained at 2 (on a scale of 0-4).

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