Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the Week 18 August – 24 August 2021

Atka – Andreanof Islands (USA) : AVO reported that small earthquakes and seismic tremors at Atka continued to be detected, though at near background levels during 18-24 August.

Ebeko – Paramushir Island (Russia) : According to volcanologists in Severo-Kurilsk (Paramushir Island), about 7 km E of Ebeko, and the Tokyo VAAC, explosions continued during 14-20 August and produced ash plumes that rose as high as 3 km (10,000 ft) a.s.l and drifted S, SE, E, and NE. Thermal anomalies were detected in satellite imagery on 13 and 14 August. On 25 August an explosion produced an ash plume that rose to 3.7 km (12,000 ft) a.s.l. and drifted 10 km SE.

Fuego – Guatemala : INSIVUMEH reported that 6-13 explosions per hour were recorded during 18-25 August at Fuego, though the weather sometimes prevented visual confirmation. The resulting ash plumes rose to 4.5-4.8 km (14,800-15,700 ft) a.s.l. and drifted as far as 15 km W, SW, S, and NW, causing daily ashfall downwind in Panimaché I and II (8 km SW), Morelia (9 km SW), Santa Sofía (12 km SW), Yucales (12 km SW), El Porvenir (8 km ENE), and Yepocapa (8 km NW). White gas-and-steam plumes rose to 4.5 km (14,764 ft) a.s.l. on 19 and 25 August. Shock waves often rattled buildings around the volcano as far as 15 km from the summit. Block avalanches accompanied the explosions, descending the Santa Teresa, Ceniza (SSW), Taniluyá (SW), Trinidad (S), Seca (W), Las Lajas (SE), and Honda drainages, sometimes reaching vegetated areas. Incandescent ejecta was visible rising 100-400 m above the summit during the nights and early mornings of 20-23 August.

Great Sitkin – Andreanof Islands (USA) : AVO reported that the lava dome at Great Sitkin remained active during 17-24 August; satellite imagery showed changes from a diameter of 800 m on 17 August to 850-860 m throughout 18-21 August. Elevated surface temperatures and daily small earthquakes were consistent with an active dome. Gas-and-steam plumes were visible to local ground observers and in satellite imagery during 20-22 and 24 August.

Ibu – Halmahera (Indonesia) : PVMBG reported that during 18-24 August gray-and-white ash plumes from Ibu rose 200-800 m above the summit and drifted N, W, and NW. On 18 August at 0810 an ash plume rose 800 m above the summit and drifted W. A thermal anomaly was visible in satellite images during 22-23 August, according to the Darwin VAAC.

Kadovar – Papua New Guinea : Based on satellite and wind model data, the Darwin VAAC reported that on 19 August an ash plume from Kadovar rose to an altitude of 1.2 km (4,000 ft) a.s.l. and drifted NW.

Karymsky – Eastern Kamchatka (Russia) : KVERT reported that ash emissions from Karymsky were observed in satellite data during 14-20 August; gas-and-steam plumes containing some ash were also noted. The Tokyo VAAC reported that multiple ash plumes rose to 2.4-3.4 km (8,000-11,000 ft) a.s.l. and drifted SE, SW, S, and E during 17-21 August. On 19 August an explosion produced an ash plume that rose 2-2.5 km (6,600-8,200 ft) a.s.l and drifted 60 km ESE. Ash plumes during 19-20 August rose to 2.4 km (8,000 ft) a.s.l. and drifted E. A thermal anomaly was identified in satellite imagery all week.

Langila – New Britain (Papua New Guinea) : Based on analyses of satellite imagery and wind model data, the Darwin VAAC reported that on 20 August ash plumes from Langila rose to 2.4 km (8,000 ft) a.s.l. and drifted WNW. A thermal anomaly was observed at the summit based on satellite imagery on 20 August.

Lewotolok – Lembata Island (Indonesia) : PVMBG reported that daily white, gray, and sometimes black plumes from Lewotolok rose 50-1,500 m above the summit and drifted SW, NW, and W during 18-24 August. Eruptive activity on 18 and 22 August generated an ash plume that rose 1 and 1.5 km above the summit, respectively, both of which drifted W. Material was ejected as far as 500 m SE on 18 August. On 22 August at 1244 an ash plume was reported 1.5 km above the summit and drifted generally W.

Merapi – Central Java (Indonesia) : BPPTKG reported that both the lava dome just below Merapi’s SW rim and the lava dome in the summit crater remained active during 13-19 August. Webcam images showed some changes in the SW dome due to lava avalanches and pyroclastic flows; there were no significant changes in the central dome. The volume of the SW lava dome was 1.35 million cubic meters. During 13-19 August a total of 20 pyroclastic flows were observed descending the SW flank as far as 3.5 km. Lava avalanches were observed 172 times to the SW, traveling up to 2 km. BNPB noted that ashfall was reported in several areas on 16 August, including Dukun, Sawangan, Tegalrejo, Secang, Gowok, Mertoyudan, Selo, Mojotengah, Temanggung, Kedu, Pringsurat, Bulu, Tlogomulyo, Kranggan, and Parakan. PVMBG reported that during 18-19 and 23-24 August white plumes rose 20-200 m above the crater and drifted in different directions. As many as 331 lava avalanches traveled a maximum distance of 1.5 km SW. Two pyroclastic flows moved as far as 2 km, though the direction was not observed.

Pacaya – Guatemala : INSIVUMEH reported that white-to-blue gas-and-steam emissions rose as high as 600 m above Pacaya’s Mackenney crater and drifted as far as 2 km S, SW, and N during 18-25 August. Seismic stations recorded some weak explosion and degassing events on 18 August.

Reventador – Ecuador : IG reported that several ash emissions from Reventador during 18-24 August rose 500-1,400 m above the summit and drifted NW, W, SW, and S; sometimes weather conditions prevented visual confirmation. Seismicity was characterized by daily explosions, harmonic tremor, long-period earthquakes, and signals that indicated emissions. The Washington VAAC reported gas-and-steam and ash plumes to 1.4 km above the summit that drifted W, NW, and SW, often observed multiple times per day in satellite imagery or webcams. Nighttime crater incandescence was frequently observed, accompanied by incandescent blocks rolling down the NE, E, and S flanks as far as 600 m. A lava flow was reported traveling down the NE flank during 17-18 August.

Sangay – Ecuador : IG reported gas-and-ash emissions from Sangay rising 500-1,500 m above the summit that drifted W and SW during 19-20 and 24 August. During 20-23 August gas-and-steam plume rose 1-2 km above the summit and drifted W, SW, and NW. Weather clouds and rain sometimes prevented visual and webcam observations of the volcano. Ash plumes were identified in satellite images by the Washington VAAC, rising 570-1,500 m above the volcano and drifting W and SW during 19-21 and 23-24 August. During the evening on 19 August explosions accompanied by incandescent blocks were reported around 1852 rolling down the SE drainage. Signals indicating lahars were recorded by the seismic network during 18-19 and 22-23 August.

Santa Maria – Guatemala : INSIVUMEH reported that daily ash plumes from Santa Maria’s Santiaguito lava-dome complex during 18-25 August rose to 2.8-3.5 km (9,200-11,500 ft) a.s.l. and drifted as far as 8 km W and SW. Ashfall was reported in San Marcos (8 km SW), Loma Linda Palajunoj (6 km WSW), and surrounding farms on 24 August. An active lava flow 600 m long extended down the W and S flanks of the dome during 18-24 August. Collapses of blocky lava from the Caliente dome generated block-and-ash avalanches down the W, S, and SW flanks, often reaching the base and causing minor ashfall on the flanks. Weak explosions accompanied these avalanches on 21 August and generated abundant gas-and-steam emissions. Nighttime incandescence was often observed from the lava flow and dome.

Semeru – Eastern Java (Indonesia) : PVMBG reported that a vertical gray-and-white plume from Semeru rose 400-500 m above the summit and drifted SW on 19 August. This eruption continued during 20-24 August, but the height of the plume was not observed due to cloud cover.

Semisopochnoi – Aleutian Islands (USA) : AVO reported that multiple explosions and seismicity at Semisopochnoi’s North Cerberus crater continued during 18-24 August. Low-level gas-and-ash emissions, including occasional sulfur dioxide emissions were detected in satellite and webcam data during 18-24 August and rose no higher than 3 km (10,000 ft) a.s.l.; views were often obscured due to weather. On 20 August minor ashfall deposits were reported; ashfall may have continued following explosive events during the rest of the week.

Sheveluch – Central Kamchatka (Russia) : KVERT reported that the growth of the lava dome at Sheveluch continued during 14-24 August, accompanied by strong fumarolic activity, dome incandescence, and hot avalanches. A thermal anomaly was identified in satellite imagery all week. Gas-and-steam plumes containing some ash drifted 370 km SW, E, and SE. On 21 and 24 August ash plumes rose to 4 km (13,100 ft) a.s.l. and drifted 86 km SE and 3.5 km (11,500 ft) a.s.l. and drifted as far as 100 km SE, respectively. The Tokyo VAAC reported ash plumes during 17-25 August that rose to 3.7-5.5 km (12,000-18,000 ft) a.s.l. and drifted E, S, SE.

Suwanosejima – Ryukyu Islands (Japan) : JMA reported that explosions at Suwanosejima’s Ontake crater were detected on 19, 20, and 21 August. The first explosion at 0137 on 19 August produced an ash plume that rose 3 km above the crater and drifted NE, followed by another at 1613 that generated an ash plume 2.2 km above the crater and drifted N. A small amount of ashfall was reported in Yakushima, Nishinoomote, and Nakatane. A third explosion at 2059 that day produced an ash plume that rose 2.5 km above the crater and drifted N; ashfall was reported in Toshima village (4 km SSW). Explosions at 0628 and 0713 on 20 August generated ash plumes that rose 2.5-3 km above the crater and drifted N, resulting in ashfall in Toshima village, with smaller amounts of ash in Yakushima, Mishima, Ibusuki, Minamikyushu, and Makurazaki. On 21 August at 0617 an explosion generated an ash plume that rose 3.2 km above the crater and drifted N. A large amount of ashfall (over 1 mm) was reported in Toshima village and smaller amounts (less than 0.1 mm) were reported in Makurazaki, Minamisatsuma, Minamikyushu, Kagoshima, Ibusuki, and Hioki. A second explosion followed at 0906 that produced an ash plume 3.2 km above the crater that drifted N. The Tokyo VAAC reported ash plumes to 1.5-3.9 km (5,000-13,000 ft) altitude that drifted NE during 18-25 August.

Taal – Luzon (Philippines) : PHIVOLCS reported that gas-and-steam plumes from Taal rose 1-3 km and sulfur dioxide emissions peaked at 15,347 tonnes/day on 19 August and declined to an average of 8,351 tonnes/day during 13-19 August.

Tengger Caldera – Eastern Java (Indonesia) : PVMBG reported that during 18-24 August white gas-and-steam plumes rose 50-400 m above Tengger Caldera’s Bromo cone and drifted SW, W, and NW. A weak thermal anomaly was visible in Sentinel-2 infrared satellite images on 23 August.

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