Roundup of Global Volcanic Activity – Ongoing Activity for the Week 1 September – 7 September 2021
Ebeko – Paramushir Island (Russia) : According to volcanologists in Severo-Kurilsk (Paramushir Island), about 7 km E of Ebeko, explosions during 28-29 August produced ash plumes that rose as high as 1.9 km (6,200 ft) a.s.l. and drifted SE and E.
Fuego – Guatemala : INSIVUMEH reported that 7-15 explosions per hour were recorded during 31 August-7 September at Fuego, generating ash plumes as high as 1.1 km above the crater rim and shock waves that often rattled buildings around the volcano. Ash plumes mostly drifted as far as 15 km SW, W, NW, and N, causing daily ashfall in several areas downwind, including Morelia (9 km SW), Panimaché I and II (8 km SW), Santa Sofía (12 km SW), Yucales (12 km SW), El Porvenir (8 km ENE), Finca Palo Verde, Sangre de Cristo (8 km WSW), and San Pedro Yepocapa (8 km NW). Block avalanches descended the Ceniza (SSW), Seca (W), Trinidad (S), Taniluyá (SW), Las Lajas (SE), and Honda drainages, often reaching vegetated areas. Explosions ejected incandescent material 100-350 m above the summit on most days. On 1 September lahars descended the SE, S, and SW flanks (the Las Lajas, El Jute, and Seca drainages), carrying fine material along with tree branches and blocks 2 m in diameter. Lahars descended the El Jute, Las Lajas, and Ceniza drainages during 6-7 September.
Great Sitkin – Andreanof Islands (USA) : AVO reported that elevated surface temperatures at Great Sitkin and daily small earthquakes were detected during 31 August-7 September, consistent with the growing lava dome. Gas plumes were observed almost daily in satellite data.
Grimsvotn – Iceland : On 1 September the Icelandic Meteorological Office (IMO) stated that the water level of the Skaftá river at Sveinstindur (the closest gauging station at 28 km downstream from the ice margin) rose, suggesting the beginning of a Skaftárhlaup or glacial outburst flood (also called a jökulhlaup), that originated from Grímsvötn’s Western Skaftá caldera. A sulfur odor was also noted in the vicinity of Skaftá and Hverfisfljót. IMO warned that hydrogen sulfide released from the floodwater as it drained from the caldera lake was particularly potent at the river outlet from the ice margin, where concentrations may reach toxic levels. The flow rate in the Skaftá peaked at 520 cubic meters per second downstream near the bridge at Eldvatn on 2 September and then declined to 412 cubic meters per second in the afternoon of 3 September. As a result, the ice shelf began to subside around 2300 on 4 September, dropping 1 m by 1145 the next morning, based on GPS data. On 6 September the discharge rate increased rapidly and peaked at 610 cubic meters per second at 1400, then declined later that day. Data suggested that the peak discharge rate on 6 September was due to a second release of water from the eastern part of the caldera lake. On 7 September the flow rate had increased to 520 cubic meters per second. Based on an overflight IMO concluded that the glacial flooding from both the E and W parts of the lake was smaller in volume and flow rates compared to a similar event in 2018.
Karymsky – Eastern Kamchatka (Russia) : KVERT reported that ash plumes from Karymsky were visible in satellite images drifting 50 km NE and E during 26-27 August, and a thermal anomaly over the volcano was visible every day during 26 August -2 September except for on 29 August.
Krysuvik-Trolladyngja – Iceland : The fissure eruption in the W part of the Krýsuvík-Trölladyngja volcanic system, close to Fagradalsfjall on the Reykjanes Peninsula, paused on 2 September. Steam-and-gas emissions were seen rising from the crater during 2-7 September.
Lewotolok – Lembata Island (Indonesia) : PVMBG reported that the eruption at Lewotolok continued during 31 August-7 September. White and gray plumes rose as high as 600 m above the summit and drifted W and NW. Rumbling and banging were heard on most days. Incandescent material was ejected 300 m on 1 September, as far as 1 km SE during 4-5 September, and 200 m during 6-7 September.
Merapi – Central Java (Indonesia) : BPPTKG reported that both of Merapi’s two lava domes, situated just below the SW rim and in the summit crater, continued to grow during 27 August-2 September. The SW dome grew 2 m taller and had an estimated volume of 1.44 million cubic meters and the summit lava dome grew 1 m taller and had an estimated volume of 2.84 million cubic meters. A total of six pyroclastic flows descended the SW flank as far as 2.5 km; as many as 80 lava avalanches traveled a maximum of 2 km SW.
Popocatepetl – Mexico : CENAPRED reported that each day during 31 August-7 September there were 66-102 steam-and-gas emissions from Popocatépetl. Cloudy weather often prevented views of the volcano. Crater incandescence was visible during the morning of 1 September and explosions were recorded at 2135, 2254, and 2345 later that same day. The Washington VAAC noted that ash plumes rose to 5.8-6.1 km (19,000-20,000 ft) a.s.l. and drifted NW and W during 5-6 September based on satellite and webcam views. Explosions were recorded by CENAPRED at 1642 on 5 September and 0820 on 6 September. Emissions had a low ash content during 6-7 September; explosions occurred at 0212 and 0414 on 7 September.
Semeru – Eastern Java (Indonesia) : PVMBG reported that at 0544 on 2 September an observer saw an ash plume from Semeru rising 200 m above the summit and drifting SW. At 0549 on 6 September an ash plume rose 500 m and drifted N.
Semisopochnoi – Aleutian Islands (USA) : AVO reported that eruptive activity at Semisopochnoi’s North Cerberus crater continued during 31 August-7 September. Multiple daily explosions were detected by seismic and infrasound networks. Ash-and-steam plumes from the explosions were sometimes confirmed in satellite and webcam images rising to altitudes lower than 3 km (10,000 ft) a.s.l., though during 6-7 September ash plumes rose as high as 4.6 km (15,000 ft) a.s.l. Local ashfall on the island was visible in satellite data. Sulfur dioxide emissions were detected in satellite images during 31 August-2 September and on 6 September.
Sheveluch – Central Kamchatka (Russia) : KVERT reported that a thermal anomaly over Sheveluch was identified in satellite images during 27 August-3 September. A gas-and-steam plume with some ash was visible in satellite data drifting 54 km NE and NW on 26 and 28 August.
Suwanosejima – Ryukyu Islands (Japan) : JMA reported that three explosions at Suwanosejima’s Ontake Crater produced eruption plumes that rose as high as 4.8 km above the crater rim during 27 August-3 September. Large volcanic bombs were ejected 700 m from the crater. Crater incandescence was visible nightly and ashfall was often reported in Toshima village (4 km SSW).
Telica – Nicaragua : INETER reported that at 0525 on 1 September an explosion at Telica produced an ash plume that rose 250 m above the crater rim and drifted N and NW. Emissions periodically continued later that day, without explosions, and caused minor ashfall in areas to the NW, W, and SW including in the communities of Aguas Frías, San Pedro Nuevo, and Las Marías (7 km NNW).