Roundup of Global Volcanic Activity – Ongoing Activity for the week 22 December – 28 December 2021
Aira – Kyushu (Japan) : JMA reported that incandescence from Minamidake Crater (at Aira Caldera’s Sakurajima volcano) was visible at night during 20-27 December. The sulfur dioxide emission rate was 600 tons per day on 20 December. Two eruptive events during 20-24 December produced plumes that rose 1.1 km above the crater rim. Very small eruptive events were detected during 24-27 December.
Great Sitkin – Andreanof Islands (USA) : AVO reported that slow lava effusion at Great Sitkin continued during 21-28 December with advancing lava flows on the N, W, and S flanks. Very low seismicity persisted. Elevated surface temperatures at the summit were detected overnight during 21-24 and 26-27 December; weather clouds prevented observations during 25-26 December.
Karymsky – Eastern Kamchatka (Russia) : KVERT reported that a thermal anomaly over Karymsky was visible in satellite images during 16-21 December.
Kilauea – Hawaiian Islands (USA) : HVO reported that lava effusion intermittently continued at a vent in the lower W wall of Kilauea’s Halema`uma`u Crater during 21-28 December. Effusion paused for a period during 21-22, and sulfur dioxide emissions were 130 tonnes per day during the pause. Strong volcanic tremor began to be recorded at 1930 on 22 December and by 2000 lava again effused from the vent into the rejuvenated a portion of the lake. The lake overflowed and fed substantial lava flows that traveled SE over older crusted parts of the lake all day on 23 December until around midnight. Lava oozed out along the E margins of the lake during 24-25 December, including onto the lowermost down-dropped block from the 2018 caldera collapse, indicating a continuing supply of lava beneath the lake’s crust. The sulfur dioxide emission rate was about 5,300 tonnes per day on 24 December, much higher than during the pause. The surface of the lava lake had begun crusting over on 25 December and by 26 December lava had again ceased erupting from the vent. An area of the lake, 50 m in diameter, to the N of the vent remained molten on 27 December. The sulfur dioxide emission rate was 125 tonnes per day during the pause. Lava again erupted from the vent later that day, beginning at 1930. The lake was incandescent around the vent and lava overflowed the margins, feeding substantial lava flows to the N and S.
Laguna del Maule – Central Chile-Argentina border : SERNAGEOMIN reported that inflation at Laguna del Maule continued in an area SW of the lake during 1-15 December, though deformation had been decreasing since October with a with a maximum rate of 1.88 centimeters per month. Deformation rates during November and December were comparable to those recorded prior to 2019. The number of volcano-tectonic events had also decreased; the largest event was a M 2.3 located 4.1 km ESE from the center of the lake at a depth of 6.1 km.
Lewotolok – Lembata Island (Indonesia) : PVMBG reported that the eruption at Lewotolok continued during 21-25 December. White-and-gray ash plumes that were sometimes dense rose as high as 600 m above the summit. Incandescent material was ejected from the vent up to 300 m in multiple directions. Rumbling, roaring, and booming were often heard.
Manam – Papua New Guinea : The Darwin VAAC reported that a large thermal anomaly over Manam was identified in satellite images during 21-22 December. A discrete ash plume rose to 3.4 km (11,000 ft) a.s.l. and drifted SE on 21 December. Ash plumes may have risen to 10.7 km (35,000 ft) a.s.l. during 0137-0300 on 22 December, though weather clouds and heavy rain obscured satellite views; the plumes were unconfirmed by ground observers. At 1200 on 22 December an ash plume rose to 4.9 km (16,000 ft) a.s.l., drifted E, and dissipated within four hours.
Merapi – Central Java (Indonesia) : BPPTKG reported no notable morphological changes to Merapi’s summit lava dome, though the dome just below the SW rim had increased about 2 m in height during 17-23 December. The estimated dome volumes were over 1.65 million cubic meters for the SW dome and just over 3 million cubic meters for the summit dome. The intensity of the seismic signals remained at high levels. As many as 112 lava avalanches traveled a maximum of 2 km SW down the Bebeng drainage, and four pyroclastic flows traveled a maximum of 2.5 km SW.
Pavlof – United States : AVO reported that seismicity at Pavlof was elevated during 22-28 December and was mainly characterized by periods of sustained tremor and discrete low-frequency events. Numerous small explosions were recorded almost daily, and strongly elevated surface temperatures were visible in satellite images, consistent with lava effusion.
Reventador – Ecuador : IG reported that a high level of activity continued at Reventador during 21-28 December. Gas-and-ash plumes, often observed multiple times a day with the webcam or reported by the Washington VAAC, rose as high as 1.2 km above the summit crater and drifted mainly NW, W, and SW. Crater incandescence was visible nightly, and lava flows were active on the NE and N flanks. Explosions, crater incandescence, and incandescent blocks rolling 500 m down the N and NE flanks were observed at night during 27-28 November.
Rincon de la Vieja – Costa Rica : OVSICORI-UNA reported that at 1015 on 25 December a small eruption at Rincón de la Vieja was recorded for about four minutes but not visually observed due to weather clouds. Rains after the event and continuing early on 26 December washed the acidic sediment deposited from the volcano downstream in the Pénjamo, Azul, and Azufrada drainages, into the aquatic ecosystem. Phreatic events were recorded at 1402 and 1630 on 28 December though weather conditions prevented visual confirmation.
Sangay – Ecuador : IG reported a high level of activity at Sangay during 21-28 December. Seismicity was characterized by daily explosions, long-period earthquakes, and signals indicating emissions. Weather clouds and rain sometimes prevented visual and webcam observations of the volcano, though almost daily ash-and-gas plumes were identified in satellite images by the Washington VAAC or in webcam views; plumes rose as high as 1.5 km above the volcano and drifted SE, S, SW, and W. Multiple (33-73 per day) daily thermal anomalies over the volcano were visible in satellite data. On 25 December volcano observers near Macas reported hearing noises coming from Sangay, possibly due to favorable weather conditions, though the intensity of explosions had slightly increased. Crater incandescence and an active lava flow on the SE flank were visible at night during 27-28 November.
Semisopochnoi – Aleutian Islands (USA) : AVO reported that low-level eruptive activity and elevated seismicity at Semisopochnoi’s North Cerberus crater continued during 22-28 December. Small explosions were detected almost daily in seismic and infrasound data. Low-level ash-and-steam emissions were observed by webcams and in satellite images during 22-25 December, when weather conditions were clear.
Sheveluch – Central Kamchatka (Russia) : KVERT reported that a thermal anomaly over Sheveluch was identified in satellite images during 17-24 December. At 1210 local time on 23 December explosions produced ash plumes that rose to 6 km (19,700 ft) a.s.l. and drifted 70 km NE.
Suwanosejima – Ryukyu Islands (Japan) : JMA reported that crater incandescence at Suwanosejima’s Ontake Crater was visible nightly during 20-27 December. The number of explosions totaled 143 during 22-24 December. Plumes rose as high as 3.1 km above the crater rim and bombs were ejected 700 m from the crater. Explosive activity increased during 24-27 December with explosions totaling 361. Plumes rose as high as 1.5 km and bombs were ejected 800 m form the vent.
Turrialba – Costa Rica : OVSICORI-UNA reported that an area of incandescence on the NW inner wall of Turrialba’s West Crater had been periodically visible at least since mid-November, and was visible during 26-27 December, suggesting that fumarolic temperatures exceeded 300 degrees Celsius. At 0644 on 28 December a one-minute-long eruption produced an ash emission that rose 50 m above the crater rim and drifted W. Another small eruption that produced ash emissions was recorded at 1105 by the seismicity and infrasound networks. The event was heard by authorities in the Parque Nacional Volcán Turrialba.
Yasur – Vanuatu : The Wellington VAAC reported that during 27-28 December ash emissions from Yasur were visible in webcam images rising above the crater rim, to 1.5 km (5,000 ft) a.s.l. Plumes containing ash were not visible in satellite images, though they were also confirmed by Vanuatu Meteorology and Geohazards Department (VMGD).