Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the week 20 October – 26 October 2021

Aira – Kyushu (Japan) : JMA reported that incandescence from Minamidake Crater (at Aira Caldera’s Sakurajima volcano) was visible at night during 18-25 October. The sulfur dioxide emission rate was 1,000 tons per day on 22 October.

Cleveland – Chuginadak Island (USA) : On 20 October AVO lowered both the Aviation Color Code and the Volcano Alert Level for Cleveland to Unassigned, noting a steady decline in volcanic unrest over the previous few months. Elevated surface temperatures were still identified in satellite images, though at a reduced frequency and strength. A short-lived explosion on 1 June 2020 was the last time eruptive activity was recorded.

Dukono – Halmahera (Indonesia) : PVMBG reported that during 19 and 22-26 October white-and-gray ash plumes from Dukono rose as high as 300 m above the summit and drifted E and W.

Ebeko – Paramushir Island (Russia) : On 22 September KVERT lowered the Aviation Color Code for Ebeko to Yellow (the second lowest level on a four-color scale), noting that a thermal anomaly over the volcano was last visible on 25 August and eruptive activity had not been recorded since 22 September.

Etna – Sicily (Italy) : Strombolian activity resumed at Etna’s Southeast Crater (SEC) beginning at 0447 on 20 October. Small ash-and-gas puffs drifted SW. Activity gradually increased and by 1920 on 21 October explosions were ejecting incandescent material out of the crater. Activity intensified during the evening of 22 October, and crater incandescence was visible in between weather clouds at night during 22-23 October. Ash plumes drifted NE. Explosive Strombolian activity increased at 1000 on 23 October, producing ash plumes that then abruptly stopped at 1035. A series of strong explosions began a few minutes later, producing visible pressure waves and ash emissions. Lava fountaining began sometime before 1043 and dense ash-and-gas plumes rose several kilometers high and drifted ENE. A fracture opened on the SE side of the SEC cone and at 1048 a pyroclastic flow traveled 1.5 km SE toward the Valle del Bove. A second pyroclastic flow observed at 1100 also traveled 1.5 km SE. Several smaller pyroclastic flows were visible on the E flank of the cone. At 1158 a pyroclastic flow bifurcated and traveled a few hundred meters S and SE. Lava fountains rose as high as 800 m during the most intense period and a lava flow originating from the E side of the crater descended SE. The ash plumes rose more than 10 km (32,800 ft) a.s.l. and caused ash and lapilli to fall in many areas downwind, including Linguaglossa, Vena, Presa, Piedimonte Etneo, Taormina, and Mascali. Explosive activity began to decrease around 1200 and then ceased at 1220. Ash emissions continued to rise from the SEC and by 1932, the lava flows on the SE flank had stopped advancing.

Great Sitkin – Andreanof Islands (USA) : AVO reported that lava effusion continued at Great Sitkin during 20-26 October. Lava advanced down the S and W flanks and were 500 m long by 20 October based on satellite images. Geophysical and web camera data streams returned back online during 22-23 October; seismicity remained slightly elevated and no explosive activity was recorded in both seismic and infrasound data through 26 October. Elevated surface temperatures were visible in satellite images during 25-26 October.

Karymsky – Eastern Kamchatka (Russia) : KVERT reported that during 19-20 October explosions at Karymsky generated ash plumes that rose as high as 5 km (16,400 ft) a.s.l. and drifted 225 km E. A thermal anomaly was visible on 21 October.

Langila – New Britain (Papua New Guinea) : The Darwin VAAC reported that on 21 October ash plumes from Langila were visible in satellite images rising 1.8-4.6 km (6,000-15,000 ft) a.s.l. and drifting NW.

Lewotolok – Lembata Island (Indonesia) : PVMBG reported that the eruption at Lewotolok continued during 20-26 October. White-and-gray plumes generally rose as high as 600 m above the summit and drifted in multiple directions.

Merapi – Central Java (Indonesia) : BPPTKG reported no morphological changes to Merapi’s SW lava dome, located just below the SW rim and in the summit crater, and the summit crater dome during 15-21 October. Two pyroclastic flows traveled 2.5 km down the SW flank and as many as 60 lava avalanches traveled a maximum of 2 km SW.

Pavlof – United States : AVO reported that the eruption at Pavlof continued during 20-26 October and was focused at a vent on the upper SE flank, near the location of the 2007 vent. Seismicity remained elevated with tremor and daily small explosions during 20-24 October. Weather clouds obscured satellite and webcam images most days, but the explosions likely produced low-level ash plumes that rose no higher than 3 km (10,000 ft) a.s.l. Elevated surface temperatures were visible in satellite images during 25-26 October.

Semisopochnoi – Aleutian Islands (USA) : AVO reported that eruptive activity at Semisopochnoi’s North Cerberus crater continued during 19-26 October. Tremor and multiple minor explosions were detected daily in seismic and infrasound data. Although weather clouds often prevented webcam and satellite views, intermittent, low-level ash emissions were visible during clear weather rising to altitudes up to 3 km (10,000 ft a.s.l.); the farthest plume drifted 250 km on 19 October. Sulfur dioxide emissions were detected during 25-26 October.

Sheveluch – Central Kamchatka (Russia) : KVERT reported that a thermal anomaly over Sheveluch was identified in satellite images during 16-17 and 20-21 October when the volcano was visible through weather clouds. A plume of resuspended ash rose as high as 4 km (13,100 ft) a.s.l. on 21 October and drifted 40 km SE.

Shishaldin – Fox Islands (USA) : AVO reported that several outages affected GPS, seismic, and infrasound stations used to monitor Shishaldin. On 20 October AVO changed both the Aviation Color Code and the Volcano Alert Level to Unassigned, reflecting the lack of this data to detect unrest. The volcano continued to be monitored with webcams, satellite data, remote infrasound, seismic, and GPS networks.

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