Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the Week 6 October – 12 October 2021

Aira – Kyushu (Japan) : JMA reported that incandescence from Minamidake Crater (at Aira Caldera’s Sakurajima volcano) was visible at night during 4-11 October. The sulfur dioxide emission rate was 400 tons per day on 5 October. An explosion at 0517 on 8 October ejected material 600-900 m away from the crater and produced an eruption plume that was obscured by weather clouds.

Kadovar – Papua New Guinea : Based on satellite and wind model data, the Darwin VAAC reported that during 8-9 October ash plumes from Kadovar rose to an altitude of 1.5 km (5,000 ft) a.s.l. and drifted W and NW.

Karymsky – Eastern Kamchatka (Russia) : KVERT reported that a thermal anomaly over Karymsky was identified in satellite images on 7 October.

Lewotolok – Lembata Island (Indonesia) : PVMBG reported that the eruption at Lewotolok continued during 6-12 October. White-and-gray plumes generally rose as high as 800 m above the summit and drifted in multiple directions. A VONA stated that on 7 October and ash plume rose 1.9 km above the summit and drifted W. Rumbling and banging sounds were reported daily. Incandescent material was ejected daily as far as 300 m away from the vent in multiple directions, though during 5-6 October incandescent material was ejected as far as 1 km SE. BNPB noted that 25-26 eruptive events per day were sometimes recorded before activity increased in October.

Merapi – Central Java (Indonesia) : BPPTKG reported minor morphological changes to Merapi’s SW lava dome, located just below the SW rim and in the summit crater, and no changes to the summit crater dome during 1-7 October. The SW dome grew about 3 m taller had an estimated volume of 1.679 million cubic meters, and the summit lava dome had an estimated volume of 2.854 million cubic meters. As many as 76 lava avalanches traveled a maximum of 2 km SW.

Nevados de Chillan – Chile : SERNAGEOMIN reported continuing explosive and effusive activity at Nevados de Chillán’s Nicanor Crater during 16-30 September though weather conditions often prevented visual confirmation. Explosions generated plumes with low ash content that rose as high as 1.1 km above the crater rim. A new lava dome (Dome 3) in the crater was first identified on 15 September and was 27 x 40 m, elongated NW-SE, and 990 square meters in area. The dome formation was preceded by a decrease in the extrusion rates and temperatures of the L5 and L6 lava flows. By 24 September growth at Dome 3 reached 36 x 43 m and covered 2,137 square meters. Dome 4 was first visible on 29 September, adjacent to Dome 3 on the NE side, and produced a new lava flow (L7) that traveled 50 m down the flank between the L5 and L6 flows. The L5 lava flow also began to advance. On 5 October the L5 and L7 lava flows advanced and nighttime incandescence from both flows increased. Incandescence from the crater was visible in webcam images at night during 8-9 October. On 9 October a long-period earthquake was recorded at 0706 on 9 October; an associated emission rose more than 240 m above the vent and drifted NW.

Pavlof – United States : AVO reported that seismicity at Pavlof remained elevated during 6-12 October. Two explosions were recorded by infrasound network during 6-7 October. Mostly cloudy conditions obscured satellite and webcam images most days.

Sabancaya – Peru : Instituto Geofísico del Perú (IGP) reported a daily average of 27 explosions at Sabancaya during 4-10 October. Gas-and-ash plumes rose as high as 2 km above the summit and drifted in multiple directions. One thermal anomaly originating from the lava dome in the summit crater was identified in satellite data. Minor inflation continued to be detected near Hualca Hualca (4 km N).

Semisopochnoi – Aleutian Islands (USA) : AVO reported that eruptive activity at Semisopochnoi’s North Cerberus crater continued during 6-12 October. Seismicity remained elevated and a few explosions per day were detected in infrasound data. Although weather clouds often prevented webcam and satellite views, discontinuous, low-level ash emissions were visible rising to altitudes up to 3 km (10,000 ft a.s.l.) and drifting E during 8-9 October. Low-level ash emissions were also visible in webcam images during 9-12 October.

Sheveluch – Central Kamchatka (Russia) : KVERT reported that a thermal anomaly over Sheveluch was identified in satellite images during 1, 4, and 6-7 October. Plumes of resuspended ash drifted 200 km SE during 6-7 October.

Stromboli – Aeolian Islands (Italy) : INGV reported that during 4-10 October 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 two vents in the N1 vent (Area N) ejected lapilli and bombs 80 m high, and produced minor ash emissions. Explosions at two N2 vents (Area N) averaged 3-8 events per hour and ejected material less than 80 m high. Explosions from the S1 and S2 vents in Area C-S were sporadic and occurred at a rate of 4-8 per hour; coarse material was ejected 150 m high. Gas emissions rose from the C vent. A short explosive event at the N2 vents began at 1617 on 6 October. Notably, a large explosion ejected tephra radially beyond the crater terrace as far as the upper part of the Sciara del Fuoco, and incandescent material rolled down to the coast. An ash cloud was produced, though it quickly dissipated. A small lava overflow from the vents followed but it did not travel past the upper part of the Sciara del Fuoco

Suwanosejima – Ryukyu Islands (Japan) : JMA reported that 52 explosions at Suwanosejima’s Ontake Crater produced eruption plumes that rose as high as 2.4 km above the crater rim during 4-11 October. Large volcanic bombs were ejected as far as 1.1 km from the crater. Crater incandescence was visible nightly.

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