Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the Week 21 October 2020 – 27 October 2020

Bulusan | Luzon (Philippines) : On 26 October PHIVOLCS lowered the Alert Level for Bulusan to 0, indicating normal conditions, though warnings remained to not enter the 4-km-radius Permanent Danger Zone (PDZ). The decision was based on monitoring data that showed sulfur dioxide flux remaining below detection levels since 2018, deformation continuing a deflationary trend since May 2019, and the frequency of volcanic earthquakes declining to baseline levels (0-2 earthquakes/day) beginning in late September 2020. Very diffuse white plumes rose from the summit vents.

Dukono | Halmahera (Indonesia) : Based on satellite and wind model data, the Darwin VAAC reported that during 21-27 October ash plumes from Dukono rose to 2.1 km (7,000 ft) a.s.l. and drifted in multiple directions. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to remain outside of the 2-km exclusion zone.

Ebeko | Paramushir Island (Russia) : Volcanologists in Severo-Kurilsk (Paramushir Island), about 7 km E of Ebeko, observed explosions during 16-23 October that sent ash plumes up to 3.5 km (11,500 ft) a.s.l. and drifted N, NE, and SE. Ash fell in Severo-Kurilsk during 20-22 October. A thermal anomaly over the volcano was visible in satellite data on 22 October. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Etna | Sicily (Italy) : INGV reported that during 19-25 October activity at Etna was characterized by intra-crater Strombolian activity at Northeast Crater (NEC), Strombolian activity at the New Southeast Crater (NSEC) cone, and gas emissions at the Voragine (VOR) and Bocca Nuova (BN) craters. During a helicopter overflight along the W side on 23 October scientists observed Strombolian explosions at NSEC that produced ash emissions and ejected shreds of lava out of the crater. Both the frequency and intensity of explosions was variable. There were several thermal anomalies on the NEC crater floor, and some on the floor of the BN crater. An ash plume from NSEC rose to 4.5 km a.s.l. and drifted SSE. The report noted that, based on drone footage from the beginning of the month, the NSEC vent was 190 m long in the NW direction and 140 m wide in the NE direction.

Great Sitkin | Andreanof Islands (USA) : AVO reported that seismicity at Great Sitkin had decreased during the previous several months and had returned to background levels by 21 October. Additionally, eruptive activity or unusual surface temperatures had not been observed in clear satellite images. The Aviation colour Code was lowered to Green and the Volcano Alert Level was lowered to Normal.

Ibu | Halmahera (Indonesia) : PVMBG reported that during 21-26 October ash plumes rose 200-800 m above Ibu’s summit and drifted N, NE, and E. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to stay at least 2 km away from the active crater, and 3.5 km away on the N side.

Langila | New Britain (Papua New Guinea) : Based on analyses of satellite imagery and wind model data, the Darwin VAAC reported that on 22 and 24 October ash plumes from Langila rose 2.1 km (7,000 ft) a.s.l. and drifted S and N, respectively. Ash plumes rose to 1.8 km (6,000 ft) a.s.l. and drifted NW on 25 October.

Reykjanes | Iceland : IMO reported that a M 5.6 earthquake was recorded at 1343 on 20 October beneath Nupshlidarhals, a hill about 5 km W of the geothermal area in Seltun. This was the largest earthquake since 2003 recorded in the Reykjanes peninsula. There were about 1,700 aftershocks recorded in the following 24-hour period. IMO received reports of rockfalls in steep areas and increased gas odors in the vicinity of Graenavatn at Nupshlidarhals. Four landslides were noted near the epicenter; some existing ground cracks were displaced and new cracks had formed in Krysuvikurbjarg. On 26 October IMO stated that seismic activity had significantly decreased in recent days; about 180 earthquakes below M 2.2 had been detected during the previous two days.

Semeru | Eastern Java (Indonesia) : PVMBG that gray-and-white ash plumes rose 500 m above Semeru’s summit and drifted S and SW during 22-24 October. The Alert Level remained at 2 (on a scale of 1-4).

Sheveluch | Central Kamchatka (Russia) : KVERT reported that a thermal anomaly over Sheveluch was identified in satellite images during 16-23 October. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Sinabung | Indonesia : PVMBG reported that white plumes rose as high as 500 m above Sinabung’s summit on most days during 20-27 October; foggy conditions sometimes prevented visual observations. On 23 October white-and-gray ash plumes rose as high as 1 km and drifted in multiple directions. Pyroclastic flows traveled 1.5-2.5 km down the E and SE flanks on 25 October. According to a news article ash plumes drifted SE of the volcano twice that same day, causing some local residents to evacuate. The report noted that a lava dome in the summit crater continued to grow. The Alert Level remained at 3 (on a scale of 1-4), with a general exclusion zone of 3 km and extensions to 5 km in the SE sector and 4 km in the NE sector.

Stromboli | Aeolian Islands (Italy) : INGV reported that during 19-25 October activity at Stromboli was characterized by ongoing explosive activity from Area N (north crater area) and in Area C-S (south-central crater area). Explosions from two vents at the N1 vent (Area N) ejected lapilli and bombs 80-150 m high, and produced ash emissions. Explosions at two N2 vents ejected a mix of coarse and fine material at a frequency of 5-10 events per hour. Explosions from vents in Area C-S also ejected both coarse and fine material 250 m high at a frequency of 1-3 events per hour.

Suwanosejima | Ryukyu Islands (Japan) : JMA reported nighttime incandescence and intermittent eruptive activity at Suwanosejima’s Ontake Crater during 16-23 October. Three explosions were recorded; an explosion at 0439 on 17 October produced a grayish-white ash plume that rose 1.4 km above the crater rim. The Alert Level remained at 2 (on a 5-level scale).

Villarrica | Chile : SERNAGEOMIN reported that a long-period (LP) event and associated explosion were recorded by Villarrica’s seismic network at 1041 on 23 October. An ash plume rose 180 m. The Alert Level remained at Yellow, the second lowest level on a four-colour scale. ONEMI maintained an Alert Level Yellow (the middle level on a three-colour scale) for the municipalities of Villarrica, Pucón (16 km N), Curarrehue, and the commune of Panguipulli, and the exclusion zone for the public of 500 m around the crater.

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