Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the Week 9 December 2020 – 15 December 2020

Aira – Kyushu (Japan) : JMA reported that during 7-14 December incandescence from Minamidake Crater (at Aira Caldera’s Sakurajima volcano) was often visible nightly and the sulfur dioxide emission rate remained high. Three explosions during 7-11 December produced ash plumes that rose as high as 2.4 km above the crater rim and ejected bombs 1.3-1.7 km away from the crater. An eruptive event at 0514 on 14 December produced a plume that rose 1.8 km and blended into weather clouds. The Alert Level remained at 3 (on a 5-level scale).

Dukono – Halmahera (Indonesia) : Based on satellite and wind model data, the Darwin VAAC reported that during 8-14 December ash plumes from Dukono rose 2.1-2.4 km (7,000-8,000 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 8-9 December that sent ash plumes up to 3.5 km (11,500 ft) a.s.l. and drifted NE and SE. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Etna – Sicily (Italy) : INGV reported that during 7-12 December activity at Etna was similar to the previous week, characterized by intra-crater Strombolian activity at Northeast Crater (NEC), and Strombolian activity, lava effusion, and pyroclastic flows at the Southeast Crater (SEC). Additionally, infrequent ash emissions at the Bocca Nuova (BN) craters and some explosions and minor ash emissions at the Voragine (VOR) were also recorded. Webcam views of activity was limited due to weather conditions; a field visit was made on 14 December. Strombolian activity originated from the E and central vents at SEC ejected lava onto the inner crater walls. Occasional ash emissions dispersed quickly near the summit. Activity intensified at 2020 on 13 December and lava fountains formed around 2300. Collapses of the SW part of the SEC cone spurred a series of pyroclastic flows. At 2315 a small pyroclastic flow traveled down the SSW flank. A second pyroclastic flow began at 2316 and traveled 2 km down the SSW flank and covered Monte Frumento Supino cone (SSW). At 2330 a third and minor pyroclastic flow traveled SSW. Around the same time as the generation of the first two pyroclastic flows, two fissures opened on the SW flank of the SEC and produced lava flows to the S and SW until about 2350. A period of lava fountaining was visible during 0050-0110 and 0210-0223 on 14 December. During a field inspection on 14 December scientists confirmed the partial cone collapses and noted that the two lava flows (S and SW) were cooling. The S lava flow had widened at the near the base of SEC and formed four lobes. One of the lobes continued on and stopped just NW of cones that had formed in 2002-2003. The SW flow traveled SSW, branched, curved around the W part of Monte Frumento Supino, and then stopped. Explosive activity from central SEC vent continued, with roaring and sporadic ash emissions. An explosion at 1352 formed an ash plume that rose about 4 km and drifted S. Strombolian explosions deposited material outside of the crater.

Fuego – Guatemala : INSIVUMEH reported that 3-15 explosions were recorded per hour during 8-15 December at Fuego, generating ash plumes as high as 1.1 km above the crater rim that drifted 10-25 km generally S, SW, and W. Shock waves rattled buildings within 20 km of the summit. Block avalanches descended the Ceniza (SSW), Seca (W), Trinidad (S), Taniluyá (SW), El Jute, Las Lajas (SE), and Honda drainages; avalanches sometimes reached vegetated areas. Incandescent material was occasionally ejected 100-200 m. Ashfall was reported most days in several areas downwind including Morelia (9 km SW), Panimaché I and II (8 km SW), Finca Palo Verde, Santa Sofía (12 km SW), El Porvenir (8 km ENE), San Pedro Yepocapa (8 km NW), and Sangre de Cristo (8 km WSW).

Kirishimayama – Kyushu (Japan) : JMA noted that no eruption had occurred at Shinmoedake (Shinmoe peak, a stratovolcano of the Kirishimayama volcano group) since 28 June 2018. Volcanic earthquakes with hypocenters just below Shinmoedake had increased around 17 November 2019, fluctuated afterwards, and then began a decreasing trend in mid-October 2020. Sulfur dioxide levels were generally low, deformation data showed no changes, and both fumarolic and geothermal area activity remained stable. The Alert Level was lowered to 1 (on a scale of 1-5) on 11 December.

Klyuchevskoy – Central Kamchatka (Russia) : KVERT reported that Strombolian and Vulcanian activity at Klyuchevskoy continued during 4-7 December and lava advanced down the Kozyrevsky drainage on the S flank. A large bright thermal anomaly was identified daily in satellite images. Steam-and-gas plumes with some ash rose to 7 km (23,000 ft) a.s.l. and drifted 130 km NW and NE. The Aviation colour Code remined at Orange (the second highest level on a four-colour scale).

Pacaya – Guatemala : INSIVUMEH reported that on 9 December a new lava flow emerged from a vent S of Cerro Chino, NNW of Pacaya’s summit, and traveled as far as 250 m WSW. The branched lava flow which had opened in October on the WSW flank was active, with lengths between 400 and 600 m. Avalanches of material from the new flow and the SW-flank lava flows descended 100 m. Strombolian explosions from the cone in Mackenney Crater were visible on most days during 9-15 December and ejected material as high as 150 m above the vent. Gray ash plumes were occasionally visible drifting S, SW, and W at generally low altitudes. On 12 December strong winds picked up ash deposits and created ash curtains that drifted 1.5 km away and dispersed. Lava flows on the SW flank varied in length between 500 m and 1,000 m. The NW-flank lava flow ceased effusing by 13 December.

Sabancaya – Peru : Instituto Geofísico del Perú (IGP) reported a daily average of 54 explosions at Sabancaya during 7-13 December. Gas-and-ash plumes rose as high as 2.8 km above the summit and drifted NW, W, and SW. Eight thermal anomalies over the crater were identified in satellite data. Minor inflation continued to be detected in areas N of Hualca Hualca (4 km N) and on the SE flank. INGEMMET stated that ashfall was noted in the towns of Cabanaconde (22 km NW), Pinchollo (20 km N), and Madrigal (20 km NE) during 9-10 December. The Alert Level remained at Orange (the second highest level on a four-colour scale) and the public were warned to stay outside of a 12-km radius.

Santa Maria – Guatemala : INSIVUMEH reported that during 9-15 December explosions at Santa María’s Santiaguito lava-dome complex generated ash plumes that rose as high as 900 m above the complex. The extrusion of blocky lava at the WSW part of Caliente dome generated block-and-ash flows that descended the NW, WSW, SW, and E flanks often reaching the base of the complex. The activity increased at 0430 on 11 December with notable avalanches of material and block-and-ash flows lava dome traveling down the W and SW flanks. Ash plumes drifted 15 km SW, causing ashfall in areas downwind including Finca Montebello, Loma Linda, and San Marcos Palajunoj. Activity remained elevated at least through 13 December; ash plumes drifted as far as 20 km W, SW, and S, and pyroclastic flows descended the flanks.

Semeru – Eastern Java (Indonesia) : PVMBG reported that the eruption at Semeru continued during 9-15 December. Incandescent material was ejected 50-100 m above the summit on 9 December and rock avalanches descended the Kobokan drainage 500 m on the SE flank. Explosions were recorded by the seismic network during 10-12 December but they could not be visually confirmed due to weather conditions. On 13 December a pyroclastic flow originating from the end of a lava flow traveled 1.5 km down the Kembar drainage (S flank), reaching a maximum distance of 3.5 km from the crater. The next day a pyroclastic flow traveled 3.5 km down the Kobokan drainage. Rock avalanches from the end of a lava flow traveled 300-1,500 m down both drainages during 14-15 December. The Alert Level remained at 2 (on a scale of 1-4), with a general exclusion zone of 1 km and extensions to 4 km in the SSE sector.

Sheveluch – Central Kamchatka (Russia) : KVERT reported that a thermal anomaly over Sheveluch was identified in satellite images during 4-11 December. The lava block, named “Dolphin,” which had emerged in the E part of the summit lava dome, was absent in an 8 December photo of the volcano. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Suwanosejima – Ryukyu Islands (Japan) : JMA reported nighttime incandescence and intermittent eruptive activity at Suwanosejima’s Ontake Crater during 4-11 December. A total of 20 explosions were recorded, ejecting bombs up to 500 m away from the crater and producing gray-and-white plumes that rose 1.5 km above the crater rim. Ashfall was reported in Toshima village (4 km SSW). The Alert Level remained at 2 (on a 5-level scale).

Villarrica – Chile : POVI reported that during an over-flight of Villarrica on 9 December scientists observed a small lava lake, 10-15 m in diameter, partially covered by floating black solidified lava. 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 of 500 m around the crater.

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