Volcanos

Roundup of Global Volcanic Activity – New Activity for the week of 29 November - 5 December 2017

Agung | Bali (Indonesia) : PVMBG reported that the eruption at Agung, which began on 21 November, continued during 30 November-5 December. On 29 November gray ash plumes levels were rising to 2 km above the crater rim, resulting in ashfall to the SE. During 30 November-5 December emissions continued to rise 2 km; most were white in colour, but dense gray ash emissions were noted during 1-2 December. Satellite data indicated that lava effusion continued at least through 1 December, and the erupted volume of lava was estimated to be 20 million cubic meters, equivalent to about a third of the total crater volume. The base of the plume was often reddish during 29 November-5 December reflecting incandescence from lava in the crater. BNPB noted on 5 December that 63,885 evacuees were distributed in 225 evacuation shelters. Lahars were first noted on 21 November and continued to be observed through 5 December. The lahars flowed down drainages on the S flank (along the Tukad Yehsa, Tukad Sabuh, and Tukad Beliaung drainages) and also down the Tukad Bara drainage on the N flank, impacting houses, roads, and agricultural areas. The Alert Level remained at 4 (on a scale of 1-4), and the exclusion zones continued at a general 8-km radius and 10 km in the NNE, SE, S, and SW directions.

Great Sitkin | Andreanof Islands (USA) : AVO reported that during 28 November-5 December low-level unrest continued at Great Sitkin. Nothing noteworthy was identified in seismic data nor in partly cloudy to cloudy satellite images. The Aviation colour Code remained at Yellow and the Volcano Alert Level remained at Advisory.

Klyuchevskoy | Central Kamchatka (Russia) : KVERT reported that strong gas-and-steam emissions at Klyuchevskoy were recorded by a webcam during 2-5 December, and contained some ash starting at 2300 on 5 December. The gas-and-ash plumes were visible in satellite data drifting 170 km E. KVERT raised the Aviation colour Code to Orange (the second highest level on a four-colour scale).

Pacaya | Guatemala : On 28 November INSIVUMEH reported that 6-8 Strombolian explosions per hour at Pacaya’s Mackenney cone ejected material as high as 25 m above the main cone. A lava flow traveled 30 m down the NW flank of the cone.

Villarrica | Chile : Gradually increasing activity at Villarrica since 15 November prompted OVDAS-SERNAGEOMIN to raise the Alert Level to Yellow (the second lowest level on a four-colour scale) on 5 December, and warn the public to stay outside of a 1-km radius around the crater. Increased activity was characterized by recorded volcano-tectonic earthquakes, increased thermal anomalies identified in satellite data, and increased lava-lake activity. The infrasound network, photos, and field observations confirmed a higher lake level and explosions that were ejecting material deposited in the crater area. Lava fountains 150 m high were documented by POVI during the second half of November.