Volcanos

Roundup of Global Volcanic Activity – New Activity for the week of 13 December - 19 December 2017

Agung | Bali (Indonesia) : PVMBG reported that during 13-19 December gray-and-white plumes rose as high as 2.5 km above Agung’s crater rim and drifted W, N, and E; weather clouds and fog sometimes prevented visual observations. Incandescence from the crater was sometimes observed at night. 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. BNPB posted two map-view images of Agung, one from 20 October showing pre-eruptive conditions and one from 16 December showing the lava that had erupted onto the crater floor, noting that about 1/3 of the crater had been filled with an estimated 20 million cubic meters of lava.

Bezymianny | Central Kamchatka (Russia) : On 18 December hot avalanches on the SE flank of Bezymianny’s lava dome were recorded by a webcam, prompting KVERT to raise the Aviation colour Code to Orange (the second highest level on a four-colour scale). A strong explosion that started at 1555 on 20 December generated ash plumes that rose 10-15 km (32,800-49,200 ft) a.s.l., prompting KVERT to raise the Aviation colour Code to Red. Ash plumes were identified in satellite data drifting 85 km NE. Later that day satellite images indicted decreased activity; the Alert level was lowered back to Orange.

Kanlaon | Philippines : PHIVOLCS reported between 1 and 7 volcanic earthquakes at Kanlaon were recorded each day during 2-8 December, prior to the phreatic eruption on 9 December. Only three events were detected on 10 December, and then the number increased to 155 the next day. The number of daily volcanic earthquakes increased to 578 on 13 December, rising to 1,007 the next day, and peaking at 1,217 on the 15th. The earthquake count dropped to 149 on 16 December before returning to six or less through 19 December. White steam plumes rose 800 and 300 m above the crater on 13 and 14 December, respectively. White plumes were diffuse on 15 December; weather clouds prevented views of the summit area during 16-18 December. Sulfur dioxide emissions were 603-687 tons per day during 13-14 December. The Alert Level remained at 2 (on a scale of 0-5).

Klyuchevskoy | Central Kamchatka (Russia) : Based on satellite observations KVERT reported that gas-and-steam plumes from Klyuchevskoy contained some ash and drifted about 95 km E and SW on 7 and 13 December, respectively. A weak thermal anomaly was visible on 11 December. The Aviation colour Code remained at Orange.

Pacaya | Guatemala : INSIVUMEH reported that during 12-19 December Strombolian explosions at Pacaya’s Mackenney cone ejected material as high as 100 m above the main cone. A 75-m-long lava flow on the NW flank was visible.

Shishaldin | Fox Islands (USA) : AVO reported that seismic and infrasound data from Shishaldin continued to indicate elevated activity during 13-19 December. Robust steaming was recorded by a webcam during 13-14 December; ice and poor weather conditions prevented views during the rest of the period. The Aviation colour Code remained at Yellow and the Volcano Alert Level remained at Advisory.

Stromboli | Aeolian Islands (Italy) : INGV reported after an effusive eruption during August-November 2014, activity at Stromboli remained at modest levels. In recent months however activity was characterized by frequent explosions from different vents on the crater terrace, punctuated by four major explosions (on 26 July, 23 October, 1 November, and 1 December 2017). Activity remained high after the last explosion, prompting authorities to restrict access to the summit areas. In the late morning on 15 December one of the vents began spattering, and by 1400 lava flows from two vents had begun to fill the crater depression. At 1430 the lava spilled onto the N flank of the Sciara del Fuoco. Spattering rapidly stopped later in the afternoon and the lava flows stopped advancing.