Volcanos

Roundup of Global Volcanic Activity – New Activity for the week of 7 June – 13 June 2017

Bogoslof | Fox Islands (USA) : colourAVO reported that a new lava dome at Bogoslof breached the surface of the ocean on or around 6 June, and was the first observation of lava at the surface since the start of the eruption that began in mid-December 2016. The dome was an estimated 110 m in diameter on 7 June, and then grew to 160 m in diameter by 9 June.

An explosive eruption began at 0318 on 10 June with a series of short infrasound signals which then, starting at about 0416, transitioned into several minutes-long continuous seismic and infrasound tremor signals. The events generated an ash-rich cloud that rose to an estimated altitude of 10.4 km (34,000 ft) a.s.l. and drifted NW. The Aviation colour Code (ACC) was raised to Red and the Volcano Alert Level (VAL) was raised to Warning. The eruption ended at 0528. Satellite data indicated that at least part of the volcanic cloud was more ash-rich than most in the current eruption period. On 11 June AVO noted no detectable activity in seismic or infrasound data after the event the day before. The ACC was lowered to Orange and the VAL was lowered to Watch. Satellite image acquired on 10 June and a photograph from an observer aboard a jet aircraft on 11 June suggested that the lava dome was no longer above the surface of the water, and was destroyed during the 10 June event.

A series of explosive events, each lasting 10-30 minutes, began at 1747 on 12 June and ended around 2035. Ash plumes rose 7.6 km (25,000 ft) a.s.l. and drifted SE. The ACC was raised to Red and the VAL was raised to Warning. At 0817 on 13 June a six-minute-long explosion was detected in seismic and infrasound data. A plume was not observed, likely because it was too small or below detection limits. The ACC was lowered to Orange and the VAL was lowered to Watch.

Karymsky | Eastern Kamchatka (Russia) : KVERT reported that a thermal anomaly over Karymsky was identified in satellite images during 3-8 June. Explosions on 8 June generated ash plumes that rose 2-3 km (6,600-9,800 km) a.s.l. and drifted 70 km E, SE, and SW. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Pavlof | United States : On 7 June AVO reported that during the past several days an increase in low-frequency earthquake activity was detected at Pavlof. This kind of activity can sometime precede eruptive episodes. In addition, several short-duration tremor bursts were observed, and a pilot reported a possible ash cloud to 1.2 km (4,000 ft) a.s.l. Infrasound data from instruments on the volcano and from a more distant network in Sand Point showed no evidence of significant explosive activity. AVO noted that since activity prior to eruptions of Pavlof had always been very subtle, they increased the Aviation colour Code to Yellow and the Alert Level to Advisory based on these observations. During 8-9 June gas emissions from the summit were observed in web camera images and by local observers in Cold Bay (60 km SW). AVO noted that vapor emissions (with or without minor amounts of volcanic ash) are common and may occur from the summit vent at any time.

Rincon de la Vieja | Costa Rica : OVSICORI-UNA reported that a small, minute-long, phreatic eruption in Rincón de la Vieja’s crater lake began at 0542 on 11 June. Poor visibility prevented visual confirmation of plume details, though the Washington VAAC reported that a thermal anomaly was present in satellite images. A small seismic signal that lasted less than one minute was recorded at 2106 on 12 June. The signal possibly represented an emission, though it was not confirmed.

Sheveluch | Central Kamchatka (Russia) : KVERT reported that during 3, 5, and 7-8 June powerful explosions at Sheveluch generated ash plumes that rose as high as 8 km (26,200 ft) a.s.l. and drifted 1,554 km SW, S, and SE. Pyroclastic flows traveled 10 km. Ashfall was reported in Klyuchi Village (50 km SW) on 8 June. A thermal anomaly was identified daily in satellite images. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

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