Roundup of Global Volcanic Activity – New Activity for the week of 28 June – 4 July 2017
Bogoslof | Fox Islands (USA) : AVO reported that an explosion at Bogoslof was detected at 0124 on 30 June and lasted about 20 minutes. A small cloud from the event drifted about 16 km N and by 1815 had dissipated. Seismicity declined afterwards but continued intermittently at low levels. Beginning at 1248 on 2 July a significant explosive event was detected in seismic and infrasound data. The event lasted about 16 minutes, and produced an ash plume that rose as high as 11 km (36,000 ft) a.s.l. and drifted E. AVO raised the Aviation colour Code (ACC) to Red and the Volcano Alert Level (VAL) to Warning. Following the eruption seismicity declined and no signs of volcanic unrest were detected in seismic, infrasound, or satellite data on 3 July; the ACC was lowered to Orange and the VAL was lowered to Watch. The ACC and VAL were again raised to Red and Warning, respectively, following an explosive event that began at 1651 on 4 July and lasted 13 minutes. An eruption cloud rose as high as 8.5 km (28,000 ft) a.s.l. and drifted SE. An 11-minute-long eruption began at 1907 on 4 July, producing a small cloud that rose 9.8 km (32,000 ft) a.s.l. and drifted SE.
Dieng Volcanic Complex | Central Java (Indonesia) : BNPB reported that a phreatic eruption at the Sileri Crater lake (Dieng Volcanic Complex) occurred at 1154 on 2 July, ejecting mud and material 150 m high, and 50 m to the N and S. The event injured 11 of 18 tourists that were near the crater. According to a news article a helicopter on the way to help evacuated people after the event crashed, killing all eight people (four crewmen and four rescuers) on board. PVMBG scientists visited the next day and observed weak white emissions rising 60 m. The report noted other events during the recent past; an event at 1303 on 30 April ejected material 10 m high and 1 m past the crater edge that formed a 1-2 mm thick deposit, and an emission at 0941 on 24 May consisting of gas and black “smoke” that rose 20 m. The Alert Level remained at 1 (on a scale of 1-4) and PVMBG warned the public not to approach Sileri Crater within a 100-m radius.
Karymsky | Eastern Kamchatka (Russia) : KVERT reported that a thermal anomaly over Karymsky was identified in satellite images during 23-24 and 27-28 June. An ash plume drifted 55 km SW on 24 June. Explosions on 26 June generated ash plumes that rose to an altitude of 6 km (19,700 ft) a.s.l. and drifted 165 km SE during 26-27 June. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).
Reventador | Ecuador : During 28 June-4 July IG reported a high level of seismic activity including explosions, long-period earthquakes, harmonic tremor, and signals indicating emissions at Reventador. During 28 June-1 July plumes of water vapor and ash rose as high as 500 m above the crater rim. A 2-km-long lava flow continued to slowly advance down the NW flank. Incandescent blocks from the crater rolled at most 300 m down the W, SW, and S flanks. Cloudy weather prevented visual observations during 2-4 July.
Sheveluch | Central Kamchatka (Russia) : KVERT reported that a thermal anomaly was identified daily in satellite images over Sheveluch during 23-30 June. Explosions on 27 June generated ash plumes that rose as high as 10 km (32,800 ft) a.s.l. and drifted 1,400 km SE. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).
Ulawun | New Britain (Papua New Guinea) : Based on analyses of satellite imagery, the Darwin VAAC reported that on 28 June ash plumes from Ulawun rose to an altitude of 2.7 km (9,000 ft) a.s.l. and drifted W.