Roundup of Global Volcanic Activity – New Activity for the week of 17 May – 23 May 2017
Manam | Papua New Guinea : Based on analyses of satellite imagery and model data, the Darwin VAAC reported that during 18-20 May ash plumes from Manam rose 2.1-2.7 km (7,000-9,000 ft) a.s.l. and drifted W and WNW.
Nishinoshima | Japan : The Japan Coast Guard reported that during an overflight of Nishinoshima during 1300-1345 on 2 May observers noted frequent (every 40-60 seconds) Strombolian explosions at a new pyroclastic cone in the crater. Ash plumes rose 500 m. Two lava flows originating from the N part of the cone traveled 180 m SW and 170 m W, and entered the ocean. The island continued to grow and was estimated to be 2 km E to W and about 1.9 km N to S, with an area of 2.75 square kilometers (it was 2.68 square kilometers on 15 September 2016).
Poas | Costa Rica : OVSICORI-UNA reported that tremor levels at Poás were at low-to-moderate levels during 17-21 May and at higher levels during 22-23 May. Low-amplitude long-period earthquakes were recorded on 19 May, and some low-frequency and volcano-tectonic events were detected during 21-22 May. Plumes consisted mainly of gas and water vapor, but sometimes included solid material, and rose no more than 1 km above the vent.
Sheveluch | Central Kamchatka (Russia) : KVERT reported that during 13-14 May a series of explosions at Sheveluch generated ash plumes that rose 4.5-5 km (14,800-16,400 ft) a.s.l. and drifted SW and SE. Powerful explosions on 16 May generated ash plumes that rose as high as 11 km (36,100 ft) a.s.l. and drifted about 150 km ENE. Pyroclastic flows descended the S flank. Two explosions were detected on 18 May. Ash plumes during 16-19 May drifted 400 km ENE. The Aviation colour Code (ACC) remained at Orange during 13-19 May, except for a few hours on 16 May when the strong explosions prompted KVERT to raise the ACC to Red.