Roundup of Global Volcanic Activity – Ongoing Activity for the week of 1 February-7 February 2017 – cont.
Kilauea | Hawaiian Islands (USA) : During 1-7 February HVO reported that the lava lake continued to rise and fall, circulate, and spatter in Kilauea’s Overlook vent. Webcams recorded incandescence from long-active sources within Pu’u ‘O’o Crater and from a vent high on the NE flank of the cone. The 61G lava flow, originating from a vent on Pu’u ‘O’o Crater’s E flank, continued to enter the ocean at Kamokuna. All surface flows were active within 2.4 km of Pu’u ‘O’o.
HVO geologists noted an extensive crack running parallel to the sea cliff about 5-10 m behind the stream of lava entering the ocean at Kamokuna. The crack was 30 cm wide on 28 January and 70 cm wide four days later, on 1 February. In addition, the seaward block bounded by this crack was visibly moving up to 1 cm, and ground shaking could be felt up to several hundred meters away. On 2 February the crack was wider and steaming, and the stream of lava that had been pouring into the ocean from an opening in a lava tube about 20 m above the water was no longer visible (though lava continued to enter the ocean). At about 1255 almost the entire section of the sea cliff that was seaward of the hot crack collapsed. The collapsed block generated a wave that propagated outward from the coast. After the collapse, no lava was visible entering the ocean though a steam plume and spatter from explosions indicated that the entry remained active.
Sabancaya | Peru : Based on webcam and satellite views, the Buenos Aires VAAC reported that sporadic gas-and-ash puffs rose from Sabancaya during 2-6 February. Weather clouds sometimes prevented visual observations.
Sheveluch | Central Kamchatka (Russia) : KVERT reported that during 27 January-3 February lava-dome extrusion onto Sheveluch’s N flank was accompanied by strong fumarolic activity, dome incandescence, ash explosions, and hot avalanches. Satellite images showed a daily thermal anomaly over the dome. The Aviation Color Code remained at Orange.
Sinabung | Indonesia : Based on PVMBG observations, satellite and webcam images, and wind data, the Darwin VAAC reported that during 2-7 February ash plumes from Sinabung rose to altitudes as high as 7.3 km (24,000 ft) a.s.l. and drifted NE, E, SE, and SW.
BNPB reported that each day during 2-7 February there were 8-12 ash-producing events with plumes rising as high as 2 km above the crater and drifting E. Pyroclastic flows traveled as far as 2 km S, SE, and E. BNPB noted that more areas had been designated disaster prone, therefore the number of people needed to be relocated also increased. The Alert Level remained at 4 (on a scale of 1-4), with an exclusion zone of 7 km from the volcano on the SSE sector, and 6 km in the ESE sector, and 4 km in the NNE sector.
Turrialba | Costa Rica : On 1 February OVSICORI-UNA reported that since 27 January the seismic network at Turrialba recorded variable-amplitude, discontinuous tremor indicative of moving pressurized volcanic fluid. Passive emissions of ash were observed during 1-2 February, rising as high as 500 m above the crater. Ashfall was reported in Desamparados, Calle Blancos, and Tres Ríos, and a sulphur odour was noted in San Pablo Heredia. An eruption at 0900 on 4 February generated an ash plume that rose 300 m and drifted W. Almost continuous ash emissions rose at most 500 above the crater during 4-5 February and drifted WSW. Variable-amplitude tremor continued to be recorded.