Volcanos

Roundup of Global Volcanic Activity – New Activity for the week of 12 September -18 September 2018

Ioto | Japan : During an overflight of Ioto (Iwo-jima) on 12 September the Japan Maritime Self Defense Force observed seawater jetting 5-10 m above the sea surface on the S coast, suggestive of a submarine eruption.

Piton de la Fournaise | Reunion Island (France) : OVPF reported that after several hours of increased seismicity at Piton de la Fournaise a seismic crisis began at 0145 on 15 September, accompanied by rapid deformation. Tremor began at 0425, contemporaneous with the opening of fissures on the S flank near Rivals Crater. Around 1000 an estimate of the lava flow rate, based on satellite data, was 30 cubic meters per second. During an overflight about an hour later observers noted five fissures. The central fissure was the most active, producing lava fountains 30 m high; two lava flows that merged downstream had already flowed more than 2 km towards the wall of the Enclos Fouqué. By the afternoon of 16 September the estimated flow rate was between 2.5 and 7 cubic meters per second. Only three vents were active and a cone had started to form. Lava flows continued to advance during 16-18 September.

Sarychev Peak | Matua Island (Russia) : SVERT and KVERT reported increased activity and ash emissions at Sarychev Peak in mid-September. A thermal anomaly had been periodically visible since 7 May 2018, though more recently anomalies were detected during 8 and 11-12 September. Explosions sometimes occurred during 11 and 13-15 September, and ash emissions rose 3-4 km (10,000-13,100 ft) a.s.l. On 14 September ash plumes drifted as far as 120 km. On 14 September KVERT stated that the Aviation Color Code was raised to Orange, though on 17 September SVERT noted that the Aviation Color Code was at Yellow. KVERT reported that explosions at 0910 on 17 September generated ash plumes that rose as high as 4.5 km (14,800 ft) a.s.l. and drifted 21 km NE.

Semisopochnoi | United States : On 16 September AVO raised the Aviation Color Code (ACC) for Semisopochnoi to Yellow and Volcano Alert Level (VAL) to Advisory after increased seismicity was detected at 0831. Retrospective analysis of satellite data acquired on 10 September revealed small ash deposits on the N flank of Mount Cerberus, possibly associated with two bursts of tremor recorded on 8 September. This new information coupled with intensifying seismicity and a strong tremor signal recorded at 1249 on 17 September prompted AVO to raise the ACC to Orange and the VAL to Watch. Seismicity remained elevated on 18 September with nearly constant tremor being recorded by local sensors.

Veniaminof | United States : AVO reported that the eruption at Veniaminof continued during 12-18 September. A lava flow had traveled 800 m down the S flank of the summit cone by 14 September, remaining confined to the ice-filled summit caldera. A webcam in Perryville (35 km S) recorded nighttime incandescence, and sporadic gas emissions in the day during clear conditions. Elevated surface temperatures were identified in satellite images, and seismicity remained elevated. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.