Roundup of Global Volcanic Activity – New Activity for the week of 19 September – 25 September 2018
Ketoi | Kuril Islands (Russia) : Based on a report from SVERT the Tokyo VAAC reported that on 21 September an ash plume from Ketoi drifted NE.
Piton de la Fournaise | Reunion Island (France) : OVPF reported that, based on visual observations and satellite data, a lava flow at Piton de la Fournaise had traveled 2.8 km S and then SE, and was 500 m from the S wall of Enclos Fouqué by 18 September. It was 660 m wide at the widest part. Volcanic tremor was at a low level and relatively stable on 19 September, and then decreased on 20 September. During fieldwork on 21 September volcanologists observed three active lava fountains that were continuing to build the cone. The E wall was 30 m high, particularly vertical, and appeared unstable with numerous fractures. The lava flows were well-channeled and had advanced several hundred meters since 19 September, threatening an OVPF seismic station. Volcanic tremor levels fluctuated during 21-22 September. Deposits of Pele’s hair were noted in the Grand Coude area (8-10 km SW) on 22 September. During an overflight that same day volcanologists noted that the three lava fountains in the cone were visible, and lava tubes had formed near the uppermost part of the channel. Volcanic tremor had doubled in intensity on 23 September. Compared to the beginning of the eruption on 15 September the sulfur dioxide emissions had decreased by a factor of six; gas plumes were small and drifted S and W, but were confined to the Enclos Fouqué.
Sarychev Peak | Matua Island (Russia) : KVERT reported a continuing eruption at Sarychev Peak (the NW part of Mantua Island) through 21 September. Island observers reported explosions at 1010 on 18 September that sent ash plumes to 4.5 km (14,800 ft) a.s.l. Ash plumes identified in satellite images during 17-18 September drifted 265 km E. The Aviation Color Code remained at Orange.
Semisopochnoi | United States : AVO reported that during 19-25 September seismicity at Semisopochnoi remained elevated, alternating between periods of continuous and intermittent bursts of tremor. Tremor bursts at 1319 on 21 September and at 1034 on 22 September produced airwaves detected on a regional infrasound array on Adak Island; no ash emissions were identified above the low cloud deck in satellite data, and the infrasound detections likely reflected an atmospheric change instead of volcanic activity. The Aviation Color Code (ACC) remained at Yellow and Volcano Alert Level (VAL) remained at Advisory.
Ulawun | New Britain (Papua New Guinea) : According to the Darwin VACC, a pilot observed an ash plume from Ulawun rising to an altitude of 3.7 km (12,000 ft) a.s.l. and drifting W. Ash was not confirmed in satellite images, though weather clouds obscured views.
Veniaminof | United States : AVO reported that the eruption at Veniaminof continued during 19-25 September, as evidenced by nighttime incandescence recorded by the FAA web camera in Perryville (35 km S), elevated surface temperatures in thermal satellite data, and elevated seismic activity. A gas plume was occasionally visible during clear daytime conditions. A lava flow had traveled 800 m down the S flank of the summit cone by 14 September, though satellite images from 18 September indicated no further advancement. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.