Roundup of Global Volcanic Activity – New Activity for the week of 11 October – 17 October 2017
Agung | Bali (Indonesia) : PVMBG reported that although foggy conditions at Agung sometimes prevented visual observations, during 11-17 October dense white plumes were seen rising 200 m above the crater rim. On 14 October BNPB stated that seismicity remained high; PVMBG noted that seismicity was dominated by shallow volcanic events, and the number of volcanic earthquakes remained steady. The governor of Bali extended the state of emergency to 26 October, noting that the Alert Level remained at 4 (the highest level on a scale of 1-4). The number of evacuees was 139,199 (spread out in 389 shelters).
Ambrym | Vanuatu : The Vanuatu Geohazards Observatory (VGO) reported that aerial observations of Ambrym on 24 and 30 September, and 1 and 6 October, and the analysis of seismic data, confirmed that minor eruptive activity within the caldera was characterized by hot volcanic gas and steam emissions. The Alert Level remained at 3 (on a scale of 0-5). Areas deemed hazardous were within a 2-km radius from Benbow Crater and a 3-km radius from Marum Crater.
Aoba | Vanuatu : Based on analyses of satellite, video, and model data, the Wellington VAAC reported that during 13-14 October ash plumes from Aoba rose 2.1-4.6 km (7,000-15,000 ft) a.s.l. and drifted NW, N, and NE, though a short-lived event generated ash plumes that rose as high as 9.1 (30,000 ft) a.s.l.
Kirishimayama | Kyushu (Japan) : JMA reported that an eruption at Shinmoedake (Shinmoe peak), a stratovolcano of the Kirishimayama volcano group, began at 0534 on 11 October, prompting the agency to raise the Alert Level to 3 (on a scale of 1-5). Ash plumes rose 300 m above the crater rim (2 km a.s.l.) and drifted NE, though some news sources stated that plumes rose 2 km above the crater rim. Volcanic-tremor amplitude increased and inflation was detected. Ashfall was noted in at least four towns in the Miyazaki and Kagoshima prefectures. On 12 October ash plumes rose as high as 2 km. Based on JMA notices, pilot observations, and satellite data, the Tokyo VAAC reported that ash plumes rose 1.8-2.1 (6,000-7,000 ft) a.s.l. on 11 October and 3.4 km (11,000 ft) a.s.l. on 12 October. Gas measurements taken during field surveys on 12 and 13 October showed that the sulfur dioxide flux was 1,400 tons/day, an increase from 800 tons/day measured on 11 October. Volcanic tremor fluctuated but the amplitude was slightly lower. During 0823-1420 on 14 October an event produced a tall plume which rose 2.3 km above the crater rim. Another event, at 1505, generated a grayish-white plume that rose 1 km and then blended into the weather clouds. Ashfall was reported in Kirishima and Sono in the Kagoshima prefecture, and from Kobayashi in the Miyazaki prefecture to Hyuga city. An event was detected at 1300 on 15 October, and an increase in low-frequency earthquakes was recorded on 16 October.
Lewotolo | Lomblen Island (Indonesia) : PVMBG reported that white plumes rose as high as 50 m above Lewotolo’s summit crater rim. The Alert Level remained at 2 (on a scale of 1-4).
Sarychev Peak | Matua Island (Russia) : A NOAA/NESDIS scientist noted that a thermal anomaly at Sarychev Peak was identified in satellite images on 12 October. Robust thermal anomalies were identified on 14 October, and were accompanied by a plume of unknown composition. Thermal anomalies were also recorded by the MODVOLC and MIROVA thermal detection systems.