Report on Karangetang (Indonesia) — 31 July-6 August 2019
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 31 July-6 August 2019
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2019. Report on Karangetang (Indonesia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 31 July-6 August 2019. Smithsonian Institution and US Geological Survey.
2.781°N, 125.407°E; summit elev. 1797 m
All times are local (unless otherwise noted)
PVMBG reported that beginning at 1858 on 20 July incandescent avalanches of material from Karangetang’s Main Crater traveled as far as 1 km W down the Pangi and Kinali drainages. By 22 July incandescent material had traveled another 500 m down the same drainages, and 1 km down the Nanitu and Beha drainages. Based on analyses of satellite imagery and model data, the Darwin VAAC reported that during 30-31 July intermittent discrete ash plumes rose to an altitude of 7.6 km (25,000 ft) a.s.l. and drifted W, and continuous ash emissions rose to 3 km (10,000 ft) a.s.l. A thermal anomaly was visible. On 5 August ash plumes rose to 3 km (10,000 ft) a.s.l. and drifted E; a thermal anomaly was again visible. The Alert Level remained at 2 (on a scale of 1-4).
Geologic Background. Karangetang (Api Siau) volcano lies at the northern end of the island of Siau, about 125 km NNE of the NE-most point of Sulawesi island. The stratovolcano contains five summit craters along a N-S line. It is one of Indonesia's most active volcanoes, with more than 40 eruptions recorded since 1675 and many additional small eruptions that were not documented in the historical record (Catalog of Active Volcanoes of the World: Neumann van Padang, 1951). Twentieth-century eruptions have included frequent explosive activity sometimes accompanied by pyroclastic flows and lahars. Lava dome growth has occurred in the summit craters; collapse of lava flow fronts have produced pyroclastic flows.