PVMBG reported that during 12-18 August lava continued to effuse from Karangetang’s Main and Dua craters. Avalanches of material traveled 1-1.5 km SW down the Nanitu and Pangi drainages, as far as 1.4 km down a drainage W of Pangi, and as far as 1.8 km down the Sense drainage. Sometimes dense white plumes rose to 500 m above the summit. The Alert Level remained at 2 (on a scale of 1-4).

Geological Summary. 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. 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 (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.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)