PVMBG reported that heavy rain that began at noon on 7 August generated lahars at around 1230 and 1239 that descended Karangetang’s Nanitu, Timbelang, and Batuawang drainages on the W, SW, and S flanks, respectively. The lahar deposit in the Batuawang drainage varied between 5 cm and 1.5 m thickness and blocked a 150-m-long section of the Ondong-Ulu Siau Road. The Alert Level remained at 2 (on a scale of 1-4) and the public was warned to stay 1.5 km away from both Main Crater and North Crater and 2.5 km away on the S and SE flanks.

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.

Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM), Antara News