During 24 February to 2 March, volcanic activity at Karangetang's South crater consisted of "white-gray ash emissions" rising to low levels, incandescent glow extending to 50 m above the crater, and a booming noise that was heard from the observatory post. During the report period, there was an increase in the number of shallow volcanic earthquakes, while the number of multiphase earthquakes decreased. Karangetang remained at Alert Level 3 (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)