During 22 April-26 May, small steam plumes rose 50-500 m above Karangetang's main crater and 10- to 25-m-high "red reflections" were visible above the crater at night. An ash explosion on 12 May at 1116 rose 750 m above the crater and drifted E over the sea. The eruption was followed by lava avalanches that traveled S down the Batu Awang river, and E down the Kahetang river to a maximum run-out distance of ~500 m. Another explosion occurred on 26 May at 1747; it produced an ash cloud to a height of 300 m above the crater that drifted to the W. Karangetang remained at Alert Level 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)