An eruption that began at Karangetang on 5 March at 1344 produced an ash cloud to a height of ~1.5 km above the volcano's summit. Ash fell to the NE of the volcano. The eruption was accompanied by lava avalanches down the volcano's slopes. After the eruption, a plume of steam and possible ash was seen reaching ~400 m above the crater rim and a "red reflection" extended up to 25 m above the crater. An increase in volcanic and tectonic earthquakes occurred in comparison to the previous week. 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)