According to PVMBG the eruption at Karangetang’s Main Crater (S crater) continued during 22-28 February. Nighttime webcam images posted with daily reports showed incandescent lava flows descending the flanks, though images from 0054 on 26 February and 0026 on 1 March showed only minor incandescence near the summit. The Darwin VAAC reported that during 22-23 February ash plume rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted SE based on analyses of satellite imagery and weather models. The Alert Level remained at 3 (on a scale of 1-4) and the public were advised to stay 2.5 km away from Main Crater with an extension to 3.5 km 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), Darwin Volcanic Ash Advisory Centre (VAAC)