Fog limited clear views of summit activity at Karangetang during the reporting period. Lava flows were observed during 27-31 July moving E toward the Kahetang and Batu Awang rivers at a maximum distance of ~750 m from the vent. Rockfalls traveled up to 2 km towards the Keting River. On 31 July, gas plumes reached a maximum height of 200 m above the summit (or ~6,500 ft a.s.l.).

According to news reports, between 3,000 and 4,000 people from five villages were evacuated on 27 and 28 July due to advancing lava flows and reports of lahars. The news also noted that on 29 July, about 1,300 people remained in shelters.

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), Agence France-Presse (AFP), Jaknews