During 9-15 July volcanic activity was at a level similar to the previous week. Seismicity was dominated by 572 small explosions, 451 multiphase earthquakes, and continuous lava avalanches. The avalanches traveled up to 2.5 km down the Keting River and lava flowed as far as 750 m down the Kahetang River. In addition, a gray plume was emitted from the volcano, which 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)