PVMBG reported that during 8-14 September observers of Lokon-Empung noted white plumes rising 25-100 m above Tompaluan Crater. On 13 September three explosions from Tompaluan Crater, at 0300, 1146, and 1229, produced white plumes that rose at most 500 m above the crater. Seismicity decreased sharply after the13 September events but continued to remain high relative to the levels detected prior to 10 September. The Alert Level remained at 3 (on a scale of 1-4).

Geological Summary. The Lokong-Empung volcanic complex, rising above the plain of Tondano in North Sulawesi, includes four peaks and an active crater. Lokon, the highest peak, has a flat craterless top. The morphologically younger Empung cone 2 km NE has a 400-m-wide, 150-m-deep crater that erupted last in the 18th century. A ridge extending 3 km WNW from Lokon includes the Tatawiran and Tetempangan peaks. All eruptions since 1829 have originated from Tompaluan, a 150 x 250 m crater in the saddle between Lokon and Empung. These eruptions have primarily produced small-to-moderate ash plumes that sometimes damaged croplands and houses, but lava-dome growth and pyroclastic flows have also occurred.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)