CVGHM reported that on 27 December seismic activity at Lokon-Empung suggested that an eruption had occurred, but fog prevented visual observations of the crater area. CVGHM noted on 28 December that the Alert Level remained at 3 (on a scale of 1-4), and reminded residents and tourists to not approach within a 2.5 km radius of the crater. Based on information from CVGHM, the Darwin VAAC reported that on 29 December an ash plume rose to an altitude of 3.7 km (12,000 ft) a.s.l.

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.

Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM), Darwin Volcanic Ash Advisory Centre (VAAC)