BNPB reported that an eruption at Soputan began at 1447 on 6 January. Observers at a nearby post reported a dense gray-to-black ash plume rising about 6.5 km above the summit and drifting ESE. Lava flows traveled 2 km down the WSW flank. The Alert Level remained at 3 (on a scale of 1-4). Based on ground reports from that same day, the Darwin VAAC reported that a significant eruption generated a plume that rose to an altitude of 8.2 km (27,000 ft) a.s.l. No ash was observed in satellite images due to weather clouds in the area.

Geological Summary. The Soputan stratovolcano on the southern rim of the Quaternary Tondano caldera on the northern arm of Sulawesi Island is one of Sulawesi's most active volcanoes. The youthful, largely unvegetated volcano is the only active cone in the Sempu-Soputan volcanic complex, which includes the Soputan caldera, Rindengan, and Manimporok (3.5 km ESE). Kawah Masem maar was formed in the W part of the caldera and contains a crater lake; sulfur has been extracted from fumarolic areas in the maar since 1938. Recent eruptions have originated at both the summit crater and Aeseput, a prominent NE-flank vent that formed in 1906 and was the source of intermittent major lava flows until 1924.

Sources: Badan Nacional Penanggulangan Bencana (BNPB), Darwin Volcanic Ash Advisory Centre (VAAC)