PVMBG reported that during 26 August-1 September emissions at Tangkubanparahu's Ratu Crater were characterized by puffs of dense black ash plumes rising as high as 20 m above the vent and white vapor plumes containing minor amounts of ash rising as high as 200 m. A larger event recorded at 0930 on 31 August generated a dense black tephra plume that rose 300 m and a white steam plume that rose 600 m. Ashfall was localized around Ratu Crater. The seismic network recorded continuous tremor. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to stay 1.5 km away from the active crater.

Geological Summary. Gunung Tangkuban Parahu is a broad stratovolcano overlooking Indonesia's former capital city of Bandung. The volcano was constructed within the 6 x 8 km Pleistocene Sunda caldera, which formed about 190,000 years ago. The volcano's low profile is the subject of legends referring to the mountain of the "upturned boat." The Sunda caldera rim forms a prominent ridge on the western side; elsewhere the rim is largely buried by deposits of the current volcano. The dominantly small phreatic eruptions recorded since the 19th century have originated from several nested craters within an elliptical 1 x 1.5 km summit depression.

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