The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that blue flames on the crater walls of Papandayan’s Baru Crater were visible at 1900 on 12 July. The blue flames suggested increased temperatures at the solfatara along with the presence of oxidized sulfur. Dense emissions were seen rising 15-30 m from the crater at 2140 during a field visit. The plumes drifted W. The report noted that white plumes rose 5-30 m from both Baru and Mas craters during 1-12 July. Blue flames were last observed in March 2023. The Alert Level remained at 1 (on a scale of 1-4) and tourists were advised to stay 500 m away from the active craters.

Geological Summary. Papandayan is a complex stratovolcano with four large summit craters, the youngest of which was breached to the NE by collapse during a brief eruption in 1772 and contains active fumarole fields. The broad 1.1-km-wide, flat-floored Alun-Alun crater truncates the summit of Papandayan, and Gunung Puntang to the north gives a twin-peaked appearance. Several episodes of collapse have created an irregular profile and produced debris avalanches that have impacted lowland areas. A sulfur-encrusted fumarole field occupies historically active Kawah Mas ("Golden Crater"). After its first historical eruption in 1772, in which collapse of the NE flank produced a catastrophic debris avalanche that destroyed 40 villages and killed nearly 3000 people, only small phreatic eruptions had occurred prior to an explosive eruption that began in November 2002.

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