The elevated seismic activity at the volcano continues to be recorded.
During 1 – 18 October, the PVMBG seismic network detected 24 volcano-tectonic earthquakes with amplitude ranging between 0.2-6 mm. On 1 October, an increased 78-minute long-lasting amplitude of tremor was monitored.
The EDM (Electronic Distance Measurement) data continues to detect the slight uplift at the Cilik station and the deflation at the Buncis and Jurangmangu stations. Since July 2023, instruments have monitored the continuing inflation (30 microradians) at 1,500 meters above sea level. During 11-18 October, the tiltmeter station at an altitude of 2,000 meters detected a ground uplift by 40 microradians.
Whether the activity will continue to increase is not clear yet, but rapid gain in inflation of the ground surface, relating to the accumulation of magma or the exolution of gas inside reservoirs or propagation of magma through intrusions or conduits, might culminate in a sudden phreatic eruption. Phreatic explosions form when the ejecta consist solely of old country rock, indicating interaction between water and heated conduit-rocks rather than magma itself.
Despite the ongoing elevated activity, a decision has been made to raise the alert level for the volcano from Level 1 (Normal) to Level 2 (Waspada).
In order to mitigate the current risk, people are advised to avoid the area of about 2 km distance from the main crater.
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi volcano activity update 20 October 2023
