A heightened activity at the volcano has been detected at 06:00 AM yesterday.
Puffs of moderate fine ash emissions could be seen rising from the crater associated with a strong pressure inside the edifice.
Over the past several months, active gas and water vapor emissions (so-called degassing ) have been monitored, rising about 50-900 meters above the vent.
Seismic recordings continue to monitor a constant volcanic tremor with an amplitude of 0.5-1 mm. The seismic station has recorded three volcano-tectonic earthquakes during December so far.
Ground deformation instruments detected the edifice inflated during December.
The current potential hazards pose an occurrence of sudden violent, either phreatic or conventional, the most likely vulcanian-type eruption generating volcanic bombs, blocks or other pyroclastic material. In order to mitigate the risk, residents, tourists and climbers are advised to avoid an area of about 1 km distance from the main crater.
The alert level for the volcano remains at Level 2 (Alert).
The 16-km-wide Tengger caldera is located at the northern end of a volcanic massif extending from Semeru volcano. The massive Tengger volcanic complex dates back to about 820,000 years ago and consists of five overlapping stratovolcanoes, each truncated by a caldera. Lava domes, pyroclastic cones, and a maar occupy the flanks of the massif. The Ngadisari caldera at the NE end of the complex formed about 150,000 years ago and is now drained through the Sapikerep Valley. The most recent of the Tengger calderas is the 9 x 10 km wide Sandsea Caldera at the SW end of the complex, which formed incrementally during the late Pleistocene and early Holocene. An overlapping cluster of post-caldera cones was constructed on the floor of the Sandsea Caldera within the last several thousand years. The youngest of these is Bromo, one of Java’s most active and most frequently visited volcanoes.
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi volcano activity update 13 December 2023
