BMKG: Bekasi Earthquake Triggered By Citarum-Baribis Fault Activities

BMKG Bekasi Earthquake Center Map Wednesday 20 August 2025 (@bmkg)

JAKARTA - The Meteorology, Climatology and Geophysics Agency (BMKG) reported that a tectonic earthquake with a magnitude of 4.9 rocked the southeast of Bekasi Regency, West Java, on Wednesday night, August 20. The epicenter of the earthquake was located near the Cirata Reservoir, in the Citarum fault segment.

"The epicenter of the earthquake last night was in the south of the Citarum segment. Because the West Java back arc thrust dived towards the south, so the epicenter was in the south of the Baribis Fault," explained the Director of the BMKG Earthquake and Tsunami, Dr. Daryono, Thursday, August 21.

Based on the seismic map released by BMKG, the epicenter or epicenter of the earthquake is characterized by a red star symbol in the coordinates near the Cirata Reservoir area. Analysis of the earthquake mechanism shown by the focal mechanism (red and white) indicates this earthquake is related to upward fault activity in the Baribis segment, which is part of the West Java back arc thrust belt system.

This fault system is a complex fault zone that dives south below Java Island. The existence of earthquakes in this segment confirms that tectonic activity in West Java is not only influenced by the subduction of the Indo-Australian Plate in the south, but also by the interaction of various active faults on land.

The BMKG map also clearly displays a main fault network around the earthquake site, including the Sesar Baribis, Citarum, Lembang, Cimandiri, and others. The included 0-50 km map scale helps estimate the relative distance of the epicenter to nearby cities and the fault structure.

"BMKG urges the public to remain calm, always be alert to potential aftershocks, and avoid information that cannot be justified," concluded Daryono.