Jakarta, Sept. 22 -- The series of earthquakes that struck the Sukabumi and Bogor regions in West Java on September 20-21 was caused by a shallow active fault with a strike-slip mechanism, the Meteorology, Climatology, and Geophysics Agency (BMKG) reported on Monday.

Daryono, head of BMKG's Earthquake and Tsunami Center, said the main shock, measuring magnitude 4.0, occurred on Saturday at 11:47 p.m. local time at a depth of 7 kilometers in Sukabumi District.

"Based on waveforms recorded by the DBJI Darmaga and CBJI Citeko seismic sensors, the quake was tectonic, not volcanic," he explained.

The quake caused minor damage to five houses in Kabandungan sub-district, which is home to around 20 residents. No casualties or injuries were rep...