A moderately strong earthquake measuring magnitude 5.1 struck off the coast of Palawan on Tuesday afternoon, June 11, despite the absence of active faults in the province.
The Philippine Institute of Volcanology and Seismology (Phivolcs) recorded the shallow quake at 2:58 p.m. on Tuesday.
Its epicenter was located 91 kilometers southeast of Roxas, Palawan, with an estimated depth of 26 kilometers.
The highest felt intensity was reported in Roxas Palawan at Intensity III (weak).
Based on Phivolcs’ observation, the earthquake was generated by a “reverse fault,” characterized by mainly vertical movement.
It explained that the earthquake occurred offshore within the northwest Sulu Sea basin, where high-resolution bathymetric data suggest deformation of the seafloor due to potential reverse faults in this region.
“These offshore faults are potential sources of earthquakes,” it added.
Phivolcs reiterated that although there are no known active faults in Palawan, the province may still be affected by earthquakes and tsunamis from nearby faults and trenches.