Philippines earthquake: Magnitude 6.9 seismic tremor hits the Pacific islands chain, reports USGS
There were no immediate reports of damage or injury from the quake, which hit at a depth of 41 km (26 miles) about 580 km (360 miles) southwest of the capital, Manila.
The USGS has since revised the details of the tremor.
The strength was revised down to 6.5 while the depth at which it struck was thought to be 6.5km.
In the immediate vicinity of the epicentre tremors were classed as strong, the service said.
It issued a yellow notice for potential economic losses, but said deaths were unlikely.
The Philippine Institute of Volcanology and Seismology said it expected some damage and aftershocks. However, there were no immediate reports of serious damage or casualties.
Local residents reported strong shaking and said people fled from their houses, and some were knocked over.
Additional reporting by agencies