The USGS said the quake occurred at 4:47 am (2047 GMT), 125 kilometres (78 miles) west of Negros, at a depth of 19 kilometres, having initially measured the quake at a magnitude of 6.6.
The Philippines sits on the Pacific Ring of Fire -- a belt around the Pacific Ocean dotted by active volcanoes and tectonic trenches, where frequent eruptions and earthquakes take place.
Citizens have been nervous about a potential killer quake following the devastating tremors that have hit Japan and New Zealand this year.
One fault line runs directly under Manila, and government seismologists have warned that the city is unprepared for a major quake.
The Philippines sits on the Pacific Ring of Fire -- a belt around the Pacific Ocean dotted by active volcanoes and tectonic trenches, where frequent eruptions and earthquakes take place.
Citizens have been nervous about a potential killer quake following the devastating tremors that have hit Japan and New Zealand this year.
One fault line runs directly under Manila, and government seismologists have warned that the city is unprepared for a major quake.