There were no immediate reports of casualties or damage from the quake, which the USGS reported occurred at a depth of 101 kilometres (63 miles) about 70 kilometres from the nearest areas of Davao Occidental province.

"The shake was not that strong, but the tables and computers here at the office shook for (about five seconds)," Marlawin Fuentes, a provincial rescuer from the tiny island of Sarangani, told AFP.

No tsunami alert was triggered.

Quakes are a near-daily occurrence in the Philippines, which is situated on the Pacific "Ring of Fire", an arc of intense seismic activity that stretches from Japan through Southeast Asia and across the Pacific basin.

Most are too weak to be felt by humans, but strong and destructive ones come at random with no technology available to predict when and where they might strike.