MANILA — A pregnant woman has died, four people injured, and nine are missing after a powerful earthquake hit the Philippines’ second-largest island of Mindanao.

Defense Secretary Gilbert Teodoro said 529 families have been affected.

The US Geological Survey measured the first tremor late on Saturday at 7.6 magnitude, followed by four major aftershocks exceeding 6.0.

The quakes had triggered tsunami warnings that were later lifted.

The powerful magnitude 7.6 quake struck off the coast of Mindanao island at a depth of 32km (20 miles) and was followed by four major aftershocks of magnitudes exceeding 6.0 over several hours into Sunday, the USGS said.

The European Mediterranean Seismological Centre, however, put the quake’s magnitude at 7.5.

The initial quake that struck at 10:37 p.m. (14:37 GMT) triggered tsunami warnings across the Pacific region and sent residents along the east coast of Mindanao fleeing buildings, evacuating a hospital and seeking higher ground.

The Philippine Institute of Volcanology and Seismology measured the quake at 7.4, and recorded at least 600 aftershocks with magnitudes raging from 1.4 to 6.2.

Earlier, residents of coastal areas of Surigao Del Sur and Davao Oriental had been told to evacuate to higher ground after the first earthquake at about 22:37 local time (14:37 GMT) off Mindanao’s eastern coast.

People in several towns not far from the quake’s epicenter were seen rushing out of buildings and staying in open areas. In Butuan City, patients were evacuated from a hospital.

In the Hinatuan municipality — about 21km from the epicenter — crowds gathered at evacuation centers. Disaster officials there are inspecting villages for damage and casualties.

One disaster official for Bilsig City told AFP that there have been no reports of major damage to buildings or infrastructure so far, but some roads in the city in the Surigao Del Sur province were cracked during the quake and the aftershocks.

In Japan, northeast of the Philippines, tsunami waves of up to 0.4m (1.3ft) were later observed on some outlying islands.

The two island nations are part of the Pacific “Ring of Fire” — a zone of major seismic activity which has one of the world’s most active fault lines.

The Mindanao quakes come nearly two weeks after a 6.7 magnitude quake hit the island, killing at least nine people, shaking buildings and causing part of a shopping mall ceiling to collapse. — BBC