MANILA, Philippines (AP) - An undersea 6.9-magnitude earthquake hit the southern Philippines on Saturday morning but it was too deep to cause any damage, officials said.
No tsunami alert was issued, said the Pacific Tsunami Warning Center, based in Hawaii. The quake hit the Moro Gulf off Mindanao Island early Friday morning, the U.S. Geological Survey said. It said the quake had a preliminary magnitude of 7.4 but the Philippine Institute of Volcanology and Seismology later reported a 6.9 magnitude.
"The origin of the quake was 606 kilometers (375 miles) underground so it was barely felt," the institute's Director Renato Solidum Jr. said in an interview on DZBB radio.
The temblor was centered about 75 miles (121 kilometers) southwest of Cotabato city and about 566 miles (910 kilometers) southeast of the capital, Manila.
The Philippine archipelago lies in the so-called Pacific Ring of Fire where earthquakes are common. It is flanked by the Pacific Ocean to the east and the South China Sea to the west with undersea trenches - potential quake triggers - running alongside its coast on both sides.
A major quake that registered a magnitude 7.7 in 1990 killed nearly 2,000 people on the main northern island of Luzon.