Is it dangerous?
The US Tsunami Warning Centre has issued no warning, advisory, watch or threat after the quake in the Celebes Sea, which lies in the western Pacific between Sulawesi and the Philippines.
Seismologists said it was too deep to cause any damage and casualties or a tsunami. The Philippines Institute of Volcanology and Seismology (Phivolcs) has, however, warned of aftershocks.
What caused the earthquake?
Renato Solidum of Phivolcs said the quake was set off by the movement of oceanic plates 625 kilometers (387 miles) under the seabed. Solidum said the undersea quake was centered 223 kilometers (138 miles) southeast of Sulu province.
Are earthquakes common in the Pacific Ocean?
Earthquakes and volcanic eruptions are common in the Pacific Ocean basin, particularly in the "Ring of Fire". A magnitude 7.7 quake killed nearly 2,000 people in the northern Philippines island of Luzon in 1990.