Two earthquakes have shaken Indonesia, The Philippines and Japan within 30 minutes of each other, but no tsunami threat has been issued.
A strong 6.4 magnitude earthquake has struck off Indonesia's Talaud islands north of Sulawesi, seismologists said.
The quake hit at 00:38 am local time (3.38am AEDT), the US Geological Survey said, and was centred around 300 kilometres northeast of Manado and 320 kilometres southeast of the Philippine city of General Santos.
The second quake struck in northern Japan just 30 minutes later, registering a preliminary magnitude of 6.0.
The Pacific Tsunami Warning Center said there was no tsunami threat from either quake.
Indonesia sits on the Pacific "Ring of Fire" where tectonic plates collide, causing frequent seismic and volcanic activity in the region.
A 6.9 quake struck in the Banda Sea in December sparked panic but no reports of damage or casualties.