A nuclear plant in Japan is closed for safety checks after a magnitude 6.5 earthquake occurred on Tuesday.
Train services were suspended for a time and highways were closed for inspection in the Tokyo region - but there were no immediate reports of major damage.
The focus of the tremor was around 150km southwest of Tokyo, 20km below the surface of Suruga Bay in Shizuoka prefecture, at 5.07am local time.
The Japan Meteorological Agency said the quake had a preliminary magnitude of 6.5, revised down from an initially reported 6.6.
The Chubu Electric Power Company halted operations at a nuclear plant in Hamaoka, Shizuoka, after two reactors shut down automatically.
The ministry of trade said an alarm was activated for high radioactivity inside one unit but there was no radioactive impact on the outside environment.
Power was cut to 9,100 houses and the main expressway down the Pacific coast was closed for damage inspection.
Quake near India triggers tsunami warning
Separately, a magnitude 7.6 earthquake occurred off the Andaman Islands in eastern India, triggering a tsunami alert across large sections of the Indian Ocean. It has now been cancelled.
The US Geological Survey said a tsunami watch was issued for India, Burma, Indonesia, Thailand and Bangladesh. It has now been cancelled.
The ABC reports the Andaman Islands quake occurred around 263km north of Port Blair, the main town in the Andamans. It was about 33km deep.
Indonesia says there are no reports of a tsunami, but it is monitoring the Aceh area.
The Andaman Islands were hit by the 2004 Asian tsunami which was triggered by an earthquake off the Indonesian island of Sumatra.
The tsunami killed more than 220,000 people - mostly in Aceh but also in Sri Lanka, Burma, Thailand and India.
