An undersea earthquake of magnitude-6.0 hit off eastern Japan, the US Geological Survey reported. No tsunami alert was issued.
There were no immediate reports of damage or injuries from the quake, which the USGS said happened at 4:53am on Tuesday local time (01.23am IST).
The USGS said the quake hit some 107 kilometres (66 miles) east of Miyako, Japan, and some 327 kilometres (526 miles) northeast of Tokyo.
Japan's Meteorological Agency and the US National Oceanographic and Atmospheric Agency issued no tsunami warnings or alerts.