A moderate earthquake with a magnitude of 5.2 struck off the Pacific Ocean coast of western Japan on Sunday, the country's Meteorological Agency said. There was no immediate report of injuries and no danger of a tsunami, it said.
The quake hit at 3:39 a.m. (1839 GMT Saturday) approximately 310 kilometers (190 miles) out to sea, southwest of Tokyo, the agency said.
It was centered about 350 kilometers (217 miles) below the earth's surface, it said.
Japan sits atop four tectonic plates and is one of the world's most earthquake-prone countries.