A 6.0-magnitude earthquake struck off northern Japan on Sunday, the US Geological Survey said, but Japanese authorities did not issue a tsunami warning and there were no immediate reports of damage.
The quake struck at 12:43 pm (0343 GMT) in the Pacific Ocean off Japan's northern Aomori prefecture at a depth of 37 kilometres (23 miles), the US agency said.
Aomori prefecture is some 600 kilometres northeast of Tokyo.
Japan's islands are situated at the conjuncture of several tectonic plates and experience a number of relatively violent quakes every year.
But, thanks to strict building codes, even powerful quakes that might wreak havoc in other countries frequently pass without causing much damage.
In May, a strong 6.0-magnitude earthquake shook buildings in the Japanese capital Tokyo, injuring 17 people.