An earthquake with a preliminary magnitude of 6.3 struck off southwestern Japan on Wednesday night, the US Geological Survey said, but there were no tsunami warnings or reports of damage.
The USGS put the epicentre of the quake in a channel that separates the islands of Kyushu and Shikoku, about 18 kilometres (11 miles) west of Uwajima, at a depth of about 25 kilometres.
