"A tsunami advisory has been issued as of 08:37 (2337 GMT) on July 30," the Japan Meteorological Agency said on X, warning that "tsunamis will strike repeatedly. Do not enter the sea or approach the coast until the warning is lifted."

Tsunamis of up to one metre were expected to hit between 10:00 am and 11:30 am (0100-0230 GMT), public broadcaster NHK said, calling for residents to stay away from coasts and riversides.