Japan is bracing for three-metre-high tsunami waves after a powerful 7.2 magnitude earthquake struck offshore on Monday. Authorities warned that the northeastern coastline could see towering waves after the quake struck off the coast of Hokkaido. Hazardous waves were possible up to 620 miles from the epicentre, threatening Japan and Russia, the Pacific Tsunami Warning Center (PTWC) said. A wider advisory was issued for smaller waves of up to a metre along the eastern coastline. Watch more on