A magnitude 7.5 earthquake struck off the northeastern coast of Japan on Monday, as authorities urged residents to stay away from coastal areas where tsunami waves of up to 9.84 ft were expected. The biggest waves were forecast to hit Iwate and Aomori prefectures at the top of Japan’s main Honshu island, and the northern island of Hokkaido, authorities said. In the hour following the earthquake, which struck at 4:52 p.m. (0752 GMT), tsunami waves as high as 31.4 in had been detected, while warnings remained for waves as high as 9.84 ft.