A powerful magnitude 7.4 earthquake off northeastern Japan late Wednesday left three people dead and more than 160 injured across 12 prefectures and caused a high-speed shinkansen to derail. Prime Minister Fumio Kishida said Thursday that authorities are looking into a total of four deaths apparently caused by the quake, while the Defense Ministry dispatched the Self-Defense Forces for disaster relief in Fukushima Prefecture to provide water service in areas where supply has been disrupted. The 11:36 p.m. temblor, which came two minutes after a magnitude 6.1 quake, registered an upper 6 on Jap…