The earthquake hit at 2.46pm (5.46am GMT) and measured magnitude 7.9. It was centered 10 kilometers below the Pacific Ocean off Miyagi prefecture. Railway and subway lines stopped, expressways closed and a nuclear power station automatically stopped. The quake, which was the strongest felt for years in Tokyo, was followed by several aftershocks. The earthquake measured 7 on the Japanese scale of 1 to 7 in Miyagi Prefecture. It is the strongest quake in Japan for years.”]
Source: https://www.csoonline.com/article/2127600/major-quake-shakes-japan.html