46 ]  Three other prefectures— Fukushima ,  Ibaraki  and  Tochigi —recorded an upper 6 on the JMA scale. Seismic stations in  Iwate , Gunma ,  Saitama  and  Chiba Prefecture  measured a lower 6, recording an upper 5 in Tokyo. In  Russia , the main shock could be felt in  Yuzhno-Sakhalinsk  (MSK