A strong earthquake with a preliminary magnitude of 6.7 jolted Aomori and Iwate prefectures Thursday morning but did not spawn significant tsunami, the Meteorological Agency said.
The agency issued Iwate Prefecture a warning for tsunami of up to 50 cm immediately after the 6:51 a.m. quake but lifted it at 7:45 a.m.
The temblor was an apparent aftershock from the magnitude 9.0 megaquake on March 11.
There were no immediate reports of injuries or damage from the quake, which registered lower 5 on the Japanese seismic intensity scale to 7 in the town of Hashikami, Aomori Prefecture, and in northern areas of Iwate Prefecture, including the city of Morioka.
Nuclear power stations in the area also escaped damage, including the crisis-hit Fukushima No. 1 nuclear plant in Fukushima Prefecture, the Higashidori plant, a reprocessing plant for radioactive waste in Aomori Prefecture, and the Onagawa plant in Miyagi Prefecture, the Nuclear and Industrial Safety Agency said.
East Japan Railways Co. said the Tohoku Shinkansen Line was temporarily suspended between Ichinoseki and Shinaomori stations, affecting some 600 people.