An earthquake with a preliminary magnitude of 5.5 has shaken eastern Japan including Tokyo. But the Japan Meteorological Agency said that there was no danger of a tsunami. The agency said that the quake struck at 7:46 p.m. or 1046 GMT Tuesday in the southern Ibaraki prefecture northeast of Tokyo. It was at a depth of about 50 kilometers or 30 miles. Authorities said that there were no reports of damage or injuries from the temblor so far. Bullet trains serving northeastern regions were temporarily suspended for safety checks.