TOKYO, Apr 2 (Reporter) An earthquake with a preliminary magnitude of 6.1 struck off Japan's northern prefecture of Iwate early on Tuesday, according to the country's weather agency. The temblor occurred at 04:24 a.m. local time at a depth of 80 km, measuring lower 5 on Japan's seismic intensity scale, which peaks at 7, said the Japan Meteorological Agency (JMA). The epicenter was located off Iwate prefecture's northern coast at a latitude of 40.1 degrees north and a longitude of 141.7 degrees east. No tsunami warnings have been issued...////...