6.1-magnitude quake strikes northern Japan

TOKYO -- An earthquake with a preliminary magnitude of 6.1 struck off Japan's northern prefecture of Iwate early Tuesday, according to the country's weather agency.

The temblor occurred at 04:24 am 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.