TOKYO - A strong earthquake hit off the coast of Japan early Thursday, the U.S. Geological Survey said, waking up people 100 miles away in Tokyo.

There were no immediate reports of injuries or damages, and no tsunami warning had been issued, public broadcaster NHK said. The magnitude 6.8 earthquake was felt as far away as Tokyo to the southwest, the broadcaster said.

The earthquake struck at 1:45 a.m. offshore at a depth of about 25 miles, according to the U.S. Geological Survey.

NHK reported that a second quake hit in the same area about half an hour later with a magnitude of 5.3.

Japan is one of the most earthquake-prone countries in the world because it sits atop four tectonic plates. Tokyo has not been hit by a major quake since 1923, when 140,000 people died in the Great Kanto Earthquake.

Source:news.yahoo