A strong earthquake has hit southern Japan, but there have been no immediate reports of damage and no tsunami was expected. The Japan Meteorological Agency says the quake Wednesday had a preliminary magnitude of 6.1. It occurred off the coast of the Minamidaito island, near Okinawa, about 1,000 miles (1,600 kilometers) southwest of Tokyo. The quake's center was 6 miles (10 kilometers) below sea surface. The agency did not issue a tsunami alert and said there was no danger of damage from waves.