Two strong earthquakes with magnitudes greater than 6 struck off the east coast of Honsu, Japan, Wednesday, the U.S. Geological Survey said. The first quake, at a depth of 16 miles, was a magnitude of 6.8, USGS said. It was about 145 miles south of Kushiro, and 457 miles northeast of Tokyo, USGS said. The Japanese Japan Meteorological Agency issued a tsunami warning, Kyodo News reported. The second quake was a 6.1-magnitude event at a depth of about 5 miles, USGS said. Its epicenter was about 151 miles south of Kushiro and 447 miles northeast of Tokyo. Reports of damage or injuries for both quakes were not available.