(Updates with Japanese data, changes dateline from London)
TOKYO, June 18 (Reuters) - A 6.4 magnitude earthquake struck off the coast of Japan early on Monday, the U.S. Geological Survey said, but there were no immediate reports of damage.
USGS put the quake 115 km (72 miles) southeast of Morioka on Japan's Pacific coast, and 31 km deep.
The Japan Meteorological Agency put it at magnitude 6.1, and slightly deeper at 40 km (25 miles).
The quake was rated only 4 on Japan's seven-point seismic scale, suggesting that no significant damage was expected, and no tsunami warning was issued.
(Editing by Kevin Liffey)