"Thursday's quake hit about 30 miles (47 kilometers) off the shore of Iwate prefecture at 6:51 a.m. (2151 GMT Wednesday), the Japan Meteorological Agency said. Much of the coast in the area is still heavily damaged from March's disasters." From earthquake.usgs.gov:
A tsunami warning was issued, but later cancelled. The location of today's quake is very near the big one that happened in March.