Just released from the US Geological Survey is a shakemap of Japan. A shakemap actually details the amount of earth movement (or shaking intensity) felt across the island. This interactive Google Earth file will give your students a good indication of how severe the quake was. (I've added a yellow pushpin to the USGS map, to indicate the location of the damaged nuclear reactors. The Google Earth file was developed after the tsunami hit but before the the fires or explosions at the powerplants.)
