This was an interplate earthquake , with a low-angle reverse fault focal mechanism , which ruptured part of the plate interface . The region of the largest slip in this earthquake coincides with the region of low seismic moment release in the 1968 Offshore Tokachi earthquake on May 16 , 1968 , implying that the 1994 Offshore Sanriku earthquake completed the incompleted fault slip in the source region of the 1968 Offshore Tokachi earthquake . The average slip of the fault was estimated to be 0.4 m and the maximal slip about 1.2 m
1968 Offshore Tokachi earthquake
1968 Tokachi earthquake
1994 offshore Sanriku earthquake