Resent studies on relationship between sites for co-seismic slip and a-seismic slip are reviewed. Through analysis of seismic wave and Global Positioning System (GPS) data set, the sites for co-seismic slip and a-seismic slip have been obtained in Hyuga-nada and Sanriku region. Those studies show three important results : (1) the sites for co-seismic slip, episodic a-seismic slip, and continuous a-seismic slip do not overlap but complementarily share the plate boundary : (2) after-slip (post-seismic slip) may play an important role especially in the triggering large earthquakes : (3) the depth range of a-seismic slip may be controlled by not only a thermal effect but also some other factors such as lateral heterogeneity of fluidpressure and serpentinization.
