Structural Anomaly at the Boundary Between Strong and Weak Plate Coupling in the Central‐Western Nankai Trough

To investigate structural characteristics associated with variations in slip behavior on the plate boundary Nankai subduction zone, we conducted seismic reflection surveys central-western Trough. Data were processed by pre-stack depth migration. The resulting map of top subducting Philippine Sea shows detailed topographic features boundary, including seamounts and large-scale undulations surface. We report presence a structurally anomalous region, potentially low velocity, overriding at between zone large coseismic during 1946 earthquake area producing slow earthquakes. This anomaly appears to be related depth-dependent style coupling