Fig. 4.

Cross-sectional views of ΔCFF for receiver faults of down-dip extension (DDE) type previously defined by Hiratsuka and Sato (2011) are shown for the profiles C–D and E-F in Fig. 3. They are calculated for the slip distribution with the center of slip close to the trench (Fig. 1(b)). In the panels (a) and (b), ΔCFF calculated for the model with the upper end of the fault situated at a depth of 6.5 km (a), and with the upper end of the fault situated at the free surface (b), are compared. The open circle indicates the event in the outer rise lying on the line C–D in Fig. 3. The focal depth of the aftershock in (b) is shifted upwards by 6.5 km relative to that shown in (a). (c) ΔCFF along the line E-F calculated for the model with the upper end of the fault placed at the free surface. The open circles indicate the two negatively-stressed normal-fault aftershocks near the trench close to the line E–F in Fig. 3. The mechanism diagrams of receiver faults are indicated in (c). Here, ΔCFF calculated for the westward dipping faults are shown. The broken lines respectively indicate the positions 10, 20, and 30 km below the plate interface.