Figure 7. Representation of the three stages of slab dehydration.

The V_P anomaly (same as Fig. 5b) is draped over the slab surface. Local earthquakes are marked by coloured dots. The location of the local V_P minimum near 50 km depth is highlighted by a dashed white line. The slab crust Moho is drawn assuming a 7 km crustal thickness. Yellow stars represent the hypocenters of large thrust earthquakes. The proposed extent of the seismogenic zone is marked by a red dashed line. Notice how the mantle wedge seismicity spatially correlates with the local V_P minimum and how intra-slab seismicity is enhanced near the fracture zone. See Fig. 5 caption for further display information. A rotating animation of the slab viewable in 3D is presented in Supplementary Movies 1 and 2.