Intraplate earthquakes in North China - Intraplate Earthquakes - page 102

(a)
(b)
Figure 5.3 P-wave travel time seismic tomography of China and the surrounding regions. (a) P-wave
velocity perturbation at 110 km depth. (b) P-wave velocity perturbation at 220 km depth. From Liu
et al . ( 2004 ) . For color version, see Plates section.
coastal regions in the east. Hence, the low-velocity mantle structures under North China
may be a horizontally expanded “mantle wedge” above both the active subducting slab in
the western Pacific and the stagnant slabs beneath much of the North China Plain (Huang
and Zhao, 2006 ) . This broad mantle wedge probably resulted from seaward retreat of the
western Pacific trench and the sinking of the Mesozoic and Cenozoic slabs now trapped at