Fig. ,. Epicenter map of earthquakes with available focal mechanisms used for determining the stress field parameters in the Wadati-Benio# zone beneath North Honshu, Hokkaido corner and Hokkaido Island. The epicenters are marked by di#erent symbols depending on the subvolumes of the WBZ they belong to : +-Plane +, shallow low-angle thrust events, in North Honshu and the Hokkaido corner, and the upper WBZ subvolume beneath Hokkaido ; ,-Plane ,, the upper surface of the WBZ, --Plane -, the lower surface of the WBZ, in North Honshu and the Hokkaido corner, and the lower WBZ subvolume beneath Hokkaido ; .-the deep earthquakes in North Honshu and the Hokkaido corner ; /-earthquakes of magnitude in the range 0.*Md0.3 ; 0-earthquakes of magnitude in the range 1.*Md2.* ; 1-active volcanoes ; 2-trench axis. The solid lines are the contours of 1* km, +** km, +/* km and ,** km hypocentral depth and show the dip trend of the WBZ. The position of the deep seated earthquakes is outlined by a thick gray contour. The gray area A+ depicts the location of the slab folding according to Morya (+312) ; the gray area A, marks the location of the transition zone where the dip of the slab steepens rapidly according to Katsumata et al. (,**-).