Fig. 5

Comparison of the spatial variation of slope angle α in the Japan Trench and the coseismic slip distribution. A Compiled coseismic slip along the Japan Trench (red contours). The epicenter of the Tohoku-Oki earthquake is shown by a yellow star, and the red lines show the positions of bathymetric profiles used to obtain α. B Distribution of the slope angle α along the Japan Trench. The red area corresponds to the coseismic slip area in the map in A (Saito et al. 2011). The orange bar indicates the peak of the α distribution histogram. C North–south variation of the effective coefficient of basal friction from the seismic profiles (Koge et al. 2014). The red dots were determined by Tsuru et al. (2002) and the black dots were determined by Tsuji et al. (2011), and the JAMSTEC (Japan Agency for Marine-Earth Science and Technology) crustal structural database site