Crust and uppermost mantle structure beneath central Japan inferred from receiver function analysis

We apply the receiver function method to estimate the structure of the crust and the uppermost mantle at an area that traverses central Japan including the Niigata-Kobe Tectonic Zone (NKTZ). The resultant receiver function images show clear seismic discontinuities, such as the subducting Philippine Sea plate, the Moho in the overriding plate, and other discontinuities inside the crust around the NKTZ. We also address station corrections for shallow structures using a synthetic receiver function. Crustal discontinuities seem to be complicated at the south side from the northern limit of the NKTZ. The dip of the discontinuities changes around the Atotsugawa active fault located in the NKTZ. The Moho discontinuity in the overriding plate is continuous and gradually dips to the south. The depths of the Moho discontinuity in the receiver function image exceed 40 km at the southern part of the profile line, and are 5–10 km deeper than that indicated by an explosion analysis of the same profile line. It seems that the differences between the estimated depths obtained by the two methods indicate complicated structures around the Moho discontinuity.