Comprehensive research on large earthquake occurrence potential in the concentrated deformation zone along the Japan Sea eastern margin

日本海东缘500公里海岸晚第四纪海相阶地倾斜和翘曲的差异隆升是由近海断层运动和相关的大地震引起的。靠近海岸线的浅层海底逆断层段无疑是海岸隆升和堆积海阶地倾斜翘曲的主要原因。与古岸线记录最吻合的同震位移分布表明，地震震级在6.7 ~ 7.6 Mw之间，重现时间为几千年。这意味着该地区在不久的将来有可能发生伴随海岸隆起的大震级地震。特别是在大尻岛、松前半岛、函馆平原西缘、滨西半岛和丰岛等目前磨损台地广泛发育的地区，下一次大地震似乎迫在眉睫。

The differential uplift showing tilting and warping of late Quaternary marine terraces along a 500 km long coast of this eastern margin of Japan Sea is understood due to offshore causative fault movements and related large earthquakes. Shallow submarine reverse fault segments close to the coastlines are undoubtedly responsible for coastal uplift and accumulative marine terrace tilting and warping. Calculating co-seismic displacement distribution to be best fit to paleoshoreline records indicates earthquake magnitude in the range of Mw 6.7-7.6 and recurrence time of several thousand years. This implies that this region has high probability of large magnitude earthquakes accompanied by coastal uplift, which will happen somewhere in near future. Particularly in the several areas, Okushiri Island, Matsumae Peninsula, western margin of Hakodate Plain, Henashi Peninsula and Tobishima Island, where present abrasion platforms widely develop, the next large earthquakes seem imminent.