横手盆地東縁断層帯・太田断層を横断する浅層反射法地震探査(2003年) : データ取得と処理について

概要

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The eastern margin of the Yokote basin fault zone extends north to south about 56 km at the western foot of the Ou Backbone Range, northeast Japan. The Rikuu earthquake (M=7.2) occurred in the Ou Backbone Range (Mahiru Range) on 31st August, 1896. Associated with this earthquake, four thrust faults3 Obonai, Shiraiwa, Ota, and Senya fault-appeared on the surface of the western foot of the Mahiru Range. These faults were highly sinuous with numerous gaps and en echelon steps. We conducted a high-resolution seismic reflection profiling survey across the Ota fault and nearby tectonic structures in 2003. The obtained seismic reflection data were processed by conventional common mid-point stacking, post-stack migration, and depth conversion. As a result, it was revealed that the subsurface structure is characterized by emergent thrust with branching faults concealed beneath the geomorphic flexure at the foreside of the surface rupture of the 1296 earthquake
東京大学の論文
2007-03-14