千屋断層(花岡)を横断する浅層反射法地震探査: データ取得と処理について

概要

論文の詳細を見る
The Senya fault, northern Honshu, Japan, which generated the Rikuu earthquake (Mj 7.2) 1896, is a typical intra-arc active thrust. Subsurface geometry provides essential information for better understanding strong ground motions and crustal deformation processes. A high-resolution seismic reflection survey was conducted along the 63km long seismic line across the toe of the thrust to reveal the subsurface geometry. The seismic source was a Mini-vibrator truck and the receiver interval was 10 m. The seismic data were processed by the standard common mid-point method. The Senya fault is clearly identified as a boundary between horizontal reflectors of the basin fill in the Yokote basin and moderately dipping reflectors beneath the Senya hills. The thrust occurred in late Miocene mudstone, and shows a flat and ramp geometry. The emergent thrust dips 30 degrees down to 500m, and changes its dip to subhorizontal following the distribution of the mudstone.
東京大学の論文
2007-03-14