鈴鹿山地東縁断層のP波浅層反射法地震探査 : 2005年時山測線

概要

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We present new, high-resolution seismic reflection data (2005 Tokiyama profile) acquired across the piggyback basin between the Yoro and Suzuka basement-involved folds to further image its subsurface geometry. A seismic source (mini-vibrator) and 180-channel digital telemetry recording system were used in an split-spread configuration with the nearest receiver adjacent to the source to record seismic waves from deeper reflection points. A 10-m source and geophone spacing give a 5-m CMP (common midpoint) spacing on the final section. The nominal CMP stacking fold had 90 traces. We also suppressed coherent noise by repeating source points 7-10 times. After data processing including surface-consistent statics, velocity analysis, normal moveout (NMO) correction, residual statics, CMP stack, and migration, the section was finally depth-converted using stacking velocities. Reflectors imaged on the seismic profile Illuminate that the forelimb composed of Pliocene-Pleistocene Tokai Group and underlying Mesozoic basement rocks are thrust over intermontane units. The uniform thickness of the Tokai Group on the west flank of the Yoro Mountains also indicates its pregrowth nature to the Yoro basement-involved fold.
東京大学の論文
2007-08-20