CRUSTAL STRUCTURE BENEATH THE AKASHI KAIKYO BRIDGE AS REVEALED BY EXPLOSION SEISMIC EXPERIMENTS

Abstract

A series of explosion seismic experiments were conducted along the 1995 Keihoku-Seidan Profile. Most of the records acquired at the foundations of the Akashi Kaikyo Bridge had very poor S/N ratios. However, the P-waves of the explosions could be successfully delected after enhancing the records. The P-wave velocity structure was subsequently derived by fitting the travel times. The shallow crustal structure beneath the bridge is composed of four layers, with P-wave velocities ranging from 5.2 to 6.0km/s. The structure derived here is an improvement to the shallow crustal structure revealed by previous explosion experiments done about thirty years ago.