爆破震動および近地地震波の Near Surface Effects について

Abstract

Various techniques of mode separation are tried to identify the near surface effects nearobservatory. Multiple filter technique, time variable filter, phase angle, direction of particlemotion are used.The seismic waves from explosion and local small earthquakes were observed at AmagaseCrustal Movement Observatory.Group arrivals of Rayleigh wavesfrom explosions are obtained and phase velocities are calcu-lated with mode separation. In relatively higher frequency ranges, these waves are effected bylocal geology and topography. In the amplitude spectra of the earthquakes, peaks in lowerfrequency ranges are caused by multiple reflections of SH waves in sedimentary layers.