Imaging P-wave scatterer distribution in the focal area of the 1995 M7.2 Hyogo-ken Nanbu (Kobe) Earthquake

Abstract

Spatial distribution of P-wave scatterers in and around the focal area of the 1995 Hyogo-ken Nahbu Earthquake (M7.2) has been estimated by using dense seismic array data. Waveforms of 12 explosions were analyzed in a frequency band of 6-10Hz range. It is difficult to estimate the inhomogeneous structure in this wavelength range from the ordinary travel time tomography, in spite of its importance for understanding earthquake-generating process. Observed waveforms were slant stacked into various directions from the array and then AGC and diffraction curve summation are applied in order to image scatterer distribution. Spatial distribution of scattering strength thus imaged shows that higher strengths are distributed beneath the hypocenter, the initiation point of the mainshock rupture, and in the southwestern part of the fault plane of the event. Copyright 1998 by the American Geophysical Union.