MEAN FREE PATH OF S-WAVES UNDER THE KANTO DISTRICT OF JAPAN

Abstract

Coda waves from local earthquakes are interpreted as single isotropic scattered waves by numerous heterogeneities distributed homogeneously and randomly in the earth. A mean free path characterizes the distribution of the scatterers in the earth. Seismograms obtained at the Iwatsuki observatory during the period between April and September, 1976 are studied. The S-wave codas of 96 local earthquakes with magnitude 3.0-5.5 are analyzed, where only the S-wave to S-wave scattering is assumed. The total seismic energy of the S-waves (1-30Hz) is estimated from the earthquake magnitude by the Gutenberg-Richter formula. The mean free path of S-waves (1-30Hz) under the Kanto district of Japan is estimated to be 10^6.92±0.50cm.