PERIODIC VARIATIONS IN TIME SERIES DERIVED BY SEISMIC MONITORING OF THE CRUST

Abstract

An analysis is presented of periodic variations in the properties of the seismic wave field base on data obtained during systematic observations of shot-excited wafes in southern Tadzhikistan between 1980 and 1984. The nature of the waves that were recorded is known. The method and the quality of the data made it possible to obtain and analyze a large number of time series representing various layers of the crust and various parameters and frequencies. In particular, we obtained travel-time difference series for waves in different layers of the crust (the granite layer, the waveguide layer, and the basalt layer, whose approximate thicknesses are 10, 15 and 15 km, respectively). The series of differences in the logarithms of the amplitudes of waves associated with the roofs and bases of the above layers, the energy ratios of the regular and random components of the wave field at certain time intervals, and standards for all of the above properties.