抄録
Recent developments in the study of crustal response to seismic waves it have necessitated research on the effect of an inclined or a concaved interface of discontinuity in the crust or upper mantle structure. In this paper, the effect of the inclination on the observed spectrum at the surface is examined by an experimental method (two-dimensional model seismology).
Ray-theoretical consideration is found to be valid even for dip angles as large as 30°. We can readily explain the main features of recorded waves and their spectra (or the transfer functions) in terms of the following properties: multiple reflections within a dipping layer; conversions between P and S phases at the free surface and at the bottom boundary of the layer; polarities of S waves.
It has been experimentally established that dip angles of the layer of less than about 5°-10°, the amplitude characteristics of the transfer functions show only slight changes in forms and in peak frequencies.
The key point of the experiment for studying the effects of a dipping layer on the transfer function is the generation of plane waves. For this purpose, many sources of cylindrical waves are used taking advantange of the superposition principle.
