Abstract
The various factors controlling the "character" of reflection seismograph records are so numerous and so complex that it is very difficult to isolate and investigate each of them experimentally. One of these factors is the frequency discrimination due to multiple reflections in the low velocity zone ("weathered layer"). With a few simplifying assumptions this problem reduces to one already treated in the classical theory of acoustics. It is shown that for a given weathering thickness the transmission is a periodic function of frequency. The ratio of the maximum to the minimum energy transmission is nearly equal to the square of the ratio of the specific acoustic impedance of the high velocity to that of the low velocity material. The phase lag due to the presence of the weathered layer is shown to be a non-linear function of the weathering thickness for any given frequency. Graphs of transmission as a function of frequency are shown for various thicknesses of the low velocity zone.
