Gusev's stochastic model for the seismic source: high-frequency behavior in the far zone

TL;DR

This paper presents a theoretical model explaining high-frequency seismic wave behavior in the far zone, highlighting how source complexity affects spectral decay and radiation directivity.

Contribution

It provides a theoretical solution showing that complex source structures can be simple and non-smooth, explaining observed high-frequency seismic phenomena.

Findings

Quadratic decay of source spectrum at high frequencies

Loss of radiation directivity in the far zone

Source front can be simple yet non-smooth

Abstract

This paper discusses local features in the source function that generate in the far zone simultaneously (a) a quadratic decay of the source spectrum and (b) the loss of radiation directivity at high frequencies. A. Gusev drew attention to this problem and suggested that a positive solution can be obtained for earthquake rupture front with a rather complex ("lace") structure. Below we give a theoretical solution of the problem and show that the front structure can be simple enough, but not smooth.