Seismic source theory

It is remarkable that seismology has progressed as far as it has while the knowledge in one vital area, that of the seismic source, has remained in a rather primitive state. However, if the recent research effort in the United States is any indication, this situation may be changing, because several promising lines of attack upon the problems of the seismic source have been generated during the past four years. For the sake of this review, studies of the seismic source will be divided into two basic groups, the theoretical studies which are directed primarily at formulating models of the earthquake process, and the observational studies which are directed primarily at obtaining the data necessary to either check the theoretical studies or investigate the consequences of interpreting earthquakes in terms of a specific model.