Regional discrimination research. Final report, 1 May 1980-31 March 1981

The objective of this project is to systematically assess the potential of regional phases for discriminating earthquakes and nuclear explosions with particular emphasis on defining the applicability of such discriminants to events in various regions of the U.S.S.R. The first research approach employs more traditional, time domain amplitude and period measurements to compare the relative excitation of different regional phases from earthquakes and explosions. The second approach focuses on the evaluation of the capabilities of other measurement or processing techniques, such as spectral ratios or narrow-band filtering, to identify seismic sources using regional phases. The principal technical phases of the regional discrimination research effort are: (1) review and assess time and frequency domain characteristics of regional seismic phases and evaluate their dependency on source type, propagation path and station environment; (2) Develop a tentative set of source identification criteria based on information from regional phases; and (3) Test proposed regional discriminants on observed data to determine their capability to identify earthquakes and explosions in various tectonic and geologic settings.