SEISMIC DISCRIMINANTS IN EURASIA

THIS PROPOSED PHASE I RESEARCH PROJECT PROVIDES A UNIQUE OPPORTUNITY TO REVIEW REGIONAL SEISMIC DISCRIMINANTS, DEVELOPA STATISTICAL METHOD FOR IDENTIFYING EVENTS, DEVELOP QUALITY CONTROL PROCEDURES FOR ALLOWING FOR EFFECTS OF NOISE AND REGIONAL PROPAGATION EFFECTS ON DISCRIMINANTS, AND TO STATISTICALLY ANALYZE THE DISCRIMINATION CAPABILITY OF THESE REGIONAL DISCRIMINANTS. THE LARGE DATABASE OFREGIONAL WAVEFORMS AND SPECTRA PRODUCED BY THE INTELLIGENT MONITORINGSYSTEM (IMS), IMPLEMENTED AT THE CENTER FOR SEISMIC STUDIES (CSS), WILL BE USED TO TEST THE DISCRIMINATION METHODS. SPECTRAL RMS LEVELS FOR EACH REGIONAL PHASE WILL BE DETERMINED FOR MANY EARTHQUAKES AND ECONOMIC EXPLOSIONS IN EURASIA AND INPUT TO THE DISCRIMINATION APPROACH. A MULTIVARIATE, MAXIMUM-LIKELIHOOD APPROACH WILL BE USED TO ESTIMATE DISCRIMINANT FUNCTIONS FOR DISTINGUISHING EXPLOSIONS AND EARTHQUAKES. THE METHOD WILL SYSTEMATICALLY ACCOUNT FOR DATA CENSORING WHEN SIGNAL LEVELS ARE LESS THAN THE NOISE. THE STATISTICAL INTERDEPENDENCE OF THE DISCRIMINANTS WILL ALSO BE EXAMINED. THE EFFECT ON THE DISCRIMINANTS OF POTENTIAL EVASION SCENARIOS, INCLUDING DECOUPLING, ARRAY SHOT, AND HIDE-IN-EARTHQUAKE, WILL BE INVESTIGATED. THE RESULTANT TECHNIQUES WILL BE INCLUDED IN THE INTELLIGENT SEISMIC EVENT SYSTEM (ISEIS) CURRENTLY BEING DEVELOPED FOR ROUTINE EVENT IDENTIFICATION IN THE IMS. ANTICIPATED BENEFITS - THE RESULTS OF THIS STUDY WILL PROVIDE A BETTER UNDERSTANDING OF REGIONAL DISCRIMINANTS ON A STATISTICAL BASIS. THE ANALYSIS OF THE LARGE IMS DATABASE, COLLECTED FROM THE NEW REGIONAL ARRAYS AND SINGLE SEISMIC STATIONS LOCATED IN EURASIA, WILL PROVIDE AN EVALUATION OF THE CAPABILITIES OF THE NEW SEISMIC DATA SOURCES FOR EVENT IDENTIFICATION. THE RESULTS OF THIS RESEARCH WILL BE DIRECTLY INCORPORATED IN THE ISEIS SYSTEM AT THE CSS.