ELECTROMAGNETIC GAGE MEASUREMENT OF COUPLING IN JOINTED ROCK

IN SUPPORT OF EXISTING AND PROPOSED NUCLEAR TESTLIMITATION TREATIES, IT IS INCREASINGLY IMPORTANT THAT IMPROVED METHODS FOR UNDERSTANDING AND PREDICTING THE SEISMIC COUPLING OF NUCLEAR DETONATIONS BE DEVELOPED. WITH THE POSSIBILITY OF BETTER DEFINE THE GEOLOGY EXISTING AT SOVIET TEST SITES, SUBTLE VARIATIONS IN COUPLING OF NUCLEAR DETONATIONS TO VARIOUS ROCK TYPES COULD BE IMPORTANT. ONE FEATURE OF NEARLY ALL ROCKS THAT COULD HAVE SIGNIFICANT INFLUENCE UPON COUPLING IS NATURAL JOING CHARACTER. PROPERLY DESIGNED AND EXECUTED SMALLAND INTERMEDIATE-SCALE EXPERIMENTS COULD ESTABLISH AND DELIMIT THE IMPORTANCE OF ROCK JOINT PROPERTIES AND JOINT DISTRIBUTIONS UPON SEISMICCOUPLING AND PROVIDE A BETTER BASIS FOR PREDICTING THE SEISMIC RESPONSE OF NUCLEAR TEST SITES. A CRITICAL ELEMENT OF SMALL AND INTERMEDIATE SCALE TESTING IS THE MEASUREMENT OF ROCK RESPONSE. ELECTROMAGNETIC VELOCITY GAGE TECHNIQUES ARE IDEALLY SUITED FOR SUCH MEASUREMENTS AS GAGE OUTPUT DEPENDS DIRECTLY UPON FARADAY'S LAW OF INDUCTION RATHER THAN UPON SOME INDEPENDENTLY DETERMINED AND POSSIBLE TEST DEPENDENT CALIBRATION FACTORS. ELECTROMAGNETIC GAGE TECHNIQUES WOULD BE DEVELOPED AND APPLIED TO BOTH SMALL-SCALE LABORATORY AND INTERMEDIATE-SCALE FIELD TESTS. THE RESULTING DATA SHOULD DEMONSTRATE AND QUANTIFY THE EFFECT OF JOINTS UPON SEISMIC COUPLING IN NUCLEAR TESTS. ANTICIPATED BENEFITS/POTENTIAL COMMERICAL APPLICATIONS OF THE RESEARCH OR DEVELOPMENT. THE TECHNIQUES AND DATA RESULTING FROM A PHASE I PROGRAM WOULD ALLOW FOR A MORE QUANTITATIVE EVALUATION OF THE ROLE OF ROCK JOINTS AND THEIRPROPERTIES ON SEISMIC COUPLING OF HIGH-EXPLOSIVE AND NUCLEAR DETONATIONS. THE RESULTS WOULD SUPPORT EFFORTS TO VERIFY EXISTING AND PROPOSED TEST BAN TREATIES. THE TECHNIQUES AND DATA WOULD BE APPLICABLE TO ROCK JOINT STUDIES IN MANY AREAS OF DYNAMIC ROCK MECHANICS, INCLUDING ROCK FRAGMENTATION IN COMMERCIAL BLASTING AND NOVEL SMALL-CHARGE EXCAVATION TECHNIQUES.