Monitoring an underground repository with modern seismological methods

An experiment utilizing microearthquake and acoustic emission techniques has been designed to investigate the discrete failure and behavior of hard rock in response to storage of high level nuclear waste. Data are presently being collected from a 15-station, three-dimensional array of piezoelectric sensors surrounding 11 canisters of spent nuclear fuel and 6 electrically heated simulator canisters. The canisters are arranged in a linear array 420 m beneath the surface in the Climax Stock at the Nevada Test Site. The velocity and attenuation characteristics within the array imply that the rock is not homogeneous at the observed frequencies. The basis for the experiment's concept, the instrumentation emplaced, and preliminary results of the monitoring program are reviewed. 22 refs