9315767 Pyrak-Nolte The PI will investigate on the laboratory time scale active seismic monitoring of fractures or interfaces undergoing frictional sliding and stick-slip behavior. Active seismic monitoring involves propagating compressional/shear waves across interfaces under shear loading. Results from this work on the laboratory scale should illuminate one of the key questions of earthquake prediction and joint stability. In order to achieve this objective, two critical issues will be addressed: (1) the observation of changes in seismic amplitudes or velocities as a fracture undergoes frictional sliding and stick-slip behavior, and (2) relating seismic precursors to the surface conditions of the fracture. ****
