Project is a multi-year effort to evaluate various surface-based site characterization methods under various seismic site conditions (1D-3D, soil to rock conditions). The requested 3Cs will be used to record active- & passive-source seismic records at a variety of seismic site conditions. Due to the nature of the blind trial, location of sites (in U.S.) cannot be divulged until 2021, after the evaluation of the trial is completed.