The RISTRA 1.5 experiment extends northwest from the center of the Colorado Plateau to a point 100 km into the Great Basin. The experiment is designed to provide detailed images of the crust and upper mantle seismic structure. This data, together with data from the LA RISTRA passive seismic array (XM99-01), which extends southeast from the center of the CP to the Rio Grande rift and beyond form a complete transect the Colorado Plateau.