Forces driving earthquakes are global ones resulting from plate motion, but we do not always know how they couple to the faults at the surface. The SAFOD project is designed to examine in great detail the processes that generate earthquakes, but on a very small scale. In order for the results from SAFOD to be applicable to other areas, we also need to know the connection between the local earthquake processes and global plate motions. This project will use the magnetotelluric method to sense the more regional structure by monitoring natural electromagnetic fields. The method has the advantage of being able to examine structure at all levels of the crust, allowing us to examine how the fault motion at the surface is linked to plate motion at depth. This project has international collaborators from Germany.