Faults around the world slip in a variety of different ways. Some fault segments slip slowly and steadily, while others slip in a series of large and hazardous earthquakes, and still others slip in slow earthquakes: episodic slip events that can last months and lack the seismic waves typically generated in earthquakes. In this group, we use geophysics to figure out how and why faults slip the way they do. For instance, we use frictional and statistical modeling to simulate the evolution of slip on faults. We compare the predicted slip evolution with seismic and geodetic observations, often with a focus on deciphering numerous small signals within seismic records and on analysing high-precision strainmeter and creepmeter observations. PhD projects would be defined in discussion with the student but are likely to have the goal of testing and improving physical models of fault deformation. Potential projects would be suited for students with backgrounds in geology, other physical sciences, or engineering.