In the earthquake mechanics group, we are interested in the physics of slip on faults: in why some faults slip slowly and steadily, others slip in large earthquakes, and still others slip in episodic slow earthquakes.  We use seismic and geodetic observations to track the accumulation of seismic and aseismic slip, and we use models to understand how slip accumulates in models that are driven by fault zone processes observed in the laboratory.  Then we compare the models and observations to determine which processes are likely active in the Earth.