Oral Presentation

Seismology provides unique tools to probe the structure and behavior of fault slip zones across a range of depths and throughout the earthquake cycle. New fault observations have been enabled by improved use of existing data and recent growth of high sensitivity instrumentation. By examining the spatiotemporal evolution of seismicity, we can make inferences about the state of stress on the fault. For example, triggering by external stress perturbations such as tides or regional and teleseismic earthquakes may highlight areas of faults that are highly stressed. Furthermore, earthquake clustering behavior allows us to map fault coupling and infer where larger asperities in future quakes may occur. Seismic observations can also illuminate the often complex and non-planar structure of active faults. As earthquake detection levels are improved and event locations refined, we can, for the first time, map the surface roughness of active faults at seismogenic depths and explore how roughness may relate to earthquake sequence behavior or other slip dynamics. Progress in understanding fault slip zones will depend on continued improvement to seismic observations and analyses, integration with geodetic and geologic data, and expansion of modeling.