The Seismic Cycle: From Observations to Models of Fault Slip

Slip along faults in the lithosphere and deformation in the rocks surrounding these faults are fundamental processes of plate tectonics that contribute to the evolution of plate boundaries and the hazards that result. Increasingly sophisticated measurement approaches from both in situ sensors and air- and satellite-borne platforms, combined with ever improving computational tools and modeling approaches, permit researchers to interrogate the nature of and causes of deformation on and around faults. This improved knowledge base in turn helps to better inform rapid response to earthquake disasters, characterize the physics and kinematics of active deformation in the lithosphere, and provide a more complete and detailed synopsis of plate tectonic processes that occur on the scales of seconds to decades. This chapter serves to provide a generalized overview of fault slip modeling—the process of using geodetic measurements of surface to displacement to infer the location and magnitude of fault slip at depth where it cannot be directly measured—with a focus on inverse modeling approaches. As with any inversion of geophysical data, there are strengths and limitations to the models derived through these approaches, and there are certain considerations that users should take when using such approaches in their work. This chapter seeks to provide a generalized view of these topics with the acknowledgment that research advances will continue to improve the accuracy, utility, and uncertainty quantification of these valuable tools.