Collaborative Research (Caltech): Interpreting High Resolution Geodetic Data with Visoelastic Models

This project is a collaborative effort bridging the gap between modern datasets and modern modeling techniques, in an effort to improve our ability to elucidate rheological structure within active tectonic zones. In particular, we will characterize the sensitivity of our estimates of lithospheric rheology to the spatial and temporal scale of available datasets. We emphasize the role of model cycle-up/spin-up, variable earthquake repeat times, and realistic variations in rheology. This effort will allow for the more effective use InSAR and GPS data, to constrain geologically reasonable models. We will apply the lessons we learn through theoretical studies to specific, well-constrained study areas, including postseismic deformation following the Landers and Hector Mine earthquakes and post-rifting deformation in the Northern Volcanic Zone, Iceland. The results and procedures developed during the course of this proposal will 1) help to minimize uncertainties associated with improper and/or geologically implausible modeling techniques, 2) allow quantitative comparison of rheological structures inferred by independent investigators, and 3) ultimately lead to more accurate estimates of rheological properties at depth, including associated uncertainties. These inferences can then be used in subsequent secondary analyses, particularly those that would benefit from an explicit assessment of model and data induced uncertainties, such as studies of fault interaction, estimation of fault slip-rates from geodetic data for seismic hazard purposes, and time-dependent probabilistic seismic hazard assessments.