Tectonic Geodesy

The broad objective of the geodesy group is to foster the availability of the variety of geodetic data collected in Southern California and the integrated use of these observations, in conjunction with other relevant data (e.g., seismic or geologic information), to address the spectrum of deformation processes which affect this region. Topics of interest include, but are not limited to, rapid earthquake response, transient deformation, long-term strain accumulation, and nontectonic effects, which appear in geodetic data. Proposed work may overlap with one or more focus areas, such as Crustal Deformation Modeling (CDM).

The following are research strategies aimed at meeting the broad objective:

• Increase the usability of high-rate GPS observations by developing community-accessible tools for processing these data. Such tools can address different goals including immediate response to major earthquakes (for which rapid availability of solutions is a priority) or detailed deformation analysis (for which the highest accuracy solutions are needed) (A5, D).
• Integrate older geodetic data (e.g., trilateration) in a consistent manner into the CMM in order to improve long-term velocity estimates in areas where recent geodetic measurements are contaminated by post-seismic deformation (A1, A2).
• Improve methods for finite-fault inversion for earthquake source parameters using multiple data types (A10, B1, D).
• Develop reliable means for detecting transient deformation signals with a range of possible spatial and temporal characteristics through the integrated use of GPS, strainmeter, and other data from Southern California. Advance descriptions of and models for observed transient deformation from tectonic and nontectonic sources (A5).
• Incorporate the use of InSAR data (where possible using processing techniques or combinations of InSAR data which provide the 3D displacement field), alone or in combination with other data, to obtain spatially-dense deformation fields and to identify nontectonic signals in other geodetic datasets (A1, A2, A5).
• Refine or extend estimates of interseismic crustal motion. Improve constraints on long-term fault slip rate and off-fault strain accumulation. Identify possible trade-offs in regional slip rate models and/or develop new models, and quantify uncertainties (especially those relating to model uncertainty) in rate estimates (A1, A2).