This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).
We are using new continuous GPS and seismic data products from EarthScope facilities to investigate possible dynamic links between vertical crustal motions and lithospheric structure. We are combining PBO and PBO NUCLEUS data with GPS data from a large network of globally distributed stations and analyzing the combined data set using the latest geodetic models, including IGS absolute phase centers. Our goal is to create high-precision regional-scale images of the vertical velocity field throughout the EarthScope focus area. In order to characterize and improve the precision of the GPS vertical rate estimates, we are developing new time series analysis methods. To interpret the vertical velocity field, we are developing new inverse analysis methods based on the flexure of elastic plates. The model parameters that we are investigating include vertical loads and load rates and (possibly time dependent) strength of the continental lithosphere. EarthScope seismic deployments are providing images of the structure of the continental lithosphere composing the deformed plate boundary zone, adding constraints on seismic velocity, density, attenuation, and anisotropy structure. The combination of geodetic and seismologic data sets should have implications for models of instantaneous mantle flow, ongoing postseismic stress relaxation, and other processes. Pilot study regions include southern California and central Utah, and similar areas where data sets are currently the strongest. Ultimately we anticipate applying the technique across the entire western conterminous US region. The associations between vertical motions, lithosphere structure, and dynamics that we are establishing constitute only one of many important avenues of scientific investigation that require precise constraints on vertical crustal motions. We anticipate that the vertical motion data products and analysis tools that we generate will have wide application concurrent with and beyond our two-year project. Our research team includes an early career female research scientist and a female PhD student.
