This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).
Project Significance: In recent years, there has been an explosion in the availability of geodetic data including continuous GPS, strainmeters and Interferometric Synthetic Aperture Radar (InSAR), opening up new possibilities for exploration of many diverse avenues of ground motion research, including subsidence, volcanic processes, tectonic deformation and landslide activity. Current barriers to full utilization of these data include the difficulty involved with assimilating observations from diverse sets of instruments, as well as extension of the data coverage to geographical areas that have traditionally posed challenges to geodetic studies. The proposed work would increase the accessibility of InSAR data by developing improved time series analysis tools and training students and researchers to apply them. We will apply our methods to the specific example of deformation across the Imperial Fault in Southern California, which experienced two large (Mw 6.6 and Mw 7.1) earthquake in the past century, and which is situated in close proximity to the southern San Andreas Fault, numerous geothermal power plants, and population centers within Southern California.
We propose improvements to InSAR time series analysis that combine strengths of traditional, whole-interferogram methods with point target analysis (also known as permanent, or persistent scatterers). We will test these methods on problems around the world spanning a wide range of signal sizes and noise characteristics, with particular emphasis on interseismic and transient fault slip for the Imperial fault in California. We will focus on the characterization of noise and sensitivity thresholds that apply to this sort of time series analysis, with the goal of improving the ease with which such methods can be applied by other researchers to new target problems.
We will make all time series analysis codes and synthetic examples available to the general community, including tutorials and course materials that address how inverse methods can be applied to studying problems in active tectonics with geodetic data. We expect that the impact of our characterization of the impact of atmospheric noise on our inversions will also be relevant to research aimed at modeling and/or correcting the effects of tropospheric water vapor in interferograms.
