SCEC Award Number 14102 View PDF
Proposal Category Individual Proposal (Integration and Theory)
Proposal Title Improve and integrate InSAR deformation map with GPS towards improved Community Geodetic Model
Investigator(s)
Name Organization
Zhen Liu University of California, Los Angeles
Other Participants Graduate student (1, TBN); Zheng-Kang Shen (UCLA, Collaborator)
SCEC Priorities 1d, 1e, 5b SCEC Groups Geodesy, SDOT, Transient Detection
Report Due Date 03/15/2015 Date Report Submitted N/A
Project Abstract
 Towards an improved time-dependent Community Geodetic Model, we have been developing InSAR time series and deformation map for the entire southern California through systematic processing and analyzing large volume of SAR data from both ascending and descending tracks of C-band ERS-1, 2 and Envisat satellites. Our present efforts focus on cross validating and improving preliminary InSAR deformation map through the combination of InSAR and GPS. For the Envisat data, we find a new source of temporally correlated ramp drifting error across the range that can significantly affect the resultant time series and mean line-of- sight (LOS) velocity map. Correction of such error source, along with other noise sources, proves important to generate accurate InSAR deformation map. We adopt an empirical approach to correct such noise and show that such correction achieves comparable result as the approach that base on a priori GPS model. The RMS misfit between corrected InSAR LOS velocity and CMM4 GPS velocity is less than a few mm/yr. We applied the improved analysis to all Envisat tracks. We also revisit our previous observation of long-term transient across Eastern California Shear Zone and show such transient are still present in broad spatial extent even after taking into account such time-dependent ramp drifting error. We presented the results in 2014 SCEC CGM workshop and SCEC Annual Meeting. Our results were also cited in 2014 SCEC Annual Science Accomplishments. We participated and contributed our result and findings to CGM group effort CosInED (Comparative study of InSAR estimates of deformation) exercise.
Intellectual Merit The project directly contributes to the development of a Community Geodetic Model (CGM) by developing improved InSAR deformation map as an immediate step towards CGM. The results improves our understanding of the processes underlying transient deformation signals and/or their seismic hazard implications by highlighting tectonic and anthropogenic related deforming areas and/or GPS sites that are subject to non-steady time-varying tectonic/nontectonic deformation processes and providing better observational constraints on their physical mechanism. It contributes to the stress and deformation over time (SDOT) by providing better constrained present-day state of deformation on crustal-scale faults in southern California for the development of community stress model, models of interseismic and earthquake cycle deformation as well as 4-D geodynamic models for improved seismic hazard analysis.
Broader Impacts The research activity promotes the solid earth component of crustal deformation and earthquake dynamics studies within the Joint Institute for Regional Earth Systems Science & Engineering (JIRESSE) where traditional focuses have been on ocean and atmosphere science. It enhances the infrastructure, research and education partnership between JIRESSE and Department of Earth & Space Sciences at UCLA.
Exemplary Figure 3