SCEC Award Number 17225 View PDF
Proposal Category Individual Proposal (Integration and Theory)
Proposal Title Integrate InSAR and GPS for Crustal Deformation Mapping
Investigator(s)
Name Organization
Zhen Liu University of California, Los Angeles
Other Participants Zheng-Kang Shen (UCLA)
Graduate Student (TBD)
SCEC Priorities 3e, 2a, 1a SCEC Groups Geodesy, SDOT, CXM
Report Due Date 06/15/2018 Date Report Submitted 11/09/2018
Project Abstract
 Towards developing a combined 3-D deformation field from a joint analysis of InSAR and GPS data, we have developed a new approach to integrate InSAR and GPS velocities for optimal 3-D deformation field and more rigorous ways to account for the interpolated GPS velocity uncertainties and uncertainties associated with InSAR deformation map. We have applied the new approach to four descending and ascending tracks in SCEC region and show that combining InSAR and GPS improves the resolution of deformation signals especially in the vertical direction. Our study shows the inclusion of InSAR not only improves the small scale deformation signals but also help better resolves broad uplift signals observed in the East California Shear Zone and Mojave desert, which probably relates to postseismic processes following past seismic events. The overall similar vertical pattern with and without use of GPS vertical constraint suggest these features are robust and likely results from a combination of tectonic and non-tectonic deformation sources. We presented the results from InSAR and GPS integration at 2017 SCEC Annual Meeting and 2018 SCEC CGM workshop held in March 2018 at Scripps Institute of Oceanography. One manuscript about integration method and application is in preparation.
Intellectual Merit The project contributes to producing a consensus secular velocity field through improved InSAR and GPS deformation map and uncertainty estimation. The combined 3-D deformation map especially vertical components will provide crucial constraint to the development of physically more realistic deformation models and other SCEC community models (e.g., CRM and CSM). Developing robust methods for GPS/InSAR integration will contribute to the development of 4-D system-wide integrated deformation model. It also contributes to developing and providing better constrained present-day state of deformation on crustal-scale faults thus contributes to addressing two major SCEC5 science questions: 1) How are faults loaded on different temporal and spatial scales? 2) What is the role of off-fault inelastic deformation on strain accumulation, dynamic rupture, and radiated seismic energy?
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 Figure 3. Combined 3-D velocities over the region covered by the InSAR tracks without use of GPS verticals in the combination. Both InSAR and GPS interpolated velocity uncertainties are used. (Left) combined horizontal velocities. (Right) combined vertical velocities. The filled color circles are GPS verticals that are not used in the combination but overlaid for comparison. As compared with Figure 4, including InSAR without GPS vertical clearly improves resolving small-scale vertical deformation signals.