SCEC Award Number 25275 View PDF
Proposal Category Collaborative Research Project (Multiple Investigators / Institutions)
Proposal Title GNSS and InSAR Integration for 3-D Deformation Field and Time Series in California
Investigator(s)
Name Organization
Zheng-Kang Shen University of California, Los Angeles Zhen Liu National Aeronautics and Space Administration
SCEC Milestones A1-1, A2-2, A3-5, A3-6, C1-1, D1-1 SCEC Groups Geodesy, CEM, PBS
Report Due Date 04/25/2026 Date Report Submitted 05/08/2026
Project Abstract
 We have developed a method to integrate GNSS and InSAR data to produce a 3-D surface velocity field of the Earth [Shen and Liu, 2025]. We have further applied this method tointegrate GNSS and InSAR data for studying 3-D crustal deformation in California and western Nevada [Shen and Liu, 2025]. We also extended the approach to incorporate UAVSAR data, enabling an integrated solution for crustal deformation with a particular focus on estimating creep rates along faults that exhibit interseismic creep. We used the method to map the 3-D deformation field along the San Andreas fault in central California. Our preliminary result reveals both along-strike and vertical components of creep along the fault, which are continuous and distributed within a ~1-km-wide fault zone.
SCEC Community Models Used Community Geodetic Model (CGM)
Usage Description The GNSS-InSAR integration work has been published in JGR-Solid Earth November 2025, and according to Google Scholar, has been cited by colleagues already.
Intellectual Merit Assessment of three-dimensional (3-D) deformation field and its evolution with time is essential in studying physical processes of tectonic, hydrological, and anthropogenic activities and earthquake hazards. A unified and well-constrained 3-D displacement time series that combines the complementary strength of InSAR, GNSS, and UAVSAR datasets will be the key product of the Community Geodetic Model (CGM) to support the SCEC’s mission for Community Earth Models (CEMs) studies.
Broader Impacts Our results were presented at the SCEC Annual Meeting, where they were shared with the broader community and extensively discussed by colleagues from a wide range of disciplines.
Project Participants The work is mainly done by Zhengkang Shen at UCLA and Zhen Liu at JPL. Yuehua Zeng at USGS also participated the discussion.
Exemplary Figure Figure 2. Joint solution of 3-D crustal deformation using integrated datasets of GNSS, InSAR, and UAVSAR. Upper: (a) and (b) are the solution for the horizontal amplitude and vertical components respectively. The white frames mark the surface imprints of the UAVSAR lines. Lower left: (a), (b), and (c) are the UAVSAR de-ramped line-of-sight rate data, model predictions, and data postfit residuals. Lower right: Solution of fault surface creep along SAF in central California. The red and green symbols denote the modeled along-strike and vertical components, and the blue symbol denotes the observed fault-parallel component of creep from a composite dataset.
Linked Publications

Add missing publication or edit citation shown. Enter the SCEC project ID to link publication.