SCEC Award Number 24081 View PDF
Proposal Category Collaborative Research Project (Multiple Investigators / Institutions)
Proposal Title Time-series InSAR analysis using OPERA DISP-S1 products in support of the Community Geodetic Model
Investigator(s)
Name Organization
Simran Sangha National Aeronautics and Space Administration Gareth Funning University of California, Riverside Marin Govorcin California Institute of Technology
SCEC Milestones A1-1, A3-5, D1-1 SCEC Groups CEM, Geodesy, RC
Report Due Date 03/15/2025 Date Report Submitted 03/14/2025
Project Abstract
 In preparation for the March 2025 official validated release of Level-3 Surface Displacement products from Sentinel-1 (DISP-S1), developed and provided through the JPL Observational Products for End-users from Remote Sensing Analysis (OPERA) project, we utilized a suite of provisional OPERA DISP-S1 products over focused sites in central California. We refined and expanded our existing workflows and methods to derive time-series and velocity products and align them to GNSS displacement time-series (Figs. 1-2). Our developments are intended to be seamlessly accessed and applied once the final products are made available, and are freely available as open-source tools. We have shared these developments and our ongoing analyses to a group of targeted academic and federal stakeholders through a series of working group meetings dedicated to the DISP-S1 product and at an annual workshop that were both facilitated by the OPERA Stakeholder Engagement Program (SEP).
Looking ahead, we aim to leverage these analyses to supplement previous efforts with the Advanced Rapid Image Analysis (ARIA) project’s formulated archive of Level-3 Sentinel-1 Geocoded Unwrapped Phase products (ARIA-S1-GUNW) products. Specifically in the context of the development of a scalable approach to separate horizontal and vertical displacements and derive quasi-vertical land motion from relative LOS InSAR observations (Govorcin et al., 2025). These efforts will support the upcoming Level-4 OPERA Vertical Land Motion (VLM) product suite, scheduled for release in April 2028.
SCEC Community Models Used Community Geodetic Model (CGM)
Usage Description To facilitate the production of a combined CGM deformation product, we will leverage our existing workflows and methods to align and reference the DISP-S1 post-analysis products to GNSS displacement time-series. This contribution will supplement the complementary suite of time-series products previously used as an input to the CGM and derived from the existing archive of standardized SAR interferogram products available through the ARIA project.
Intellectual Merit Our work aligns with SCEC objectives to assess geophysical data quality and analyze geophysical variables influencing seismicity and occurrence patterns across the SAFS. Specifically, we have (1) leveraged OPERA DISP-S1 provisional displacement products covering the SAFS; (2) developed tools to combine individual products, reconstruct time-series, and analyze interseismic deformation rates (2014–2025); and (3) combined the derived line-of-sight products with GNSS rates to tie them into the geodetic reference frame. These efforts can help improve constraints on permanent, off-fault deformation.
Broader Impacts This effort is performed in collaboration between SCEC-affiliated and JPL researchers. Our analyses will seamlessly serve future versions of the CGM beyond the current v2 product. We shared updates on our developments and analyses to a group of targeted academic and federal stakeholders through a series of DISP-S1 working group meetings and at an annual workshop that were both facilitated by the OPERA Stakeholder Engagement Program (SEP). We also supported an EarthScope Consortium training course focused on InSAR processing and analysis, where we demonstrated how to properly use open-source software (used and developed in part under our proposed efforts).
Project Participants Sangha coordinated with the OPERA team and collaborator David Bekaert, a Radar Scientist at JPL and OPERA Project Manager, to process provisional DISP-S1 across target cases in Central California. Sangha led the efforts to develop post-analysis workflows to reconstruct time-series and constrain the interseismic velocities. Co-I Marin Govorcin helped to manage these developments and cross-validate with previous time-series analysis efforts derived from the ARIA-S1-GUNW product archive. Co-I Gareth Funning coordinated efforts to compare time-series results generated by this project with other, independent efforts.
Exemplary Figure Figure 1: (Left) Preliminary LOS surface velocities for multiple sample DISP-S1 descending pass frames over California, which span from 2016 through 2024. (Right) InSAR-GNSS comparison scatter plots of collocated LOS rates over two highlighted frames. Black dashed lines represent agreement. Rates outside of ± 2.5 cm/yr range have been truncated, and generally correspond to aliasing where InSAR is underestimating the high subsidence rates. Displacement within the vicinity of the denoted epicenters needs to be separated out with step function fits to better constrain the velocity field.
Linked Publications

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