SCEC Award Number 23109 View PDF
Proposal Category Individual Proposal (Data Gathering and Products)
Proposal Title Updating the ARIA standardized InSAR product and refining the derived time-series analysis in support of the Community Geodetic Model
Name Organization
Simran Sangha National Aeronautics and Space Administration Gareth Funning University of California, Riverside Marin Govorcin California Institute of Technology
Other Participants Collaborator: David Bekaert
SCEC Priorities 1a, 4b, 3e SCEC Groups CXM, Geodesy, CS
Report Due Date 03/15/2024 Date Report Submitted 03/14/2024
Project Abstract
Through the performance period of this proposed effort, we have leveraged developments and updates to an archive of standardized interferometric products available through the JPL ARIA project and spanning the SCEC5 area of interest to generate more reliable and robust time-series products and facilitate the analysis of geophysical processes of interest. Specifically, we densified the archive of interferometric products up through 2023 and used these products to generate updated interseismic line-of-sight (LOS) time-series and velocity products. We also compare the performance of different weather models to estimate tropospheric path delays for radar. From our LOS time-series and velocity products, we work to resolve shallow aseismic slip (‘fault creep’) and vertical land motion. Finally, we continue to collaborate with the SCEC Community Geodetic Model (CGM) InSAR working group, for which we contributed our solution as part of the latest CGM version now available through the SCEC CGM website.
Intellectual Merit We worked to densify and improve our existing time-series products behind a motivation to improve the precision of the interseismic velocity field for the SCEC5 area of interest. These updates allow us to more reliably capture and constrain earthquake-cycle processes (e.g. fault creep) and vertical land motion. We also experimented with tropospheric corrections derived from the the Raytracing Atmospheric Delay Estimation for RADAR (RAiDER) package, estimates tropospheric delay at high resolution by combining global weather models with ground-based radar observations, to find the most effective means of mitigating tropospheric 'noise' in our displacement data.
Broader Impacts This effort is performed in collaboration between SCEC-affiliated researchers and researchers at JPL, which is specifically encouraged in the 2024 SP. We continue our participation in the regular teleconferences and workshops of the CGM InSAR working group, and will continue to contribute results to that effort. Each of the four different subgroups used distinct approaches to extend their time-series to span the 2019 Ridgecrest earthquakes, an effort which was captured in a SCEC presentation held under our combined proposed effort (#23136).

In terms of community training and outreach, last year PI Sangha and Co-PI Funning had supported the 2023 InSAR Processing and Analysis (ISCE+) short course, our 5th training activity in as many years. This course is an annual affair intended to train students and other workers interested in learning about InSAR processing and analysis methods, and on how to properly use open-source software (used and developed in part under this proposed effort) to be leveraged for their own scientific interests and research efforts. Thus a motivation for involvement in these trainings is to facilitate open science activities.
Exemplary Figure Figure 2. Map of statewide surface creep estimates. Colored boxes indicate areas where creep estimates were made by measuring offsets from our InSAR velocities. Red colors indicate right-lateral creep; blue colors, left-lateral creep; white boxes indicate no creep.