Updates and improvements of the consensus InSAR Community Geodetic Model

Ekaterina Tymofyeyeva, Michael Floyd, Kathryn Materna, Gareth J. Funning, Zhen Liu, Katherine A. Guns, Xiaohua Xu, Kang Wang, Simran S. Sangha, & Eric J. Fielding

Published September 11, 2022, SCEC Contribution #12571, 2022 SCEC Annual Meeting Poster #268

The continuing efforts of the InSAR Community Geodetic Model (CGM) working group have been focused toward advancing research into improving InSAR processing techniques, establishing best practices, reaching a community consensus for the best InSAR-based deformation time series and velocity model for Southern California, exploring integration with GNSS, and providing the community with easily accessible products and tools. We present the latest version of the InSAR CGM, consisting of time series and velocities from four overlapping InSAR tracks in Southern California, from a combination of six different solutions, provided by groups at SIO/UC San Diego, UC Berkeley, USGS, UC Riverside, and NASA JP. We have improved the model by correcting the InSAR velocities for the absolute bulk plate motion, and we show that this correction significantly improves the agreement between InSAR and GNSS velocity datasets. We have explored and compared several methods for estimating InSAR velocity and time series uncertainties. To calculate uncertainties for our consensus InSAR velocity product, we chose to apply a method that is commonly used with GNSS time series, incorporating both white and temporally correlated noise sources. Using an assumption of flicker noise, we calculate the covariance matrix for every pixel following the equations of Zhang et al. (1997) and perform a time series model inversion (including velocity and seasonal terms) to obtain the uncertainty estimate. This approach allows us to obtain a robust uncertainty estimate without requiring individual measurement uncertainties. Our updated InSAR CGM, including the latest corrections and uncertainties as well as the tools for working with the dataset, will be made available on the SCEC website. Future work will focus on the integration of the InSAR velocities and time series with GNSS for a joint Community Geodetic Model.

Citation
Tymofyeyeva, E., Floyd, M., Materna, K., Funning, G. J., Liu, Z., Guns, K. A., Xu, X., Wang, K., Sangha, S. S., & Fielding, E. J. (2022, 09). Updates and improvements of the consensus InSAR Community Geodetic Model. Poster Presentation at 2022 SCEC Annual Meeting.

Related Projects & Working Groups
SCEC Community Models (CXM)