Identification of Previously Unmapped Faults using Phase Gradient Interferometry Nearby Major Earthquakes

Rubi M. Garcia-Gonzalez, David T. Sandwell, & Yehuda Bock

Submitted September 7, 2025, SCEC Contribution #14707, 2025 SCEC Annual Meeting Poster #TBD

We investigate the capability of phase gradient InSAR techniques to resolve small- scale surface deformation associated with large earthquakes, while avoiding errors due to phase unwrapping. Using data from C-band spaceborne satellite missions (ERS and ENVISAT),we generate phase gradient maps to detect subtle offsets caused by the 1992 Mw 7.3 Landers and 2010 Mw 7.1 El Mayor–Cucapah earthquakes. Our results are compared with the USGS Quaternary Fault and Fold Database and high-resolution LiDAR datasets from OpenTopography. We find that phase gradient InSAR is a valuable tool for recovering small-scale deformation often masked by unwrapping artifacts in conventional InSAR. Fractures with displacements smaller than 1 cm are detected, including many not previously mapped. Ongoing research is focused on assessing the broader applicability of this method to better characterize deformation patterns in strike-slip fault systems

Key Words
insar, phase gradient, mm, fault

Citation
Garcia-Gonzalez, R. M., Sandwell, D. T., & Bock, Y. (2025, 09). Identification of Previously Unmapped Faults using Phase Gradient Interferometry Nearby Major Earthquakes. Poster Presentation at 2025 SCEC Annual Meeting.

Related Projects & Working Groups
Tectonic Geodesy