Estimating Earthquake Ground Acceleration using InSAR Coherence and Topographic Gradient

Matthew C. Brandin, & David T. Sandwell

Submitted September 8, 2024, SCEC Contribution #13670, 2024 SCEC Annual Meeting Poster #085

We explore the potential for using InSAR coherence to estimate earthquake ground acceleration in hilly and sloped terrain. We use simple Newmark sliding models, along with a Digital Elevation Model (DEM) of local topography, and InSAR coherence data from multiple satellites (ERS, Envisat, ALOS, Sentinel-1), to estimate the Peak Ground Acceleration (PGA) from the 2010 El Mayor Cucapah Earthquake. We use data from the TanDEM-X mission to generate our DEM due to its moderately high 12 meter resolution, its global coverage, and its high correlation with 1-meter resolution Lidar data of the Cucapah mountains region provided by OpenTopography. We show that areas of low Newmark critical acceleration correspond to areas of low InSAR coherence in the near field of the rupture. Work is being done on crafting a quantitative model relating InSAR coherence and topographic gradient to PGA, enabling a lower bound on earthquake ground acceleration directly from InSAR coherence observations. This method will enhance our understanding of seismic effects on remote sensing data, providing valuable insights for earthquake monitoring and hazard assessment.

Key Words
InSAR, Coherence, PGA

Citation
Brandin, M. C., & Sandwell, D. T. (2024, 09). Estimating Earthquake Ground Acceleration using InSAR Coherence and Topographic Gradient. Poster Presentation at 2024 SCEC Annual Meeting.

Related Projects & Working Groups
Tectonic Geodesy