GIRS-2024-08: Geometric Parameterization of Sedimentary Basins in Southern California for Site Response Analysis and Modeling

By: Rashid Shams and Chukwuebuka C. Nweke
DOI: 10.34948/N3988K

Abstract: Site response in sedimentary basins is influenced by complex three-dimensional (3D) features, including trapped seismic waves, focusing of seismic energy, and resonance of the entire basin structure. Current ground motion models (GMMs) incorporate basin effects using one-dimensional (1D) parameters like VS30 and iso-surface depths, which are limited in capturing lateral and 3D effects. This study explores geometric features as predictive parameters to improve site response characterization in sedimentary basins, focusing on the Los Angeles Basin (LAB). Using geological cross-sections and community velocity models, we define the shape and depth constraints of LAB. We then investigate a suite of geometric parameters, including standard deviation of crystalline basement depth, distance from basin margin, and spatial area of influence based on VS30 variability, and others. (full abstract available in the report)