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The i-FSC Proxy: A Physics-Based Model for Predicting Near Field Topographic Site Effects and Studying Earthquake-Induced Landslide Distributions

Description: 

Our study focuses on predicting the ground motion seismic amplification caused by the surface topography during an earthquake. This thematic is directly motivated by one of the consequences of the topographic site effects variations: the high variability in the damage distributions (structural damage and coseismic landslides), observed at fine spatial scales in the near-field regions of earthquakes in mountainous areas. The effect of the surface topography has long been documented but is still poorly understood and rarely considered in buildings specification codes.
Our study relies on the neural network analysis of data obtained from 3D numerical simulation of seismic wave propagation to derive a physics-based estimator of topographic site effects in the near field (the i-FSC proxy: illuminated Frequency-Scaled Curvature proxy). The proxy relies on the S-wavelength value, the topographic curvature of the free surface, and a novel quantitative parameter called normalized illumination angle that allows to quantify the slope exposure to the incoming wavefield. The estimator is a user-friendly tool that only uses a digital elevation map (DEM), a seismic source position, and the studied S-wavelength value to predict the amplification factors at any given point of the DEM. Besides the fact that it does not require high computational resources, it enables researchers to investigate the amplification variations caused by a nearby seismic source. This is a significant breakthrough since the areas that sustain the most damage during earthquakes are those that are closest to the fault. The obtained results open direct perspectives for predicting seismic hazards and studying earthquake-induced landslides in mountainous areas.

Session: Future Directions in Physics-based Ground-motion Modeling in Preparation for the Fall 2023 Meeting

Type: Oral

Date: 4/18/2023

Presentation Time: 05:15 PM (local time)

Presenting Author: Aline Bou Nassif

Student Presenter: Yes

Invited Presentation: 

Authors