Characterize Earthquake Ground Motions along the Cascadia Margin Using Seismic Interferometry

Session: Amphibious Seismic Studies of Plate Boundary Structure and Processes [Poster]
Type: Poster
Date: 4/29/2020
Time: 08:00 AM
Room: Ballroom
Description: 

As one of the most active convergent margins on the Earth, the Cascadia subduction zone is the locality of potentially devastating earthquakes that could cause severe damages to large coastal cities. Additional hazards may come from the tsunami induced by megathrust earthquakes. It is, therefore, critical to estimate the ground shaking during large earthquakes and model the influence of sediments along the accretionary wedge on the ground shaking and on the dynamics of shallow earthquakes. Here we use seismic interferometry to characterize the propagation of surface waves along the Cascadia margin, particularly the accretionary wedge. We extracted 0.02-2.4 Hz daily empirical Green’s functions from ambient seismic noises recorded by 227 Ocean Bottom Seismometers and 228 onshore stations from all available networks between 2010 and 2015. The amplitudes of the surface waves from ambient noise cross-correlations demonstrate strong variations along the Cascadia margin at different frequencies. We examine the propagation of seismic waves from virtual earthquakes and calibrate them with waveforms from local earthquakes. Results from this study will contribute to ground motion and dynamic rupture modeling for large earthquakes and, hence, the validation of earthquake early warning systems in the Cascadia region.

Presenting Author: Xiaotao Yang

Authors