Effect of the Los Angeles Basin Revealed by the Ridgecrest Earthquakes Recorded on the Community Seismic Network

Session: Near-Surface Effects: Advances in Site Response Estimation and Its Applications [Poster]
Type: Poster
Date: 4/28/2020
Time: 08:00 AM
Room: Ballroom
Description: 

The M 6.4 and M 7.1 Ridgecrest earthquakes were well recorded by the 300-station CSN array located in the northern Los Angeles (LA) Basin. The analysis of these data show rapid variations in amplification over a 25x25 km area, particularly at shorter periods. Ground motions around 1 sec period exhibit substantial scattering, while longer period (3-8 sec) motions show the broader, larger-scale amplification of the LA Basin. A comparison of the data with simulations using the SCEC-CVM-H15.1 (cvmh) and SCEC-CVM-S4.26.M01 (cvmsi) velocity models show major differences at 1 second period as expected, but also at longer periods. These differences reflect both the differences in the structural surfaces of the models, as well as the velocities used to describe the basin sediments. For example, cvmh has generally lower velocities in the shallow basin compared to cvmsi, which results in relatively stronger amplification of the simulated motions. We plan to use these differences to improve the velocity models along this basin edge. The goal is to produce a model that is able to reproduce the scattering and basin amplification as an example of what might be done over the whole basin.

Presenting Author: Robert W. Clayton

Authors