Variations in Ground Motion Amplification in the Los Angeles Basin During the 2019 M7.1 Ridgecrest Earthquake: Implications for Mid-Rise and High-Rise Structure Response

Session: Observations From the 2019 Ridgecrest Earthquake Sequence [Poster]
Type: Poster
Date: 4/28/2020
Time: 08:00 AM
Room: Ballroom
Description: 

Coherent patterns and large variations in ground shaking amplification were observed in the Los Angeles basin during the M7.1 2019 Ridgecrest earthquake. In particular, 3 s to 6 s responses showed variations due to shallow basin geological structure that have implications for mid-rise and high-rise response to large earthquakes, even if epicentral distances are several hundred kilometers. The Ridgecrest strong-motion data were recorded by seismic stations from the spatially dense Community Seismic Network, the Southern California Seismic Network and the California Strong Motion Instrumentation Program. The observations are compared at the same locations with ground motion simulations and response spectra using the simulations to examine the regions that experienced the largest shaking and to identify the geological sources of large-amplitude shaking. The simulations were computed for the two most commonly-used regional community seismic velocity models, CVM-S4.26.M01 and CVM-H 15.1.0. Both observations and simulations are used in dynamic analysis with a finite-element model of an existing 52-story high-rise located in downtown Los Angeles. The geographical variation in maximum story drift and story shear values show that if high-rise structures had been located only a few km north or west where some of the largest amplifications were recorded, more significant response and damage may have been observed.

Presenting Author: Monica Kohler

Authors