Toward an Alternative Approach for Using VS Profiles in Estimating Seismic Site Response
Description:
Two techniques dominate the assessment of seismic site response in engineering practice. First, ground motion models (GMMs) that use the slowness at the top 30 m (VS30) as a proxy to capture the effects of the shallow sediments on the site amplification. Second, 1D site response analyses (1D SRAs) that use shear-wave velocity (VS) profiles. It is expected that 1D SRAs lead to more accurate site response estimates at frequencies higher than a given site’s fundamental frequency, as the entire VS profile is used and provides additional information compared to VS30 alone. However, various studies have shown that 1D SRA-based site response estimates carry a significant bias and uncertainty. These observations raise the question of whether the information carried by VS profiles adds additional value in 1D SRAs compared to VS30 in GMMs or whether alternative approaches for leveraging VS profiles to estimate site response can be developed.
We investigate the ability of VS profile-related parameters to contribute to the predictability of site response in the linear elastic range. A systematic evaluation using synthetic VS profiles is conducted to examine the ability of VS profile-related parameters to add to the predicting ability of VS30 alone in GMMs. VS profile-related parameters considered in this study include (1) the maximum impedance contrast between consecutive soil layers, (2) the impedance contrast between the bedrock and the deepest soil layer, and (3) the VS profile gradient. Preliminary results confirm that the investigated parameters have the potential to increase the predictive ability of site response models. In this presentation, I will show the trends observed for various site conditions, and preliminary results from an initial assessment using observations from borehole array sites.
Session: How Well Can We Predict Broadband Site-Specific Ground Motion and Its Spatial Variability So Far? -III
Type: Oral
Date: 5/1/2024
Presentation Time: 02:00 PM (local time)
Presenting Author: Renmin
Student Presenter: No
Invited Presentation:
Authors
Renmin Pretell Presenting Author Corresponding Author rpretell@unr.edu University of Nevada, Reno |
Santosh Katuwal skatuwal@nevada.unr.edu University of Nevada, Reno |
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Toward an Alternative Approach for Using VS Profiles in Estimating Seismic Site Response
Category
How Well Can We Predict Broadband Site-Specific Ground Motion and Its Spatial Variability So Far?