2024 Volume 10 Issue 52 Pages 1940-1945
The accurate prediction of site effects is closely related to the quality of the seismic site characterization. Furthermore, increasingly probabilistic design procedures require not only a single seismic velocity profile, but a suite of profiles that rigorously accounts for epistemic and aleatory uncertainties. The quantification of these uncertainties is particularly important for non-invasive site characterization techniques that require inversion, such as surface wave methods, as the non-uniqueness of the derived velocity profiles depends on the uncertainties of the experimental data, which are dependent on the type and number of non-invasive measurements as well as the site's geologic setting. This work expands upon previous efforts to develop shear wave velocity (Vs) profile’s whose corresponding uncertainty is consistent with that of the experimental data and that rigorously address the non-uniqueness in the inverse problem. In particular, this work addresses three key points. First, how experimental data from multiple active-source and/or passive-wavefield surface wave arrays can be statistically combined to quantify site-specific aleatory uncertainty. Second, how multiple inversion parameterizations can and should be used to quantify epistemic uncertainty in the inverse problem. Third, how site-specific statistical models can be derived from non-invasive site characterization efforts as an alternative to existing Vs randomization techniques commonly used in practice. These advances are demonstrated at the Garner Valley Downhole Array (GVDA) site located in southern California. As a result of this study, new uncertainty-consistent shear and compression wave velocity profiles have been produced at the GVDA site for use in future forward and backward prediction efforts.
