Project Abstract
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We evaluate how simulation methods on the SCEC Broadband Platform (BBP) compare with each other (in terms of pseudo-spectral acceleration, Sa, over the frequency range 0.1-100 Hz) given the same rupture scenarios. These insights serve as a baseline for referencing the future differences observed between models when default parameter settings are adjusted in sensitivity studies and for earthquake validations and forward simulations, to allow for meaningful comparisons. The first validation phase of the BBP was recently evaluated by Dreger et al. (2013) for simulated Sa using version 13.6.1 of the BBP code. The Dreger et al. (2013) evaluation focused on the mean ground motion estimates for five simulation methods. Based on the validation tests, three methods were determined to be suitable for broadband simulation of median Sa from 0.01s to 3s period within the validation magnitude range (Dreger et al, 2013). These three methods (EXSIM, G&P and SDSU) have been implemented on the BBP in a frozen version of the code, meaning that no further changes to that release are allowed. This frozen version of the code is being used in multiple projects, including the ongoing Pacific Earthquake Engineering Research Center (PEER) NGA East validations, and the South-western U.S. (SWUS) Ground Motion Characterization (GMC) SSHAC Level 3 study for the Diablo Canyon Power Plant (DCPP) and the Palo Verde Nuclear Generating Station (PVNGS). Results are presented by comparing the simulation methods over a suite of earthquake scenarios for various source to site distances and azimuths. In addition to analyzing the average results with respect to spectral period, spatial comparison results are presented in map form – both to compare simulation techniques with each other, and to compare simulation predictions with those of several Ground Motion Prediction Equations (GMPEs). The remaining simulation methods will be analyzed in the same fashion as they become available on the SCEC BBP in their final, frozen form. |
