Engineering evaluation of the EQSIM simulated ground‐motion database: The San Francisco Bay Area region

Abstract

AbstractGround‐motion simulations for infrequent earthquake scenarios are gaining increasing interest in the engineering community for their potential to inform performance‐based structural design and assessment, particularly in regions where major earthquakes are expected, but recordings from consistent historical events are not available. However, the absence of empirical data makes the evaluation of such scenarios and the interpretation of the simulation results very challenging. In this context, this paper presents the evaluation of the first EQSIM (v.1.1.0) ground‐motion simulations generated for the San Francisco Bay Area (SFBA) region. The current database, which is at the first stages of development, includes eight realizations of a Hayward Fault Mw7 event. The evaluation of the simulated motions is first conducted on the average ground‐motion amplitudes through comparison against the NGA‐W2 GMPEs and a selected population of real records. A methodology for selecting a population of real records consistent with the simulated event is proposed. The objective of the proposed evaluation is twofold: (1) build confidence in the realistic character of the simulated motions for their use in engineering applications and (2) offer a critical physics‐based interpretation of the simulation results that can help improve key features of the simulation models. To further investigate the implications of using the simulated ground motions for site‐specific structural assessments, the ASCE7‐16 approach is employed for the analysis of two hazard‐consistent near‐field sites in the SFBA. Results are discussed. This study offers a critical review of the EQSIM (v.1.1.0) SFBA ground‐motion simulations and suggestions for improving the earthquake rupture models.