Findings from a Decade of Ground Motion Simulation Validation Research and a Path Forward

Sanaz Rezaeian, Jonathan P. Stewart, Nicolas Luco, & Christine A. Goulet

Published September 11, 2022, SCEC Contribution #12238, 2022 SCEC Annual Meeting Poster #271

Simulated ground motions can advance seismic hazard and risk assessments and structural response analyses, particularly for conditions with limited recorded ground motions such as large magnitude earthquakes at short source-to-site distances. Rigorous validation of simulated ground motions is required before hazard and risk analysts, practicing engineers, or regulatory bodies can be confident in their use. A decade ago, validation exercises were mainly limited to comparisons of simulated-to-observed waveforms and median values of spectral accelerations for selected earthquakes. The Southern California Earthquake Center (SCEC) Ground Motion Simulation Validation (GMSV) group was formed to increase coordination between simulation modelers and research engineers with the aim of devising and applying more effective methods for simulation validation. Here, we summarize what has been learned in over a decade of GMSV activities. We categorize different validation methods according to their approach and the metrics considered. Two general validation approaches are to compare validation metrics from simulations to those from historical records or those from semi-empirical models. Validation metrics consist of ground motion characteristics and structural responses. In our categorization, ground motion characteristic metrics include (1) waveforms (i.e., time series), (2) response spectral intensity measures (IMs) such as median spectral acceleration (Sa) and amplitude parameters such as peak ground acceleration (PGA) or velocity (PGV), and (3) any other IMs computed directly from the seismograms such as duration of motion. Structural response validation metrics include (1) responses of simple idealized structural models such as inelastic single-degree-of-freedom (SDoF) systems, and (2) more complex and realistic structural models such as multi-degree-of-freedom (MDoF) and finite-element models of buildings for which we may track interstory drift ratios, or models of bridges, slopes, or geotechnical systems. We discuss example validation studies that have been impactful in the past decade and suggest future research directions. Key lessons learned are that validation is application-specific, our outreach and dissemination need improvement, and much validation-related research remains unexplored. This work has been prepared for submission as a journal article to Earthquake Spectra.

Key Words
ground motions, simulation, validation, engineering applications

Citation
Rezaeian, S., Stewart, J. P., Luco, N., & Goulet, C. A. (2022, 09). Findings from a Decade of Ground Motion Simulation Validation Research and a Path Forward. Poster Presentation at 2022 SCEC Annual Meeting.

Related Projects & Working Groups
Earthquake Engineering Implementation Interface (EEII)