Lessons Learned from a Decade of Ground Motion Simulation Validation (GMSV) Exercises and a Path Forward

Simulated ground motions can advance seismic hazard 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 regulatory bodies, practicing engineers, or hazard analysts 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. The Southern California Earthquake Center (SCEC) Ground Motion Simulation Validation (GMSV) group was formed to increase coordination among simulation modelers and research engineers with the aim of devising and applying effective methods for simulation validation. Here, we categorize alternate validation methods according to their approach and the metrics considered. Two general validation approaches are to compare various metrics from simulations to their counterparts from historical records or to their estimated values from existing empirical models. Validation metrics consist of ground motion characteristics and structural responses. We describe this categorization, provide examples that have been valuable in the past decade, and provide potential research directions. Key lessons learned by our GMSV group are that validation is application specific, our outreach and communication warrants improvement, and much research remains unexplored

Findings from a decade of ground motion simulation validation research and a path forward

Simulated ground motions can advance seismic hazard 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 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. In this presentation, 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 to those from semi-empirical models. Validation metrics consist of ground motion characteristics and structural responses. 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 presentation is a summary of our recent paper, Rezaeian et al. (2024), referenced below