Summary

Simulated earthquake ground motions can support nonlinear response history analysis (RHA) and probabilistic seismic hazard analysis (PSHA), but their effective and responsible use depends on readily accessible simulation databases that include model information and uncertainty documentation, as well as validation evidence and guidelines to select simulations appropriate for the intended application.

The new SCEC Ground Motion Simulation, Validation, and Utilization (GM-SVU) Technical Activity Group (TAG) builds on more than a decade of research demonstrating that validation is application-specific and benefits from iterative collaboration among simulation modelers, research engineers, and hazard analysts. Through a broader effort focused on simulation selection, validation, utilization, and iterative improvement, the new GM-SVU TAG aims to address the gaps identified by previous researchers and the community as obstacles to further advancing the use of simulations in practice. The goal of the TAG is to curate an initial documented simulation dataset, provide validation evidence, and utilize it in example applications; concurrently, the TAG aims to develop guidelines for both RHA and PSHA applications using this initial dataset and examples; finally, the TAG will establish pathways for the example dataset’s iterative evaluation and refinement. The longer-term goal is to develop trusted, application-ready simulation resources accompanied by practical guidance for both RHA and PSHA applications.

Two focused working meetings (Workshop 1 on October 29, 2026, and Workshop 2 on January 21, 2027) are planned in the first year of this TAG’s efforts to achieve the above goals from curating an initial dataset, using them in example applications, drafting guidelines for their use, and collecting community feedback on this process. Plans for finalizing the guidelines and establishing pathways for iterative evaluation and refinement of simulations for future application-ready simulation resources will be the focus of the TAG after these two workshops.

Workshop 1 will bring together participants with relevant expertise to review earlier validation research and SCEC simulation capabilities, assess the proposed initial dataset, and refine plans for example use studies. Participants will also review a framework for the RHA and PSHA utilization guidelines. Plans for example use studies include RHA of a building and a bridge for code-based design and reviewing available literature and tools on simulation needs for PSHA applications. Workshop 1 will conclude by identifying needed revisions, responsibilities, and next steps required before convening for Workshop 2, when results of the use studies and a draft of the guidelines will be shared. Although the meeting is intentionally focused, the datasets, application examples, and guidance advanced through this work are intended to benefit the broader earthquake science and engineering communities.

Workshop 1 Goals

The workshop will establish a shared foundation for the GM-SVU TAG’s Year 1 work and refine plans for the initial simulation dataset, nonlinear RHA example use studies, and development of guidelines for use of simulations in PSHA and RHA applications. Specific objectives include:

1. Establish a shared foundation for the Year 1 work. Review lessons from the previous ground motion simulation validation (GMSV) efforts, community feedback, and current and emerging SCEC simulation capabilities to identify the research priorities and validation questions most relevant to PSHA and RHA applications.
2. Review the plan for the initial simulation dataset. Present the proposed CyberShake simulations, supporting information, and validation evidence, and gather feedback on whether they meet the needs of the planned  RHA example use studies and needs of the PSHA community before the dataset is finalized and distributed.
3. Refine the proposed RHA application exercises. Review existing research, present the building and bridge teams’ simulation needs and analysis plans, and gather feedback on the proposed simulation dataset, validation metrics, structural demands, and other considerations. 
4. Discuss the needs of the PSHA community. Review existing simulation-based PSHA tools and recent literature on the simulation needs of the PSHA community. Discuss the proposed guidelines and gather feedback on its development.

Participation

The workshop will bring together simulation developers, research engineers, hazard analysts, structural and geotechnical engineers, and others with expertise relevant to nonlinear RHA and PSHA applications.

Because the workshop is structured as a collaborative working meeting, in-person participation is limited to approximately 25 invited participants whose expertise can help refine the initial dataset and application plans. Participants are strongly encouraged to attend in person for the full day so they can follow the progression of discussions and contribute fully to the workshop plans and next steps. Refreshments and meals will be provided as noted on the agenda.

Remote participation will be available for invited participants who cannot travel and for others whose interests or expertise align with the workshop goals. Those interested in participating remotely should contact the workshop organizers.

Travel Information

The workshop will be held in Irani Hall, Room 421 on the University of Southern California’s University Park Campus, 1050 Childs Way, Los Angeles, CA 90089. Participants driving to campus should park in the Royal Street Parking Structure, approximately a 10-minute walk from Irani Hall. Follow the posted instructions to purchase a daily permit using the text-to-pay system.

Los Angeles International Airport (LAX) and Hollywood Burbank Airport (BUR) provide convenient air access to the Los Angeles area. Rideshare, taxi, rental-car, and public-transit options are available throughout the region. Lodging will be provided for invited participants who require an overnight stay at The USC Hotel or another nearby hotel.

SCEC Technical Activity Group 

GM-SVU TAG Co-PIs & Organizers: Sanaz Rezaeian (USGS), Scott Callaghan (SCEC), Chukwuebuka (Buka) Nweke (USC), Maha Kenawy (OK State), Farzin Zareian (UCI), Nicolas (Nico) Luco (USGS), Ahmed Elbanna (SCEC), Tran Huynh (SCEC), Brad Aagaard (USGS)

GM-SVU TAG Members: Albert Kottke (PG&E), Arben Pitarka (LLNL), Artie Rodgers (LLNL), Audrey Dunham (USGS), Brendon Bradley (U of Canterbury), Camilo Pinilla-Ramos (GFZ Potsdam), Claire Doody (LLNL), Elham Shokrgozar (U of Wyoming), Erin Wirth (USGS), Evan Hirakawa (USGS), Fabio Silva (SCEC), Felipe Kuncar (U of Canterbury), Greg Deierlein (Stanford), Jeffrey Bayless (AECOM), Jonathan Stewart (UCLA), Kevin Milner (USGS), Kim Olsen (SDSU), Kyle Withers (USGS), Morgan Moschetti (USGS), Norman Abrahamson (UC Berkeley), Pengfei Wang (Old Dominion University), Rie Nakata (LBNL), Robert Graves (SCEC), Xiaofeng Meng (SCEC), Yongfei Wang (Verisk)

References

For additional background and motivation for the SCEC GM-SVU TAG, please see:

• Rezaeian, S., Stewart, J. P., Luco, N., & Goulet, C. A. (2024). Findings from a decade of ground motion simulation validation research and a path forward. Earthquake Spectra, 40(1), 346-378. https://doi.org/10.1177/87552930231212475. SCEC Contribution 15034.
• Baker, J. W., Rezaeian, S., Goulet, C. A., Luco, N., & Teng, G. (2021). A Subset of CyberShake Ground Motion Time Series for Response History Analysis. Earthquake Spectra, 37(2), 1162-1176. https://doi.org/10.1177/8755293020981970. SCEC Contribution 10077.
• Kenawy M. & Pitarka, A. (2025). Performance assessment of near-fault buildings subjected to physics-based simulated earthquake ground motions with fling step, Earthquake Spectra, 41(1), 381-411. https://doi.org/10.1177/87552930241285022. SCEC Contribution 15681.
• Kenawy, M., McCallen, D. B., & Pitarka, A. (2021). Variability of near‐fault seismic risk to reinforced concrete buildings based on high‐resolution physics‐based ground motion simulations. Earthquake Engineering & Structural Dynamics, 50(6), 1713-1733. https://doi.org/10.1002/eqe.3413. SCEC Contribution 11018.
• Kenawy, M., McCallen, D. B., & Pitarka, A. (2023). Characteristics and selection of near-fault simulated earthquake ground motions for nonlinear analysis of buildings. Earthquake Spectra, 39(4), 2281-2322. https://doi.org/10.1177/87552930231182164. SCEC Contribution 15683.
• Liou, I. Y., Cotton, F., Weatherill, G., & Abrahamson, N. A. (2026). Advancing the Use of Simulated Ground Motions in Physics-Based Probabilistic Seismic Hazard Analysis From Research to Practice. Bulletin of the Seismological Society of America, (under review). SCEC Contribution 15685.
• Aagaard, B., Askan, A., & Rezaeian, S. (2026). Developing International Standards and Guidelines for Validating, Disseminating, and Utilizing Simulated Earthquake Ground Motions. Presentation at 2026 SCEC/USGS GM-SVU Workshop. See Slides.
• Callaghan, S. (2026, 08). SCEC’s Physics-Based Seismic Hazard Modeling Platforms. Oral Presentation at 2026 SCEC Annual Meeting. SCEC Contribution 15653.
• Callaghan S. (2025). CyberShake Study 22.12, SCECpedia, available at https://strike.scec.org/scecpedia/CyberShake_Study_22.12.
• Silva, F., Goulet, C. A., Maechling, P. J., & Ben-Zion, Y. (2023, 09). The SCEC GMSV Toolkit: Open-Source Tools for Ground Motion Simulation Processing and Validation. Poster Presentation at 2023 SCEC Annual Meeting. SCEC Contribution 12787.
• Crouse, C., Jordan, T. H., Milner, K. R., Goulet, C. A., Callaghan, S., & Graves, R. W. (2018, 06). Site-Specific MCER Response Spectra for Los Angeles Region based on 3-D Numerical Simulations and the NGA West2 Equations. Oral Presentation at 11th National Conference in Earthquake Engineering. Paper #518. SCEC Contribution 8024.
• Pauk, E. (2026). Meeting the Need for Site-Specific, Long-Period MCER Response Spectra: The SCEC UGMS Tool for LA. Presentation at 2026 SCEC/USGS GM-SVU Workshop. See Slides.