Seismic safety |
From ground motion to confidence
The challenge today is not simply whether one dam will withstand an earthquake, but whether entire systems can continue to serve safely when the ground moves. Melanie Walling, Dina Hunt, Aimee Corn, Justin Beutel, Kwestan Salimi, and Michael Gray from GFT in the US explain how they are working towards integrating seismic safety for resilient hydropower systems
SEISMIC SAFETY IN HYDROPOWER infrastructure is not a handoff between disciplines – it’s a continuum of understanding that begins with the fault and ends with the foundation and structure. When separate teams perform seismic hazard, deformation, and structural analyses, subtle differences in assumptions can compound into inconsistent results. True resilience emerges when these disciplines operate as a single, integrated analytical chain. At GFT, seismic hazard, deformation, and structural analyses are performed within one integrated team. “Integration is what allows our work to move
beyond compliance,” said GFT’s Vice President and Chief Seismic Hazard Engineer Dina Hunt, PE. “When the same team carries the analysis from ground motion through structure, every assumption is transparent, and that’s what builds trust with dam owners, regulators, and everyone who depends on the reliability of our work.”
Defining the hazard: where resilience begins
Below: Seismic safety in hydropower infrastructure is a continuum of understanding
Every dam’s seismic story begins with understanding the ground it stands on. Comprehensive seismic hazard analysis integrates deterministic and probabilistic approaches to characterise the full range of potential ground motions. “At its core, seismic hazard analysis is storytelling,” said Chief Seismic Hazard Engineer Melanie Walling, PhD, PE. “We’re defining how the earth beneath a
dam could behave over its lifetime, and that narrative shapes every decision that follows.” For a major hydroelectric facility in the Pacific Northwest, the team updated the seismic hazard framework and developed site-specific time histories, working closely with Federal Energy Regulatory Commission (FERC) regulators. The same specialists who defined the ground motions also participated in deformation discussions, ensuring that every assumption remained transparent and traceable. “That continuity eliminates the ‘translation gap’ between teams,” added Senior Geotechnical Analyst Kwestan Salimi, PhD, PE. “It’s one story told consistently from beginning to end.” “From a geological perspective, every seismic model is only as good as the foundation it’s built on,” said Principal Engineering Geologist Michael Gray, PG, CEG. “Our role is to ensure that the fault mapping, site characterisation, and subsurface data model what’s happening in the ground, because that’s where seismic resilience starts.”
From hazard to behaviour: modelling
dam response If hazard analysis tells us how the ground moves, deformation analysis tells us how the dam will respond to those movements. At an embankment dam in Hawaii, nonlinear deformation modelling helped evaluate performance under a major seismic event. “Our geotechnical and hazard teams sat side by side
30 | December 2025 |
www.waterpowermagazine.com
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