Local soil conditions can dramatically amplify — or in some cases attenuate — the ground shaking that reaches a structure during an earthquake. For more than five decades, one-dimensional (1D) site response analysis has been the foundational tool for simulating these effects, and it remains central to seismic design practice today. Yet the method has evolved substantially, and understanding this evolution is essential for anyone who relies on site response results for seismic hazard assessments, design ground motions, or performance-based evaluations.
This lecture traces that evolution through the lens of Prof. Rathje’s extensive experience on seismic hazard projects for nuclear facilities — a context that demands exceptional rigour, transparency, and defensibility, and one that has consistently pushed the boundaries of engineering practice. The lecture traces the developments that span the full arc of site response analysis, from advances in small-strain site characterisation (shear wave velocity, damping, and HVSR measurements) to improved approaches for modeling large-strain behaviour. It also examines the role of Random Vibration Theory (RVT), which enables robust analyses without the need for input ground motion time histories, as well as emerging methods for quantifying parametric uncertainty in key model inputs.
The practical role of open-source tools — particularly strata and the Python-based pystrata — is highlighted, demonstrating how these platforms have made advanced analysis methods more accessible to practicing engineers. The lecture concludes with a forward-looking discussion of the field’s priorities, including the need for broader validation across diverse site conditions and shaking intensities, and the challenges associated with incorporating multi-dimensional site response effects.
For further information about the Mallet-Milne Lecture, SECED’s biennial prestige lecture, and its previous awardees, see the main page for the 20th Mallet-Milne Lecture.
Dr. Ellen M. Rathje is the Janet S. Cockrell Centennial Chair in Engineering in the Fariborz Maseeh Department of Civil, Architectural, and Environmental Engineering and a Senior Research Fellow at the Bureau of Economic Geology at the University of Texas at Austin. She is an expert in the areas of engineering seismology, seismic ground response, and earthquake-induced ground failure. Dr. Rathje is the current President of the Earthquake Engineering Research Institute and she is a founding member and previous Co-Chair of the Geotechnical Extreme Events Reconnaissance (GEER) Association. She leads the DesignSafe cyberinfrastructure that supports research in natural hazards engineering. Her awards include the 2022 Peck Lecture Award from the ASCE Geo-Institute, the 2018 William B. Joyner Lecture Award from the Seismological Society of America and the Earthquake Engineering Research Institute, and election to the National Academy of Engineering in 2025.
The Mallet-Milne Lecture is a biennial event established by the SECED in honour of the pioneering British scientists Robert Mallet (1818-1883) and John Milne (1850-1913). There is no charge to attend the lecture. Sponsorships are also available – for further information, please contact Damian Grant. More details and registration link will be published in due course.
The lecture will take place at the Institution of Civil Engineers (see map below). Sponsors to this event will be confirmed in due course.
Details will be confirmed in due course.
| Event Date | 26/05/2027 6:00 pm |
| Event End Date | 26/05/2027 9:00 pm |
| Location | Institution of Civil Engineers |