NZSEE Otto Glogau Award winner Brendon Bradley presentation on Seismic hazard with deterministic maximum limits: Considerations in a New Zealand-specific context

NZSEE invites you to join a webinar presented by the winner of the 2026 Otto Glogau award.

Title: Seismic hazard with deterministic maximum limits: Considerations in a New Zealand-specific context
Presented by: Brendon Bradley, University of Canterbury
When: Thursday, 10 September 2026
Time: 12:00pm – 1:00pm
Where: Online

This paper outlines the consideration of deterministic limits on maximum ground motion levels within seismic design codes and standards. The specific motivation is to outline the basis for the exclusion of such a limit in the 2024 draft Technical Specification for NZS1170.5 [1], despite the presence of such limits in NZS1170.5:2004 [2]. An overview of the historical consideration of so-called ‘deterministic’ and probabilistic seismic hazard analysis methods is provided, as well as how they have translated into contemporary seismic design codes and standards in New Zealand (NZ) and internationally. The fundamental issues with deterministic maximum limits are outlined through the use of examples in a NZ-specific context. The underlying reason ‘well above average’ ground-motion intensity levels (for a given earthquake scenario) are prevalent in regions of high seismicity is discussed, as well as other common misconceptions that lead to the use of deterministic limits to achieve apparently realistic design ground motion intensities. Finally, in the vein of the hazard-risk separation principle, sentiments are expressed for achieving economic and resilient seismic design in regions of high seismicity without resorting to implementing deterministic limits.

Brendon Bradley

Brendon is a Professor of Earthquake Engineering at the University of Canterbury, New Zealand.  His areas of interest include engineering seismology, strong ground motion prediction, seismic response analysis of structural and geotechnical systems, and seismic performance and loss estimation methods.  He obtained his BE(Hons) in 2007 and PhD in 2009. Brendon was a co-developer of QuakeCoRE: The NZ Centre for Earthquake Resilience, serving as its Deputy Director (2016-2018), and subsequently as Director (2019-2024).  He is Editor of the journal Earthquake Spectra.   He is an author of the textbook Seismic Hazard and Risk Analysis published by Cambridge University Press, and has provided consulting services in this field in partnership with leading consultants in New Zealand and internationally. Brendon has received several accolades, including, the 2013 Royal Society of New Zealand Rutherford Discovery Fellowship; 2014 Shamsher Prakash Foundation Research Award; 2014 NZ Engineering Excellence Awards Young Engineer of the Year; 2015 University of Canterbury Teaching Award; 2015 TC203 Young Researcher Award; 2015 EERI Shah Innovation Prize; 2016 ASCE Norman Medal; 2016 NZ Prime Minister’s Emerging Scientist Prize, 2019 NZ Geotechnical Society Geomechanics Award, 2023 UC Research Medal, and 2025 Royal Society of NZ RJ Scott Medal. In 2022 he was elected as a Fellow of the Royal Society of New Zealand.

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