The Seismic Engineering Subgroup of the NEA Working Group on Integrity and Ageing of Components and Structures (WGIAGE) held the Workshop on Seismic Input Motion Development (SIMD) for Analysis and Design of Nuclear Installations from 11 to 13 May 2026 at the US Nuclear Regulatory Commission, bringing together more than 100 experts from 21 countries for engaging discussions.
As this year marks the 100th anniversary of Prof. Kyoji Suyehiro’s groundbreaking invention of the response spectrum method in Japan, the workshop reflected on its historical development. Prof. Koichi Kusunoki from the Earthquake Research Institute, the University of Tokyo, delivered a lecture entitled “Evolution of Response Spectrum-Based Seismic Loads in Japan: From Dr Suyehiro to Modern Building Codes”, providing an opportunity to revisit the history of damage caused by major earthquakes, as well as the evolution of response spectrum evaluation methods and seismic design codes, thereby reaffirming the importance of seismic assessment.
Presentation by Prof. Koichi Kusunoki from the Earthquake Research Institute, the University of Tokyo
The workshop was structured around thematic sessions: “Response spectra, power spectra, and other intensity measures”; “Time history applications and other practices”; and “From Source to the Future”. In total, 26 presentations and three panel discussions were organised.
During the final panel discussion, participants collectively reviewed the status and associated challenges, and engaged in discussions on future activities, including a roadmap spanning the short, medium, and long term.
