Development of probabilistic seismic site coefficients of Korea

It is current practice to use seismic site coefficients that are derived deterministically with ground motion parameter(s) from probabilistically derived seismic hazard maps. Even though there is an inherent incompatibility between two approaches, they are linked to develop the design response spectrum. This paper applied a novel probabilistic seismic hazard analysis procedure that integrates the seismic site effects and developed probabilistic site coefficients that are compatible with seismic hazard maps of Korea. The analysis method accounted for the uncertainties and randomness of the ground properties by randomly selecting the site profiles and dynamic curves from the measured database. The calculated coefficients were compared to those recommended in the Korean seismic design guideline and another set of site coefficients developed in Korea. The comparisons indicate that the site coefficients recommended in the current design guideline are not suitable for soil profiles of Korea. Further comparison with another set of site coefficients demonstrate the differences between the probabilistically and deterministically derived values.

► We derived fully probabilistic seismic site coefficients compatible with hazard maps of Korea.
► Uncertainties of dynamic soil properties and ground motions were systematically accounted for.
► Site coefficients recommended in the seismic code are not suitable for soil profiles of Korea.
► Comparison with another set of deterministically derived site coefficients are also presented.