Comparing predicted and observed ground motions from UK earthquakes

The selection of appropriate ground motion predictive equations (GMPEs) is one of the major sources of uncertainty in probabilistic seismic hazard assessment (PSHA) and this uncertainty is usually addressed by combining several equations within a logic-tree framework. In the United Kingdom (UK), the uncertainty is large due to the limited number of ground motion records that can provide knowledge on the nature of the ground motions, in particular from M>5.0 earthquake events that are more relevant to the hazard. This data limitation has necessitated the use in the UK of GMPEs derived based on earthquake records from stable continental regions as well as active crustal regions from elsewhere in the world. This paper presents the application of methodology to systematically compare ground motions recorded during recent UK earthquakes with published GMPEs to inform the selection of GMPEs for use in PSHA for important facilities (such as nuclear facilities) in the UK.