Strong Ground Motion Prediction for Scenario Earthquakes

Abstract

Strong ground motion is the most basic information to estimate seismic damage and examine the earthquake-resisting capacity of buildings. It’s very important to predict strong ground motions, estimate seismic damage and conduct earthquake countermeasures for a future large earthquake. Firstly, three basic components of seismic motions, i.e., source, path and site characteristics are mentioned to understand essence of method for strong ground motion prediction. Secondary, methods of strong ground motion prediction based on fault rupture propagation model such as empirical Green’s function method and stochastic Green’s function method are explained. In empirical Green’s function method, seismic motion from large earthquake is synthesized using that from small earthquake according to scaling laws of spatial and temporal growth of fault rupture. These are scaling laws of fault parameters for small and large earthquakes and the omega-squared source spectra. When there is no suitable observed record as Green’s function, stochastic Green’s function method can be adopted to predict strong ground motions. Instead of observed seismic motions from small earthquake, the method uses simulated motions as Green’s function and synthesizes seismic motions from a large earthquake using the same concepts of empirical Green’s function method. Thirdly, recipe for predicting strong ground motion from future large earthquakes is introduced. The recipe is summarized standard methodology for prediction of strong ground motions. The broadband strong ground motions can be predicted accurately by applying the recipe. Moreover, theoretical and empirical methods to evaluate path and site characteristics are explained. Finally, the stochastic Green’s function method is demonstrated on example of strong ground motion prediction for existing active fault in Iran.