Validation of the Recipe for Broadband Ground‐Motion Simulations of Japanese Crustal Earthquakes
The robustness of broadband ground‐motion simulation can promote seismic‐hazard assessment. A broadband ground‐motion simulation technique called “the recipe” is used in the scenario earthquake shaking maps of the National Seismic Hazard Maps for Japan. The recipe represents a fault rupture based on a multiple asperity model referred to as the characterized source model. Broadband ground‐motion time histories on the engineering bedrock are computed by a hybrid approach of the 3D finite‐difference method and the stochastic Green’s function method for the long‐ (>1  s) and short‐period ( 70  km); such conditions are outside of the target range of the recipe. Simulations using a 1D velocity structure model were also examined. The simulation results for the 1D and 3D velocity structure models indicated that the 3D velocity structure models are important in reproducing PGV and the later phases with long duration, especially on deep sediment sites.