Evolutionary Kanai-Tajimi Type Earthquake Models

A versatile mathematical framework based on the concept of random pulse train is proposed for the modeling of hypothetical ground acceleration in a future earthquake for engineering design purposes. This framework is potentially capable of incorporating various physical features arising from propagation, reflection and refraction of seismic waves in the ground. Three specific simplified models are then investigated: an evolutionary Kanai-Tajimi model, a one-dimensional elastic model, and a one-dimensional Maxwell model. Artificial seismograms are generated from these models to simulate the 1985 Mexico earthquake, and the results are compared with an actual record. It is shown that all the random pulse train models have an evolutionary spectral representation which permits variation of both mean-square intensity and frequency contents, and that the random vibration analyses of linear and nonlinear structures under such excitations can be simply formulated.