Simulation of Ground Motion From Finite‐Fault Modeling Incorporating the Influence of Duration

Abstract

Abstract On 21 May 2021 (local time), an Mw 6.1 earthquake struck the Yangbi County, Yunnan Province, China. The finite fault stochastic simulation approach is usually used to simulate ground motions in high‐frequency band (f > 1 Hz). Model parameters needed for earthquake ground motion simulation mainly include source, path, and site. In the high‐frequency ground motion simulation program widely used in earthquake engineering, the reciprocal of corner frequency is typically used to define the source rise time; however, the complete step‐wise derivation process is unavailable. In deriving the static corner frequency f0, source rise time is typically estimated to be the time required for the rupture to reach 50% of the final location, and the source rise time then can be obtained as 0.27/f0, which is consistent with the hypothesis of corner frequency and rupture velocity, and the correlation and integrity between parameters are established. This study also focuses on the influence of different source rise times and path durations on the simulation results, such as Fourier acceleration spectrum, pseudo‐spectral acceleration, and peak ground acceleration. The results show that the source rise time recommended in this simulation can improve the accuracy of near‐fault ground motion simulations. This study provides suggestions for a reasonable selection of path duration in different engineering applications.

Keywords

• stochastic finite‐fault model
• path duration
• source rise time
• ground‐motion duration
• local site amplification