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Ground motion path duration model of the Jiashi earthquake. The red circle indicates the 90% ground motion duration calculated by the selected stations triggered in Jiashi earthquake; the red dotted line represents the fitting result; the filled areas (pink) represent 95% confidence band, and the filled areas (light pink) represent 95% prediction band.
Source publication
A 6.0‐magnitude (Mw) earthquake was reported to have occurred in Jiashi County, Xinjiang at 21:27 on 19 January 2020, Beijing time (13:27 UTC). This study applied a stochastic finite‐fault approach based on the dynamic corner frequency (EXSIM) to simulate 23 near‐field stations within a distance of 120 km from the epicenter. The stochastic finite‐f...
Citations
... In addition, in order to obtain better fitting results, Dang et al. attempted to introduce non-stationary phase to improve the model [35], making frequency non-stationary. Besides, in order to improve the accuracy of model parameters, scholars used earthquake data to invert and identify the model parameters [36][37][38][39]. By trial-and-error method, partial good results could be obtained [40], while the genetic algorithm is an effective parameter inversion method [41]. ...
In the seismic reliability analysis of engineering structures, it is often necessary to adopt stochastic ground motions as inputs. However, the current methods used to generate stochastic samples, such as the spectral representation method, the spectral transfer method, the dynamic source method, the physical source method,
and the comprehensive method, etc., are not very convincing since they do not contain the complete information of seismic occurrence and propagation. In this study, an improved finite-fault model for stochastic simulation of ground motions is proposed. Compared to existing stochastic finite-fault model, the improved model considers the propagation law of phase spectrum, local site effect, and the impact of wave velocity on the arrival time of seismic waves. Besides, identification and statistics of model parameters are carried out based on ground motion records. Reasonable samples of stochastic ground motions are then obtained. In addition, parameter sensitivity analysis is conducted to determine critical random variables, which reduces the complexity of stochastic simulation. Simulation results are compared with recorded accelerograms from the 1999 Chi-Chi earthquake. It
is shown that the improved stochastic finite-fault model is reliable, and the acceleration response spectra of simulated samples are consistent with those of station records collected at various site classes and the design spectra.
On September 5, 2022 (local time), a magnitude 6.6 earthquake was reported to have occurred in Luding County, Sichuan Province, Southwest China. In this simulation, a widely used stochastic finite-fault model was used to analyze how the source models affect the near-fault earthquake ground motion simulations of the 2022 Mw 6.6 Luding earthquake in China. Seven different slip models, one of them obtained from common fault parameters and random distributed slip amount, were used to yield the best match with the recordings. The simulated earthquake ground motions calculated in the frequency band of 0.05–20 Hz were compared with the observed values in both the time and frequency domains. Twelve acceleration observation stations located near the fault plane were selected in our simulation for comparison. The average H/V curves were estimated using the available acceleration records to consider the local site effect at each selected station. The research results indicate that none of the source models adopted in this study fully estimate the observed values at all the selected ground-motion stations. The simulated values of some slip models underestimate the level of the Fourier amplitude spectrum at frequencies above 6 Hz. The underestimation may be attributed to the directivity effect, which may produce a higher amplitude of observed ground motion in the high-frequency band. All the slip models show similar average model deviations except for the random slip model. Finally, the peak ground accelerations and peak ground velocities were predicted at these selected near-fault observation stations. The results indicate that the peak accelerations and velocities obtained from seven slip models correlate well with each other, but are slightly lower than the recorded values at most stations. In addition, the synthetized results calculated from the random and inverted slip models can be the same level only if a greater stress drop is adopted in the random model.
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.
