An estimation model of high frequency attenuation coefficient of ground motion for local site

When using the stochastic finite fault method for ground motion simulation, how to select reasonable parameters to describe the near-surface high-frequency attenuation characteristics of a specific local site has important practical significance for evaluating the correctness of ground motion simulation results. In the prediction of ground motion parameters of engineering sites, how to quickly determine the value of parameters is an urgent problem to be solved in practical applications. Firstly, we analyzed the correlation between the high-frequency attenuation coefficient κ₀ of the site and the average shear wave velocity v_S30. Then, based on the 546 κ₀ coefficients calculated by domestic and foreign scholars, the root mean square value of κ₀ in a certain time window was used to discuss its variation trend with the increase of the average shear wave velocity v_S30.The results showed that although κ₀ had obvious regional differences, its root mean square value showed a decreasing trend with the increase of v_S30. In order to obtain a reasonable κ₀ estimation model, the linear function, polynomial function, logarithmic linear function and log-log linear function were used to preliminarily fit the relationship between the root mean square value of κ₀ and v_S30. The results show that the logarithmic linear function can better describe the relationship between κ₀ and v_S30. Finally, based on the 477 data obtained from the screening, the model parameters were fitted by the least square method, and a practical model of κ₀-v_S30 suitable for engineering applications was obtained. The analysis of the applicability of the model shows that the κ₀ estimation model constructed in this study can reasonably estimate the high-frequency attenuation of ground motion when predicting engineering site ground motion parameters.