西南地区水平向峰值速度、峰值位移衰减关系研究

本文收集西南地区79个4.0＜Ms≤8.0主震、0＜Rrup＜300 km的自由场地加速度记录,采用合理可靠的数据处理方法获得峰值速度(PGV)和峰值位移(PGD)的水平分量几何均值各1600个.建立包含西南地区强震动数据及相应的震源、距离、场地参数等各项元数据的数据集.统计回归得到西南地区包含震级饱和效应、震级相关几...

Ground motion attenuation relationship of horizontal component of PGV and PGD in southwest China

We collect accelerograms recorded on free-field of 79 mainshocks with 4.0 < MS≤8.0 and 0 < Rrup < 300 km that occurred in southwest China and use reasonable and reliable data processing method to obtain 1600 geometric mean horizontal component of PGV and PGD. We then establish a dataset containing strong motion data and various metadata such as corresponding earthquake sources, distances, and site parameters in southwest China. Based on this dataset, the attenuation relationship of horizontal PGV and PGD, including the effects of magnitude saturation, magnitude-dependent geometric attenuation, linear and nonlinear site response, and inelastic attenuation in southwest China, are obtained by statistical regression. The evaluation of inter-event residual, intra-event residual, and model is carried out. This attenuation relationship of horizontal PGV and PGD is compared with the actual observations, attenuation relationship of horizontal PGV in the Sichuan-Tibet area, and the attenuation relationship of horizontal PGD of NGA-West1. The results show that our model effective in estimating horizontal PGV and PGD for events with 4.0 < MS≤8.0 and 10 < R < 300 km in southwest China. Most observed PGVs and PGDs of the Wenchuan, Lushan, Ludian, and Jiuzhaigou earthquakes are distributed within ±1 standard deviation of the PGV and PGD attenuation curves of our model. Our model's PGV and PGD attenuation curves clearly show the magnitude-dependent attenuation and the average effect of soil nonlinearity. Compared with the common domestic attenuation relationship and NGA-West1 ground motion model, our model can better reflect the influence of earthquake source characteristics, propagation media, and site nonlinearity on the horizontal PGV and PGD attenuation characteristics in southwest China.