垂直和平行于断层方向的脉冲参数特性分析

如何实现速度脉冲参数化并对其参数进行特性分析是一个值得深究的问题。从NGA-West2强震动数据库选取126组近断层脉冲型地震动记录,采用速度脉冲模型,基于最小二乘法拟合得到水平分量的速度脉冲模型特征参数,研究震级、断层距、场地类别对脉冲参数的影响,并对比垂直和平行断层分量脉冲参数的特性差异。结果表明:垂直断层分量的脉冲峰值随震级和断层距的变化速率均快于平行断层分量的相应值,场地条件对脉冲峰值随震级和断层距的变化规律具有较大影响;半脉冲周期与主脉冲周期存在强线性相关性,两者随震级的变化规律存在差异;当震级相同时,基岩场地上的脉冲峰值时刻小于土层场地;对于集集地震来说,较小的形状参数主要分布于靠近破裂断层处,随着断层距的增大,不同分量之间的脉冲形状参数的差异也随之变大。

Characteristics of Pulse Parameters Perpendicular and Parallel to the Fault Direction

How to realize the parameterization of velocity pulse and analyze the characteristics of parameters is a problem worthy of further study. In this paper, 126 groups of near-fault pulse-like ground motion records were selected from the NGA-West2 database. The velocity pulse model was used to obtain the characteristic parameters of horizontal component based on the least square method. The effects of magnitude, fault distance, and site type on the pulse parameters were studied, and the characteristics of the pulse parameters of fault-normal component and fault-parallel component were compared. The results showed that the change rate of peak pulse value of fault-normal component with magnitude and fault distance is faster than that of fault-parallel component, and the site conditions have a great influence on the variation of peak pulse with magnitude and fault distance. There is a strong linear correlation between the half pulse period and the main pulse period, and the variation of them with the magnitude is different. With the same magnitude, the pulse peak moment in bedrock site is smaller than that in soil site. For the Chi-Chi earthquake, the small shape parameters are mainly concentrated near the rupture fault. With the increase of fault distance, the difference of pulse shape parameters between different components also increases.