反应谱对构造环境剪应力场的依赖性  

THE DEPENDENCE OF RESPONSE SPECTRUM ON THE TECTONIC AMBIENT SHEAR STRESS FIELD

作　　者：李保昆[1] 陈培善[1] 白彤霞[1] 

机构地区：[1]中国地震局地球物理研究所

出　　处：《地震学报》2005年第3期292-300,355,共9页Acta Seismologica Sinica

基　　金：国家自然科学基金(49874010);地震科学联合基金重点项目(9507441)资助.

摘　　要：在以前理论工作的基础上,导出了构造环境剪应力值对反应谱的影响.在美国知名学者Boore等建立的预测公式BJF94的基础上,提出了新的预测公式CLB20.在CLB20中引进了应力场量值τ0对SA的影响项.BJF94主要是基于美国西部的强震观测资料作出的经验预测公式,而SEA99是基于全球张性地区的强震观测资料作出的预测公式.我们把两者的预测结果进行了全面的比较,发现BJF94的预测值lg(Y)减去0.16个对数单位后,与SEA99的预测值十分接近.这说明张性地区的lg(Y)较小;地区性差异主要表现在构造环境剪应力场的差异上.如果这个因素在预测公式中能得到适当体现,同时预测公式中的震级标度都用全球统一的矩震级,距离都使用多数人倾向使用的断层投影距,那么预测公式的地区性差异将大大减轻,以至最后消失,有可能构造出全球适用的预测公式.我们的抗震设计直接引用美国研究者发表的反应谱衰减结果(例如BJF94和SEA99),不会导致太大的误差.It has been analyzed the influence of the tectonic ambient shear stress value on response spectrum based on the previous theory. Based on the prediction equation BJF94 presented by the famous American researchers, CLB20, a new prediction formula is proposed by us, where it is introduced the influence of tectonic ambient shear stress value (τ_0) on response spectrum. BJF94 is the prediction equation which mainly depends on strong ground motion data from western USA, while the prediction equation SEA99 is based on the strong ground motion data from extensional region all over the world. Comparing these two prediction equation in details, it is found that after BJF94's prediction value lg(Y) minus 0.16 logarithm units, the value is very close to SEA99′s one. This case demonstrates that lg(Y) in extensional region is smaller; the differences of prediction equation are mainly owe to the differences of tectonic ambient shear stress value. If the factor of tectonic ambient shear stress value is included into the prediction equation, and the magnitude is used seismic moment magnitude to express, which is universal used around the world, and the distance is used the distance of fault project, which commonly used by many people, then regional differences of prediction equation will become much less, even vanish, and it can be constructed the universal prediction equation proper to all over the world. The error in the earthquake-resistant design in China will be small if we directly use the results of response spectrum of USA (e.g. BJF94 or SEA99).

关 键 词：加速度反应谱 构造环境剪应力场 反应谱预测公式 矩震级 断层投影距 

分 类 号：P315.727[天文地球—地震学]