摘要
在分析了对峰值加速度 PGA 的影响因素之后,我们发现构造环境剪应力场参数τ_0对 PGA起了重要的作用,将τ_0引入 PGA 的预测公式中,同时考虑了 PGA 对频率的依赖性。大地震的PGA 的优越频率 f_a 较低,小地震的 f_a 较高.因此,小地震的衰减系数较大,PGA 衰减较快。基于上述两点改进,提出了新的 PGA 预测公式。在该公式中,构造环境应力场、震级、距离和场地条件是预测将来强地面运动的重要变量。此公式有很大的适用范围,可以用于大地震(矩震级 M_w=6—7.8),也可以用于较小地震(M_w=3—6)的 PGA 预测;在考虑了世界各个地区不同的构造环境应力值水平以后,新预测公式可以应用于世界不同地区(例如美国加州和中国华北、西南等)。用实际观测资料检验结果表明,预测效果良好。
The parameter τ_0 of tectonic ambient shear stress field has been introduced into the prediction equation of peak acceleration.Authors have found that peak ground acceleration (PGA) strongly depends on τ_0,and also depends on frequency.Because predominent frequency f_a for large earthquake is lower than that for small earthquake, the attenuation coefficient of PGA for large earthquake is smaller than that for small one,and PGA attenuation for large earthquake is slower.Based on above two improvements,a new prediction equation of PGA (equation (16) in text) has been put forward,which can be used not only for large earthquakes (M_W=6.0-7.8) but for small earthquakes (M_W=4.0—6.0),and which can be used for larger range of epicenter With consideration of the different level of τ_0 of each region around the world,the new prediction equation can be used for various regions all over the world (e.g.California in USA,North China and South-West China).Proved by observation data,the effect of prediction is encouraging.
出处
《地球物理学报》
SCIE
EI
CAS
CSCD
北大核心
1998年第4期502-517,共16页
Chinese Journal of Geophysics
基金
国家自然科学基金(49474222)
地震学联合基金项目(95075)
国家地震局地球物理研究所论著(98A02039)
关键词
峰值
加速度预测
构造环境应力
衰减系数
地震
Prediction of peak ground acceleration
Tectonic ambient shear stress field
comer frequency
Attenuation coefficient
