根据构造环境应力场预测峰值水平加速度

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τ₀对 PGA起了重要的作用,将τ₀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。

PREDICTION OF PEAK HORIZONTAL ACCELERATION IN THE LIGHT OF TECTONIC AMBIENT SHEAR STRESS FIELD

The parameter τ₀ 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 τ₀,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 τ₀ 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.