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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。
After analyzing the influencing factors of peak acceleration PGA, we find that the τ_0 of tectonic environment shear stress plays an important role in PGA, and introduces τ_0 into the prediction formula of PGA, taking into account the dependence of PGA on frequency. The superior frequency f_a of PGA for large earthquakes is lower and the f_a for small earthquakes is higher, so the attenuation coefficient of small earthquakes is larger and the PGA attenuation is faster. Based on the above two improvements, a new PGA prediction formula is proposed. In this formula, the tectonic environment stress field, magnitude, distance and site conditions are important variables for predicting strong ground motion in the future. This formula has a great range of applicability and can be used for large earthquakes (moment magnitude M_w = 6-7.8) and PGA forecasts for smaller earthquakes (M_w = 3-6) After the construction of environmental stress level, the new prediction formula can be applied to different parts of the world (for example, California of the United States, North China of China, Southwest of China). The actual observation data test results show that the prediction effect is good.