断层滑动分布和位错模型影响效应的显著性分析

摘要

利用4种已有的汶川地震断层同震滑动分布模型,采用Okada经典弹性半空间位错模型和孙文科球形位错模型,分别计算了汶川地震同震位移场,并将计算结果与GPS实测位移场进行对比分析;最后采用二元方差分析的方法,研究了断层滑动分布和位错模型对同震位移场的显著性影响.结果表明,基于沈正康断层滑动分布模型由球形位错计算的同震位移场与GPS实测值吻合性最好,模拟结果的残差均值△(v)为0.007 m,残差协方差阵的迹tr∑为0.006 m;在断层破裂附近,滑动因子和位错因子都引起较大的均方离差,最大值分别为S2A=7.170 16 m2,S2B=91.407 7 m2;滑动分布和位错模型的显著性影响呈现出不同的空间分布特征,具体表现为:滑动分布的显著性影响体现在近场区域,位错模型主要体现在远场区域.%The co-seismic displacement caused by Wenchuan earthquake (Ms8.0)was calculated with four seismic slip models using half-space(Okada) and spherical dislocation theory(Shen et al),respectively,and the displacement field calculated and the observation result were compared.Statistical significance caused by fault slipping and dislocation models were analyzed using the method of two-factor variance.Results show that co-seismic displacements calculated by the spherical dislocation model is consistent with the observation results,the mean value of residual is 0.007 m,and its trace is 0.006 m.Near the fault rupture,both slipping factor and dislocation factor causing larger mean square deviation,the maximum is S2A =7.170 16 m2,S2B =91.407 7 m2,respectively.The significant influence of slipping distribution and dislocation model shows the characteristics of different space distribution,the former is embodied in the near field area,while dislocation model is mainly embodied in the far-field region.