基于地壳分层的唐山地震断层震后变形分析

The postseismic deformation analysis based on crustal layering due to Tangshan earthquake fault

本文利用球体粘弹性地球模型研究唐山地震断层基于地壳分层的震后变形影响,计算四种不同类型的地球分层模型(均匀模型和三种地壳分层模型)产生的震后变形场,分析不同模型对地表变形的影响异同,定量研究了实际地壳分层模型与均匀地壳模型计算的地表变形差异.计算结果显示,相对均匀粘弹性地球模型,利用分层的地壳结构模型,计算的唐山地震断层附近区域震后28年积累的变形,两者最大差值水平方向可达20mm,垂直变形相差10mm左右.计算的结果显示地壳结构的差异对震后地表变形的影响很大,超过现有高精度测量技术的精度.如果利用该区的实测资料进行反演研究,必须根据实际地壳构造情况考虑地壳分层的影响.

The spherical visco-elastic earth model has been used to study the postseismic accumulated 28 years deformation field based on the crustal layering due to Tangshan seismic fault in 1976, compute the accumulated postseismic deformation field due to four different type models （three crustal layering models and one homogeneous model）, analyze the different effect by the four models, quantitatively compare the difference of surface deformation between the realistic crustal layering and homogeneous model. The computation result shows that the difference of horizontal deformation is about 20mm comparing the results get from the different models, while the difference of vertical deformation is about 10mm. These results illustrate that the effect on post seismic deformation by different crustal structure is so large that exceeds the precision of high accuracy observation technology. If one wants to use the observation data to do the inversion research, the effect by the stratified crutal structure could not been ignored.