基于定点形变资料获取断裂浅层倾向和倾角的方法研究—以唐山台为例

Method for obtaining shallow fault inclination and dip angle based on the fixed-points deformation data:A case study of Tangshan seismic station

  • 摘要: 本文利用唐山地震台1978—2016年跨断层定点形变资料探究唐山地震台所跨断层的浅层倾向和倾角。首先,对形变资料进行数字滤波处理,消除原始观测数据中的非构造信息;其次,对数据精度进行评价,得出1997—2016年滤波后的形变数据年累计残差普遍较小、精度较高;最后,采用精度较高的形变数据计算SE和NW两倾向不同倾角下基线与水准和的累计残差分布,进而获取断层的浅层倾向和倾角。结果显示,依据跨断层定点形变资料获得唐山地震台所跨断层的浅层倾向为SE,倾角为89°,该结果与前人探槽剖面中断层产状相一致,反映出本文提出的基于长期跨断层定点形变资料通过数字滤波、数据精度评价来获取断裂浅层倾向和倾角的方法具有可行性,但本文所得反演结果与唐山地震台目前采用的断层倾向NW、倾角72°存在一定偏差。

     

    Abstract: Based on the data of the Tangshan seismic station during 1978−2016, shallow incli-nation and dip angle of the fault which crosses Tangshan seismic station were investigated. Firstly, eliminate non-geologic structure information by digital filtering; secondly, evaluate data precision and obtain that annual accumulated residual error of the filtered data from 1997 to 2016 is generally small and accurate; finally, accumulated residual distribution of baselines and leveling lines are calculated with different dip angles by using these processed data, and the shallow fault inclination and dip angle are obtained. The results show that, according to the cross-fault deformation data of fixed-points, the inclination of shallow fault is SE and dip angle is 89°, which is consistent with the fault attitude in the previous exploration profiles, suggesting that the method proposed in this paper is feasible. However, our inversion result is partly different from the fault inclination NW and dip angle 72° adopted at present by Tangshan seismic station.

     

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