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

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.