A new model for quantitative analysis of kinematic properties of faults: Examples from the Jiyang Depression, NE China

Calculating the strike-slip component of fault displacement is challenging, making quantitative determination of the kinematic properties of a fault zone difficult. This study introduces a novel fault zone model to offer improved opportunities to reconstruct the history of fault evolution. We provide a new quantitative calculation method of fault geometry that can identify piercing points where branch faults are offset by a master fault. This method is based on the geometric relationships between the attitude of a master fault and its branch faults. From these observations, it is possible to quantitatively calculate the displacement components and kinematic properties of a fault zone. Additionally, the existing stereographic projection method is adapted by considering the attitude of fault planes to provide an alternative approach to solve the problem of fault kinematics. This method can be used to derive the pitch angle of a fault with the new model by analyzing the intersection attitudes of a master fault and its branch faults through intersecting planes. Applied to 3D seismic data with well control from the Jiyang Depression, results show higher strike-slip intensity near principal displacement zones adjacent to the Tan-Lu and Lan-Liao fault zones, whereas extensional deformation dominates the central sector. Moreover, both methods yield consistent results in reconstructing the structural history of fault zones. This demonstrates the practical application of the new model and demonstrates that methods employed for the model can be used in the kinematic analysis of fault zones more generally, which has previously been challenging in subsurface studies.