Improvement of the Fault Intensity Index Calculation Method Based on High-density 3D Seismic Exploration Results

Abstract

Structural quantification serves as a critical task in evaluating mine water hazards and structural complexity. The selection of quantification methodologies significantly impacts the authenticity and precision of mine-related assessments. To address the limitation of conventional Fault Strength Index (FSI) calculations, which approximate fault morphology as rectangular geometries—leading to discrepancies between calculated FSI values and actual fault developmental characteristics—this study focuses on the No. 32 Mining Panel of Liangbei Coal Mine. Utilizing high-density 3D seismic exploration data and inversion results of faults within the study area, fault throws exceeding 5 m were calculated at discrete points along fault extensions via the interpolation method applied to coal seam floor contour maps. Based on the morphological characteristics of faults depicted in geological graphics, optimal coordinate points were selected to establish a 2D coordinate system. Fault extension lengths and throw values were then processed into 2D coordinates. MATLAB’s curve-fitting toolbox was employed to derive fitting equations describing the relationship between fault throw and extension length. An improved FSI calculation method was proposed by integrating fault fitting functions into the quantification framework. Comparative analysis with traditional FSI results demonstrates that the enhanced methodology better aligns with the actual developmental morphology of faults. This refinement not only resolves subjective biases inherent in conventional rectangular approximations but also establishes a more robust foundation for structural complexity zoning and hydrogeological risk management in underground mining environments.