Avoidance distance and influence range of active faults: A case study of Litang fault

Objective Active faults can not only trigger strong earthquakes, but also cause engineering breaks, creep deformation, and geological disasters, which seriously threaten the planning, construction, and safe operation of major projects. Methods In this study, based on the statistics of coseismic surface ruptures, the avoidance distances of faults with different properties and the ranges of extremely strong, strong, less strong, and moderately affected areas of active fault zones are established. Remote sensing, a geological survey, dislocation landforms, and shallow seismic exploration were used to analyze, the avoidance distance and affected area of the Litang fault on the Qinghai-Tibet Plateau. Conclusion This study concludes that the hanging wall and footwall avoidance distances of normal faults are not less than 30 m and 15 m, respectively; the hanging wall and footwall avoidance distances of thrust faults are not less than 45 m and 15 m, respectively; the avoidance distance of strike-slip faults is not less than 30 m. The Litang fault is mainly characterized by strike-slip with normal fault components, and its hanging-wall avoidance distance is 30 m and its footwall avoidance distance is 15 m. The extremely strong, strongly, less strong, and moderately affected areas of the Litang fault zones are 154 m, 154-500 m, 500-1000 m, and 1000-3000 m, respectively. [Significance] The research provides basic data for the planning and construction of major projects and the spatial control of the national land.