Document Type : Original Research Paper
Authors
1 Ph.D. Student, Department of Geology, University of Birjand, Birjand, Iran
2 Professor, Department of Geology, University of Birjand, Birjand, Iran
3 Assistant Professor, Research institute for Earth sciences, Geological Survey of Iran, Tehran, Iran
Abstract
The aim of this research is to investigate triggering of fault slip due to stress perturbation caused by hydraulic fracturing. The importance of this issue is to study the observed destructive effects of dam construction at locations adjacent to the superficial faults. Therefore, we use the Matlab programming and SimDesigner system as an analytical extension. Concentrated stresses are applied after defining the nodes for fracture surfaces. By having the fault surface, analyses start to reach an equilibrium state. By defining the reaction forces in boundary condition, comparison of nodal dislocations become possible. The basis for vertical stress calculation is the upper rock layer and for horizontal stress is Coulomb failure stress. We estimate the stress perturbation through theory of tip stress about tensile fractures. The resultant stress field obtained from combination of fractural and regional stresses gives primary condition to study triggered fault slip and related earthquake magnitude. The results show a maximum 2 meters of cumulative slip along the fault surface close to the hydraulic fracturing. Based on moment magnitude of earthquake calculations, this slip gives a magnitude of 3.8 upon the Richter scale. This process needs the increased precision for nodal dislocations and optimized finite elements in order to better improve the future works.
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