Finite element analysis of shear stress evolution in fault-related folds: implications for subsurface geomechanics and energy applications

Fault-related folds are critical subsurface structures that strongly influence fluid flow, reservoir integrity, and fault stability in a wide range of energy and environmental applications. Reliable predictions of their mechanical behavior are essential for assessing risks associated with hydrocarbon production, geothermal operations, carbon storage, and induced seismicity. In this study, we employ two-dimensional finite element models to quantify the evolution of shear stress component in three end-member fold types—detachment, fault-propagation, and fault-bend folds. Stress–time histories extracted from representative elements on fold surfaces and fault planes reveal systematic spatiotemporal patterns. The results show that (i) maximum shear stresses localize at fault tips and fold forelimbs, whereas minima occur near detachment terminations and fold crests; (ii) layer buckling enhances shear stress magnitudes and reorients principal stress axes, promoting strain localization; and (iii) shear stresses consistently peak at ∼45° to bedding, independent of fold rotation. These findings provide new quantitative insights into the mechanical evolution of fault-related folds and offer practical guidance for geomechanical modeling strategies in subsurface energy and environmental applications.