The mechanics of initiation and development of thrust faults and thrust ramps

This study integrates the results of numerical modeling analyses based on outcrop studies and structural kinematic restorations to evaluate mechanics thrust fault initiation development in mechanically layered sedimentary rocks. A field-based reconstruction a mesoscopic at Ketobe Knob central Utah provides evidence ramp nucleation competent units, propagation upward downward into weaker units both tips. We investigate effects mechanical stratigraphy stress heterogeneity, rupture direction, fold formation, geometry motivated by Utah; finite element examines how stratigraphy, load conditions, configurations influence temporal spatial variation strain. Our focuses predicted deformation distributions four model domains: (1) an intact, stratified rock sequence, (2) section with range interlayer frictional strengths, two faulted models, (3) one loading condition, (4) displacement condition. The models show that early increase layers are accompanied low stresses reveal heterogeneous variations contact strength. Faulted 20° dipping most unit result increases above below tips, extremely high ‘back thrust’ location lower tip. These findings support hypothesis faults associated folds developed accordance ramp-first structures was significantly influenced nature stratigraphy.