Mohr-Coulomb Faulting Simulator

Real fractures in the crust do not form on the plane of maximum shear stress — they form where shear stress first overtakes the rock's frictional strength, on planes predicted by the Mohr-Coulomb failure criterion. This simulator renders a stressed rock volume with a candidate fracture plane and its Andersonian conjugate, lets you switch between normal, reverse and strike-slip stress regimes, tune the principal stresses, cohesion and internal friction angle, and rotate the plane while a live Mohr circle diagram tracks the normal and shear stress on it against the failure envelope. A one-click "snap to optimal" control jumps to the Coulomb-predicted fracture angle θ = 45° − φ/2, showing why real conjugate faults cluster around 25–35° from σ1 instead of the naive 45°.