Wavefield snapshots of the x-component velocity for both impermeable and permeable faults with different initial shear stresses: (a) |${\tau }_{\rm{0}}$| = 68 MPa (S = 2.65), (b) |${\tau }_{\rm{0}}$| = 71 MPa (S = 1.28), and (c) |${\tau }_{\rm{0}}$| = 73 MPa (S = 0.82).