Dynamic modeling of brittle crustal rocks under tectonic stresses. The models depict how ruptures may propagate along faults and offset (break) the ground surface in an earthquake. Each model shows a different kind of fault in 3D, with elastic strain energy accumulating, and the rupture propagating from the focus. The ground, roads, power lines, commuter train, structures, and Leeper's 2016 Awesome Tacoma are shown at the surface responding to the seismic waves and permanent ground deformation during the earthquake. Each model plays as a looping video.
Interactive 3DTry the Normal Fault modelRotate, move and zoom it yourselfStrike-Slip Faults
Fault blocks slip laterally past each other along a near-vertical fault.
Lateral offset · shear stressRight-Lateral Strike-SlipDynamic model of earthquake cycle on a right-lateral strike-slip fault. Elastic strain accumulates along the fault because it is locked due to friction…
Lateral offset · shear stressLeft-Lateral Strike-SlipDynamic model of earthquake cycle on a left-lateral strike-slip fault. Elastic strain accumulates along the fault because it is locked due to friction…Dip-Slip Faults
Fault blocks slip vertically (up or down) relative to each other along the dip of the fault.
Pulling apart · tensionNormal FaultWhen the brittle crust is extended and thinned due to tensional stress, it breaks along a normal fault. The block above the fault (the hanging wall) drops down relative to the block below (the footwall).
Squeezing · compressionReverse FaultWhen the brittle crust is compressed, it shortens and thickens as the hanging wall is pushed up the fault relative to the footwall.
Squeezing · low angleThrust FaultA thrust fault is a reverse fault with a gentle dip, about 30° or less (here 30°). The hanging wall rides up and over the footwall, stacking older rock on top of younger rock.
Hidden thrust · folds the surfaceBlind Thrust FaultA thrust fault that stops below the ground. The slip dies out at the buried fault tip, so instead of breaking, the rock above bends into a fold that grows a little with each…Oblique Faults
Slip along the fault blocks runs diagonally, combining dip-slip (vertical) and strike-slip (lateral) motion.
Pulling apart and slidingOblique-Normal FaultThe slip runs diagonally across the fault. The hanging wall moves down the fault and sideways at the same time, combining normal and strike-slip motion.
Squeezing and slidingOblique-Reverse FaultThe slip runs diagonally across the fault. The hanging wall moves up the fault and sideways at the same time, combining reverse and strike-slip motion.Complex Faults
Strike-slip faults that step over from one strand to another, pulling the ground apart or pushing it up along the step-over.
Releasing step-over · transtensionRight‑Lateral, Right Step‑OverTwo right-lateral fault strands are offset, and the second one picks up where the first ends, stepping to the right. Oblique-normal faults branch from the end of each strand and…
Restraining step-over · transpressionRight‑Lateral, Left Step‑OverTwo right-lateral fault strands are offset, and the second one picks up where the first ends, stepping to the left. Oblique-reverse faults branch from the end of each strand and…
Releasing step-over · transtensionLeft‑Lateral, Left Step‑OverTwo left-lateral fault strands are offset, and the second one picks up where the first ends, stepping to the left. Oblique-normal faults branch from the end of each strand and die…
Restraining step-over · transpressionLeft‑Lateral, Right Step‑OverTwo left-lateral fault strands are offset, and the second one picks up where the first ends, stepping to the right. Oblique-reverse faults branch from the end of each strand and…© 2026 Earthquake Answers. All rights reserved.