Structural geology · rock deformation

Structural Geology Lab

Push, pull or shear the crust. Change the stress history, depth and rock properties, then watch how the same rock package folds, fractures and faults.

Simplified teaching model. Depth controls a simplified pressure-temperature state, while stress magnitude and timing control how deformation is divided between distributed strain and brittle fault slip. Designed for investigation, not real-world geomechanical prediction.

Experiment controls

Set the tectonic conditions.

Run any setup first. If you want a controlled comparison, set that result as your reference and change one control only.

Stress regime Compression

Changes the direction of differential stress and therefore the family of structures that can form.

Maximum stress 110 MPa

lowhigh

The highest differential stress reached during the experiment.

Time to max stress 3.0 Myr

rapid loadinggradual loading

More time to reach peak stress allows more distributed deformation before the maximum stress is reached.

Total time 6.0 Myr

shortlong

How long the chosen tectonic conditions act. If a fault forms, more time allows more slip to accumulate.

Depth 10 km

shallowdeep crust

Confining pressure270 MPa

Temperature265 °C

Greater depth raises both pressure and temperature in this simplified crustal model.

Rock package Layered

Mechanical contrast changes how easily deformation becomes distributed or localised.

Ductile tendency 50%

Failure proximity at max stress 0%

Likely final response Distributed deformation

Dual view structural model · 0.0 / 6.0 Myr

Live cross section

Watch the rock package deform.

Subsurface geometry: folds, faults and the brittle-ductile transition.

Cross section · Primary view

The cross section shows the subsurface response to tectonic stress.

Deformation style Intact No permanent strain yet.

Dominant structure None yet Run the model to deform the rock.

Accumulated strain 0.0% Calculated from the current stress history.

Current stress 0 MPa Target: 110 MPa.

Brittle tendencyDuctile tendency

Surface expression

Map the same deformation.

Topography + structural traces + stress orientation.

Surface map · Linked view

The map links fault orientation and topographic pattern to the same model shown in cross section.

higher ground lower ground fault trace fold axis

What just happened?

Read the deformation.

Stress builds gradually, then remains at the chosen maximum.

stress regime→distributed strain→damage→fault localisation→fault slip

Interpret the result

What controlled the response?

The same stress regime can produce very different structures. Higher temperature and confining pressure generally favour ductile deformation, while cool shallow conditions favour brittle failure. Rock type, stress magnitude and loading history matter too.

The science

Rocks can bend, break, or do both.

Structural geology examines how rocks respond to stress. Near the surface, lower temperature and pressure often favour brittle fractures and faults. Deeper in the crust, hotter and more strongly confined rocks can deform more gradually.

That transition is not a single fixed depth. Rock type, stress magnitude and the time available for deformation all matter.

This is a simplified teaching model, not a geomechanical forecast. Real deformation also depends on strain rate, fluids, mineralogy, pre-existing structures, anisotropy and many other factors.

Investigation ideas

Change one thing. Watch what shifts.

1. Go deeperKeep everything else fixed. Does the deformation become more or less ductile?
2. Slow the loadingIncrease only the time to max stress. Does more distributed strain develop before failure?
3. Give the fault more timeKeep the stress history fixed but increase total time. How does final fault slip change?
4. Change the rockRepeat one tectonic setup with different rock packages and compare the outcome.