Input data
Enter measured offsets, elapsed time, uncertainties, and optional structural details to estimate net, horizontal, vertical, and down-dip slip rates.
Example data table
This example shows how a geomorphic offset and dated landform can be converted into horizontal, vertical, and net slip-rate estimates.
| Fault segment | Horizontal offset | Vertical offset | Elapsed time | Net offset | Net slip rate |
|---|---|---|---|---|---|
| Terrace Marker A | 12.4 m | 3.1 m | 4,800 yr | 12.78 m | 2.66 mm/yr |
| Channel Offset B | 18.7 m | 1.8 m | 7,200 yr | 18.79 m | 2.61 mm/yr |
| Scarp Surface C | 6.5 m | 2.4 m | 2,900 yr | 6.93 m | 2.39 mm/yr |
Formula used
1) Net displacement
Net offset = √(horizontal² + vertical²) when manual net displacement is not supplied.
2) Slip-rate calculation
Slip rate = displacement / elapsed time. The calculator reports horizontal, vertical, and net rates using the same observation interval.
3) Uncertainty propagation
σ(rate) = √[(σx / t)² + (x·σt / t²)²]. This propagates displacement and age uncertainty into the final rate estimate.
4) Dip-related estimate
Down-dip slip = vertical offset / sin(dip angle). This is shown only when a dip angle and vertical component are entered.
5) Reference accumulation time
Time to reference displacement = reference displacement / net slip rate. This estimates how long the fault would need to accumulate a chosen offset.
How to use this calculator
- Enter the mapped horizontal and vertical displacement values.
- Select the displacement unit used during measurement.
- Add a manual net offset only when it is independently known.
- Enter the elapsed time and matching time unit.
- Include uncertainty values to estimate confidence bounds.
- Set a reference displacement to estimate accumulation time.
- Optionally enter fault dip angle and segment length.
- Click Calculate Slip Rate to display results above the form.
- Use the export buttons to save a CSV or PDF report.
FAQs
1) What does fault slip rate mean?
Fault slip rate is the average displacement per unit time along a fault. It helps compare tectonic activity, crustal deformation, and long-term seismic behavior.
2) When should I enter a manual net offset?
Use a manual net offset when a field study, trench, lidar model, or published source already reports total displacement directly. Otherwise, the calculator resolves it from horizontal and vertical components.
3) Why are multiple rate units shown?
Geological studies often compare slip rates in mm/yr, cm/kyr, or m/Myr. Showing several units helps you match reporting standards without manual conversion.
4) How is uncertainty handled here?
The calculator propagates uncertainty from displacement and time into the rate estimate. A confidence multiplier then scales the spread to show an interval around each rate.
5) What is the shear strain proxy?
This value is net displacement divided by mapped segment length. It is a quick comparative indicator, not a full mechanical strain model.
6) What does the dip-related estimate represent?
If you provide fault dip and vertical displacement, the tool estimates down-dip slip and its rate. This helps interpret motion along the fault plane.
7) Can this replace a tectonic inversion study?
No. This calculator is a fast analytical aid. It does not replace detailed structural modeling, geodesy, paleoseismology, or full uncertainty analysis.
8) What data quality gives the best results?
The best estimates come from well-constrained offsets, carefully dated surfaces, consistent units, and realistic uncertainty bounds taken from field or laboratory methods.