Seismic Wave Travel Calculator for Arrival Time and Path Length

Calculator Inputs

Use preset values or switch to custom velocities. Custom velocities are entered in km/s.

Horizontal Distance

Source Depth

Distance Unit

Velocity Preset

Path Curvature Factor (%)

Station Delay (s)

Custom P Velocity (km/s)

Custom S Velocity (km/s)

Custom Love Velocity (km/s)

Custom Rayleigh Velocity (km/s)

Formula Used

Body-wave path: √(horizontal distance² + source depth²) × (1 + path factor ÷ 100)

Surface-wave path: horizontal distance × (1 + path factor ÷ 100)

Travel time: path length ÷ wave velocity + station delay

Arrival gap: slower arrival time − faster arrival time

This calculator uses a simplified straight-path model for body waves and a horizontal-path model for surface waves. It is useful for quick estimates, teaching, and comparisons across different velocity assumptions.

How to Use This Calculator

Enter the horizontal distance from the source to the station.
Enter the earthquake source depth in the same unit.
Choose kilometers or meters.
Select a preset material model or choose custom velocities.
Optionally add a path curvature factor and station delay.
Click the calculate button.
Review the result cards, travel-time table, and Plotly graph.
Use the export buttons to download CSV or PDF output.

Example Data Table

These sample values are illustrative and help verify expected trends.

Case	Preset	Distance (km)	Depth (km)	P Time (s)	S Time (s)	Love Time (s)	Rayleigh Time (s)
1	Continental Crust	80	10	13.44	23.04	25.81	27.59
2	Continental Crust	120	15	20.16	34.55	38.71	41.38
3	Upper Mantle	250	30	31.09	54.74	60.98	65.79
4	Sedimentary Basin	50	5	14.36	25.12	27.78	31.25

Frequently Asked Questions

1) What does this calculator estimate?

It estimates body-wave and surface-wave travel times, path lengths, arrival order, S-P separation, and total wave spread from your distance, depth, velocity, and delay inputs.

2) Why are P waves usually faster than S waves?

P waves compress material in the travel direction, so they normally move faster. S waves shear material sideways and need more rigidity, which makes them slower.

3) Why do Love and Rayleigh waves use horizontal distance here?

These waves mainly travel along or near the surface. For quick educational estimates, the calculator uses the horizontal path instead of a deeper three-dimensional surface model.

4) Can I enter my own velocities?

Yes. Choose the custom option and enter your own P, S, Love, and Rayleigh velocities in kilometers per second.

5) What is the S-P gap useful for?

The S-P gap helps estimate how far a seismic station is from an event. A larger gap usually indicates a greater source-to-station distance.

6) Does this replace a full seismic modeling package?

No. It is a practical estimate tool. Real seismic travel paths depend on layered media, refraction, anisotropy, attenuation, and regional structure.

7) Which units are supported?

Distance and depth can be entered in kilometers or meters. Velocities in this calculator are entered and interpreted in kilometers per second.

8) What do the CSV and PDF exports include?

They export the current summary and wave-result table after calculation. This makes it easier to save, share, or document your estimate.