How to use the earthquake distance from s–p time calculator
Estimate distance to an earthquake from the S-P arrival gap. Enter s–p time difference in the field above; the distance is computed instantly and plotted on the chart so you can see how the answer changes.
Formula
Variables
- dt — S–P time difference (s)
Worked example
With s–p time difference = 30 s, the calculator gives distance ≈ 240 km.
Frequently asked questions
What is the formula for the earthquake distance from s–p time calculation?
Distance (km) = dt × 8. Here dt is s–p time difference (s).
What inputs do I need for the earthquake distance from s–p time calculator?
You need s–p time difference in s. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use this calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.