Earthquake Distance Calculator

Epicenter distance from P-wave and S-wave arrival times.

S-P time interval (seconds)

P-wave velocity (km/s)

S-wave velocity (km/s)

Tab to move between fields

Distance to epicenter (km)

252

Distance (miles)156.59

Distance (degrees)2.27

P-wave travel time (s)42

S-wave travel time (s)72

Verified S-P interval (s)30

How to Use This Calculator

Read the seismogram and measure the S-P time interval — the gap in seconds between the first P-wave and first S-wave arrival.
Enter the P-wave velocity (km/s) for the local crust; the default 6.0 km/s is a typical continental average.
Enter the S-wave velocity (km/s); 3.5 km/s is standard for continental crust.
The calculator returns the Distance to epicenter (km). Use readings from three stations to triangulate the exact epicenter location.
Check the Verified S-P interval output — it should match your measured interval, confirming consistent inputs.

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