Enter the arrival time of first shear wave (s) and the arrival time of first compressional wave (s) into the Epicenter Distance Calculator. The calculator will evaluate and display the Epicenter Distance. 

Epicenter Distance Formula

The following formula is used to calculate the Epicenter Distance. 

ED = (S-P) * 8.4

  • Where ED is the Epicenter Distance (km)
  • S is the arrival time of first shear wave (s) 
  • P is the arrival time of first compressional wave (s) 

How to Calculate Epicenter Distance?

The following example problems outline how to calculate Epicenter Distance.

Example Problem #1:

  1. First, determine the arrival time of first shear wave (s). 
    • The arrival time of first shear wave (s) is given as: 24.
  2. Next, determine the arrival time of first compressional wave (s). 
    • The arrival time of first compressional wave (s) is provided as: 12.
  3. Finally, calculate the Epicenter Distance using the equation above: 

ED = (S-P) * 8.4

The values given above are inserted into the equation below and the solution is calculated:

ED = (24-12) * 8.4 = 100.8 (km)

Example Problem #2: 

For this problem, the variables needed are provided below:

arrival time of first shear wave (s) = 40

arrival time of first compressional wave (s) = 30

This example problem is a test of your knowledge on the subject. Use the calculator above to check your answer. 

ED = (S-P) * 8.4 = ?