Using Maths to Determine the Depth of an Earth Layer.
MS Word version of this file
(requires: graphing, trigonometry and rearranging of equations)
An explosion sends seismic waves into the ground. An array of geophones has been
positioned to record the ‘First Arrival Times’ of the waves. The array starts
30m from the explosion and has 10m spacings.
Analysis of the data gives the following first arrival times.
| Geophone position (m) | 30 |
40 |
50 |
60 |
70 |
80 |
90 |
100 |
110 |
| Time for first arrival (s) | 0.0353 |
0.0471 |
0.0589 |
0.0706 |
0.0806 |
0.0872 |
0.0938 |
0.1000 |
0.1069 |
