Figure 1. Source-receiver geometry employed when recording seismic wave-test data. The distance “X” from source point SP1 to source point SPN should equal or exceed the depth to the deepest target that needs to be imaged. Distance “L” between successive source stations is the same as the length of the stationary geophone spread. The separation “d” between successive geophones stations should be small (two to three meters), and the receiver-patch length L needs to be reasonably long (200 to 400 meters).