Theory
The basic travel time equation for the direct wave between shot A and geophone 1 is
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(10) |
where is the distance between the shot A and geophone 1. The overburden velocity
is given by and the observed first arrival time is .
We set up a matrix problem in the form
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(11) |
which expands to
|
(12) |
The ordinary least squares (OLS) solution is given by Menke (1989)
|
(13) |
It follows that the overburden velocity determination is
.
Figure 39:
BREF: Output plot.ps for direct wave analysis. Title shows the least squares solution for the overburden velocity,
. Range of offsets 0 -> 30 m.
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