SUSTKVEL - convert constant dip layer interval velocity model to the stacking velocity model required by sunmo

sustkvel v= h= dip=0.0 outpar=/dev/tty

Required parameters:
v= interval velocities
h= layer thicknesses at the cmp

Optional parameters:
dip=0.0 (constant) dip of the layers (degrees)
outpar=/dev/tty output parameter file in the form
required by sunmo:
tv=zero incidence time pick vector
v=stacking velocities vector

Examples:
sustkvel v=5000,6000,8000,10000 h=1000,1200,1300,1500 outpar=stkpar
sunmo <data.cdp par=stkpar >data.nmo

sustkvel par=intpar outpar=stkpar
sunmo <data.cdp par=stkpar >data.nmo

If the file, intpar, contains:
v=5000,6000,8000,10000
h=1000,1200,1300,1500
then the two examples are equivalent. The created parameter file,
stkpar, is in the form of the velocity model required by sunmo.

Note: sustkvel does not have standard su syntax since it does not
operate on seismic data. Hence stdin and stdout are not used.

Caveat: Does not accept a series of interval velocity models to
produce a variable velocity file for sunmo.


Credits:
CWP: Jack

Technical Reference:
The Common Depth Point Stack
William A. Schneider
Proc. IEEE, v. 72, n. 10, p. 1238-1254
1984

Formulas:
Note: All sums on i are from 1 to k

From Schneider:
Let h[i] be the ith layer thickness measured at the cmp and
v[i] the ith interval velocity.
Set:
t[i] = h[i]/v[i]
t0[k] = 2 Sum t[i] * cos(dip)
vs[k] = (1.0/cos(dip)) sqrt(Sum v[i]*v[i]*t[i] / Sum t[i])
Define:
t0by2[k] = Sum h[i]/v[i]
vh[k] = Sum v[i]*h[i]
Then:
t0[k] = 2 * t0by2[k] * cos(dip)
vs[k] = sqrt(vh[k] / t0by2[k]) / cos(dip)