rayt2d vfile=
tfile= [optional parameters]
Required
parameters:
vfile=stdin file containning velocity
v[nx][nz]
tfile=stdout file containning traveltime
tables
t[nxs][nxo][nzo]
Optional
parameters
dt=0.008 time sample interval in ray
tracing
nt=401 number of time samples in ray
tracing
fz=0 first depth sample in
velocity
nz=101 number of depth samples in
velocity
dz=100 depth interval in velocity
fx=0 first lateral sample in
velocity
nx=101 number of lateral samples in velocity
dx=100 lateral interval in velocity
fzo=fz first depth sample in traveltime
table
nzo=nz number of depth samples in traveltime
table
dzo=dz depth interval in traveltime
table
fxo=fx first lateral sample in traveltime
table
nxo=nx number of lateral samples in
traveltime table
dxo=dx lateral interval in traveltime
table
surf="0,0;99999,0"
Recording surface "x1,z1;x2,z2;x3,z3;..."
fxs=fx x-coordinate of first source
nxs=1 number of sources
dxs=2*dxo
x-coordinate increment of sources
aperx=0.5*nx*dx ray tracing aperature in
x-direction
fa=-60 first take-off angle of rays
(degrees)
na=61 number of rays
da=2 increment of take-off
angle
amin=0 minimum emergence angle
amax=90 maximum emergence angle
fac=0.01 factor to determine radius for
extrapolation
ek=1 flag of implementing
eikonal in shadow zones
ms=10 print verbal information at
every ms sources
restart=n job is restarted (=y yes; =n
no)
npv=0 flag of computing quantities
for velocity analysis
if npv>0 specify
the following three files
pvfile=pvfile input file of velocity variation
pv[nxo][nzo]
tvfile=tvfile output file of traveltime variation
tables
tv[nxs][nxo][nzo]
csfile=csfile output file of cosine tables
cs[nxs][nxo][nzo]
Notes:
1. Each traveltime
table is calculated by paraxial ray tracing; then
traveltimes in
shadow zones are compensated by solving eikonal
equation.
2. Input velocity is
uniformly sampled and smooth one preferred.
3. Traveltime table
and source ranges must be within velocity model.
4. Ray tracing
aperature can be chosen as sum of migration aperature
plus half of
maximum offset.
5. Memory
requirement for this program is about
[nx*nz+4*mx*nz+3*nxo*nzo+npa*(nx*