notes

su 的源代码库

This is the first example of generating shot data.  Both cshot1 and cshot2
must be run this time.

Here is param1 for cshot1:

simplemodel                         :model file
4                                   :#interfaces in model
plotcolors                          :model colors file
m                                   :first plot descriptor (mwq)    ...SEE
don't care                          :well coordinates                  FILE
s                                   :shooting mode (sd)               NOTES...
geometry4                           :receiver geometry              ..........
sg                                  :second plot descriptor (sgq)   ...THIS
rt                                  :job descriptor (rlt)              DIRECTORY
demo8                               :output filename(s)
-90.   90.                          :range of takeoff angles 
1.                                  :increment in takeoff angle
4000.0  6000.0  9000.0
10000.0 13000.0                     :velocities
n                                   :direct wave? (y or n)
                                    :headwave interface numbers (1, 2, ...)
y                                   :primaries? (y or n)
0 1                                 :source ghost + reflection from interface 1
0 1 0 1                             :reverberation in layer 1

In Record 9 of param1 we have asked for rays (r) and time section (t).
When we specify t here, cshot1 writes out pertinent information needed to 
construct the time data. (As is the case for all output files, 
the first part of this filename comes from Record 10.  The last part of the
filename is 'shot', so the file created here will be demo8shot.)

We have asked for data from 4 primaries and 2 additional events (described by
the last 2 records in param1).


After demo8shot has been created, by running cshot1, we can run cshot2 and
actually construct the traces.
Program cshot2 requires only one input parameter file.  This file
must be called param2.
Here is param2 for this example:


s                                :job option (s,r)
1  1                             :first, last shot for sort
1  100                           :first, last trace OR first last receiver
10.  25.   35.  50.              :frequency spectrum of wavelet
.150                             :wavelet length (secs)
.004                             :sample rate (secs)
2.                               :record length (secs)
demo8shot                        :input filename
demo8traces                      :output filename


The following notes refer to the records in param2.

(1) The first record in param2 specifies the sort option.  Besides
constructing shot records it is also possible to produce a receiver
sort.  The choices for Record 1 are s or r.  To build shot records
choose s.  For a receiver sort choose r. 


(2) The second record of param2 defines the shot records to include in
the sort.


(3)  The third record of param2 also depends on your choice of s or r.

    (i) Record 1 = s
	For the shot option, Record 3 contains the first and last trace
	to build from each shot, eg, to build traces 30-50 from each
	shot just specify 30 50 here.

   (ii) Record 1 = r
	For the receiver sort option, Record 3 contains the first and last 
	receiver sort to build.  The number of traces you get in each
	sort depends on the number of shots for which each receiver was
	live, or active, within the range of shots given in Record 2.

(4)-(7) These records used to be in file ftdata in the old version of the code.
        Note that the sample rate is specified in seconds now.

(8)     Record 8 of param2 is the name of the file generated by cshot1.
	It contains traveltimes, amplitudes, etc. for all the shots in the
	cards file.

(9)     The last record in param2 is the name to be given to the file
	containing the actual traces built by cshot2.


It is also possible to generate a common offset sort.  This is done
with the shot option by specifying only one trace to build in Record 3,
eg, to build trace 10 only from all shots in Record 2, specify 10 10 in
Record 3.  (I am assuming, of course, that the trace in question is
recorded at a receiver which is always the same distance from the
shot.  You need to be careful enough in the shot cards file if you want
to make this happen.  What it means is that the shot and receivers must
move up the same amount from one shot to the next.)