Editing the waves.d file

One can edit the waves.d file, perhaps after copying it to a new file with a different name. For example, if you wish to compute only the fundamental, you would change the modes line to the following


modes=1,0,0,0,0,0,0,0,0,


To compute only the second mode above the fundamental, the modes line would be as follows:


modes=0,0,3,0,0,0,0,0,0,


You can change the source moment tensor, the location or number of geophones, and their orientation. Just about anything can be edited. However, you can not ask for more frequencies than were computed in the disper run, since you are limited to those frequencies in the earth.crv file. For example, let's just edit the file to compute the in-line horizontal component of motion. This would be like deploying horizontal phones aligned with the x-axis (axis of propagation). The new file, wavesR.d might look like this:


   &waves
  ksw= 0, stepz=20,
  modes=1,2,3,4,5,6,7,8,9,
  fmin=    10.0000, fmax=  100.0000,
  fsamin=   0.00100,
  curve='earth.crv', 
  mapmat=0,
  matlb1='matc.m',   scilb1='matc.sci', 
  matlb2='matu.m',   scilb2='matu.sci', 
  irvsel=1,
  ofile='waves.tmp', /
  &source
  tm= 0.0, 0.0, 0.0,
     0.0, 0.0, 0.0,
     0.0, 0.0, 1.0, /
  sz=    0.00, sy=0.00, sx=0.00, /
  &recvr
  nrec=48,
  rz=48*0.0, 
  ry=48*0.0, 
rx=      1.000,     2.000,     3.000,     4.000,     5.000,
     6.000,     7.000,     8.000,     9.000,    10.000,
    11.000,    12.000,    13.000,    14.000,    15.000,
    16.000,    17.000,    18.000,    19.000,    20.000,
    21.000,    22.000,    23.000,    24.000,    25.000,
    26.000,    27.000,    28.000,    29.000,    30.000,
    31.000,    32.000,    33.000,    34.000,    35.000,
    36.000,    37.000,    38.000,    39.000,    40.000,
    41.000,    42.000,    43.000,    44.000,    45.000,
    46.000,    47.000,    48.000,
  /


What has changed? We change the orientation of the receivers by setting irvsel=1. We can also change the name of the listing file to wavesR.tmp. All else remains the same. The program will automatically change the name of the output BSEGY file. These names are hardwired. For vertical component synthetics, the name is wavV.seg, and for horizontal component data wavR.seg. A trace equalized plot of the synthetic seismogram is shown in Figure 60.

Figure 60: Plot of horizontal component motion, trace equalized to remove amplitude decay with offset. This permits viewing the waveform changes with offset. Compare this to the vertical motion in Figure 58.
\includegraphics[scale=0.7]{FigureCC}