Explanation of genwav parameters
- xnear near offset in meters
- delx spacing between channels in meters
- nrec number of receivers (ie. traces in shot gather)
- minimum group velocity expected used in estimating needed record length.
- tmax length of traces in seconds (need not match the recommended, depending on gendis run).
- fsamin sample interval in time, seconds
- fmin, fmax minimum and maximum frequencies. Recommend that these be wider than what you think you need, then filter back for your final result using a filter program (like BFIL). NOTE: Wavelet used is minimum phase, set by fmin and fmax.
- maximum mode to include Must be
- ksw dispersion plot, sets wavenumber (1=k) or velocity (0=c)
- mapmat Format for plots. Recommend Octave (Matlab)
- output option, irvsel signals will be vertical or inline radial.
- source depth depth of source in meters
- moment tensor diagonal (radial,transverse,vertical). 0,0,1 is a vertical impulse. You can edit the waves.d file if you want a double couple instead.
The waves.d listing for this example:
&waves
ksw= 0, stepz=20,
modes=1,2,3,4,5,6,7,8,9,
fmin= 1.0000, fmax= 100.0000,
fsamin= 0.00100,
curve='earth.crv',
mapmat=0,
matlb1='matc.m', scilb1='matc.sci',
matlb2='matu.m', scilb2='matu.sci',
irvsel=0,
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=24,
rz=24*0.0,
ry=24*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,
/
This file can be edited in case the genwav options don't cover what you want. If you want only the fundamental mode, for example, change the modes line:
modes=1,0,0,0,0,0,0,0,0,
The irvsel parameter is an easy way to change between vertical or horizontal radial signals on the receivers. For guidance on the moment tensor, tmll, see Aki & Richards (1980)