PERL PROGRAM NAME:
AUTHOR: Juan Lorenzo (Perl module only)
DATE:
DESCRIPTION:
Version:
accuracy Rapid Expansion Method (REM) time integration suremel2dan [parameters] Required parameters: nx= number of grid points in horizontal direction nz= number of grid points in vertical direction nt= number of time samples dx= spatial increment in horizontal direction dz= spatial increment in vertical direction dt= time sample interval in seconds isx= grid point # of horizontal source positions isz= grid point # of vertical source positions styp= source types (pressure, shear, single forces) samp= amplitudes of sources amode= 0: isotropic, 1: anisotropic vmax= global maximum velocity (only if amode=1) vmin= global minimum velocity (only if amode=1) Optional parameters: fx=0.0 first horizontal coordinate fz=0.0 first vertical coordinate irx= horizontal grid point # of vertical receiver lines irz= vertical grid point # of horizontal receiver lines rxtyp= types of horizontal receiver lines rztyp= types of vertical receivers lines sntyp= types of snapshots 0: P, 1: S, 2: UX, 3: UZ w=0.1 width of spatial source distribution (see notes) sflag=2 source time function 0: user supplied source function 1: impulse (spike at t=0) 2: Ricker wavelet fmax= maximum frequency of Ricker (default) wavelet amps=1.0 amplitudes of sources prec=0 1: precompute Bessel coefficients b_k (see notes) 2: use precomputed Bessel coefficients b_k vmaxu= user-defined maximum velocity dtsnap=0.0 time interval in seconds of wave field snapshots iabso=1 apply absorbing boundary conditions (0: none) abso=0.1 damping parameter for absorbing boundaries nbwx=20 horizontal width of absorbing boundary nbwz=20 vertical width of absorbing boundary verbose=0 1: show parameters used 2: print maximum amplitude at every expansion term c11file=c11 c11 filename c13file=c13 c13 filename c15file=c15 c15 filename c33file=c33 c33 filename c35file=c35 c35 filename c55file=c55 c55 filename vpfile=vp P-velocity filename vsfile=vs S-velocity filename densfile=dens density filename sname=wavelet.su user supplied source time function filename Basenames of seismogram and snapshot files: xsect=xsect_ x-direction section files basename zsect=zsect_ z-direction section files basename snap=snap_ snapshot files basename jpfile=stderr diagnostic output Notes: 0. The combination of the Fourier method with REM time integration allows the computation of synthetic seismograms which are free of numerical grid dispersion. REM has no restriction on the time step size dt. The Fourier method requires at least two grid points per shortest wavelength. 1. nx and nz must be valid numbers for pfafft transform lengths. nx and nz must be odd numbers. For valid numbers see e.g. numbers in structure 'nctab' in source file $CWPROOT/src/cwp/lib/pfafft.c. 2. Velocities and densities are stored as plain C style files of floats where the fast dimension is along the z-direction. 3. Units must be consistent, e.g. m, s and m/s. 4. A 20 grid points wide border at the sides and the bottom of the modeling grid is used for sponge boundary conditions (default: iabso=1). Source and receiver lines should be placed some (e.g. 10) grid points away from the absorbing boundaries in order to reduce reflections due to obliquely incident wavefronts. 5. Dominant frequency is about fmax/2 (sflag=2), absolute maximum is delayed by 3/fmax from beginning of wavelet. 6. If source is not single force (i.e. pressure or shear source) it should be not a spike in space; the parameter w determines at which distance (in grid points) from the source's center the Gaussian weight decays to 10 percent of its maximum. w=2 may be a reasonable choice; however, the waveform will be distorted. 7. Horizontal and vertical receiver line sections are written to separate files. Each file can hold more than one line. 8. Parameter vmaxu may be enlarged if the modeling run becomes unstable. This happens if the largest eigenvalue of the modeling operator L is larger than estimated from the largest velocity. 9. Bessel coefficients can be precomputed (prec=1) and stored on disk to save CPU time when several shots need to be run. In this case computation of Bessel coefficients can be skipped and read from disk file for reuse (prec=2). For reuse of Bessel coefficients the user may need to define the overall maximum velocity (vmaxu). 10. If snapshots are not required, a spike source (sflag=1) may be applied and the resulting impulse response seismograms can be convolved later with a desired wavelet. 11. Output is written to SU style files. ", Basenames of seismogram and snapshot output files will be extended by the type of the data (p, s, ux, or uz). Additionally seismogram files will be consecutively numbered. Caveat: Time sections and snapshots are kept entirely in memory during run time. Therefore, lots of time section and snapshots may eat up a large amount of memory.
collects switches and assembles bash instructions by adding the program name
max index = number of input variables -1
To install App::SeismicUnixGui, copy and paste the appropriate command in to your terminal.
cpanm
cpanm App::SeismicUnixGui
CPAN shell
perl -MCPAN -e shell install App::SeismicUnixGui
For more information on module installation, please visit the detailed CPAN module installation guide.