NAME

Fdmod2 - Finite-Difference MODeling (2nd order) for acoustic wave equation


USAGE

Fdmod2 <vfile >wfile nx= nz= tmax= xs= zs= [optional parameters]


PARAMETERS

stdin - sepfile

                file containing velocity[nx][nz]

stdout - sepfile

                file containing waves[nx][nz] for time steps

tmax - float

                        maximum time

src_file - sepfile

   file (2,nsrc) containg src locations (z,x)

xs - float*

                        x coordinates of sources

zs - float*

    z coordinates of source

nt - int

 [1+tmax/dt]  number of time samples (dt determined for stability)

mt - int

 [1]            number of time steps (dt) per output time step

fmax -float

[vmin/(10.0*h)] maximum frequency in source wavelet

fpeak -float

[0.5*fmax] peak frequency in ricker wavelet

dfile- sepfile

  input file containing density[nx][nz]

vsx - float

  [o2] x coordinate of vertical line of seismograms

hsz - float

   [o1] z coordinate of horizontal line of seismograms

vsfile -sepfile

  [none]        output file for vertical line of seismograms[nz][nt]

hsfile -sepfile

  [none]        output file for horizontal line of seismograms[nx][nt]

ssfile -sepfile

  [none] output file for source point seismograms[nt]

verb -int

  [0]           =1 for diagnostic messages, =2 for more

abs - int[4]

  [1,1,1,1]             Absorbing boundary conditions on top,left,bottom,right
                        sides of the model. 0,1,1,1 for free surface condition on the top

pml_max - float

  [1000.0]       PML absorption parameter

pml_thick - int

 [0]           half-thickness of pml layer (0 = do not use PML)


NOTES

1. This is sufdmod2 for SEPlib

2. The sources specification order is

  a. src_file - seplib file containing source locations
  b. xs=3,4,5 zs=4,5,6  command list of sources
  c. oxs= dxs= nxs= ozs= dzs nzs - which will increase the dimensionality
    of the output by 1 ( ., , nxz, nzs)

Notes:
This program uses the traditional explicit second order differencing
method.

Two different absorbing boundary condition schemes are available. The first is a traditional absorbing boundary condition scheme created by Hale, 1990. The second is based on the perfectly matched layer (PML) method of Berenger, 1995.


CATEGORY

seis/model