NAME

Iso2d - Isotropic modeling


SYNOPSIS

Iso2d par=Par < Hsourcefn > Hverticalgeophone


INPUT PARAMETERS

moduli - file
       velocity model file(c11,c44,and rho)(next 4 from file)
n1 - integer
       #of z grid points(becomes nz in the program)max=400
n2 - integer
       #of x grid points(becomes nx in the program)max=400
d1 - real
       1  z grid point spacing (becomes dz in the program)
d2 - real
       x grid point spacing (becomes dx in the program)
       The constants are 3 panels in order c11,c44,rho and
       are stored nz(fast) by nx
       Recall Vp=sqrt(c11/rho) and Vs=sqrt(c44/rho)
Hsource - file
       Source function file (next two pars from file)
n1 - integer
       length of source
d1 - real
       time sample interval (this will be used for
       calculations)so it should be within stability limits
nt - integer
       number of time steps to run, max=4000
nsrc - integer
       # of shots to make (default=1)
src_1 - integer
       Position of first source (in grid points)
src_type - integer
       vertical force =1; horizontal =2; shear source =3
       explosive force=4
src_inc - integer
       shot increment (in x grid points) default=1
group_1 - integer
       Position of first receiver for first
       shot default=1
off_1 - integer same as group_1 but in relation to src_1
ngroup - integer
       Number of receivers default=nx
src_depth - integer
       Shot depth (grid points)
geo_depth - integer
       depth of geophones (in grid points)
surf_type - integer
       free surface (default) =1; absorbing =0
snap_i - integer
       number of time steps between snapshots
rollalong - integer
       receiver spread rollalong with the
       shots? 1=yes=default; 0=no
vpmax - integer
       maximum velocity in model (optional stability
       check) for stability vpmax*dt/dx <.5
       since isotropic sqrt(max(c11)/rho)*dt/dx <.5
       for no dispersion (vmin/fmax)/dx >2.8
verbose - integer
       Verbose (1) or not (0,default)


DESCRIPTION

   Program to do isotropic heterogenous elastic modelling in 2d,
   explicit finite-difference 2nd order in time 16th order in x and z


OUTPUT PARAMETERS

Hverticalgeophone -file
      output file for the vertical component seismogram


SEE ALSO

the Aniso2d manpage


CATEGORY

seis/model