fdmod <mod1.vel >mod.slice  \
         nx=501 dx=1 fx=0.0 \
         nz=501 dz=1 fz=0.0 \
         xs=250 dxs=12.0\
         zs=5 dzs=0.0 ns=1\
         tmax=0.08 mt=5 \
         verbose=2 \
         abs=1,1,1,1 pml_max=10000\
         pml_thick=20 \
     hsz=5 hsfile=un.wave 
ximage <un.wave n1=961