www.pudn.com > Raytrace3D.rar > README
README for the dynamic ray tracing from a lens velocity model. The program RAYTRACE3D implements a ray-theoretical modeling method that uses smoothing of models, dynamic ray tracing and wavefront construction. All the quantities in the Kirchhoff inversion formula can be determined by this program. To run demo, Table Build the forward modeling from a lens velocity model. The traveltime, amplitude and phase shift index of the three different arrivals are computed. Xplot slices of modeling output PSplot slices of modeling output (PostScript plot) RAYTRACE3D requires an input file (drt.inp) that the program can read the input parameters from the file. The following lists the parameters and their default values. xs=0.0 x-coordinate of single source location ys=0.0 y-coordinate of single source location zs=0.0 z-coordinate of single source location vx_file= name of input velocity file nz_vel=1 number of z samples (1st dimension) in velocity z0_vel=0.0 first z sample of velocity dz_vel=1.0 z sampling interval of velocity nx_vel=1 number of x samples (2nd dimension) in velocity x0_vel=0.0 first x sample of velocity dx_vel=1.0 x sampling interval of velocity ny_vel=1 number of y samples (3rd dimension) in velocity y0_vel=0.0 first y sample of velocity dy_vel=1.0 y sampling interval of velocity v0=2000.0 constant background velocity vx=0.0 x coefficient of linear velocity vy=0.0 y coefficient of linear velocity vz=0.0 z coefficient of linear velocity na=10 number of initial samples of polar take-off angle a0=0.0 first sample of polar take-off angle a1=90.0 last sample of polar take-off angle nb=10 number of initial samples of azimuthal take-off angle b0=0.0 first sample of azimuthal take-off angle b1=360.0 last sample of azimuthal take-off angle tim_type=DRAY forward modeling type, (this version only allows DRAY) =EIK eikonal solver =PRAY paraxial raytracing =DRAY dynamic raytracing t_scale=10 number of micro-steps in each macro-step of ray tracing inter_type=1 type of arrivals stored in output grids =1 most energetic =2 first arrival =3 shortest raypath =4 smallest maximum velocity =5 longest travel time =6 longest raypath num_add=1 number of macro-steps that adding rays function is called t0_ray=0.0005 initial ray tracing time (in second) t1_ray=10.0 maximum ray tracing time (in second) dt_ray=0.02 macro ray tracing step in time (in second) dr_ray=250.0 distance limit between rays for new rays to be inserted m_ray=10001 maximum number of rays to be generated maxangle=180.0 maximum take-off angle to stop adding rays and tracing rays mx_tab=1 number of x samples in output grids dx_tab=1.0 x sampling interval of output grids my_tab=1 number of y samples in output grids dy_tab=1.0 y sampling interval of output grids mz_tab=1 number of z samples in output grids dz_tab=1.0 z sampling interval of output grids outlog_file= name of output log file that contains reading parameter values outt_file= name of output travel time table outamp_file= name of output amplitude table outpha_file= name of output phase shift index table outa1_file= name of output polar angle table outb1_file= name of output azimuth angle table outdet21_file= name of output table for Beylkin determinant components outdet22_file= name of output table for Beylkin determinant components outdet23_file= name of output table for Beylkin determinant components outdet31_file= name of output table for Beylkin determinant components outdet32_file= name of output table for Beylkin determinant components outdet33_file= name of output table for Beylkin determinant components Notes: The smoothness of velocity model representation is critical to the calculation of amplitudes. RAYTRACE3D does not include an internal velocity smoother in the program. Therefore, smoothing procedure (e.g. application CWP code smooth3d) is recommaned to the velocity input specified by vx_file. If velocity input is not provided, RAYTRACE3D will take the values in parameters v0, vx, vy, vz to generate a linearly distributed background velocity model. John Stockwell | john@dix.Mines.EDU Center for Wave Phenomena (The Home of Seismic Un*x) Colorado School of Mines Golden, CO 80401 | http://www.cwp.mines.edu/cwpcodes voice: (303) 273-3049 | fax: (303) 273-3478.