TETRAMOD - TETRAhedron MODel builder. In each layer, velocity gradient is constant or a 2-D grid; horizons could be a uniform grid and/or added by a 2-D grid specified. tetramod [parameters] > tetrafile Required parameters: nxhz= number of samples (2nd dimension) for horizons nyhz= number of samples (1st dimension) for horizons hzfile= output xhz,yhz,zhz,v0hz,v1hz for viewer3 Optional parameters: xmin=0 x of the lower left point in the model ymin=0 y of the lower left point in the model xmax=2 x of the upper right point in the model ymax=2 y of the upper right point in the model zmax=(max z) max z in the model blt=1.0 bottom layer thickness nhz=1 number of layers in the model (except the model base) ficth=-1 ficticious horizons (no velocity interpolation based on them) The following four numbers define the four corners for 3-D model; z00=0,0.6,1.2,... z at (xmin,ymin) on each horizon z01=0,0.6,1.2,... z at (xmin,ymax) on each horizon z10=0,0.6,1.2,... z at (xmax,ymin) on each horizon z11=0,0.6,1.2,... z at (xmax,ymax) on each horizon v00=1.0,2.0,3.0,... v at (xmin,ymin) on each horizon v01=1.0,2.0,3.0,... v at (xmin,ymax) on each horizon v10=1.0,2.0,3.0,... v at (xmax,xmin) on each horizon v11=1.0,2.0,3.0,... v at (xmax,xmax) on each horizon dvdz00=0,0,0,... dvdz at (xmin,ymin) on each horizon dvdz01=0,0,0,... dvdz at (xmin,ymax) on each horizon dvdz10=0,0,0,... dvdz at (xmax,xmin) on each horizon dvdz11=0,0,0,... dvdz at (xmax,xmax) on each horizon x0file= x grid for horizon 0 y0file= y grid for horizon 0 z0file= z grid for horizon 0 added to 4-z interpolation v0file= v grid for horizon 0 added to 4-v interpolation dvdz0file= dvdz grid for horizon 00 added to 4-dvdz interpolation x1file= x grid for horizon 1 y1file= y grid for horizon 1 z1file= z grid for horizon 1 added to 4-z interpolation v1file= v grid for horizon 1 added to 4-v interpolation dvdz1file= dvdz grid for horizon 1 added to 4-dvdz interpolation ... for horizon #2, #3 #4, etc... verbose=0 =1 print some useful iinformation Remarks: TETRAMOD defines its own grammar to describe a 3-D model (including a tetra file for ray tracer SUTETRARAY and a horizon file for VIEWER3 Disclaimer: This is a research code that will take considerable work to get into the form of a a production level 3D migration code. The code is offered as is, along with tetramod and sukdmig3d, to provide a starting point for researchers who wish to write their own 3D migration codes. Credits: CWP: Zhaobo Meng, 1996 Reference: Zhaobo Meng and Norman Bleistein, Wavefront Construction (WF) Ray "Tracing in Tetrahedral Models -- Application to 3-D traveltime and ray path computations, CWP report 251, 1997