BREF

BREF can build matricies for ground consistent inversion of either direct waves, or refracted head waves. The method is the delay time method for refractions, and the formulation is limited to a single refractor under overburden (Michaels, 1995). One typically decides on the offset where the transition from direct wave to refracted wave arrivals occurs (cross-over distance, Figure 13, OCTAVE refplot). The arguments are:

 bref line# nshots rmin rmax irefdir irecip infil1 infil2 infil3 
  
 line#:  =line number for refraction/direct analysis
 nshots  =number of shot records to use (<=10)
 rmin    =minimum offset to include
 rmax    =maximum offset to include
 irefdir =0 refraction analysis 
         =1 direct wave analysis 
 irecip  =0 normal shooting, shot fixed 
         =1 reciprocal shooting, receiver fixed
 infil1  =input file 1
 infil2  =input file 2
 infil3  =input file 3 etc....

Note that the argument, irefdir determines if the setup will be for direct wave or refracted wave. The following data examples are taken from Michaels (1999). Also, see the bsu-user-guide3-1.pdf for more.