Running bref

This is an interactive program which prompts the user as the following dialog illustrates. The user responses are boxed.

  enter: line number (4 characters)

0003

Enter: number of shots

2

Enter: minimum offset to include

40

Enter: maximum offset to include

200

Is output for refraction or direct analysis?

0=refraction 1=direct

0

irecip 0=normal 1=reciprocal shooting

0

Enter: input file name

k010.seg

Enter: input file name

k011.seg

shot x,y= 9927. 9773.

shot x,y= 9883. 9666.

Traces Processed = 48

====> output in G0003

====> listing in brefk010.lst

 

In the above example, the program writes 3 files, the last 4 characters of which are the line number as specified in the dialog.

  1. G0003     system matrix, G, of equation (32)
  2. D0003     data vector, d, of equation(32)
  3. E0003     elevation file (3 columns; trace#, station_name, elevation)
In general, you will have to edit the Gxxxx and Dxxxx files. The sample data set (ID-102.zip) includes examples of these files as created by bref (G0003.org etc.) and as modified to produce a constrained solution (G0003.mod etc., 15 constraints). Specific files created by bref will be highly dependent on the first break picks in the *.seg file trace headers. The convention is to flag picks exactly equal to zero as being unable to be picked. If none of the *.seg files has a pick at a particular geophone station, then the problem will be singular (unless you manually edit the file and add some rows to constrain the solution). Bref will make an attempt to add constraint rows to the bottom of the Gxxxx file, but they will be incomplete, since the user must decide what to do (don't expect this code to make critical decisions, that is your job). To replicate samples in archive, see README file in slopeLine directory.