anchor.diff:        staf = 'none'
         haff = 'none'
         trgf = 'none'
  +      volf = 'none'
         dspf = 'none'
         stnf = 'none'
         stsf = 'none'
  
positive.code: 
  C======================================================================C
  
        SUBROUTINE chksrc(ffmf,fltf,magf)
  C----
  C Check (a) that fault source files were defined in gcmdln and (b) that
  C these fault files exist.
  C----
        IMPLICIT NONE
        CHARACTER*40 ffmf,fltf,magf
        LOGICAL ex
        INTEGER kffm,kflt,kmag,ksta,khaf,ktrg
        COMMON /ICHECK/ kffm,kflt,kmag,ksta,khaf,ktrg
  
  C Verify input fault files were defined on command line
        if (kffm.eq.0.and.kflt.eq.0.and.kmag.eq.0) then
            write(*,*) '!! Error: No fault file specified'
            call usage('!! Use -ffm FFMFILE, -flt FLTFILE, or -mag '//
       1                  'MAGFILE')
        endif
  
  C Look for defined files in working directory
  
negative.code:      1       rak(FMAX),dx(FMAX),dy(FMAX),slip(FMAX)
        REAL*8 uN,uE,uZ,strain(3,3),stress(3,3),norml,shear,coul,estrs
        REAL*8 az,hdsp
        INTEGER kffm,kflt,kmag,ksta,khaf,ktrg,kvol
        INTEGER kdsp,kstn,ksts,knor,kshr,kcou,kgmt
        COMMON /ICHECK/ kffm,kflt,kmag,ksta,khaf,ktrg,kvol
        COMMON /OCHECK/ kdsp,kstn,ksts,knor,kshr,kcou,kgmt
  C     Open files specified for output
        if (kdsp.ne.0) open(unit=21,file=dspf,status='unknown')
  