anchor.diff:  
   C----------------------------------------------------------------------C
   
  +      SUBROUTINE errmes(text)
  +      IMPLICIT none
  +      CHARACTER text*(*)
  +      write(0,*) text
  +      STOP
  +      END
  +
  +C----------------------------------------------------------------------C
  +
         SUBROUTINE usage(str)
         IMPLICIT NONE
         INTEGER lstr
  
positive.code:           stdp = stdp*1.0d3
  C         If NTRG=NSTA, read target fault parameters here
            if (ntrg.eq.nsta.and.ktrg.eq.1.and.nsta.ne.1) then
                read(13,*) trgstr,trgdip,trgrak,frict
            endif
  C         Compute displacements
            if (kdsp.ne.0) then
  
negative.code:           call progbar(i,nsta,progout)
        endif
  C     If NTRG=1, read target fault parameters here
        trgstr = -12345.0d0
        trgdip = -12345.0d0
        trgrak = -12345.0d0
        frict  = -12345.0d0
        if (ktrg.eq.2) then
            read(trgf,*,end=202) trgstr,trgdip,trgrak,frict
        endif
        if (ktrg.eq.1) then
            open(unit=13,file=trgf,status='old')
        endif
        if (ntrg.eq.1.and.ktrg.eq.1) then
             read(13,*,end=202) trgstr,trgdip,trgrak,frict
        endif
    202 if (trgrak.lt.-10000.0d0) then
            call errmes('!! Error: Not enough arguments in target '//
       1                'fault geometry input')
        elseif (frict.lt.-10000.0d0) then
            write(0,*) 'Coefficient of friction not defined; using 0.5'
            frict = 0.5d0
        endif
  C     Compute deformation for each receiver location
        open(unit=12,file=staf,status='old')
        do 201 i = 1,nsta
  