anchor.diff:  C an isotropic elastic half-space due to shear dislocations.
   C----
         IMPLICIT NONE
  +      INTEGER STER
  +      PARAMETER (STER=0)
         CHARACTER*40 fltfile,stafile,haffile,dspfile
         LOGICAL ex
         INTEGER auto
  
positive.code:      1                  evlo,evla,evdp,str,dip,rak,dx,dy,area,slip,
       2                  vp,vs,dens,flttyp)
            write (11,9999) stlo,stla,uNnet,uEnet,uZnet
            goto 101
    103 continue
  
  
negative.code: C----------------------------------------------------------------------C
  
        SUBROUTINE xy2NE(uN,uE,ux,uy,str)
        IMPLICIT none
        REAL*8 uN,uE,ux,uy,str,theta,uhor
        REAL*8 pi,d2r
        PARAMETER (pi=4.0d0*datan(1.0d0),d2r=pi/1.8d2)
        theta = datan2(uy,ux)
        uhor = dsqrt(ux*ux+uy*uy)
        theta = d2r*str - theta
        uN = uhor*dcos(theta)
        uE = uhor*dsin(theta)
        RETURN
        END
  
  C----------------------------------------------------------------------C
  
        SUBROUTINE sethafdef(vp,vs,dens)
        IMPLICIT none
        REAL*8 vp,vs,dens
        vp = 6800.0d0
        vs = 3926.0d0
        dens = 2800.0d0
        RETURN
        END
  
  