Fixed zisodisp tracking to work only when isobc is true

src/DOUAR.f90

@@ -1233,7 +1233,7 @@ do while (istep.le.params%nstep)
      call show_time (total,step,inc,1,'Compute isostasy and adjust vertical velocity$')
      !allocate(ov%wpreiso(ov%nnode),stat=err) ; if (err.ne.0) call stop_run ('Error alloc ov%wpreiso in main$')
      call isostasy (params,weightel,ov,surface,mat,0,zi)
-     zi%zisodisp=zi%zisodisp-zi%zisoinc
+     if (params%isobc) zi%zisodisp=zi%zisodisp-zi%zisoinc
 
      do is=1,params%ns
        if (current_time+tiny(current_time).ge. surface(is)%activation_time) then