Structures in fault jogs.

In bedded siltstone, near Lillooet, British Columbia.

The white area, shown by the star in the interpretation, is a calcite-filled pull-apart--which formed by extension between the overlapping fault surfaces. The calcite-filled zone and associated fractures near the bottom of the photo formed by dilation near the termination of the fault.

In granitic rock, northern Wisconsin

Notice that the areas between the right-stepping jogs show a marked increase in the degree of fracturing. This fracturing likely formed from extensional stresses resulting from discontinuous right-lateral faulting.

Link to research on a segment boundary in a normal fault system, Colorado.

Back to slip directions in faults.