Abstract

Margin-parallel strike-slip faults commonly develop along convergent plate margins where an oceanic plate subducts obliquely beneath a continental plate. Such faults detach a "sliver' of continental crust from the leading edge of the overriding plate; fault motion then causes the sliver to move parallel to the continental margin, in the direction of the transverse component of relative plate motion. However, few slivers move as rapidly as predicted by simple analyses of the forces acting on them. This discrepancy must be due principally to the "buttress effect': resistance to displacement of the sliver arising from a space problem at its leading edge. A strongly buttressed sliver will move only insofar as the buttress can be overcome. Obvious ways in which a buttress can be overcome are by thickening the crust or widening the sliver. -from Authors