Patterns of Quaternary deformation and rupture propagation associated with an active low-angle normal fault, Laguna Salada, Mexico: Evidence of a rolling hinge?

The Laguna Salada rift basin is within the zone of shearing between the Pacific and North American plates and is an asymmetric half-graben controlled on its eastern margin by the Laguna Salada fault and the Canada David detachment. Both faults dip west, have accommodated >10 km of offset since the middle-late Miocene, and are associated with an extensive late Quaternary fault array. The Laguna Salada fault is a high-angle fault that strikes northwest and has an oblique normal-dextral sense of shear. The Canada David detachment is a low-angle normal fault with a curvilinear trace that extends ~55–60 km and contains two prominent megamullion antiform-synform pairs. The late Quaternary scarp array that extends along the entire mountain front shows remarkable variations with antiformal and synformal megamullions. In antiformal domains, the scarp array is generally wider, closer to the mountain front (