Abstract
Reflection data were used with aerial photography and DEMs of early 20th-century topography to refine the location, geometry and kinematics of shallow faulting and folding along the alignment. In the eastern PVP, the PVFZ is approximately 2,000 m wide and consists of three principal strands: the southern, middle and northern splays (PFVS, PVFM and PVFN, respectively). Collectively, these faults define a steep, asymmetric flower structure. The dip and style of faulting changes progressively to the northeast: PVFS is a near vertical strike-slip fault; PVFM is a right-oblique reverse fault with an 80- to 85-deg southwest dip; and PVFN is a blind reverse fault with a 75-deg southwest dip. Our preferred estimates of right-lateral offset of an abandoned channel of the LA River that crosses the PVFZ are 109 m (PVFS) and 250 m (PVFM). No discernible lateral offset is observed where the abandoned channel crosses PVFN. The abandoned channel is incised into the OIS 5e marine terrace (120 ka). Assuming a ~5,000-year lag between the 5e highstand and subsequent channel incision, our preferred post-Late-Pleistocene slip rates are 0.91 mm/yr (PVFS) and 2.17 mm/yr (PVFM), though uncertainties in age and offset amounts permit a range of 2 to 5.6 mm/yr for the entire PVFZ. Topographic profiles of the OIS 5e abrasion platform and thalweg of the abandoned channel show approximately 115 m of uplift across the PVFZ since 120 ka, and >15 m since channel abandonment, ~35 ka. The northern edge of the broad uplift pattern has a sharp hinge above the tipline of PVFN and north of the PVFM; it then tapers off across and south of PVFS. Distribution and patterns of deformation across the PVFZ may reflect partitioning of oblique slip in the upper crust due to a change in fault strike at the PVP.