Spatial Evolution of Neogene Normal Faults, Northern Owens Valley: Constraints on Oblique-slip Partioning Within the Eastern California Shear Zone.

Simple geometric constraints can be used to predict fault interaction at depth. Such interaction within crustal scale fault populations plays an important role in the tectonic evolution of extensional tectonic settings. Here we use a theoretical relationship between fault dip, horizontal fault spacing, and depth to the base of the seismogenic zone to explain the late Cenozoic temporal and spatial evolution of faulting within the Eastern California shear zone, including the northern extent of Owens Valley, California. Our results show that during its evolution, the east-dipping Sierra Nevada frontal fault in northern Owens Valley became inactive due to intersection with the larger west-dipping range-bounding fault of the White Mountains. The horizontal spacing of 10 km between these two conjugate faults is such that they intersect within the brittle seismic layer resulting in the locking of this segment of Sierra Nevada frontal fault. Continued accumulation of normal displacement along the White Mountains fault zone has since resulted in the present-day half-graben basement structure of northern Owens Valley. This down-dropping along the eastern margin of the valley imposes a flexural tension across the surface of the Coyote Warp, which can be considered a large relay zone between the Sierra Nevada frontal fault and the Round Valley fault further west. It is suggested that this tension is responsible for the formation of west-dipping antithetic normal faults that are distributed locally around the Coyote Warp. This extensional fault geometry has imposed a kinematic restraint on the development and distribution of right-lateral shear within this part of the Eastern California shear zone, including northeastward transfer of right-lateral slip from the Owens Valley fault to the White Mountains fault.