Evolution of Neogene fault populations in northern Owens Valley, California and implications for the eastern California shear zone

Field observations of faulting and associated deformation are used here to reconstruct the structural and kinematic evolution of northern Owens Valley, California. This work consists of three stand-alone research contributions (Chapters Three, Four, and Five). Chapter Three presents a model for the structural evolution of northern Owens Valley; focusing on the origin and evolution of the "Coyote Warp", as well as the relationship between normal shear along the Sierran Nevada range-front and dextral shear along the Owens Valley fault zone. This model relies on the theoretical relationship between fault spacing, fault dip, and seismogenic thickness in order to make predictions of crustal-scale conjugate normal fault intersection. Application of this model suggests that the structural evolution of northern Owens Valley can be explained in the context of a failed conjugate system, whereby fault intersection within the seismogenic crust results in the locking of one of the graben faults, and subsequent asymmetric range uplift and adjacent basin subsidence. Chapter Four presents a geologically based extensional slip rate history for the central portion of northern Owens Valley. Results suggest that the rate of extensional strain increased significantly since Middle Pleistocene time. These results are in agreement with similar observations of extension within and around northern Owens Valley, and correspond to a decrease in nearby rates of dextral shear over the same time interval. These observations are explained by a counter-clockwise rotation in the orientation of regional shear since Middle Pleistocene time. Furthermore, results from this study contribute to a geologically based extensional slip budget that is in agreement with geodetic based estimates of present-day strain accumulation. In Chapter Five, observations of fault length from several normal fault populations are used to examine the mechanisms that control the distribution of strain within the Eastern California Shear Zone. Results suggest that boundary fault spacing within shear induced fault networks plays a significant role in the redistribution of slip by placing geometric limitations on intermediary cross-cutting normal faults. Such redistribution is expected to occur over a timescale that is related to the lifespan of these constrained faults.