Paleoseismologic and slip rate studies of three major faults in southern California: Understanding the complex behavior of plate boundary fault systems over millennial timescales

Understanding the complex behavior of plate boundary faults and fault systems has been an area of ongoing study in the geological sciences. This dissertation focuses on the spatial and temporal patterns of paleo-earthquakes at three different study sites in southern California, which exhibit non-steady slip histories over millennial timescales. Elucidating the long-term patterns of seismicity along a fault or fault system by extending the paleoseismic record of that fault allows us to better understand fault mechanics, possible fault interactions and improve next generation seismic hazard analysis.;Using Light Detection and Ranging (LiDAR) digital topographic data to map and measure offset geomorphic features, paleoseismic trenching to determine paleoearthquakes recorded in the rock record, and luminescence (OSL and IRSL) and 14C Radiocarbon dating methods, I constrain the timing of paleo-earthquakes along the Panamint Valley Fault and calculate a late-Holocene slip rate for the Garlock Fault. These new paleoseismic data from the Panamint Valley Fault support the notion that earthquake occurrence in the eastern California shear zone (ECSZ) may be spatially and temporally complex, with earthquake clusters occurring in different regions at different times. Our new slip rate for the Garlock Fault provides evidence for an elevated late-Holocene slip rate that is significantly faster than the full-Holocene/latest Pleistocene rate. This new slip rate provides insight into the behavior of the Garlock Fault on 103 timescales and documents the temporal variability in slip behavior during the Holocene. The results presented here further validates the suggestion that the Garlock Fault experiences periods rapid fault slip that correlate with earthquake clusters interspersed with millennia-long periods of no activity and presumably a 0 mm/yr "slip-rate". These new data also provide a unique opportunity in which we can compare Holocene slip rates at multiple time intervals with a well-constrained late Holocene paleoseismologic record.;In addition, I use a multi-disciplinary approach that combines high-resolution seismic reflection profiles, borehole excavations, and cone penetration testing to analyze the near-surface fault-related folding related to the blind faulting of the Ventura and southern San Cayetano Faults at seismogenic depths. Our results provide evidence for at least two temporally discrete uplift events during the Holocene, which together with events recorded by marine terraces to the west, document the possibility of system wide ruptures in the western Transverse Ranges.;The results of this dissertation provide a better understanding of the paleo-earthquake behavior along the Panamint Valley, Garlock and Ventura-southern San Cayetano Fault system's and illustrate the complexities of their spatial and temporally variable slip histories. Understanding the complex behavior of these faults has significant implications for regional seismic hazard in southern California.