Thesis (Ph.D.)--The Ohio State University, 2006. / (UMI)AAI3226518. Adviser: C. K. Shum. Source: Dissertation Abstracts International, Volume: 67-07, Section: B, page: 3654.

<p> Light detection and ranging (LiDAR) data and field observations were used to create a new tectonogeomorphic strip map along the San Andreas Fault from Wrightwood 47 km southeast to Highland. Three hundred and thirty one geomorphic features were identified and the displacements of 23 offset and deflected streams were measured using Quick Terrain Modeler (QTM). Offsets cluster around 10-50 m, and only one offset is smaller than 5 m, and a few larger offsets (100 m-200 m). </p><p> The primary purpose of this project, besides creating the strip map, was to determine how slip is transferred between the northern San Jacinto fault and Mojave-San Bernardino segments in the Cajon Pass area. Previously published slip rate data suggests slip transfer from the San Jacinto fault to the San Andreas fault between Badger Canyon and Cajon Creek at Cajon Pass area. However, there are no significant changes in offset amounts along the northern end of the San Bernardino segment, and the most likely location for slip transfer would be Cajon Pass.</p>

<p> The transition between the two distinct structural regimes of the Walker Lane and the Basin and Range allows for complex transtensional fault interactions. The Carson Sink is the surface expression of the interaction of shear and extensional strains that cause both crustal extension and block rotation. This study investigates this tectonic shift at the Soda Lake geothermal field by comparing the direction and rate of deformation from both regional GPS and a 34 sq km 3D seismic survey. The GPS stations in the region estimate the strain field by comparing tensor solutions that show changing direction and magnitude of strain across the Carson Sink. Using stations surrounding the Soda Lake 3D seismic survey, the strain tensor produced is comparable in orientation to Basin and Range strain but has larger magnitudes. To quantify deformation within the Soda Lake 3D seismic survey, we calculate fault dip and offset of a deformed paleo-planer lacustrine mudstone. Plotting the mean dip direction of the faults in the seismic reflectivity, matches the mean surrounding GPS extensional direction, suggesting fault displacement is likely to be normal dipslip. Using a minimum age of 0.51 Ma from nearby sedimentation rates, the measured extension across the 5.4 km length of this study has a rate of 0.19 mm/yr. This is quite a high value for Basin and Range extension and it is likely a result of some influence from the Northern Walker Lane. The lack of an obvious piercing point for shear observed within the seismic volume precludes a clear estimate of strike-slip related motion within the Soda Lake 3D seismic survey. Clear extension and a large fault bend, indicates a localized relay ramp model. With focused extension indicated by two late Quaternary extrusive volcanic bodies, a model of a transtensional pull-apart basin is also considered. Given the few mapped intrabasinal faults at the surface, this study gives a unique view into fault offsets inside the Carson Sink.</p>

<p> Geomorphologic methods document poorly exposed tectonically active structures in the first study to determine quantified ages for Quaternary Age fluvial terraces at Santa Cruz Creek. GPS surveys of three flights of terrace surfaces and a stream gradient profile reveal deformation at the Baseline/Los Alamos fault zone and Little Pine fault. Optically Stimulated Luminescence (OSL) dating was employed to determine ages for the terraces. The formation age of Terrace 1 is 19.3 ka with an incision rate of 1.63 to 1.82 mm/yr, Terrace 2 was dated at 32.9 ka with incision rate of2.02 to 1.82 mm/yr. Based on incision rates an estimated age of 44.0-47.0 ka was calculated for Terrace 3. Offsets in T-2 and T-3 were used to calculate a short term faulting rates of .91 mm/yr and a long term faulting rate of 0.67 to 0. 73 mm/yr for the Baseline/Los Alamos fault.</p>

Thesis (Ph.D.)--The Ohio State University, 2008. / (UMI)AAI3292725. Source: Dissertation Abstracts International, Volume: 68-12, Section: B, page: 7892. Adviser: Terry J. Wilson.

<p> Strain evolution and stress evolution following the 4 April 2010 M7.2 El Mayor-Cucapah earthquake are modeled using an adaptation of the strain transient detection tool developed by <i>Holt and Shcherbenko</i> 2013. The evolution of stress is calculated from postseismic strains, which are modeled from continuous GPS horizontal displacements. Strain fields are modeled in 2 ways; the total strain field based on total observed cGPS displacements, and the residual strain field, which subtracts a reference field from the total model. The residual shows anomalous strains resulting from the postseismic relaxation of the 2010 event. Anomalous and total strains are modeled in 0.1 year epochs for 2.4 years following the event. Both total and anomalous strains are converted into stress changes over time, assuming elastic incompressible behavior. Following the El Mayor event, the GPS constrained strain evolution shows the following: (1) The Southern San Andreas experiences a reduced rate of right-lateral strike slip strain accumulation between 3 July 2010 and 7 August 2012 (Figure 16a-d). (2) The San Jacinto Fault has normal rate of right-lateral strike-slip strain accumulation during this time. (3) Before the Brawley swarm of 26 August 2012, the state of strain evolves to enable unclamping of a left-lateral fault zone in the Brawley Seismic Zone (Figure 16a-d). (4) Large shear strains accumulate on the Laguna Salada Fault (northernmost segment)/southern Elsinore FZ (Figure 16a-d). We converted the strain changes into Coulomb stress changes on existing faults (both right-lateral and left-lateral). Several regions show increased Coulomb stress changes throughout the postseismic process. Furthermore, the Coulomb stress changes on the faults in the region progressively increase toward failure up to the time of the Brawley swarm.</p>

<p> The Truckee Meadows (Reno, NV) sits in a tectonically complex area of western Nevada, where Walker Lane-style transtension is dominant throughout the region. A new Light Detection and Ranging (LiDAR) study focuses on the Truckee Meadows region of western Nevada, including the Reno/Sparks metropolitan area in Washoe County. We use the airborne LiDAR imagery (1485 sq. km) to create high quality, bare-earth topographic maps that were previously unattainable in vegetated, populated or alpine terrain. This approach gives us an opportunity to improve fault maps that may be outdated or incomplete in the area. Here we provide LiDAR imagery of a large section of Washoe County and an updated fault map of the greater Truckee Meadows region. </p><p> We also use this new LiDAR survey of the Truckee Meadows and nearby basins to constrain geometry, length, distribution, and slip rates along faults imaged by this new dataset. Estimated slip rates are compared to those derived from a geodetic block model constrained by Global Positioning Station (GPS) data to test for consistency. GPS station data and geologic mapping show that both east-west oriented extension and northwest-oriented right-lateral strike slip accommodate transtension as a backdrop for tectonics studies of region, with some northeast-oriented left-lateral strike slip. This study aims to better understand how this transtension is partitioned along remapped faults and newly identified structures in this urban setting, as the framework for strain accommodation in this area remains poorly understood. </p><p> Faults with normal offset were measured along strike using bare-earth LiDAR returns to determine the amount of vertical separation across geomorphic surfaces, and then converted to extension assuming a fault dip of 60 (+/-10) degrees. Since the primary geomorphic surfaces in this region are the result of Sierra Nevadan glacial outwash episodes, we use previously published geologic maps to link each surface to an associated date. When integrated across several basin perpendicular transects within the Mt. Rose pediment, we calculate a total extension rate of 0.87 (+0.40/-0.48) mm/yr for the southern Truckee Meadows basin. Integrated slip rates from fault scarp offsets are within the bounds of 1.23 (+/-0.70) mm/yr suggested by geodetic modeling. Block modeling highlights that north-striking faults primarily accommodate east-west extension, and so northwest-striking faults and/or block rotations must accommodate the northwest-directed shear seen in GPS velocities. This trend is bolstered by the discovery of a new northwest-oriented fault on Peavine Mountain 6 km east of the Mogul (2008) seismicity trend. Our study provides further evidence that the Truckee Meadows sits at a critical transition from north-striking normal faults in the southern part of the basin to northwest-oriented strike-slip faults to the north, an observation that mimics regional tectonics and geomorphology of the adjacent Lake Tahoe/Truckee system to the west.</p>

<p> Light Detection And Ranging (LiDAR) data can be used to accurately model three- dimensional surfaces for quantifying fluvial erosion and deposition. Terrestrial LiDAR is typically used for monitoring banks, but can be used for monitoring planar forms such as point bars. Point bars are topographic features that form on the convex bank of a meander. While point bars are considered to be formed by depositional processes, they display features such as chute channels and scour holes that suggest that erosion, due to high flow events, may significantly influence point bar evolution. Through the use of Terrestrial Laser Scanning (TLS), we observed how a point bar on the White Clay Creek near Newark, Delaware, responded to a flood event with a return period of 6.1 years, and to multiple small events over a 1 year period with return periods between 1.00 and 1.25 years. Scans of the point bar were completed on April 11, 2014, May 8, 2014, and April 16, 2015. Scans were referenced to a common coordinate system, scan data representing vegetation points were removed, and three 0.1 m x 0.1 m gridded Digital Elevation Models (DEMs) were created from the remaining data. DEMs of Difference (DoDs) were calculated by subtracting the cell values in subsequent DEMs and by thresholding out positional and surface roughness errors. The 6.1 year flood that occurred between the April 11, 2014 scan and the May 8, 2014 scan resulted in 88.53 m³ of erosion and 39.12 m³ of deposition. The net volumetric change was -49.40 m³ over an area of 631.72 m². The smaller events that occurred between the May 8, 2014 scan and the April 16, 2015 scan resulted in 13.33 m³ of erosion and 53.46 m³ of deposition. The net volumetric change was x i 40.13 m³ over an area of 620.74 m². Our results suggest that 1) sediment deposited on point bars is eroded frequently by flood events; and 2) TLS can provide useful estimates of erosion and deposition. Although our results are for a short period, longer datasets can be used to calculate sediment residence times for point bar deposits. Additionally, we can gain a better understanding of how point bar deposits are preserved in the geologic record. This information is useful for creating accurate sediment budgets, remediating contamination issues, and interpreting geologic history.</p>

<p>Quantifying groundwater recharge is of crucial importance for sustainable groundwater management. While many recharge quantification techniques have been devised, few provide spatially and temporally distributed estimates for regional-scale water resource assessments. In this study, a GIS-based and USGS-developed recharge quantification tool ? the Soil Water Balance (SWB) model ? was applied to produce fine-tuned recharge constraints and document spatial and temporal dynamics of recharge. SWB has, as of yet, been tested solely in coastal and continental temperate-humid climate zones. This study expands testing of SWB to a Mediterranean climate zone, focusing on Catalina Island, California. Catalina has experienced significant water supply issues due to a prolonged drought. Using available climate, land use/land cover and hydrology data, the SWB model yields annual recharge values for the time period 2008-2014 of 0.05 mm/year to over 82 mm/year. Results of this thesis provide information on spatial and temporal patterns of groundwater recharge on Catalina Island.

Thesis (Ph. D.)--University of Washington, 1999. / Vita. Includes bibliographical references (leaves 114-131).