An investigation of extensional tectonics of southern California

Geologic mapping and interpretation of Landsat TM imagery has filled in a significant gap in the geologic database for southwestern Arizona and southeastern California. The new data acquired, along with interpretation of existing data, forms the basis for a proposed reconstruction of late Tertiary faults in these regions. This reconstruction integrates available geological and geophysical data to define the eastern limit of deformation related to the San Andreas fault, and has significant implications for other recently proposed reconstructions of Tertiary deformation in the region. This progress in interpreting deformation during the last 10 Ma in the region forms a foundation for developing and testing models of older deformation in this region, including the initiation of San Andreas fault system, and the interaction of Early Miocene extension in the Basin and Range with the evolving San Andreas system

Neotectonics of the San Andreas fault system: Basin and range province juncture

Several new details regarding the surficial patterns of neotectonic activity of the Eastern Transverse Ranges and vicinity were discovered. Additionally a number of data display and analysis techniques were developed. These findings will be useful both in the continued development of neotectonic models for southern California and for the future application of remote sensing methodologies elsewhere

Climate in Earth history

Complex atmosphere-ocean-land interactions govern the climate system and its variations. During the course of Earth history, nature has performed a large number of experiments involving climatic change; the geologic record contains much information regarding these experiments. This information should result in an increased understanding of the climate system, including climatic stability and factors that perturb climate. In addition, the paleoclimatic record has been demonstrated to be useful in interpreting the origin of important resources-petroleum, natural gas, coal, phosphate deposits, and many others

Neotectonics of the San Andreas Fault system, basin and range province juncture

The development, active processes, and tectonic interplay of the southern San Andreas fault system and the basin and range province were studied. The study consist of data acquisition and evaluation, technique development, and image interpretation and mapping. Potentially significant geologic findings are discussed

Helicopter low-speed yaw control

A system for improving yaw control at low speeds consists of one strake placed on the upper portion of the fuselage facing the retreating rotor blade and another strake placed on the lower portion of the fuselage facing the advancing rotor blade. These strakes spoil the airflow on the helicopter tail boom during hover, low speed flight, and right or left sidewards flight so that less side thrust is required from the tail rotor

Electron Photodetachment from Aqueous Anions. I. Quantum Yields for Generation of Hydrated Electron by 193 and 248 nm Laser Photoexcitation of Miscellaneous Inorganic Anions

Time resolved transient absorption spectroscopy has been used to determine quantum yields for electron photodetachment in 193 nm and (where possible) 248 nm laser excitation of miscellaneous aqueous anions, including hexacyanoferrate(II), sulfate, sulfite, halide anions (Cl-, Br-, and I-), pseudohalide anions (OH-, HS-, CNS-), and several common inorganic anions for which no quantum yields have been reported heretofore: SO3=, NO2-, NO3-, ClO3- and ClO4-. Molar extinction coefficients for these anions and photoproducts of electron detachment from these anions at the excitation wavelengths were also determined. These results are discussed in the context of recent ultrafast kinetic studies and compared with the previous data obtained by product analyses. We suggest using electron photodetachment from the aqueous halide and pseudohalide anions as actinometric standard for time-resolved studies of aqueous photosystems in the UV.Comment: 41 page, 6 figures; supplement: 3 pages, 12 figures; to be submitted to J. Phys. Chem.

Tropical Cyclone Storm Surge Detection in Slash Pine Radial Growth along the Northern Gulf of Mexico Coastline

My thesis examines the ecological impact of tropical cyclone (TCs) storm surge on coastal slash pine (Pinus elliottii var. elliottii Engelm) communities along the Gulf of Mexico in the southern United States (U.S.). Previous research has shown slash pine radial growth trends can be examined to identify long and short-term growth changes associated with TC passage, providing insight into overall stand health and resiliency through time. However, this previous research encompasses just one site in Mississippi. My thesis expands the spatial footprint of TC-surge impact on slash pine radial growth with the addition of three new sites. I examined seasonally resolved tree-ring data from two sites in Alabama and one in Florida and discovered differences in geography and seasonality to suppressions and recovery. The Weeks Bay, Fairhope, Alabama site was the most responsive to storm-surge suppressions, and this was perhaps due to lack of dune protection and proximity to a concave coastline. Latewood growth recorded the highest percentage of suppressions associated with storm surge and was generally the quickest growth metric to recover to normal growing conditions. TCs are predicted to become larger and more powerful in the 21st century, and it will be necessary to consider the negative impacts that these storms can have on coastal pine savannas while constructing plans to protect and preserve these unique environments

The California Coast Ranges

Western California between the 37th and 40th parallels is part of an active mobile orogenic belt in which sedimentation, deformation, volcanism, and plutonism have been intimately associated since the mid-Mesozoic. At present, the region is still undergoing folding and warping as shown by data from geodetic triangulation networks and geomorphology, and several major high-angle fault zones are seismically active. These faults continue to acquire displacement both suddenly during earthquakes and slowly by gentle creep with no recordable shocks. Pleistocene beds and terraces at places are steeply warped. Strong deformation occurred during the late Pliocene and early Pleistocene. Most of the Tertiary was characterized by fragmentation of the region into basins and intervening ranges following comparatively more widespread sedimentary transgressions and regressions during the early Tertiary and late Mesozoic. The structural significance and history of the San Andreas fault system are still under study. In central California, Pliocene and Pleistocene sedimentary facies are apparently offset laterally as much as 25 miles, but in this region strike-slip of greater amounts in older rocks has not yet been documented. The San Andreas separates very different terranes, with mismatched stratigraphic sections facing across the fault. These probably can be matched only through recourse to major right-slip, increasing in displacement with age. Right-slip of about 200 miles is reasonably well established in southern California, and such displacements, extended into central and northern California, probably account for the contrast in terranes, including basement. Here the San Andreas separates the Franciscan complex of disturbed graywacke, mudstone, chert, conglomerate, limestone, mafic and ultramafic volcanic rocks and serpentine, and associated metamorphic rocks from the basement of granites and gneiss. The magnitude and timing of displacements on the San Andreas and related faults, which probably originated in the early Tertiary, will only be determined through the mapping and correlating of sedimentary facies that are cut and offset by the fault. As yet this analysis has but barely commenced. The Sierra Nevada and Klamath Mountains were the site of rapid eugeosynclinal sedimentation and volcanism in early Late Jurassic time. These strata were deformed, metamorphosed, faulted, and intruded by serpentine and granitic plutons in turn; all in the mid-Late Jurassic. Following uplift, deep erosion, and subsidence, sedimentation in the latest Jurassic transgressed and overlapped eastward across the ancient Sierran margin. Altogether, 40,000 feet of mudstone, graywacke, and conglomerate were deposited in the Great Valley sequence by the end of the Cretaceous. Beginning also in the early Late Jurassic nearby, but in unclear tectonic relationship to the Great Valley sequence, Franciscan sedimentation, volcanism, and downbuckling carried strata to depths of about 70,000 feet. Here deeper beds were converted to the blueschist metamorphic facies and then rapidly elevated and perhaps in part thrusted in mid-Late Jurassic time. Following continued eugeosynclinal sedimentation, major thrusting or downslope sliding and mixing on a grand scale took place in the Franciscan terrane in the Middle Cretaceous. The complexity of the Franciscan is the consequence of these events together with overprints of Tertiary deformation, which at places also included major thrusting and near isoclinal folding, diapir or piercement structures, limited gravitational sliding, and strong deformation along high-angle shear zones. Ancient and complex rocks of the thick continental crust give way abruptly to the simple, thin, and presumably younger crust beneath the Pacific Ocean. The Moho discontinuity has a depth of about 18 miles (29 km) under the Coast Ranges and rises to about 8 miles (13 km) under the basaltic oceanic crust. Pacific fault zones apparently pass largely beneath, and only slightly disturb, the continental plate. Faults of the San Andreas system probably are mainly confined to the continental plate and may converge and merge to constitute the continental margin

Two-dimensional aerodynamic characteristics of several polygon-shaped cross-sectional models applicable to helicopter fuselages

A wind-tunnel investigation was conducted to determine 2-D aerodynamic characteristics of nine polygon-shaped models applicable to helicopter fuselages. The models varied from 1/2 to 1/5 scale and were nominally triangular, diamond, and rectangular in shape. Side force and normal force were obtained at increments of angle of flow incidence from -45 to 90 degrees. The data were compared with results from a baseline UH-60 tail-boom cross-section model. The results indicate that the overall shapes of the plots of normal force and side force were similar to the characteristic shape of the baseline data; however, there were important differences in magnitude. At a flow incidence of 0 degrees, larger values of normal force for the polygon models indicate an increase in fuselage down load of 1 to 2.5 percent of main-rotor thrust compared with the baseline value. Also, potential was indicated among some of the configurations to produce high fuselage side forces and yawing moments compared with the baseline model