The Ethiopian Plateau, situated in the northernmost part of the East African Rift System, has been uplifted and incised by the Blue Nile River, creating the 1.5 km-deep Blue Nile Canyon, the only extensive canyon within the Nile drainage basin. Much of this canyon incision is related to the Ethiopian Plateau uplift, which is due to a combined tectonic influence linked to the East African Rift System and the Afar Mantle Plumerelated upwelling since the Oligocene. The Blue Nile Canyon incision followed this plume-related upwelling, which resulted in extensive flood basalt emplacement around ~30 Ma. This study employs low-temperature apatite (U-Th)/He thermochronology to better understand the timeline and mode of the Blue Nile Canyon incision and the landscape geodynamics of the Ethiopian Plateau. Neoproterozoic basement rocks and Mesozoic sedimentary rock samples were collected in a vertical transect along the Blue Nile Canyon for AHe dating. Euhedral apatite grains that are inclusion-free and fractureless were selected for dating. The Australian Scientific Instrument (ASI) Alphachron and Inductively Coupled Plasma Mass Spectrometer (ICP-MS) measured the concentrations of radiogenic isotopes uranium (U), thorium (Th), and helium (He) to obtain apatite helium (AHe) dates, providing (U-Th)/He cooling ages ranging from 64 to 460 Ma. These AHe dates are much older than the 30 Ma flood basalt event, thus older than the canyon incision. In this study, a cooling/thermal history is suggested by explaining the data dispersion by the radiation damage effect in the dated apatite grains, which is related to He retention with time. The apatite suite has been subjected to protracted cooling, longer residence time in the He partial retention zone, and partial resetting due to Mesozoic rift-related burial and subsidence from deposition of ~1.2 kmthick sedimentary rocks, the extensive emplacement of ~1 km-thick flood basalt at 30 Ma, and differential incision. Radiation Damage Accumulation and Annealing Model (RDAAM) time-temperature thermal models indicate a rapid cooling event, suggesting rapid incision after 10 Ma, which is explained by an increase in uplift of the Ethiopian Plateau, likely due to mantle delamination.

Multiple geophysical and geological data sets were compiled, reprocessed, and interpreted using state-of-the-art signal processing and modeling algorithms to characterize the complex post-Paleozoic geology that overlies the southwestern projection of the Fluorspar Area Fault Complex (FAFC) in western Kentucky. Specific data included 21.5 km of SH-wave seismic reflection, 1.5 km of P-wave seismic reflection, 2 km of electrical resistivity, vertical seismic profiles, Vp and Vs sonic-suspension logs, and 930 lithologic borehole logs. The resultant model indicates three general northeast–southwest-oriented fault zones pass through the study area as southwestern extensions of parts of the FAFC. These fault zones form two significant subparallel grabens with ancillary substructures. The geometry of the interpreted fault zones indicates that they have undergone episodic tectonic deformation since their first formation. Evidence of thickening and steeply dipping reflectors within Tertiary and Quaternary sediment in the downthrown blocks indicate syndepositional movement. Subtle thickening and lack of steeply dipping intraformational reflectors in the Cretaceous suggest a more quiescent period, with sediment deposition unconformably draping and filling the earlier Paleozoic structural surface. There is also evidence that the Tertiary and early Quaternary reactivation was associated with an extensional to compressional regional stress reversal, as manifested by the antiformal folds seen in the hanging wall reflectors and the potential small-amplitude force folds in the Quaternary alluvium, as well as a clear displacement inversion along the Metropolis-loess seismic horizon in two high-resolution reflection images. A surface shear-wave splitting experiment proved to be an efficient and effective tool for characterizing shallow subsurface azimuthally anisotropic geologic inclusions in low-impedance water-saturated sediment environments. The measured azimuthal anisotropy across a well-constrained N60ºE-striking fault exhibited a natural coordinate system that had a fast direction coincident with the fault strike and an orthogonal slow direction. This is also one indicator that faults inactive during significant geologic intervals (i.e., Holocene) do not "heal". Integrated shear-wave velocity models and electrical resistivity tomography profiles across the fault zones exhibit lower shear-wave velocities and resistivities within the deformation zones compared with values outside the boundaries. This is additional evidence that the deformed sediment does not reconsolidate or heal, but that the sediment particle configuration remains more loosely packed, providing an increase in the overall porosity (i.e., hydraulic conductivity). This can wholly or in large part explain the anomalous contaminant plume migration path that is coincident with the deformed zones of the regional gravel groundwater aquifer.

Research has demonstrated that equivalent temperature (TE), which incorporates both the surface air temperature (T) and moist heat content associated with atmospheric moisture, is a better indicator of overall heat content. This thesis follows up on a study that used TE to determine the impacts of land use/land cover and air masses on the atmospheric heat content over Kentucky during the growing season (April-September). The study, which used data from the Kentucky Mesonet, reveals that moist weather types dominate the growing season and, as expected, differences between T and TE are smaller under dry atmospheric conditions but larger under moist conditions. For example, the lowest TE-T difference was 10.04 °C on a dry weather day on the 18th of April, 2010 (T = 8.91 °C and TE = 18.95 °C). On the other hand, the highest estimated difference for a day of moist tropical weather was 46.54 °C on the 11th of August, 2010 (T = 26.54 °C and TE = 73.08 °C). Since land cover type influences both moisture availability and temperature in the lower atmosphere, the research shows that TE is larger in areas with higher physical evaporation and transpiration rates. Results support the hypothesis that the influence of different weather types over a region is a likely cause of interannual variation in TE.

The Nepalese Himalaya, one of the most active regions within the Himalayan Mountain belt, is characterized by a thick succession of Miocene age Siwalik sedimentary rocks deposited at its foreland basin. To date, much of its tectonic evolution, including exhumation in the Nepalese Siwalik, is poorly understood. This study of a quantitative analysis of the bedrock river parameters should provide crucial information regarding tectonic activities in the area. The study investigated geomorphic parameters of river longitudinal profiles from 54 watersheds within the Siwalik section of the Nepalese Himalaya, for the first time. A total of 140 bedrock rivers from these watersheds were selected using stream power-law function and 30-meter resolution ASTER DEM. The quantitative data from the river longitudinal profiles were integrated with published exhumation ages. Results of this study show, first, a presence of major and minor knickpoints, with a total of 305 knickpoints identified, of which 180 were major knickpoints and the rest were minor knickpoints. Further classifications of knickpoints were based on structures (lineaments extracted from SRTM DEM), lithology, and possible uplift. Second, the Normalized Steepness index (ksn) values exhibited a range from 5.3 to 140.6. Third, the concavity index of streams in the study area ranged from as low as -12.1 to as high as 31.1 and the values were consistently higher upstream of the knickpoints. Finally, integration of the river profile data with the published exhumation ages show that the regions with a high ksn value correspond to the regions with higher incision and, therefore, are likely to have high uplift. The presence of a break in ksn in the eastern section of the study area suggests that the incision is likely accelerated by Main Frontal Thrust (MFT) movements. Erosion of the thrust sheet could have influenced the rapid uplift of the Siwalik due to isostatic processes. Thus, the timing of the source-region exhumation and its rate suggests that MFT-related tectonics, and/or climate processes, likely influenced the landscape evolution of the study area. The results of this study should help in comprehending the neo-tectonic deformation of the Nepalese Himalaya.

The western portion of the Mississippi/Atwater fold belt in the Gulf of Mexico contains what is known as The Green Knoll Salt Dome. The creation and growth of this salt diapir is punctuated by salt deposition, salt migration, sediment loading, and is linked to the “Frampton” fold belt. An indicator of these growth periods is exhibited in an angular unconformity (halo-kinetic sequence boundary) that flanks the diapir. This unconformity developed during the Miocene-Pliocene chronostratigraphic boundary. The “Redwood” (Green Canyon 1001) prospect was drilled after the discovery of middle Miocene sands containing hydrocarbons in the Mad Dog field (GC 826). The objective Miocene sand in the “Redwood” borehole was thin due to this angular unconformity causing the sand to pinch out. An evaluation of seismic and well log data provided by Bureau of Ocean Energy Management indicated that the unconformity might not provide the seal needed to trap hydrocarbons on the flank of the salt dome, or it did not allow enough sand to be deposited. A palinspastic structural restoration of the Green Knoll Salt Dome revealed that the growth of the Green Knoll and Frampton are connected. It is still possible that if a well were to be drilled further down dip from where The “Redwood” prospect was drilled, one may find a potential hydrocarbon reservoir.

Beneath Keathley Canyon (KC) off the Southern Coast of Louisiana and Texas, allochthonous salt bodies have attained thicknesses of over 7620 m (25000 feet), providing excellent seals and migration pathways for hydrocarbons produced by post-rift sedimentary deposition. This study analyzes a small portion of the KC area, utilizing Petrel Seismic software and well information from the KC102 (Tiber) well. An intra-Miocene wedge, expressed beneath salt, may provide information about movement of allochthonous salt over Wilcox sands, sediment compaction, and hydrocarbon pathways. Progradational sedimentation is the driving force which leads to faulting in the early Miocene, allowing Jurassic salt to rise, spreading laterally and upwards towards the surface, scarring the sediments beneath it in glacier-like form. This intrusion helped to create the proper conditions for formation of a petroleum play system, maintain reservoir quality sands and temperatures, and create a four way closure in the Eocene for prospective well location.

The Pile Mound survey includes magnetometry paired with targeted ground-penetrating radar (GPR) and electromagnetic induction (EMI) surveys of the mound and testing of associated features over the ca. 6.5 ha site. The GPR survey discovered six rock features (five large rock features within the mound and one marking the outside of the mound). Knowledge of mounds in the Upper Cumberland Plateau (UCP) is lacking—the closest other studied sites are at the Corbin Site, Croley-Evans, Bell Site, and Beasley Mounds, approximately 75 – 100 km away. However, the most similar mound construction is found at Corbin and Cherokee sites, some 175 – 275 km away. In addition, the associated ceramic assemblage appears to reflect more similarity to the East Tennessee Valley rather than the Middle Cumberland region. These data provide a unique opportunity to better understand the Mississippian occupation in the UCP of Tennessee.

South Sudan, a new country formed in 2011, has been planning to develop its mineral sector by allocating exploration licenses to investors. This decision requires preliminary knowledge of geology and mineral occurrences, both of which are unavailable because the country has been engaged in a civil war for more than 50 years. Exploration of mineral resources in South Sudan has lagged behind its petroleum industry, except for artisanal gold mining, which is practiced intermittently by local communities. Freely available satellite gravity and remote-sensing data were used to map the basement architecture as well as zones of hydrothermal alteration in the Didinga Hills; both basement architecture and hydrothermal alteration are of prime importance in exploration and development of mineral resources in the study area. Qualitative interpretation of gravity data is consistent with the known geology of petroleum fields and the Precambrian basement complex. Remote-sensing data and techniques—optimal band combination, band ratioing, and principal component analysis—have been effective in extracting information related to lithology, hydrothermal alteration, and geologic structures. The resulting basic information and methods have identified additional prospective exploration areas where more detailed gravity, magnetic, electromagnetic, and seismic surveys should be carried out; this will assist decision makers in matters related to land use, mineral titles, and exploration of natural resources, and lead to prosperity for the new nation of South Sudan.

The Charleston Uplift (CU), a 30-km-long by 7-km-wide, N46°E-oriented subsurface geologic anomaly in the northern Mississippi embayment near Charleston, Missouri, exhibits up to 36 m of vertical relief across the Paleogene/Quaternary unconformity. Subsurface structural relief, along with the CU’s coincident boundary alignment with contemporary microseismicity and the New Madrid North Fault (NMNF), suggest a structural origin. Subsequent seismic soundings indicate vertical structural relief is present in Cretaceous and Paleozoic horizons, supporting the fault-controlled origin. The southern boundary (CU-s) had not been investigated, nor had any direct fault images been acquired. Integrated microgravity and seismic-reflection methods across the inferred CU-s establish the first image of this fault. Forward modeling indicated that the vertical variation of strata across the CU-s would induce a microgravity anomaly of 1.6 mGal. The observed microgravity anomaly survey across the southern boundary is 1.616 ± .004 mGal, and is consistent with the tectonic interpretation. A subsequently acquired seismic-reflection profile corroborates this interpretation. The imaged fault shows approximately 60, 35, and 35 meters of vertical down-to-the-south throw across the tops of Paleozoic, Cretaceous, and Tertiary horizons, respectively. This confirms the CU is not an erosional feature, but a structurally controlled extension of the NMNF.

The San Andreas Fault stretches for over 800 miles through California. Along the foothills of the San Bernardino Mountains, areas in close proximity to the San Andreas Fault Zone may be subject to site amplification of ground motion caused by seismic activity via wave propagation through the subsurface. These seismic hazards are being addressed via the Alquist-Priolo Earthquake Faulting Zone Act and the National Earthquake Hazards Reduction Program (NEHRP). Shear wave velocity of the subsurface has served as a proxy for ground motion amplification and is therefore a useful parameter to help analyze and reduce seismic hazards. Low shear wave velocities of the subsurface have been known to correlate with higher amplitude ground motion. This study focuses on refraction microtremor analysis (ReMi) of the subsurface in Northern San Bernardino; more specifically, areas encompassing California State University San Bernardino, in close proximity to the San Andreas Fault. The technique will resolve shear wave velocity values for the top 30 meters (Vs30) of the subsurface. This depth of investigation has proven to be an effective means in determining subsurface conditions. ReMi profiles were situated 0.25 to 2.0 miles away from the San Andreas Fault, and in some instances, strategically positioned next to housing developments and structures. Phase velocity dispersion curves were generated by processing ReMi seismic data and subsequently inverted to attain average shear wave velocity profiles with depth. The geologic units in the study area consist of very young wash deposits, young alluvial fan deposits and Pelonist schist deposits. These geologic units may be an indicator to how seismic waves behave in subsurface lithology. To highlight differences in Vs30 values across the project area, a microzonation map was constructed.