Open Access. Powered by Scholars. Published by Universities.®

Geology Commons™

Open Access. Powered by Scholars. Published by Universities.®

30,010 Full-Text Articles 16,221 Authors 7,015,459 Downloads 178 Institutions

All Articles in Geology

Faceted Search

30,010 full-text articles. Page 1136 of 1251.

Planetary-Scale Low-Level Circulation And The Unique Development Of Hurricane Wilma In 2005, Jinwoong Yoo, Robert V. Rohli, Jennifer Collins 2016 Purdue University

Planetary-Scale Low-Level Circulation And The Unique Development Of Hurricane Wilma In 2005, Jinwoong Yoo, Robert V. Rohli, Jennifer Collins

School of Geosciences Faculty and Staff Publications

Large‐scale atmospheric and oceanic conditions in the western Atlantic basin were analyzed to understand the unique tropical cyclogenesis (TCG) and intensification mechanism of Hurricane Wilma in 2005, the most intense Atlantic basin tropical cyclone (TC) on record. An analysis of 850 hPa circulations depicted in the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis data suggests that anomalous development of the 850 hPa circulation pattern triggered by Hurricane Vince (October 8–11, 2005) contributed to the development of a large‐scale low‐level vortex that preceded Wilma's TCG in the eastern Caribbean. In particular, weakened easterly winds in the central …


Future Changes In Mean And Extreme Monsoon Precipitation In The Middle And Lower Yangtze River Basin, China, In The Cmip5 Models, Yanjuan Wu, Shuang-Ye Wu, Jiahong Wen, Felipe Tagle, Ming Xu, Jianguo Tan 2016 Shanghai Normal University

Future Changes In Mean And Extreme Monsoon Precipitation In The Middle And Lower Yangtze River Basin, China, In The Cmip5 Models, Yanjuan Wu, Shuang-Ye Wu, Jiahong Wen, Felipe Tagle, Ming Xu, Jianguo Tan

Department of Earth, Environment and Sustainability Faculty Publications

In this study, the potential future changes of mean and extreme precipitation in the middle and lower Yangtze River basin (MLYRB), eastern China, are assessed using the models of phase 5 of the Coupled Model Intercomparison Project (CMIP5). Historical model simulations are first compared with observations in order to evaluate model performance. In general, the models simulate the precipitation mean and frequency better than the precipitation intensity and extremes, but still have difficulty capturing precipitation patterns over complex terrains. They tend to overestimate precipitation mean, frequency, and intensity while underestimating the extremes. After correcting for model biases, the spatial variation …


Passive Rifting Of Thick Lithosphere In The Southern East African Rift: Evidence From Mantle Transition Zone Discontinuity Topography, Cory A. Reed, Kelly H. Liu, Patrick R. N. Chindandali, Belarmino Massingue, Hassan Mdala, Daniel Mutamina, Youqiang Yu, Stephen S. Gao 2016 Missouri University of Science and Technology

Passive Rifting Of Thick Lithosphere In The Southern East African Rift: Evidence From Mantle Transition Zone Discontinuity Topography, Cory A. Reed, Kelly H. Liu, Patrick R. N. Chindandali, Belarmino Massingue, Hassan Mdala, Daniel Mutamina, Youqiang Yu, Stephen S. Gao

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

To investigate the mechanisms for the initiation and early-stage evolution of the nonvolcanic southernmost segments of the East African Rift System (EARS), we installed and operated 35 broadband seismic stations across the Malawi and Luangwa rift zones over a 2 year period from mid-2012 to mid-2014. Stacking of over 1900 high-quality receiver functions provides the first regional-scale image of the 410 and 660 km seismic discontinuities bounding the mantle transition zone (MTZ) within the vicinity of the rift zones. When a 1-D standard Earth model is used for time-depth conversion, a normal MTZ thickness of 250 km is found beneath …


Mantle Structure Beneath The Incipient Okavango Rift Zone In Southern Africa, Youqiang Yu, Kelly H. Liu, Zhouchuan Huang, Dapeng Zhao, Cory A. Reed, Moikwathai Moidaki, Jianshe Lei, Stephen S. Gao 2016 Missouri University of Science and Technology

Mantle Structure Beneath The Incipient Okavango Rift Zone In Southern Africa, Youqiang Yu, Kelly H. Liu, Zhouchuan Huang, Dapeng Zhao, Cory A. Reed, Moikwathai Moidaki, Jianshe Lei, Stephen S. Gao

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Numerous investigations of the mature segments of the East African rift system (EARS) have significantly improved our understanding of the structure and processes associated with well-developed continental rifts. In contrast, knowledge of rifting processes at their early stage is still significantly limited. Here we present results from a teleseismic P-wave tomography investigation of the incipient Okavango rift zone (ORZ), which is located at the southwestern terminus of the EARS. P-wave relative travel-time residuals recorded by 17 recently deployed portable seismic stations were manually picked and inverted for three-dimensional upper-mantle and mantle transition-zone tomographic images beneath the ORZ and its adjacent …


Exploring The Potential Linkages Between Oil-Field Brine Reinjection, Crystalline Basement Permeability, And Triggered Seismicity For The Dagger Draw Oil Field, Southeastern New Mexico, Usa, Using Hydrologic Modeling, Y. Zhang, Stanislav S. Edel, Jeff D. Pepin, Mark A. Person, Ronald F. Broadhead, J. P. Ortiz, Susan L. Bilek, Peter S. Mozley, James P. Evans 2016 New Mexico Institute of Mining and Technology

Exploring The Potential Linkages Between Oil-Field Brine Reinjection, Crystalline Basement Permeability, And Triggered Seismicity For The Dagger Draw Oil Field, Southeastern New Mexico, Usa, Using Hydrologic Modeling, Y. Zhang, Stanislav S. Edel, Jeff D. Pepin, Mark A. Person, Ronald F. Broadhead, J. P. Ortiz, Susan L. Bilek, Peter S. Mozley, James P. Evans

Geosciences Faculty Publications

We used hydrologic models to explore the potential linkages between oil-field brine reinjection and increases in earthquake frequency (up to Md 3.26) in southeastern New Mexico and to assess different injection management scenarios aimed at reducing the risk of triggered seismicity. Our analysis focuses on saline water reinjection into the basal Ellenburger Group beneath the Dagger Draw Oil field, Permian Basin. Increased seismic frequency (>Md 2) began in 2001, 5 years after peak injection, at an average depth of 11 km within the basement 15 km to the west of the reinjection wells. We considered several scenarios …


The Purdue Agro-Climatic (Pac) Dataset For The U.S. Corn Belt: Development And Initial Results, Xing Liu, Elin Jacobs, Anil Kumar, Larry Biehl, Jeff Andersen, Dev Niyogi 2016 Purdue University

The Purdue Agro-Climatic (Pac) Dataset For The U.S. Corn Belt: Development And Initial Results, Xing Liu, Elin Jacobs, Anil Kumar, Larry Biehl, Jeff Andersen, Dev Niyogi

Department of Earth, Atmospheric, and Planetary Sciences Faculty Publications

This study is a result of a project titled ‘‘Useful to Usable (U2U): Transforming Climate Variability and Change Information for Cereal Crop Producers”. This paper responds to the project goal to improve farm resiliency and proftability in the U.S. Corn Belt region by transforming existing meteorological dataset into usable knowledge and tools for the agricultural community.

A high-resolution agro-climatic dataset that covers the U.S. Corn Belt was built for the U2U project based on a Land Data Assimilation System (LDAS) framework. This data referred to as the Purdue Agro-climatic (PAC) dataset is a gridded, continuous dataset suitable for agrocli- matic …


Lava Flow Hazard Assessment For The Idaho National Laboratory, Idaho Falls, And Pocatello, Idaho, U.S.A., Elisabeth Gallant 2016 University of South Florida

Lava Flow Hazard Assessment For The Idaho National Laboratory, Idaho Falls, And Pocatello, Idaho, U.S.A., Elisabeth Gallant

USF Tampa Graduate Theses and Dissertations

This study presents a probabilistic lava flow hazard assessment for the Idaho National Laboratory (INL) and the cities of Idaho Falls and Pocatello, Idaho. The impetus of this work is to estimate the conditional probability that a lava flow on the eastern Snake River Plain (ESRP) will impact the areas of interest given the formation of a new volcanic vent in the region. A list of 288 eruptive events, derived from a previously published inventory of 506 surface and 32 buried vents, was created to reduce the biasing of spatial density maps towards eruptions with multiple dependent vents. Conditional probabilities …


Mapping Robinia Pseudoacacia Forest Health Conditions By Using Combined Spectral, Spatial And Textureal Information Extracted From Ikonos Imagery, H. Wang, Ruiliang Pu, Z. Zhang 2016 Hohai University

Mapping Robinia Pseudoacacia Forest Health Conditions By Using Combined Spectral, Spatial And Textureal Information Extracted From Ikonos Imagery, H. Wang, Ruiliang Pu, Z. Zhang

School of Geosciences Faculty and Staff Publications

n this study grey-level co-occurrence matrix (GLCM) textures and a local statistical analysis Getis statistic (Gi), computed from IKONOS multispectral (MS) imagery acquired from the Yellow River Delta in China, along with a random forest (RF) classifier, were used to discriminate Robina pseudoacacia tree health levels. The different RF classification results of the three forest health conditions were created: (1) an overall accuracy (OA) of 79.5% produced using the four MS band reflectances only; (2) an OA of 97.1% created with the eight GLCM features calculated from IKONOS Band 4 with the optimal window size of 13 × 13 and …


Abundance Of Archaias Angulatus On The West Florida Coast Indicates The Influence Of Carbonate Alkalinity Over Salinity, Sean Thomas Beckwith 2016 University of South Florida

Abundance Of Archaias Angulatus On The West Florida Coast Indicates The Influence Of Carbonate Alkalinity Over Salinity, Sean Thomas Beckwith

USF Tampa Graduate Theses and Dissertations

Archaias angulatus, a large symbiont-bearing foraminifer (Order Miliolida) that produces a Mg-calcite shell, is common throughout the Caribbean and warm western Atlantic region. This species lives abundantly in seagrass beds along the Springs Coast of northwest Florida (up to 4 adults per gram of sediment) where spring-fed rivers emerge from a limestone aquifer, and in Florida Bay to the southeast (25 adults/g) where the sediment is primarily biogenic carbonate. In contrast, live specimens are seldom found in the seagrass beds along the central-west coast of Florida, where barrier islands are dominated by quartz sand. My working hypothesis is that substratum …


Slip Distribution Of The 2014 Mw=8.1 Pisagua, Northern Chile, Earthquake Sequence Estimated From Coseismic Fore-Arc Surface Cracks, John P. Loveless, Chelsea P. Scott, Richard W. Allmendinger, Gabriel González 2016 Smith College

Slip Distribution Of The 2014 Mw=8.1 Pisagua, Northern Chile, Earthquake Sequence Estimated From Coseismic Fore-Arc Surface Cracks, John P. Loveless, Chelsea P. Scott, Richard W. Allmendinger, Gabriel González

Geosciences: Faculty Publications

The 2014 Mw = 8.1 Iquique (Pisagua), Chile, earthquake sequence ruptured a segment of the Nazca-South America subduction zone that last hosted a great earthquake in 1877. The sequence opened >3700 surface cracks in the fore arc of decameter-scale length and millimeter-to centimeter-scale aperture. We use the strikes of measured cracks, inferred to be perpendicular to coseismically applied tension, to estimate the slip distribution of the main shock and largest aftershock. The slip estimates are compatible with those based on seismic, geodetic, and tsunami data, indicating that geologic observations can also place quantitative constraints on rupture properties. The earthquake sequence …


A New Image Processing Procedure Integrating Pci-Rpc And Arcgis-Spline Tools To Improve The Orthorectification Accuracy Of High-Resolution Satellite Imagery, Hongying Zhang, Ruiliang Pu, Xiuguo Liu 2016 University of South Florida

A New Image Processing Procedure Integrating Pci-Rpc And Arcgis-Spline Tools To Improve The Orthorectification Accuracy Of High-Resolution Satellite Imagery, Hongying Zhang, Ruiliang Pu, Xiuguo Liu

School of Geosciences Faculty and Staff Publications

Given the low accuracy of the traditional remote sensing image processing software when orthorectifying satellite images that cover mountainous areas, and in order to make a full use of mutually compatible and complementary characteristics of the remote sensing image processing software PCI-RPC (Rational Polynomial Coefficients) and ArcGIS-Spline, this study puts forward a new operational and effective image processing procedure to improve the accuracy of image orthorectification. The new procedure first processes raw image data into an orthorectified image using PCI with RPC model (PCI-RPC), and then the orthorectified image is further processed using ArcGIS with the Spline tool (ArcGIS-Spline). We …


Revised Scec Final Report On The New East Shoreline Strand Of The San Andreas Fault, Susanne U. Jänecke, Daniel K. Markowski 2016 Utah State University

Revised Scec Final Report On The New East Shoreline Strand Of The San Andreas Fault, Susanne U. Jänecke, Daniel K. Markowski

Geosciences Faculty Publications

This report consists of three parts: Original proposal (2011), provisional report (Janecke, 2013), and a final summary in the form of the MS thesis of Daniel Markowski (2016). The abstract herein is the abstract of Janecke's provisional report except that I updated the name of the fault to East Shoreline strand of the SAF. A different "Shoreline fault" is already in the Quaternary fault and fold database. See Markowski (2016) and Janecke et al. 2016 for additional updates.

Summary:

In 2013 Janecke submitted a provisional report to SCEC about our research along the newly identified East Shoreline strand of …


A Complex Origin For The Kelso Dunes, Mojave National Preserve, California, Usa: A Case Study Using A Simple Geochemical Method With Global Applications, Daniel R. Muhs, Nicholas Lancaster, Gary L. Skipp 2016 U.S. Geological Survey

A Complex Origin For The Kelso Dunes, Mojave National Preserve, California, Usa: A Case Study Using A Simple Geochemical Method With Global Applications, Daniel R. Muhs, Nicholas Lancaster, Gary L. Skipp

United States Geological Survey: Staff Publications

The Kelso Dune field in southern California is intriguing because although it is of limited areal extent (~100 km2), it has a wide variety of dune forms and contains many active dunes (~40 km2), which is unusual in the Mojave Desert. Studies over the past eight decades have concluded that the dunes are derived primarily from a single source, Mojave River alluvium, under a dominant, westerly-to-northwesterly wind regime. The majority of these studies did not, however, present data to support the Mojave River as the only source.We conducted mineralogical and geochemical studies ofmost of the 14 geomorphically defined dune groups …


In Situ Ion Exchange In A Micro-Porous Transition Metal Silicate Framework, Jason M. Lively 2016 Western Kentucky University

In Situ Ion Exchange In A Micro-Porous Transition Metal Silicate Framework, Jason M. Lively

Masters Theses & Specialist Projects

Ion selectivity of minerals has traditionally been utilized in industry as a catalyst, metal separation, and environmental reclamation/sequestration tool. There is an increased interest in understanding ion selectivity mechanisms of micro-porous minerals and mineral-like structures and how they can be applied in various industries: environmental and, potentially, pharmaceutical. This study seeks to understand the ion exchange mechanisms in micro-porous zirconosilicates using time-resolved Raman spectroscopy and X-ray diffraction. The thesis material was exchanged with H+, Na+, K+, and Cs+ in order to better understand structural changes as well as the influence of the H+-bonding during the exchange process. It is hypothesized …


Several Methods To Assess Groundwater Surface-Water Interactions In Lolo Creek, Montana, Michael Chambers 2016 Montana Tech

Several Methods To Assess Groundwater Surface-Water Interactions In Lolo Creek, Montana, Michael Chambers

Graduate Theses & Non-Theses

This study addressed potential groundwater surface-water interactions along the lower reach of Lolo Creek in Lolo, Montana as part of a larger ongoing study conducted by the Montana Bureau of Mines and Geology (MBMG) Groundwater Investigation Program (GWIP). The GWIP focus is to address the causes of late summer dewatering along the lower reaches of Lolo Creek. This study’s work attempts to: (1) identify gaining/losing reaches along a 6.5 km stretch and (2) test several methods for investigating groundwater and surface-water interactions. The methods included measuring incremental streamflow, hydraulic gradients, one-dimensional temperature profiles, and collection and evaluation of radon-222. Four …


Collecting, Preparing, And Synthesizing Well Log Data For Subsurface Mapping: Example From The Bakken Formation, Asel Sherimkulova 2016 Montana Tech

Collecting, Preparing, And Synthesizing Well Log Data For Subsurface Mapping: Example From The Bakken Formation, Asel Sherimkulova

Graduate Theses & Non-Theses

Late Devonian and Early Mississippian Bakken Formation consists of three distinct members: the upper shale, middle, and lower shale. The upper and lower shales are excellent source rocks, rich in organic content. The organic material in the shales was derived from planktonic algae. Both the upper and lower shales were deposited during a transgressive event in hypoxic to anoxic conditions. The original total organic carbon content in the Bakken shales ranges from 20 to 22 weight percent, however; the content decreases to 10 to 17 weight percent as a result of maturation of hydrocarbons and primary expelling of oil. High …


Modeling The Thickness Of Perennial Ice Covers On Stratified Lakes Of The Taylor Valley, Antarctica, Maciej K. Obryk, Peter T. Doran, Jared A. Hicks, Christopher P. McKay, John Charles Priscu 2016 Portland State University

Modeling The Thickness Of Perennial Ice Covers On Stratified Lakes Of The Taylor Valley, Antarctica, Maciej K. Obryk, Peter T. Doran, Jared A. Hicks, Christopher P. Mckay, John Charles Priscu

Geology Faculty Publications and Presentations

A 1-D ice cover model was developed to predict and constrain drivers of long-term ice thick-ness trends in chemically stratified lakes of Taylor Valley, Antarctica. The model is driven by surface ra-diative heat fluxes and heat fluxes from the underlying water column. The model successfully reproduced 16 a (between 1996 and 2012) of ice thickness changes for the west lobe of Lake Bonney (average ice thickness = 3.53 m) and Lake Fryxell (average ice thickness = 4.22 m). Long-term ice thick-ness trends require coupling with the thermal structure of the water column. The heat stored within the temperature maximum of …


Variations In Geochemistry And Mineralogy Of Aeolian Dust Deposition To Mountains In Utah And Nevada, Usa, Dylan Binder Dastrup 2016 Brigham Young University

Variations In Geochemistry And Mineralogy Of Aeolian Dust Deposition To Mountains In Utah And Nevada, Usa, Dylan Binder Dastrup

Theses and Dissertations

Major and trace metal loading to mountains in the western US depends on dust sources, intensity of storms and their availability for transport during snowmelt and runoff. Previous work has been conducted on dust production, composition, and its affect on solar radiation and timing of snow melt. This study was conducted to 1) examine temporal and spatial variability in dust chemistry; 2) evaluate form and availability of major and trace elements in dust; and 3) identify potential dust sources affecting mountains in Utah and Nevada. Spring and summertime dust was collected across northern Utah over the course of three years …


Distributed Fiber-Optic Temperature Sensor Validations Using Field Deployments In The Flooded Orphan Boy Mine Shaft In Butte, Mt, Elliott Mazur 2016 Montana Tech

Distributed Fiber-Optic Temperature Sensor Validations Using Field Deployments In The Flooded Orphan Boy Mine Shaft In Butte, Mt, Elliott Mazur

Graduate Theses & Non-Theses

The process of sensor validation through experimentation with the Omnisens Distributed Temperature and Strain (DITEST) Brillouin Optical Time Domain Analyzer (BOTDA) proved to be a challenging project. The project encompassed sensor calibrations, system error minimization, sensor network design and deployment, and the characterization of temperatures in the Orphan Boy Mine shaft. Fiber-optic cable sensor calibrations yielded linear relationship coefficients 0.6-1.0MHZ/°F, indicating a strong positive correlation between Brillouin Frequency Shifts and temperature. Calibrated sensors demonstrated accuracies near ±0.8°F using the corrected error bounds from residual analyses as the benchmark. Fiber-optic measurement accuracy and repeatability were controlled by user-selected signal interrogator settings …


A Dual-Porosity-Stokes Model And Finite Element Method For Coupling Dual-Porosity Flow And Free Flow, Jiangyong Hou, Meilan Qiu, Xiaoming He, Chaohua Guo, Mingzhen Wei, Baojun Bai 2016 Missouri University of Science and Technology

A Dual-Porosity-Stokes Model And Finite Element Method For Coupling Dual-Porosity Flow And Free Flow, Jiangyong Hou, Meilan Qiu, Xiaoming He, Chaohua Guo, Mingzhen Wei, Baojun Bai

Mathematics and Statistics Faculty Research & Creative Works

In this paper, we propose and numerically solve a new model considering confined flow in dual-porosity media coupled with free flow in embedded macrofractures and conduits. Such situation arises, for example, for fluid flows in hydraulic fractured tight/shale oil/gas reservoirs. The flow in dual-porosity media, which consists of both matrix and microfractures, is described by a dual-porosity model. And the flow in the macrofractures and conduits is governed by the Stokes equation. Then the two models are coupled through four physically valid interface conditions on the interface between dual-porosity media and macrofractures/conduits, which play a key role in a physically …


Digital Commons powered by bepress