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2013

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Articles 841 - 870 of 965

Full-Text Articles in Earth Sciences

Loess Origin, Transport, And Deposition Over The Past 10,000 Years, Wrangell-St. Elias National Park, Alaska, Daniel R. Muhs, James R. Budahn, John P. Mcgeehin, E. Arthur Bettis Iii, Gary Skipp, James B. Paces, Elisabeth A. Wheeler Jan 2013

Loess Origin, Transport, And Deposition Over The Past 10,000 Years, Wrangell-St. Elias National Park, Alaska, Daniel R. Muhs, James R. Budahn, John P. Mcgeehin, E. Arthur Bettis Iii, Gary Skipp, James B. Paces, Elisabeth A. Wheeler

United States Geological Survey: Staff Publications

Contemporary glaciogenic dust has not received much attention, because most research has been on glaciogenic dust of the last glacial period or non-glaciogenic dust of the present interglacial period. Nevertheless, dust from modern glaciogenic sources may be important for Fe inputs to primary producers in the ocean. Adjacent to the subarctic Pacific Ocean, we studied a loess section near Chitina, Alaska along the Copper River in Wrangell-St. Elias National Park, where dust has been accumulating over the past ~10,000 years. Mass accumulation rates for the fine-grained (<20 >µm) fraction of this loess section are among the highest reported for the …


Comparative Embryotoxicity Of A Pentabrominated Diphenyl Ether Mixture To Common Terns (Sterna Hirundo) And American Kestrels (Falco Sparverius), Barnett A. Rattner, Rebecca S. Lazarus, Gary H. Heinz, Natalie K. Karouna-Renier, Sandra L. Schultz, Robert C. Hale Jan 2013

Comparative Embryotoxicity Of A Pentabrominated Diphenyl Ether Mixture To Common Terns (Sterna Hirundo) And American Kestrels (Falco Sparverius), Barnett A. Rattner, Rebecca S. Lazarus, Gary H. Heinz, Natalie K. Karouna-Renier, Sandra L. Schultz, Robert C. Hale

United States Geological Survey: Staff Publications

Concentrations of polybrominated diphenyl ethers (PBDEs) in Forster’s tern (Sterna forsteri) eggs from San Francisco Bay have been reported to range up to 63 µg g-1 lipid weight. This value exceeds the lowest-observed-adverse-effect level (1.8 µg g-1 egg wet weight; ~32 µg g-1 lipid weight) reported in an embryotoxicity study with American kestrels (Falco sparverius). As a surrogate for Forster’s terns, common tern (Sterna hirundo) eggs were treated by air cell injection with corn oil vehicle (control) or a commercial penta-BDE formulation (DE-71) at nominal concentrations of 0.2, 2, and 20 µg g …


Use Of Nmr Logging To Obtain Estimates Of Hydraulic Conductivity In The High Plains Aquifer, Nebraska, Usa, Katherine Dlubac, Rosemary Knight, Yi-Qiao Song, Nate Bachman, Ben Grau, Jim Cannia, John Williams Jan 2013

Use Of Nmr Logging To Obtain Estimates Of Hydraulic Conductivity In The High Plains Aquifer, Nebraska, Usa, Katherine Dlubac, Rosemary Knight, Yi-Qiao Song, Nate Bachman, Ben Grau, Jim Cannia, John Williams

United States Geological Survey: Staff Publications

Hydraulic conductivity (K) is one of the most important parameters of interest in groundwater applications because it quantifies the ease with which water can flow through an aquifer material. Hydraulic conductivity is typically measured by conducting aquifer tests or wellbore flow (WBF) logging. Of interest in our research is the use of proton nuclear magnetic resonance (NMR) logging to obtain information about water-filled porosity and pore space geometry, the combination of which can be used to estimate K. In this study, we acquired a suite of advanced geophysical logs, aquifer tests, WBF logs, and sidewall cores at the …


Abiotic Nitrate And Nitrite Reactivity With Iron Oxide Minerals, Prakash Dhakal Jan 2013

Abiotic Nitrate And Nitrite Reactivity With Iron Oxide Minerals, Prakash Dhakal

Theses and Dissertations--Plant and Soil Sciences

Under iron (Fe3+)-reducing conditions where aqueous Fe2+ and unreduced solid Fe3+-oxides commonly coexist, soil Fe2+ oxidation has been shown to be coupled with nitrate (NO3-) reduction. One possible secondary reaction is the involvement of NO3- and nitrite (NO2-) with Fe-oxide minerals found in many natural environments. Yet, spectroscopic measurements and kinetic data on reactivity of NO3- and NO2- with Fe-containing oxide minerals such as goethite (a-FeOOH), and magnetite (Fe3O­4) are not found in the literature. The reactivity of …


Putting Local Knowledge And Context To Work For Gunnison Sage-Grouse Conservation, Corrine Noel Knapp, James Cochran, F. Stuart Chapin Iii, Gary Kofinas, Nathan Sayre Jan 2013

Putting Local Knowledge And Context To Work For Gunnison Sage-Grouse Conservation, Corrine Noel Knapp, James Cochran, F. Stuart Chapin Iii, Gary Kofinas, Nathan Sayre

Human–Wildlife Interactions

Successful conservation requires adequate understanding of focal species and ecology, practices that may assist species survival, and a community of people willing and able to conserve the species. For many species at risk, we operate with imperfect knowledge in complex conservation contexts. In this case study involving the Gunnison sage-grouse (Centrocercus minimus), we interviewed 26 community-defined local experts, including both those with and without related academic degrees, to assess the utility of local knowledge for understanding and informing conservation opportunities.This project suggests several benefits of integrating local knowledge that apply specifically to rare and endemic populations, including the …


Occurrence And Success Of Greater Sage-Grouse Broods In Relation To Insect-Vegetation Community Gradients, Seth M. Harju, Chad V. Olson, Lisa Foy-Martin, Stephen L. Webb, Matthew R. Dzialak, Jeffrey B. Winstead, Larry D. Hayden-Wing Jan 2013

Occurrence And Success Of Greater Sage-Grouse Broods In Relation To Insect-Vegetation Community Gradients, Seth M. Harju, Chad V. Olson, Lisa Foy-Martin, Stephen L. Webb, Matthew R. Dzialak, Jeffrey B. Winstead, Larry D. Hayden-Wing

Human–Wildlife Interactions

A community-level approach to identify important brood habitats of greater sage-grouse (Centrocercus urophasianus) may prove useful in guiding management actions because it acknowledges that important habitat components are not ecologically independent from each other. We used principal components analysis to combine insect and vegetation variables into community gradients and used logistic regression to link these components with brood survival and occurrence. We found that brood success was higher when broods occurred in specific insect-vegetation community types. A relationship between brood occurrence and insect-vegetation gradients was not apparent. The high resolution of the data and the solid validation performance …


Winter Habitat Use By Juvenile Greater Sage-Grouse On Parker Mountain, Utah: Implications For Sagebrush Management, Danny Caudill, Terry A. Messmer, Brent Bibles, Michael R. Guttery Jan 2013

Winter Habitat Use By Juvenile Greater Sage-Grouse On Parker Mountain, Utah: Implications For Sagebrush Management, Danny Caudill, Terry A. Messmer, Brent Bibles, Michael R. Guttery

Human–Wildlife Interactions

Greater sage-grouse (Centrocercus urophasianus; hereafter, sage-grouse) are entirely dependent on sagebrush (Artemisia spp.) for food and cover during winter. Loss or fragmentation of important wintering areas could have a disproportionate affect on population size. We radio-marked and monitored 91 juvenile sage-grouse in south-central Utah from 2008 to 2010. Thirty-four individuals survived to winter (January to March) and were used to evaluate winter habitat use. Resource use was calculated using kernel density estimation of radio-marked individuals and compared to available habitat using a G-test. We found that juvenile sage-grouse used winter habitats characterized by 0 to 5% slopes …


Response Of A Small Population Of Greater Sage-Grouse To Tree Removal: Implications Of Limiting Factors, S. Nicole Frey, Rachel Curtis, Kevin Heaton Jan 2013

Response Of A Small Population Of Greater Sage-Grouse To Tree Removal: Implications Of Limiting Factors, S. Nicole Frey, Rachel Curtis, Kevin Heaton

Human–Wildlife Interactions

In Utah, greater sage-grouse (Centrocercus urophasianus; hereafter, sage-grouse) range has been reduced to 50% of what is considered historical availability due to habitat degradation and loss. In an effort to improve sage-grouse habitat in southern Utah, the U.S. Bureau of Land Management (BLM) conducted a tree-removal treatment in 2005. We conducted a study to determine if (a) the tree-removal treatment was effective at creating new sage-grouse habitat, and (b) if characteristics of used habitat were similar to those reported in previous literature. The treatment resulted in increased abundance of grasses and forbs. Additionally, shrub percentage cover and height …


Stakeholder Contemporary Knowledge Needs Regarding The Potential Effects Of Tall Structures On Sage-Grouse, Terry A. Messmer, Robert Hasenyager, James Burruss, Sherry Liguori Jan 2013

Stakeholder Contemporary Knowledge Needs Regarding The Potential Effects Of Tall Structures On Sage-Grouse, Terry A. Messmer, Robert Hasenyager, James Burruss, Sherry Liguori

Human–Wildlife Interactions

The U.S. Energy Policy Act of 2005 required all state and federal agencies to grant utilities access permits to promote reliable, renewable energy production and transmission. Contemporary transmission relies largely on above-ground electric transmission structures and lines. The construction, operation, and maintenance of tall structures, such as power lines, communication towers, wind turbines, and other installations and their associated activities in sage-grouse (Centrocercus spp.) habitats were identified as a conservation threat by the U.S. Fish and Wildlife Service in its decision to designate greater sage-grouse (C. urophasianus; hereafter, sage-grouse) as a candidate species for protection under the Endangered …


Factors Influencing Survival And Productivity Of Pronghorn In A Semiarid Grass-Woodland In East-Central New Mexico, Louis C. Bender, Jon C. Boren, Heather Halbritter, Shad Cox Jan 2013

Factors Influencing Survival And Productivity Of Pronghorn In A Semiarid Grass-Woodland In East-Central New Mexico, Louis C. Bender, Jon C. Boren, Heather Halbritter, Shad Cox

Human–Wildlife Interactions

Pronghorns (Antilocapra americana) are an important source of revenue and recreation for property managers throughout New Mexico, but have been declining in number. We documented body condition, survival, production of fawns, and trends in population size of pronghorns on the Corona Range and Livestock Research Center (CRLRC), a working research ranch and wildlife enterprise located in east-central New Mexico, from 2006 through 2011. Accrual of all indices of condition and size of both adult female and adult male pronghorns was positively associated with precipitation during June to July, August to September, and annually. Annual survival rates of females …


Livestock Predation By Common Leopard In Binsar Wildlife Sanctuary, India: Human-Wildlife Conflicts And Conservation Issues, Chandra Prakash Kala, Kishor Kumar Kothari Jan 2013

Livestock Predation By Common Leopard In Binsar Wildlife Sanctuary, India: Human-Wildlife Conflicts And Conservation Issues, Chandra Prakash Kala, Kishor Kumar Kothari

Human–Wildlife Interactions

We investigate livestock predation by the common leopard (Panthera pardus) and emerging conflicts between this species, local people, and wildlife authorities at the Binsar Wildlife Sanctuary in the Himalayan region of India. We scrutinized secondary data that were collected by wildlife authorities; we also conducted informal interviews of villagers living within sanctuary, and wildlife staff to understand various human–leopard conflicts. Leopard density was approximately 0.33/km2 in the sanctuary. Leopards killed 1,763 domestic animals, about 90% of which were cattle, during a 14-year period. Within the sanctuary, leopards killed 1 person and injured 9 others. This high depredation rate …


Response To Perryman Comment On Siemer Et Al. (2013), William F. Siemer, Daniel J. Decker, Sandra A. Jonker Jan 2013

Response To Perryman Comment On Siemer Et Al. (2013), William F. Siemer, Daniel J. Decker, Sandra A. Jonker

Human–Wildlife Interactions

No abstract provided.


Vitals Rates And Seasonal Movements Of Two Isolated Greater Sage-Grouse Populations In Utah's West Desert, Jason D. Robinson, Terry A. Messmer Jan 2013

Vitals Rates And Seasonal Movements Of Two Isolated Greater Sage-Grouse Populations In Utah's West Desert, Jason D. Robinson, Terry A. Messmer

Human–Wildlife Interactions

Declines in greater sage-grouse (Centrocercus urophasianus; hereafter, sage-grouse) populations in Utah over the last century parallel range-wide trends. However, little is known about the ecology of sage-grouse populations that inhabit Utah’s naturally fragmented habitats. Utah’s West Desert sage-grouse populations occupy sagebrush (Artemisia spp.) habitats that are geographically separated by the Great Salt Lake, and largely confined to the Sheeprock and Deep Creek watersheds. From 2005 to 2006, we monitored sage-grouse that were radio-collared in each watershed to determine the factors affecting the vital rates in these isolated populations. Livestock grazing by domestic cattle was the dominate land use, …


Comment On Siemer Et Al. (2013), Heidi Perryman Jan 2013

Comment On Siemer Et Al. (2013), Heidi Perryman

Human–Wildlife Interactions

As a psychologist with special concern for public attitudes toward beaver (Castor canadensis) management, I read with interest the Siemer, Jonker, Becker, and Organ article appearing in your spring issue (Siemer et al. 2013). I was surprised to see that the article was based on data >10 years old and that the report did not even mention the Needham and Morzillo (2011) survey from Oregon that looked at such parallel issues with contrasting results. I was especially disheartened to see that the study did not address in any way the successful use of flow devices that has made …


Validation Of A 'Displacement Tomography' Inversion Method For Modeling Sheet Intrusions, Sarah J. Menassian Jan 2013

Validation Of A 'Displacement Tomography' Inversion Method For Modeling Sheet Intrusions, Sarah J. Menassian

Dissertations, Master's Theses and Master's Reports - Open

The study of volcano deformation data can provide information on magma processes and help assess the potential for future eruptions. In employing inverse deformation modeling on these data, we attempt to characterize the geometry, location and volume/pressure change of a deformation source. Techniques currently used to model sheet intrusions (e.g., dikes and sills) often require significant a priori assumptions about source geometry and can require testing a large number of parameters. Moreover, surface deformations are a non-linear function of the source geometry and location. This requires the use of Monte Carlo inversion techniques which leads to long computation times. Recently, …


Computational Prediction Of The Sporulation Network In Clostridium Thermocellum, Changyi Jiang Jan 2013

Computational Prediction Of The Sporulation Network In Clostridium Thermocellum, Changyi Jiang

Dissertations, Master's Theses and Master's Reports - Open

Sporulation is a process in which some bacteria divide asymmetrically to form tough protective endospores, which help them to survive in a hazardous environment for a quite long time. The factors which can trigger this process are diverse. Heat, radiation, chemicals and lacking of nutrition can all lead to the formation of endospores. This phenomenon will lead to low productivity during industrial production. However, the sporulation mechanism in a spore-forming bacterium, Clostridium theromcellum, is still unclear. Therefore, if a regulation network of sporulation can be built, we may figure out ways to inhibit this process. In this study, a …


A Comparison Of Pixel-Based Versus Object Oriented Analysis Of Landslides Using Historical Remote Sensing Data, Ren N. Keyport Jan 2013

A Comparison Of Pixel-Based Versus Object Oriented Analysis Of Landslides Using Historical Remote Sensing Data, Ren N. Keyport

Dissertations, Master's Theses and Master's Reports - Open

With recent advances in remote sensing processing technology, it has become more feasible to begin analysis of the enormous historic archive of remotely sensed data. This historical data provides valuable information on a wide variety of topics which can influence the lives of millions of people if processed correctly and in a timely manner. One such field of benefit is that of landslide mapping and inventory. This data provides a historical reference to those who live near high risk areas so future disasters may be avoided. In order to properly map landslides remotely, an optimum method must first be determined. …


An Exploration Of The Development And Proliferation Of Hydraulic Fracturing, Ellee G. Cook, Travis Dodson, Kara Shervanick, Alice Whitten Jan 2013

An Exploration Of The Development And Proliferation Of Hydraulic Fracturing, Ellee G. Cook, Travis Dodson, Kara Shervanick, Alice Whitten

Environmental Studies Student Works

No abstract provided.


Water Conservation In San Antonio, Tx: The Economics Of Water Pricing And The Effectiveness Of The Watersaver Landscape Rebate, Mark Wilkinson, Mitch Hagney, Yemi Idowu, Megan Miller Jan 2013

Water Conservation In San Antonio, Tx: The Economics Of Water Pricing And The Effectiveness Of The Watersaver Landscape Rebate, Mark Wilkinson, Mitch Hagney, Yemi Idowu, Megan Miller

Earth and Environmental Geosciences Student Works

We address the effort to decrease residential water use in San Antonio, Texas, because recent droughts have made water conservation a high priority there. Since the city’s water utility—the San Antonio Water System (SAWS)—maintains water prices below economically efficient levels, demand is outstripping supply. To address this problem, we apply microeconomic analysis to the utility’s residential water pricing structure and the drought restrictions it imposes. We make recommendations for incentivizing water conservation in high-volume consumers by increasing the progressivity of SAWS pricing policies. SAWS also offers water conservation rebates, such as the WaterSaver Landscape Rebate, whose effectiveness we analyze herein. …


Exploring The Future Of Friesenhahn Cave, Dylana Watford, Katherine Banick, Graham Bates, Tori Carey Jan 2013

Exploring The Future Of Friesenhahn Cave, Dylana Watford, Katherine Banick, Graham Bates, Tori Carey

Earth and Environmental Geosciences Student Works

Friesenhahn Cave in San Antonio, Texas, offers a wealth of paleontological artifacts. The cave is owned by Concordia University and is primarily managed by Dr. Laurence Meissner, professor of biology at Concordia. Since its discovery in the early twentieth century, researchers have discovered numerous Pleistocene fossils; aside from the La Brea Tar Pits in California, Friesenhahn Cave is the most Pleistocene fossil-rich site in the United States. Recently, little research has been conducted in the cave, though it is believed that many fossils remain to be discovered. We propose the establishment of the Friesenhahn Cave Foundation, a non-profit organization whose …


Temperature And Pressure Conditions Of Archean Amphibolite-Granulite Facies Metamorphic Xenoliths From The Eastern Beartooth Mountains, Montana And Wyoming, Usa, Celina N. Will Jan 2013

Temperature And Pressure Conditions Of Archean Amphibolite-Granulite Facies Metamorphic Xenoliths From The Eastern Beartooth Mountains, Montana And Wyoming, Usa, Celina N. Will

LSU Master's Theses

Compositionally-diverse Archean metamorphic rocks occur as xenoliths within the well-dated 2.8 Ga granitic gneisses that volumetrically-dominate the eastern Beartooth Mountains of the northern Wyoming Province. Common mafic lithologies in the Quad Creek-High Line Trails-Christmas Lake-Wyoming Creek-Line Creek Plateau area include granitic gneiss, amphibolites, mafic granulites and biotite and garnet-bearing peraluminous gneisses. The region also has sillimanite-biotite ± cordierite ± garnet gneisses and migmatites, as well as a single occurrence of a noteworthy orthopyroxene-cordierite gneiss with late-stage anthophyllite. A combination of detailed petrographic analysis and thermobarometric modeling were used to constrain the metamorphic conditions of the xenoliths prior to inclusion in …


Geol 440/840: Tectonics—A Peer Review Of Teaching Project Inquiry Portfolio, Caroline M. Burberry Jan 2013

Geol 440/840: Tectonics—A Peer Review Of Teaching Project Inquiry Portfolio, Caroline M. Burberry

UNL Faculty Course Portfolios

This document is a follow-up document to the Benchmark Portfolio for this course, created in 2012. It details the changes made to the course following the observations from the Benchmark Portfolio and demonstrates that discussion of the metacognitive issues surrounding critical thinking does have some effect on increasing student learning. The document concludes with changes which will be made to the 2014 iteration of the class, to continue this inquiry and improvement process.


Geol 106: Environmental Geology—A Peer Review Of Teaching Project Benchmark Portfolio, Leilani Arthurs Jan 2013

Geol 106: Environmental Geology—A Peer Review Of Teaching Project Benchmark Portfolio, Leilani Arthurs

UNL Faculty Course Portfolios

The Peer Review of Teaching (PRT) program provides faculty members the environment, support, structure, and time to carefully think about how they teach a particular course. PRT benchmark portfolios are prepared as a part of this program to assist faculty members in reflecting on and documenting their instructional practices and the potential impact they have on student learning.

This benchmark portfolio targets the Spring 2013 semester of GEOL 106: Environmental Geology. It documents the course objectives that provided the foundation for the instructional approach, the course-level learning goals that defined what students should be able to do by the end …


Ballistics Analysis Of Volcanic Ejecta: Miter Crater, Ice Springs Volcanic Field, Black Rock Desert, Utah, William Cary Jan 2013

Ballistics Analysis Of Volcanic Ejecta: Miter Crater, Ice Springs Volcanic Field, Black Rock Desert, Utah, William Cary

Senior Independent Study Theses

Ice Springs Volcanic Field, located in the Black Rock Desert west of Fillmore, Utah, is composed of three large craters, Crescent, Miter, and Terrace, and several smaller craters. Concern over the hazards of the volcanic field, ±660 years old, reactivating prompted the creation of a hazards model. This study focuses on Miter Crater in order to conduct a ballistic analysis of the blocks and bombs observed along the crater rim. Data analysis of Miter Crater ejecta was then used to create a hazards model for ballistic volcanic ejecta. Thirty-four blocks and bombs were recorded along the rim of Miter Crater. …


Olivine Ca Content Measured By Icp-Oes To Estimate P-T, Bradley Benavides Jan 2013

Olivine Ca Content Measured By Icp-Oes To Estimate P-T, Bradley Benavides

Open Access Theses & Dissertations

Ca is a trace element in olivine and its concentration is pressure and temperature dependent, providing a rare opportunity to estimate pressure conditions at which mantle-derived rocks (xenoliths) last equilibrated. This P-T dependence has previously been calibrated for mantle xenoliths, and we applied this technique to samples from Jasper Seamount (Jasper Seamount), an oceanic intraplate volcano (OIV) off the coast of the Baja California Peninsula of Mexico. Preliminary compositions for xenoliths from this location appear to define a magmatic plumbing system that features magma storage near the bottom of the crust. A more detailed analysis of the samples is required …


Rare Earth Element Geochemistry Of The Sierra Blanca Laccoliths, Texas, Amed Gomez Jan 2013

Rare Earth Element Geochemistry Of The Sierra Blanca Laccoliths, Texas, Amed Gomez

Open Access Theses & Dissertations

No abstract provided.


In-Situ, Integrated U-Pb, Hf And O Isotopic Study Of Igneous, Metamorphic And Detrital Zircons. Implications To Crustal Evolution And Geodynamics, Munazzam Ali Mahar Jan 2013

In-Situ, Integrated U-Pb, Hf And O Isotopic Study Of Igneous, Metamorphic And Detrital Zircons. Implications To Crustal Evolution And Geodynamics, Munazzam Ali Mahar

Open Access Theses & Dissertations

Zircon data from South Karakoram gneiss dome provide evidence for Proterozoic inherited cores (1.8-1.9 Ga and 2.3-.2.5 Ga) surrounded by migmatitic overgrowth with ages ranging from ~6 to ~20Ma. Oxygen isotopic data of Neogene migmatite and inherited core is similar and indistinguishable ranging from 7.5 to 9.5 /. However, Neogene overgrowth is significantly less evolved than the inherited core in terms of Hf composition. This implies that the Hf composition of the migmatitic zircons is not controlled exclusively by the dissolution of the inherited cores and that contamination by external melts is likely. Isotopic data from the Baltoro plutonic unit …


The Eolian-Sabkha Transition In The Permian Cedar Mesa Sandstone, Se Utah, Alexandra Massad Jan 2013

The Eolian-Sabkha Transition In The Permian Cedar Mesa Sandstone, Se Utah, Alexandra Massad

Open Access Theses & Dissertations

This study focuses on the depositional transition between the Permian Cedar Mesa sand dune sea and the adjoining fluvial, lacustrine, playa and a sabkha facies. This transition provides insights into how climate and environment interacted in this unique setting where up to 300 m of eolian sands transition into evaporites. The evaporites are less common as tongues within the eolianites than previously thought and there were several environments that were observed that haven't been previously described or observed in the Cedar Mesa. The arrangement of the various units within the study area support the climate control on stratigraphy.

The intertonguing …


Estimating Variations In Locking Depth For The Mojave Segment Of The San Andreas Fault Over The Past 1500 Years From Paleoseismic Stress Drop, Teira Solis Jan 2013

Estimating Variations In Locking Depth For The Mojave Segment Of The San Andreas Fault Over The Past 1500 Years From Paleoseismic Stress Drop, Teira Solis

Open Access Theses & Dissertations

The most fundamental model for characterizing earthquake occurrence [Reid, 1910] assumes a constant stress accumulation rate on a locked fault segment, which eventually fails at a threshold stress level. While this model provides a conceptual framework for investigating the conditions that prepare a fault for failure, there is little evidence that faults rupture periodically or at a uniform threshold stress. Moreover, this model fails to explain the large differences in earthquake recurrence intervals and paleoseismic slip for segments of major fault systems: why do some faults rupture on the order of 10's of years, while others require 100's of years …


Software Development For A 3d Gravity Inversion And Application To Study Of The Border Ranges Fault System, South-Central Alaska, Rolando Cardenas Jan 2013

Software Development For A 3d Gravity Inversion And Application To Study Of The Border Ranges Fault System, South-Central Alaska, Rolando Cardenas

Open Access Theses & Dissertations

The Border Ranges Fault System (BRFS) bounds the Cook Inlet and Susitna Basins, and is an important petroleum province within south-central Alaska. A primary goal of our research is to test several plausible models of structure along the BRFS using a novel three-dimensional inversion technique utilizing gravity data, constrained with other geophysical, borehole and surface geological information. This research involves the development of 3D inversion modeling software using C++ Builder from Embarcadero's XE2 Suite. The novel inversion approach directly models known geology with a priori uncertainties assigned to the geologic model to allow researchers to compare alternative interpretations. This technique …