Earth Sciences Commons^™

The Mechanics Of Initiation And Development Of Thrust Faults And Thrust Ramps, Sarah S. Wigginton, Elizabeth S. Petrie, James P. Evans

Geosciences Faculty Publications

This study integrates the results of numerical modeling analyses based on outcrop studies and structural kinematic restorations to evaluate the mechanics of thrust fault initiation and development in mechanically layered sedimentary rocks. A field-based reconstruction of a mesoscopic thrust fault at Ketobe Knob in central Utah provides evidence of thrust ramp nucleation in competent units, and fault propagation upward and downward into weaker units at both fault tips. We investigate the effects of mechanical stratigraphy on stress heterogeneity, rupture direction, fold formation, and fault geometry motivated by the geometry of the Ketobe Knob thrust fault in central Utah; the finite …

Rising Demand For Meat And Milk In Developing Countries: Implications For Grasslands-Based Livestock Production, C. L. Delgado

IGC Proceedings (1977-2023)

Key points

1. Meat and milk consumption in developing countries has grown three times as fast as in developed countries over the past 30 years.

2. By 2020, developing countries will consume 72 million metric tons (mmt) more meat and 152 mmt more milk compared to 2002/3, dwarfing developed-country increases of 9 mmt for meat and 18 mmt for milk.

3. Ruminant livestock will account for 27% of the increase in global meat consumption between 2003 and 2020, up from 23% over the previous two decades.

4. The inflation-adjusted prices of livestock and feed grains are expected to fall only …

Grassland In Ireland And The Uk, Myles Rath, S. Peel

IGC Proceedings (1977-2023)

Key points

1. Grassland is the dominant land use option in Ireland and the UK, and is characterised by a long growing season.

2. Dynamic, interactive systems of grassland management have been developed which combine high grass dry matter intakes with good sward quality. In the better grassland areas milk yields in excess of 7000 kg/cow are attainable with low levels of concentrate supplementation.

3. In the times to come, measures to protect the environment will constrain stocking rates, and fertiliser and manure use on intensive grassland enterprises.

4. A high proportion of beef and sheep farms participate in voluntary, …

Simulation Of Infrasonic Acoustic Wave Imprints On Airglow Layers During The 2016 M7.8 Kaikoura Earthquake, P. A. Inchin, J. Aguilar Guerrero, J. B. Snively, Y. Kaneko

Publications

Simulations of hypothesized but unobserved mesopause airglow (MA) disturbances generated by infrasonic acoustic waves (IAWs) during the 2016 M7.8 Kaikoura earthquake are performed. Realistic surface displacements are calculated in a forward seismic wave propagation model and incorporated into a 3-D nonlinear compressible neutral atmosphere model as a source of IAWs at the surface-air interface. Inchin et al. (2021), https://doi.org/10.1029/2020av000260 previously showed that Global Positioning System-based total electron content (TEC) observations can be used to constrain the finite-fault kinematics of the Kaikoura earthquake. However, due to limitations of Global Navigation Satellite System network coverage and coalescence of nonlinear IAW fronts, they …

Analysis Of Groundwater Recharge In Mongolian Drylands Using Composite Vadose Zone Modeling, Khulan Batsukh, Vitaly A. Zlotnik, Paolo Nasta

Department of Earth and Atmospheric Sciences: Faculty Publications

Knowledge of groundwater recharge (GR) is important for the effective management of water resources under semi-arid continental climates. Unfortunately, studies and data in Mongolia are limited due to the constraints in funding and lack of research infrastructures. Currently, the wide accessibility of freely available global-scale digital datasets of physical and chemical soil properties, weather data, vegetation characteristics, and depths to the water table offers new tools and basic information that can support low-cost physically based and process-oriented models. Estimates of GR over 41 study sites in Mongolia were obtained using HYDRUS-1D in a 2-m-thick soil profile with root …

New Hampshire Continental Shelf Geospatial Database: Surficial Geology Maps And Sediment Grain Size Data, Larry G. Ward, Zachary S. Mcavoy, Rachel C. Morrison

Data Catalog

The “New Hampshire Continental Shelf Geospatial Database: Surficial Geology Maps and Sediment Grain Size Data” consists of high-resolution surficial geology maps of the continental shelf off New Hampshire to Jeffreys Ledge in the Western Guff of Maine (WGOM) and supporting sediment grain size information. The surficial geology maps cover ~3,250 km² (Figure 1). The maps depict three different classifications based on the Coastal and Marine Ecological Classification Standards (CMECS; FGDC, 2012): Geoforms (major morphologic or physiographic features; Figure 2; Table 1), Geologic Substrate Subclass (Figure 3; Table 2), and Geologic Substrate Group (Figure 4; Table 2). The maps are …

Evidence For Short Temporal Atmospheric Variations Observed By Infrasonic Signals: 1. The Troposphere, G. Averbuch, M. Ronac-Giannone, S. Arrowsmith, J. F. Anderson

Geosciences Faculty Publications and Presentations

Infrasound monitoring is used in the forensic analysis of events, studying the physical processes of sources of interest, and probing the atmosphere. The dynamical nature of the atmosphere and the use of infrasound as a forensic tool lead to the following questions; (1) what is the timescale of atmospheric variability that affects infrasonic signals? (2) how do infrasound signals vary as a function of time? This study addresses these questions by monitoring a repetitive infrasound source and its corresponding tropospheric returns 54 km away. Source-receiver empirical Green's functions are obtained every 20 s and used to demonstrate the effect of …

Developing A Soil Column System To Measure Hydrogeophysical Properties Of Unconsolidated Sediment, Taylor Bienvenue, Jing Xie, Qifei Niu

Geosciences Faculty Publications and Presentations

Geophysical methods have been increasingly used to characterize the Earth's critical zone (CZ) and monitor hydrological processes occurring within it. For a quantitative interpretation, geophysical studies of CZ materials are necessary, and thus require more sophisticated laboratory setups. In this study, we develop a hydrogeophysical soil column system to measure key hydraulic and electrical properties of regolith in CZs. The developed soil column system consists of two components: (a) a novel hydrogeophysical probe that measures pore water pressure and electrical potential in soils and (b) a cylindrical cell to hold soil samples. The system can be arranged to perform both …

Co-Seismic And Post-Seismic Deformation For The 1995 Colima–Jalisco And 2003 Tecoman Thrust Earthquakes, Mexico Subduction Zone, ́ From Modelling Of Gps Data, Beatriz Cosenza-Muralles, Charles Demets, O. Sanchez, Enrique Cabral-Cano, J. Stock, B. Márquez-Azúa, Robert Mccaffrey

Geology Faculty Publications and Presentations

We invert ∼25 yr of campaign and continuous Global Positioning System daily positions at 62 sites in southwestern Mexico to estimate co-seismic and post-seismic afterslip solutions for the 1995 M_w = 8.0 Colima–Jalisco and the 2003 M_w = 7.5 Tecomán earthquakes, and the long-term velocity of each GPS site. Estimates of the viscoelastic effects of both earthquakes from a 3-D model with an elastic crust and subducting slab, and linear Maxwell viscoelastic mantle are used to correct the GPS position time-series prior to our time-dependent inversions. The preferred model, which optimizes the fit to data from several years …

Hydrologic Profiles And Geospatial Trend Analysis Evaluating Recurrent Flooding At Coastal U.S. Air Force Installations, Dylan D. Bechen

Theses and Dissertations

Military installations are exposed to numerous threats, including a changing climate and the risk of recurrent flooding. The four components of recurrent flooding are sea-level rise, tidal fluctuations, storm surges, and precipitation. This research analyzed 40 years of historical precipitation and tidal data at 17 coastal U.S. Air Force installations using indicators of both peak and threshold exceedances to identify long-term temporal trends in the hydrologic components that make up recurrent flood risk, establishing an installation’s “hydrologic profile” which can be used to better inform decision makers when evaluating portfolio-wide adaptation strategies and prioritization of long-term infrastructure investments.

Irrigation’S Impact On A Precipitation Event During Grainex In Nebraska, Usa, Daniel Whitesel

School of Natural Resources: Dissertations, Theses, and Student Research

Numerous precipitation events were observed during the Great Plains Irrigation Experiment (GRAINEX). However, the precipitation event that was observed the morning of 23 July 2018 is the focus of this thesis. Six experiments were conducted which involved increasing or decreasing soil moisture by 5% increments over the irrigated cropland. An additional experiment, which changed the irrigated land use to grassland, showed precipitation increases. It was found that regardless of strength of irrigation, average precipitation decreased. Average precipitation decreased by up to 72% when irrigation increased compared to the control simulation and decreased by up to 85% when irrigation decreased compared …

Toward The Understanding Of The 2018 Arnold, Ne Earthquake Cluster: Relocation Of Hypocenters And Establishment Of New Gravity Base Stations, Kris Guthrie

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

In 2018, 27 unexpected earthquakes occurred in central Nebraska near Arnold. These earthquakes have no readily apparent cause and no evidence of the responsible fault system is seen at the surface. A joint analysis of vintage, regional gravity and magnetic datasets before the first earthquake revealed a lineament that could represent a pre-existing fault system. New high resolution potential fields data are needed to confidently map the subsurface features around the cluster. To design a survey and collect the data, the following tasks need to be addressed: [1] The earthquakes’ hypocenters need to be improved (relocated) to increase the efficiency …

Soil Chemistry And Clay Mineralogy Of An Alluvial Chronosequence From The North Carolina Sandhills Of The Upper Coastal Plain, Usa, Bradley E. Suther, David S. Leigh, Larry T. West

Faculty Articles

Temporal changes in soil development were assessed on fluvial terraces of the Little River in the upper Coastal Plain of North Carolina. We examined five profiles from each of six surfaces spanning about 100,000 years. Soil-age relationships were evaluated with inter-surface clay mineral comparisons and regression of chemical properties versus previously reported optically-stimulated luminescence ages using the most developed subsoil horizon per profile. Bases to alumina (Bases/Al2 O3 ) ratios have negative correlations with age, whereas dithionite-Fe (FeD ) concentrations are positively correlated with time and differentiate floodplain (BP) from terrace (≥10 ± 2 ka) soils and T4 pedons (75 …

Contrasting Styles Of Inter-Caldera Volcanism In A Peralkaline System: Case Studies From Pantelleria (Sicily Channel, Italy), Pierangelo Romano, John C. White, Silvio G. Rotolo, Nina J. Jordan, Rosolino Cirrincione, Giovanni De Giorgio, Patrizia Fiannacca, Epifanio Vaccaro

EKU Faculty and Staff Scholarship

The recent (<190 ka) volcanic history of Pantelleria is characterized by the eruption of nine peralkaline ignimbrites, ranging in composition from comenditic trachyte to comendite to pantellerite. The ~46 ka Green Tuff (GT) was the last of these ignimbrites, which was followed by many effusive and explosive low-volume eruptions of pantellerite from vents within the caldera moat and along the caldera rim. Although recent studies have shed additional light on the age, petrochemistry, and volcanology of the older ignimbrites, there is very little knowledge of magmatism that occurred between these older ignimbrites, primarily due to the very scarce exposures. In this paper, we present new field descriptions and geochemical data for three local peralkaline centers never studied before, two pre-GT and one post-GT, which share a similar setting with respect to the caldera scarps but differ in terms of their age, composition, and eruptive style. These centers include: (i) the older (~125 ka) Giache center (comenditic trachyte), (ii) the ~67 ka Attalora center (comendite, pantellerite), and (iii) the younger (~14 ka) Patite center (pantellerite).

Comparative Evaluation Of Physicochemical And Fermentative Responses Of Three Sorghum Varieties From Dryland And Irrigated Land And The Properties Of Proteins From Distillers’ Grains, Jikai Zhao, Thomas Weiss, Zhenjiao Du, Shan Hong, Scott R. Bean, Yonghui Li, Donghai Wang

School of Earth, Environmental, & Marine Sciences Faculty Publications

Three sorghum varieties [waxy sorghum (WS), high protein sorghum (HPS), and normal sorghum (NS)] grown under dryland and irrigated conditions were evaluated with respect to the physicochemical and fermentative properties. The proteins were extracted from wet distillers' grains with solubles (WDGS) and characterized in terms of purity and in vitro digestibility. Starch, crude protein, crude fat, and fiber contents of the sorghums ranged from 64.16 to 68.05 g/100 g, 11.49–13.54 g/100 g, 2.45–2.98 g/100 g, and 1.62–1.80 g/100 g, respectively. For the same variety, the sorghums grown under dryland conditions had higher protein (0.33–0.91 g/100 g) and lower …

Comparative Assessment Of Pollutant Concentrations And Meteorological Parameters From Tceq Cams Sites At Houston And Rio Grande Valley Regions Of Texas, Usa In 2016, Esmeralda Mendez, Jonathan Rodriguez, August Luna, Amit U. Raysoni

School of Earth, Environmental, & Marine Sciences Faculty Publications

Spatial and temporal heterogeneity in pollutant concentrations exists at the intra-urban level. In this research work, the concentrations of various pollutants and meteorological parameters are characterized between various central ambient monitoring sites at Houston, TX, and the Rio Grande Valley Regions of South Texas. Meteorological (temperature, relative humidity, wind speed and direction) and pollutant (O3, SO2, CO, NO2, and various PM species) concentrations were downloaded from the appropriate Texas Commission on Environmental Quality (TCEQ) Central Ambient Monitoring Station (CAMS) sites for the year 2016. Correlation Analyses and Coefficient of Divergence (COD) analyses suggest that statistically significant differences occur between the …

Now You See Me: “First” Records Of The Greater Amberjack Seriola Dumerili At Rapa Nui Range Extension Or Increased Scientific Effort?, Naiti Morales, Amy Rose Coghlan, Erin E. Easton, Alan M. Friedlander, James J. Herlan, Carlos F. Gaymer

School of Earth, Environmental, & Marine Sciences Faculty Publications

We report new records of the fisheries-harvested subtropical greater amberjack Seriola dumerili for the south-east Pacific Ocean. Previously, only one species of Seriola (the yellowtail amberjack Seriola lalandi) was scientifically recorded for Rapa Nui (also known as Easter Island) despite local fishers' asserting that three Seriola morphotypes are found in the region. Here we present the first 'scientific record' of what could be a pre-existing (albeit transient) species of the Rapa Nui ecoregion. Establishing the existing range limits of commercially and ecologically valuable species is key for observing climate-driven distribution shifts, and the inclusion of traditional ecological knowledge is likely …

An Analysis Of The Effects Of Large Wildfires On The Hydrology Of Three Small Catchments In Central Chile Using Tritium-Based Measurements And Hydrological Metrics, Francisco Balocchi, Diego Rivera, José Luis Arumi, Uwe Morgenstern, Donald A. White, Richard P. Silberstein, Pablo Ramírez De Arellano

Research outputs 2022 to 2026

Wildfires are an important disturbance affecting catchments’ soil and hydrological processes within. Wildfires are predicted to increase in both frequency and severity under climate change. Here, we present measurements of tritium (3H) in surface water of three streams before and after the ‘las Máquinas’ megafire of January 2017 in central Chile and streamflow metrics. Mean transit times (MTTs) of water were calculated in three coastal catchments with the Mediterranean climate type, covered by native forest, a mixture of native forest and Pinus radiata D. Don, and P. radiata. Lumped parameter models (LPMs) were used to obtain MTTs. Tritium activities from …

Prolonged Drying Trend Coincident With The Demise Of Norse Settlement In Southern Greenland, Boyang Zhao, Isla S. Castañeda, Jeffrey M. Salacup, Elizabeth K. Thomas, William C. Daniels, Tobias Schneider, Gregory A. De Wet, Raymond S. Bradley

Geosciences: Faculty Publications

Declining temperature has been thought to explain the abandonment of Norse settlements, southern Greenland, in the early 15th century, although limited paleoclimate evidence is available from the inner settlement region itself. Here, we reconstruct the temperature and hydroclimate history from lake sediments at a site adjacent to a former Norse farm. We find no substantial temperature changes during the settlement period but rather that the region experienced a persistent drying trend, which peaked in the 16th century. Drier climate would have notably reduced grass production, which was essential for livestock overwintering, and this drying trend is concurrent with a Norse …

Nebraska Statewide Groundwater-Level Monitoring Report 2021, Aaron R. Young, Mark E. Burbach, Leslie M. Howard, Sue Olafsen Lackey, Robert Matthew Joeckel

Conservation and Survey Division: Faculty and Staff Publications

This report is a synthesis of groundwater-level monitoring programs in Nebraska. It is a continuation of the series of annual reports and maps produced by the Conservation and Survey Division (CSD) of the University of Nebraska in cooperation with the U.S. Geological Survey (USGS) since the 1950s. Groundwater-level monitoring began in Nebraska in 1930 in an effort to survey the state’s groundwater resources and to observe changes in its availability on a continuing basis. The CSD and USGS cooperatively developed, maintained, and operated an observation-well network throughout the state. These two agencies were responsible for collecting and archiving this information, …

Estimation Of The Optimal Nitrogen Dose In A Brachiaria Humidicola-Corn Rotation System In The Colombian Eastern Plains, K. Enciso, S. Burkart

IGC Proceedings (1977-2023)

Improving nitrogen (N) use efficiency by optimizing the N fertilizer application dose is one way to reduce greenhouse gas (GHG) emissions in agriculture and livestock production, especially in higher demanding crops such as corn. Taking a Brachiaria humidicola (Bh)-corn rotation system in the Colombian Eastern Plains, we seek to determine both the optimal economic dose (OED) and the optimal technical dose (OTD) of N, which allow to maximize income at producer level and minimize environmental impacts. This particular rotation system was chosen as research subject given the presence of the residual effect of Biological Nitrogen Inhibition (BNI) in …

Screening And Breeding For Bermudagrass Stem Maggot (Bsm) Resistance Using U.S. Bermudagrass Germplasm, W. F. Anderson, D. Hancock, L. Baxter, W. Hudson, Esteban F. Rios

IGC Proceedings (1977-2023)

Bermudagrass (Cynodon sp.) is an important perennial forage grass grown in many parts of the world. Bermudagrass Stem Maggot (BSM) (Atherigona reversura Villeneuve) is an insect pest that reduces forage yield and nutritive value if it is not controlled. The pest, native to SE Asia, was first documented in North America in 2009 and is now considered invasive. A collection of over 300 forage bermudagrass accessions was evaluated in the field for susceptibility to BSM in 2014 and 2015. Tolerant lines and susceptible checks were then evaluated for yield loss due to BSM in a replicated field study …

What And Who Has Determined Adoption? A Study On Improved Forage Technologies In Colombia From An Agricultural Innovation System (Ais) Perspective, K. Enciso, N. Triana, M. Díaz, S. Burkart

IGC Proceedings (1977-2023)

The complex process behind the adoption of improved forages in Colombia remains largely unexplored. Despite governmental and scientific efforts to promote and disseminate the implementation of improved forages for the sake of sustainable livestock production, local livestock producers continue to extensively use native species and adoption rates of more efficient forages remain low. This study explores the dynamics behind the development and diffusion of improved forage technologies in Colombia, from the 1960's to the present through an Agricultural Innovation Systems (AIS) perspective. Here we map the agents involved, classify the roles they exerted over time and reconstruct the historical context …

From Theory To Practice: What Should We Have In Mind When Building Effective And Sustainable Payments For Ecosystem Services (Pes) Schemes For Silvo-Pastoral Systems? Evidence From Colombia, M. Díaz, K. Enciso, N. Triana, S. Burkart

IGC Proceedings (1977-2023)

In most Latin American countries, payment for ecosystem services (PES) can be a useful strategy for restoration and conservation of the environment, increasing productivity and promoting sustainable development in rural areas. Despite these plausible benefits, PES implementation can be challenging due to the contextual framework in which it takes place (e.g. institutional weakness in the implementation and monitoring stages, limited connectivity among stakeholders, low adoption levels of agricultural technology). This study aims at evaluating PES schemes for silvo-pastoral systems in Colombia by considering six dimensions based on an extensive literature review: policy and governance; social context; environmental context; risks and …

Smallholder Dairy Farmers In The Peruvian Andes Fulfilling The Role Of Extension Agents, C. S. Pinares-Patino, J. Manhire, R. Garcia Ticllacuri, J. L. Bernal Madrid, V. M. Velez Marroquin

IGC Proceedings (1977-2023)

Dairy farming in the Peruvian Andes is mostly undertaken by smallholder farmers (4-6 cows/family) and of relatively recent development. In fact, over the last 2 decades dairy farming at high altitudes (3,500‒4200 masl) has grown rapidly, replacing the camelids and sheep farming that once predominated. Dairying growth has been catalysed by subsides from state and private organizations. It promotes high input systems based on feedlot technology. Compared to sheep and camelids farming, dairying at the Andes does not have yet an inherent local/indigenous knowledge associated to it. High altitude Andean ecosystems pose many constraints for dairy farming (hypoxia and high …

Pastoralists’ Perception Of Poverty: A Case Of The Somali And Turkana Of Northern Kenya, W. P. Watete, Kogi-Makau

IGC Proceedings (1977-2023)

Poverty is a complex phenomenon, without a single definition or standard methods of reducing it. Income based methods of assessing poverty have been shown to have limitations that undermine their application in measuring and attacking poverty among pastoral households. Stages of progress method of poverty assessment was used to assess poverty among pastoral households in Turkana and Mandera Counties of Northern Kenya. Three hundred and three hundred and fifty-four households in Mandera and Turkana Counties respectively were sampled across three different livelihood zones: pastoral, agro-pastoral and off-farm. Accumulation of livestock was regarded as a key indicator of wealth among pastoral …

Pastoralist Conservation: Local Ecological Knowledge And Collective Action For Grassland Conservation In Sierra De Segura (Spain), P. Sanosa-Cols, F. Ravera, F. Dominguez, M. Ventura

IGC Proceedings (1977-2023)

Even if Pastoralism is not practised anymore by a majority of families in the Sierra de Segura (south-eastern Andalusia, Spain), it is still considered a paradigmatic way of life and management of its highlands and a key cultural heritage deeply rooted in local identity. In this article we explore two pastoral communities of this region, Santiago and Pontones, with their body of situated knowledge of the territory and natural resources, which helps pastoralists to organize their livelihoods, while requiring collective organization to manage access to grasslands. Through an ethnographic research based on participant observation and in-depth interviews, we explore the …

Intensification Of Pastoralism As A Driver Of Degradation In The Algerian Steppe, S. Bencherif, P. Manzano

IGC Proceedings (1977-2023)

Land degradation linked to pastoralism use has been a worldwide concern for decades. A biological approach has often been use to understand such phenomena, usually disregarding economic and social factors. Radical transformations of pastoralism at the Algerian steppe constitute a good case study to provide an integrated understanding and to better orient development in other pastoralist areas across the world. Different actions by the public sector since the 1960s, as well as the land legislation adopted and the strong agricultural subventions during 2000-2010, have favored a massive conversion of land and resource management. This translates into conversion of many pastures …

Perceptions Of Rangeland Degradation In The Peruvian Altiplano Dry Puna And Implications, C. Turin, J. Gilles

IGC Proceedings (1977-2023)

The Peruvian altiplano’s dry puna is the main feed source for specialized alpaca pastoralist systems. Experts argue that rangelands are severely degraded and have formulated policies and programs to address this. However, these programs have had little success. This paper presents a qualitative case study of the perceptions of rangeland degradation held in three Aymara communities, by range scientists of academia, personnel of NGOs operating in the region and by government officers. We found that each of these groups had distinct views of the level and causes of degradation in the region. Differences in perceptions undermined cooperation and trust between …

Endangered Sustainable Innovation: Indigenous Milk Hygiene And Preservation Techniques By Maasai Too Valuable To Lose, J. Y. Laffa, C. R. Mcculloch, D. Schoder

IGC Proceedings (1977-2023)

The indigenous Parakuyo Maasai communities of Tanzania are traditional pastoralists who depend on fresh cow’s milk as a staple food. However, the arid climate and a lack of clean water challenge milk production and conventional milk hygiene practices.

By conducting informational interviews in eight Parakuyo Maasai regions and 13 districts of Tanzania we sought to identify the key indigenous plants preferred and establish their traditional manner of use. A semi-structured questionnaire was designed to: (i) determine the plants used, (ii) the parts used, (iii) methods of preparation and utensil smoking, (iv) therapeutic applications and associated health benefits of these plants, …