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2020

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Articles 2941 - 2970 of 3204

Full-Text Articles in Earth Sciences

Detecting Groundwater Discharge In The Clark Fork River Near Stone Container Using Spectral Alpha Decay Detection For Dissolved Radon In Surface Water Samples Abstract, Daniel William Forsland Jan 2020

Detecting Groundwater Discharge In The Clark Fork River Near Stone Container Using Spectral Alpha Decay Detection For Dissolved Radon In Surface Water Samples Abstract, Daniel William Forsland

Undergraduate Theses, Professional Papers, and Capstone Artifacts

Radon-222 (222Rn) was measured along 8.7 kilometers of the Clark Fork River, between Harper’s Bridge and Frenchtown, MT. Twelve water samples were taken along the stretch. Samples 1 through 4 and 10 through 12 were collected on a 1 km interval, samples 5 through 9 were taken on a 500 meter interval. Samples were analyzed for dissolved 222Rn using a RAD7 spectral alpha decay detector. Instream 222Rn was modeled to quantify groundwater discharge to the river. Literature on the Missoula Valley aquifer was analyzed, revealing an alluvial aquifer system to the east consisting of interbedded gravel, …


Reconstruction Of The 2018 Anak Krakatau Collapse Using Planetscope Imaging And Numerical Modeling, Davide Saviano Jan 2020

Reconstruction Of The 2018 Anak Krakatau Collapse Using Planetscope Imaging And Numerical Modeling, Davide Saviano

Dissertations, Master's Theses and Master's Reports

The study was focused on the Anak Krakatau sector collapse that occurred on 22 December 2018 in the Sunda Strait (Indonesia). The goal of the study was to monitor and analyze changes of the volcanic edifice and to try to understand causes that may have predisposed and triggered the sector collapse.

The use of different remote sensing techniques allowed the acquisition of thermal data, SO2 emission data, structural data and the identification and analysis of the eruptive events that occurred on Anak Krakatau in the period from 1° January 2016 to 28 February 2019. The acquisition of 1221 thermal …


Stable Carbon And Oxygen Isotopes As Environmental Indicators Of The Late Pleistocene Inel Arenoso, Sonora, Northwest Mexico, Victor Adrian Perez Crespo, Tamara Cruz Y Cruz, Alejandro Terrazas Mata, Pedro Morales Puente, Martha Benavente, Edith Cienfuegos-Alvrado, Francisco J. Otero Jan 2020

Stable Carbon And Oxygen Isotopes As Environmental Indicators Of The Late Pleistocene Inel Arenoso, Sonora, Northwest Mexico, Victor Adrian Perez Crespo, Tamara Cruz Y Cruz, Alejandro Terrazas Mata, Pedro Morales Puente, Martha Benavente, Edith Cienfuegos-Alvrado, Francisco J. Otero

Turkish Journal of Earth Sciences

The paleoenvironment conditions that existed in the Late Pleistocene at the archaeological-paleontological site of El Arenoso, Sonora, NW Mexico, were inferred using the carbon and oxygen stable isotopes from one bison, one mammoth, and thirteen horses as well as the pedological characteristics and the carbon isotopes of calcium carbonates from paleosoil. The values δ13C of the bison (-1.4‰), the horses (-2.8‰), and the mammoth (-4.3‰) show that these animals fed mainly on C4 plants and carbon isotopic values from profile horizons of locality 4Bgk (-3.4‰), 3Ck (-3.4‰), and 2Bgk2 (-5.7‰) indicated the presence of C3/C4 vegetation mixed in El Arenoso. …


Rheological Behaviour In Continental And Oceanic Subduction:Inferences For The Seismotectonics Of The Aegean Region, Massimiliano Maggini, Riccardo Caputo Jan 2020

Rheological Behaviour In Continental And Oceanic Subduction:Inferences For The Seismotectonics Of The Aegean Region, Massimiliano Maggini, Riccardo Caputo

Turkish Journal of Earth Sciences

We reconstructed several rheological transects across the Aegean Region, comparing the behaviour in collisional versus subducting settings. We interpolated closely spaced 1D strength envelopes, realized through a dedicated MATLAB script, for determining the shallow lithospheric distribution of brittle and ductile layers. We mainly used literature data and geodynamic considerations to fix the parameters for the rheological modelling and took particular care in reproducing reliable thermal models. The results of the mechanical-rheological model highlighted the following features and differences between the northern continental collision and the southern oceanic subduction settings: i) a slightly shallower brittle-ductile transition (BDT) in the western sectors …


Paleoecological Insights On Latest Oligocene-Early Miocene Planktonic Foraminifera From The J-Anomaly Ridge (Iodp Hole U1406a), Alessio Fabbrini, Luca Maria Foresi Jan 2020

Paleoecological Insights On Latest Oligocene-Early Miocene Planktonic Foraminifera From The J-Anomaly Ridge (Iodp Hole U1406a), Alessio Fabbrini, Luca Maria Foresi

Turkish Journal of Earth Sciences

This paper focuses on a paleoecological study conducted on planktonic foraminifera from upper Oligocene-lower Miocene deposits of the J-Anomaly Ridge (North Atlantic Ocean). Paleoclimatic studies are crucial to better comprehend how climatic changes occurred in the past and how they might influence global climate in the next few decades. Oceanic currents are the predominant vehicle for heat transport across the globe and therefore organisms living within the water mass can supply much information on paleoceanographic settings. In total, 53 samples from IODP Hole U1406A were selected in the core interval 96-24 CCSF-M to perform statistical analyses (R-mode cluster analysis, principal …


Determining The Lake Protected Zones Using Gis-Based Drastic Model To Groundwatervulnerability In Salda Lake Basin (Burdur/Turkey), Si̇mge Varol, Ayşen Davraz, Erhan Şener, Şehnaz Şener, Fatma Aksever, Bülent Kirkan, Ahmet Tokgözlü Jan 2020

Determining The Lake Protected Zones Using Gis-Based Drastic Model To Groundwatervulnerability In Salda Lake Basin (Burdur/Turkey), Si̇mge Varol, Ayşen Davraz, Erhan Şener, Şehnaz Şener, Fatma Aksever, Bülent Kirkan, Ahmet Tokgözlü

Turkish Journal of Earth Sciences

Groundwater quality is a crucial parameter for sustainable wetland management. The evaluation of the aquifer vulnerability is important for the protection of groundwater resources. The DRASTIC model is the most significant technique for the assessment of aquifer vulnerability. This study aimed to build a vulnerability map for groundwater of the Salda Lake wetland basin by DRASTIC method in a GIS environment. Seven environmental parameters (depth to water table, net recharge, aquifer media, soil media, topography, impact of the vadose zone media, and hydraulic conductivity of the aquifer) were used in the DRASTIC method and GIS was used to constitute a …


Daily Variations In Stratification In İzmit Bay, Hüsne Altiok, Lalehan Can, Sabri̇ Mutlu Jan 2020

Daily Variations In Stratification In İzmit Bay, Hüsne Altiok, Lalehan Can, Sabri̇ Mutlu

Turkish Journal of Earth Sciences

We studied the diurnal variation of stratification in İzmit Bay with temperature and current velocity, and investigated the influence of atmospheric conditions. In the east of the bay entrance, 10-min temperature and hourly current measurements were made between the dates of 4 February 2015 and 24 April 2015, down to about 40 m depth in the water column. In addition to this, hourly temperature and salinity with depth data were collected between the dates of 4 and 7 February 2015 by a research vessel. The meteorological parameters for the atmospheric conditions were obtained from the closest weather stations (Yalova, Çınarcık, …


Nature Of Clays In Late Cretaceous Dacitic Rocks In The Eastern Sakarya Zone (Ne Turkey):A Geochemical And Isotopic Approach, Ferkan Si̇pahi̇, Mehmet Ali̇ Gücer, Münür Burhan Sadiklar Jan 2020

Nature Of Clays In Late Cretaceous Dacitic Rocks In The Eastern Sakarya Zone (Ne Turkey):A Geochemical And Isotopic Approach, Ferkan Si̇pahi̇, Mehmet Ali̇ Gücer, Münür Burhan Sadiklar

Turkish Journal of Earth Sciences

Late Cretaceous felsic rocks are common in the eastern Pontides (NE Turkey). These rocks developed as an island arc from the Jurassic to the Miocene; they also host numerous volcanogenic massive sulfide deposits. The Late Cretaceous dacites that outcrop around Zigana Mountain (Gümüşhane, NE Turkey) were exposed to intensive hydrothermal alteration. Widespread hydrothermal alteration of Late Cretaceous dacite in Zigana Mountain has led to the formation of well-developed clay minerals. Their main alteration products are sericite, chlorite, and carbonates (ankerite and calcite). The clay minerals identified by X-ray diffraction and differential thermal analysis include illite, chlorite, small amounts of kaolinite, …


Heavy Metal Contamination In Groundwater And Surface Water Due To Active Pb-Zn-Cumine Tails And Water-Rock Interactions: A Case Study From The Küre Mine Area (Turkey), Tülay Ekemen Keski̇n, Emre Özler Jan 2020

Heavy Metal Contamination In Groundwater And Surface Water Due To Active Pb-Zn-Cumine Tails And Water-Rock Interactions: A Case Study From The Küre Mine Area (Turkey), Tülay Ekemen Keski̇n, Emre Özler

Turkish Journal of Earth Sciences

This study aimed at elucidating the groundwater and surface water pollution resulting from water-rock interaction, mine tailings, and mining activities at Küre (Kastamonu) sulfidic Pb-Zn-Cu mine area and its vicinity. The study area has a surface area of approximately 2990 km2. The Küre River drainage site covering the study area is approximately 440 km2. The concentrations of SO4, Al, As, Ba, Mn, Ni, Sb, and Pb in some groundwater (K10, K20, K21, K27, K28, K29, K30), and surface water (KR3) exceed the maximum limit values with respect to the Turkish Standards for Water Intended For Human Consumption and World Health …


New Geosite Candidates From Urla (İzmir, Western Anatolia, Turkey): A List Of Geologicalassets Nested With Antique And Modern Cultural Heritage, Ökmen Sümer, Mehmet Akbulut, Hülya İnaner Jan 2020

New Geosite Candidates From Urla (İzmir, Western Anatolia, Turkey): A List Of Geologicalassets Nested With Antique And Modern Cultural Heritage, Ökmen Sümer, Mehmet Akbulut, Hülya İnaner

Turkish Journal of Earth Sciences

The Urla Basin is an approximately 20 km wide and 30 km long N-S-trending strike-slip basin, located in the westernmost part of the Western Anatolia Extensional Province. Although the basin-fill units are generally composed of sedimentary and volcanic rocks of Miocene to Recent, Triassic and Late Cretaceous-Paleocene sedimentary rocks are also exposed in the middle and western part of the basin. In addition to this geological diversity, the basin hosts many ancient settlements due to its geographical position and close contact with the Aegean Sea. This study mostly focuses on the northern part of the basin with a concentration on …


Altitude Of The Potentiometric Surface In The Mississippi River Valley Alluvial Aquifer, Spring 2018, Virginia L. Mcguire, Ronald C. Seanor, William H. Asquith, Anna M. Nottmeier, David C. Smith, Roland W. Tollett, Wade H. Kress, Kellan R. Strauch Jan 2020

Altitude Of The Potentiometric Surface In The Mississippi River Valley Alluvial Aquifer, Spring 2018, Virginia L. Mcguire, Ronald C. Seanor, William H. Asquith, Anna M. Nottmeier, David C. Smith, Roland W. Tollett, Wade H. Kress, Kellan R. Strauch

United States Geological Survey: Publications

The Mississippi River Valley alluvial (MRVA) aquifer is an important surficial aquifer in the Mississippi Alluvial Plain (MAP) area. The aquifer is generally considered to be an unconfined aquifer (fig. 1; Clark and others, 2011), and withdrawals are primarily used for irrigation (Maupin and Barber, 2005). These groundwater withdrawals have resulted in substantial areas of water-level decline in parts of the aquifer. Concerns about water-level declines and the sustainability of the MRVA aquifer have prompted the U.S. Geological Survey (USGS), as part of the USGS Water Availability and Use Science Program and with assistance from other Federal, State, and local …


Water Quality Of Groundwater Used For Public Supply In Principal Aquifers Of The Western United States, Celia C. Rosencrans, Marylynn Musgrove Jan 2020

Water Quality Of Groundwater Used For Public Supply In Principal Aquifers Of The Western United States, Celia C. Rosencrans, Marylynn Musgrove

United States Geological Survey: Publications

Groundwater provides nearly half of the Nation’s drinking water. As the Nation’s population grows, the importance of (and need for) high-quality drinking-water supplies increases. As part of a national-scale effort to assess groundwater quality in principal aquifers (PAs) that supply most of the groundwater used for public supply, the U.S. Geological Survey National Water-Quality Assessment (NAWQA) Project staff sampled six principal aquifers in the western United States between 2013 and 2017: (1) the Basin and Range carbonate-rock aquifers, (2) Basin and Range basin-fill aquifers, (3) Rio Grande aquifer system, (4) High Plains aquifer, (5) Colorado Plateaus aquifers, and (6) Columbia …


Estimated Groundwater Withdrawals From Principal Aquifers In The United States, 2015, John K. Lovelace, Martha G. Nielsen, Amy L. Read, Chid J. Murphy, Molly A. Maupin Jan 2020

Estimated Groundwater Withdrawals From Principal Aquifers In The United States, 2015, John K. Lovelace, Martha G. Nielsen, Amy L. Read, Chid J. Murphy, Molly A. Maupin

United States Geological Survey: Publications

In 2015, about 84,600 million gallons per day (Mgal/d) of groundwater were withdrawn in the United States for various uses including public supply, self-supplied domestic, industrial, mining, thermoelectric power, aquaculture, livestock, and irrigation. Of this total, about 94 percent (79,200 Mgal/d) was withdrawn from principal aquifers, which are defined as regionally extensive aquifers or aquifer systems that have the potential to be used as sources of water of suitable quality and quantity to meet various needs. The remaining 6 percent (5,400 Mgal/d) was withdrawn from other, nonprincipal aquifers in the United States. Sixty-six principal aquifers belonging to 5 major lithologic …


Estimating Abiotic Thresholds For Sagebrush Condition Class In The Western United States, Stephen Boyte, Bruce K. Wylie, Yingxin Gu, Donald J. Major Jan 2020

Estimating Abiotic Thresholds For Sagebrush Condition Class In The Western United States, Stephen Boyte, Bruce K. Wylie, Yingxin Gu, Donald J. Major

United States Geological Survey: Staff Publications

Sagebrush ecosystems of the western United States can transition from extended periods of relatively stable conditions to rapid ecological change if acute disturbances occur. Areas dominated by native sagebrush can transition from species-rich native systems to altered states where non-native annual grasses dominate, if resistance to annual grasses is low. The non-native annual grasses provide relatively little value to wildlife, livestock, and humans and function as fuel that increases fire frequency. The more land area covered by annual grasses, the higher the potential for fire, thus reducing the potential for native vegetation to reestablish, even when applying restoration treatments. Mapping …


Applied Injected Air Into Subsurface Drip Irrigation: Plant Uptake Of Pharmaceuticals And Soil Microbial Communities, Matteo D'Alessio, Lisa M. Durso, Clinton Williams, Christopher A. Olson, Chittaranjan Ray, Ellen Paparozzi Jan 2020

Applied Injected Air Into Subsurface Drip Irrigation: Plant Uptake Of Pharmaceuticals And Soil Microbial Communities, Matteo D'Alessio, Lisa M. Durso, Clinton Williams, Christopher A. Olson, Chittaranjan Ray, Ellen Paparozzi

Nebraska Water Center: Faculty Publications

The growing global food security crisis is complicated by the need for increased crop production with less arable land and limited water resources. Reuse of treated wastewater for agricultural irrigation is becoming more common, often paired with other conservation measures such as subsurface drip irrigation (SDI). Passively injecting air into SDI systems increases crop yields and overcomes root zone wetting issues. However, when used with treated irrigation water, contaminants in the water might be taken up by the crops. This paper investigates the impact of air-injected water containing caffeine, carbamazepine, and gemfibrozil on plant uptake and soil microbial communities in …


Droughtscape, Winter 2019, Cory Matteson Jan 2020

Droughtscape, Winter 2019, Cory Matteson

DroughtScape: Quarterly Newsletter of the National Drought Mitigation Center (2007–2023)

Contents

From the Director

4th quarter climate summary

2019 year in review summary

4th quarter drought impact summary

2019 drought impact summary

New form helps ‘see more’ drought

Landscape photographers invited to submit photos

Helping Central and South America planning

Database includes more drought planning


Phytoremediation Of Saline-Sodic Soils In East Central South Dakota Utilizing Perennial Grass Mixtures, Douglas J. Fiedler Jan 2020

Phytoremediation Of Saline-Sodic Soils In East Central South Dakota Utilizing Perennial Grass Mixtures, Douglas J. Fiedler

Electronic Theses and Dissertations

Several decades of above average precipitation in South Dakota has increased the area of saline and sodic soils, which reduce crop yields and inhibit sensitive plant growth. Saline and sodic soils are difficult to remediate using traditional agricultural crops. Establishing salt tolerant perennial species may restore productivity to salt affected areas. Two perennial grass mixtures (mix 1: slender wheatgrass, beardless wildrye; mix 2: slender wheatgrass, western wheatgrass, green wheatgrass, creeping meadow foxtail) were dormant frost seeded along a topographic gradient in Clark Co., SD. Soils were Forman-Cresbard loam and a Cresbard-Cavour loam with surface electrical conductivity (EC1:1) that …


Lake Or Estuary? Sedimentary And Benthic Foraminiferal Characterization Of A Gulf Of Mexico Coastal Dune Lake, Kaylyn C. Bellais, Samuel T. Barber, Donald A. Beebe, Murlene W. Clark Jan 2020

Lake Or Estuary? Sedimentary And Benthic Foraminiferal Characterization Of A Gulf Of Mexico Coastal Dune Lake, Kaylyn C. Bellais, Samuel T. Barber, Donald A. Beebe, Murlene W. Clark

Gulf and Caribbean Research

Coastal dune lakes are shallow estuaries located within dune environments that share a permanent or intermittent connection with the sea. Because coastal dune lakes are found in few locations worldwide (e.g. Australia, New Zealand, Florida, etc.) they represent unique environments worthy of protection. However; there is a distinct lack of scientific data related to the function and ecology of coastal dune lakes, especially in the Gulf of Mexico. Therefore, the purpose of this study was to characterize the sedimentology and foraminifera of a representative coastal dune lake in Walton County, FL (i.e. Eastern Lake) and determine whether it shares geologic …


Eocene-Oligocene Succession At Kıyıköy (Midye) On The Black Sea Coast In Thrace, Aral I. Okay, Michael D. Simmons, Ercan Özcan, Stephen Starkie, Michael D. Bidgood, Andrew R.C. Kylander-Clark Jan 2020

Eocene-Oligocene Succession At Kıyıköy (Midye) On The Black Sea Coast In Thrace, Aral I. Okay, Michael D. Simmons, Ercan Özcan, Stephen Starkie, Michael D. Bidgood, Andrew R.C. Kylander-Clark

Turkish Journal of Earth Sciences

A belt of Upper Eocene-Lower Oligocene marine sedimentary rocks extends from Kıyıköy on the Black Sea coast to Pınarhisar in the Thrace Basin, suggesting a marine connection between the Black Sea and the Thrace Basin during this period. The Cenozoic succession of this marine corridor was studied in the vicinity of Kıyıköy along two measured stratigraphic sections. The sequence lies unconformably over metamorphic basement rocks and consists of ~75 m of bioclastic limestone and sandstone of the Soğucak Formation, overlain by ~40 m of limestone, marl, mudstone, sandstone, and acidic tuff, which are assigned to the newly defined Servez Formation. …


Geotechnical Engineering: Particle Size Distribution Of Layered Glacial Lake Columbia And Ice Age Flood Deposits In Latah Valley, Spokane, Wa, Aaron Cleveland, Kassie Allen Jan 2020

Geotechnical Engineering: Particle Size Distribution Of Layered Glacial Lake Columbia And Ice Age Flood Deposits In Latah Valley, Spokane, Wa, Aaron Cleveland, Kassie Allen

2020 Symposium Posters

We collected samples from the Latah Valley in Spokane, WA, of Missoula Flood deposits interbedded with Glacial Lake Columbia Sediments. We conducted tests on these soils according to ASTM standards. We performed Specific Gravity tests according to ASTM D854, and determined particle size distribution for these soils by conducting sieve and hydrometer analyses according to ASTM D422. We then plotted these data to create particle size distribution curves. Specific Gravities for the all of the samples collected range from 2.36 to 2.67. The flood deposits are dominated by coarse sand and gravel and the Glacial Lake Columbia deposits are dominated …


Mariana Serpentinite Mud Volcanism Exhumes Subducted Seamount Materials: Implications For The Origin Of Life, Patricia Freyer, C. G. Wheat, Trevor Williams, Christopher Kelley, Kevin Johnson, Jeffrey Ryan, Walter Kurz, John Shervais, Elmar Albers, Barbara Bekins Jan 2020

Mariana Serpentinite Mud Volcanism Exhumes Subducted Seamount Materials: Implications For The Origin Of Life, Patricia Freyer, C. G. Wheat, Trevor Williams, Christopher Kelley, Kevin Johnson, Jeffrey Ryan, Walter Kurz, John Shervais, Elmar Albers, Barbara Bekins

School of Geosciences Faculty and Staff Publications

The subduction of seamounts and ridge features at convergent plate boundaries plays an important role in the deformation of the overriding plate and influences geochemical cycling and associated biological processes. Active serpentinization of forearc mantle and serpentinite mud volcanism on the Mariana forearc (between the trench and active volcanic arc) provides windows on subduction processes.  Here, we present (1) the first observation of an extensive exposure of an undeformed Cretaceous seamount currently being subducted at the Mariana Trench inner slope; (2) vertical deformation of the forearc region related to subduction of Pacific Plate seamounts and thickened crust; (3) recovered Ocean …


Scientist Of The Week!, Sarah L. Sheffield, Lisette Melendez, Kristin Houdyshell, Mathew Burgos Jan 2020

Scientist Of The Week!, Sarah L. Sheffield, Lisette Melendez, Kristin Houdyshell, Mathew Burgos

School of Geosciences Faculty and Staff Publications

No abstract provided.


Space-Time Hierarchical Clustering For Identifying Clusters In Spatiotemporal Point Data, David S. Lamb, Joni Downs, Steven Reader Jan 2020

Space-Time Hierarchical Clustering For Identifying Clusters In Spatiotemporal Point Data, David S. Lamb, Joni Downs, Steven Reader

School of Geosciences Faculty and Staff Publications

Finding clusters of events is an important task in many spatial analyses. Both confirmatory and exploratory methods exist to accomplish this. Traditional statistical techniques are viewed as confirmatory, or observational, in that researchers are confirming an a priori hypothesis. These methods often fail when applied to newer types of data like moving object data and big data. Moving object data incorporates at least three parts: location, time, and attributes. This paper proposes an improved space-time clustering approach that relies on agglomerative hierarchical clustering to identify groupings in movement data. The approach, i.e., space–time hierarchical clustering, incorporates location, time, and attribute …


Agua Para El Futuro: Estrategia De Seguridad Hídrica Para América Latina Y El Caribe, Fernando Bretas, Guillermo Casanova, Thomas L. Crisman, Antonio Embid, Liber Martin, Fernando Miralles Jan 2020

Agua Para El Futuro: Estrategia De Seguridad Hídrica Para América Latina Y El Caribe, Fernando Bretas, Guillermo Casanova, Thomas L. Crisman, Antonio Embid, Liber Martin, Fernando Miralles

School of Geosciences Faculty and Staff Publications

No abstract provided.


Measuring Functional Urban Shrinkage With Multi-Source Geospatial Big Data: A Case Study Of The Beijing-Tianjin-Hebei Megaregion, Qiwei Ma, Zhaoya Gong, Jing Kang, Ran Tao, Anrong Dang Jan 2020

Measuring Functional Urban Shrinkage With Multi-Source Geospatial Big Data: A Case Study Of The Beijing-Tianjin-Hebei Megaregion, Qiwei Ma, Zhaoya Gong, Jing Kang, Ran Tao, Anrong Dang

School of Geosciences Faculty and Staff Publications

Most of the shrinking cities experience an unbalanced deurbanization across different urban areas in cities. However, traditional ways of measuring urban shrinkage are focused on tracking population loss at the city level and are unable to capture the spatially heterogeneous shrinking patterns inside a city. Consequently, the spatial mechanism and patterns of urban shrinkage inside a city remain less understood, which is unhelpful for developing accommodation strategies for shrinkage. The smart city initiatives and practices have provided a rich pool of geospatial big data resources and technologies to tackle the complexity of urban systems. Given this context, we propose a …


Boosting Computational Effectiveness In Big Spatial Flow Data Analysis With Intelligent Data Reduction, Ran Tao, Zhaoya Gong, Qiwei Ma, Jean-Claude Thill Jan 2020

Boosting Computational Effectiveness In Big Spatial Flow Data Analysis With Intelligent Data Reduction, Ran Tao, Zhaoya Gong, Qiwei Ma, Jean-Claude Thill

School of Geosciences Faculty and Staff Publications

One of the enduring issues of spatial origin-destination (OD) flow data analysis is the computational inefficiency or even the impossibility to handle large datasets. Despite the recent advancements in high performance computing (HPC) and the ready availability of powerful computing infrastructure, we argue that the best solutions are based on a thorough understanding of the fundamental properties of the data. This paper focuses on overcoming the computational challenge through data reduction that intelligently takes advantage of the heavy-tailed distributional property of most flow datasets. We specifically propose the classification technique of head/tail breaks to this end. We test this approach …


Geoscience Videos And Animations: How To Make Them With Your Students, And How To Use Them In The Classroom, Robert J. Stern, Jeff Ryan, Ning Wang, Victor J. Ricchezza, Siloa Willis Jan 2020

Geoscience Videos And Animations: How To Make Them With Your Students, And How To Use Them In The Classroom, Robert J. Stern, Jeff Ryan, Ning Wang, Victor J. Ricchezza, Siloa Willis

School of Geosciences Faculty and Staff Publications

We are in the midst of a “tectonic shift” in the way that undergraduate students want to learn. They will attend lectures and read assignments if they must, but they are especially interested in information that they can receive as videos on their cell phones and other mobile devices (Prensky, 2001; Thomas, 2011). The geosciences are uniquely well-suited to presentation via well-crafted, scientifically robust videos and animations. Geologic processes often take place over thousands to hundreds of millions of years and occur deep under water or within the Earth, where direct observation is not possible. Geology is synonymous with travel: …


Mapping Long-Term Spatiotemporal Dynamics Of Pen Aquaculture In A Shallow Lake: Less Aquaculture Coming Along Better Water Quality, Juhua Luo, Ruiliang Pu, Ronghua Ma, Xiaolong Wang, Xijun Lai, Zhigang Mao, Li Zhang, Zhaoliang Peng, Zhe Sun Jan 2020

Mapping Long-Term Spatiotemporal Dynamics Of Pen Aquaculture In A Shallow Lake: Less Aquaculture Coming Along Better Water Quality, Juhua Luo, Ruiliang Pu, Ronghua Ma, Xiaolong Wang, Xijun Lai, Zhigang Mao, Li Zhang, Zhaoliang Peng, Zhe Sun

School of Geosciences Faculty and Staff Publications

Pen aquaculture is the main form of aquaculture in some shallow lakes in eastern China. It is valuable to map the spatiotemporal changes of pen aquaculture in eutrophic lakes to assess its effect on water quality, thereby helping the relevant decision-making agencies to manage the water quality (WQ) of lakes. In this study, an automatic approach for extracting the pen aquaculture area was developed based on Landsat data. The approach integrates five algorithms, including grey transformation, discrete wavelet transform, fast Fourier transform, singular value decomposition and k-nearest neighbor classification. It was successfully applied in the automatic mapping of the pen …


New Insights Into The 2070calyrbp Pyroclastic Currents At El Misti Volcano (Peru) From Field Investigations, Satellite Imagery And Probabilistic Modeling, Sylvain J. Charbonnier, J.-C. Thouret, Valentin Gueugneau, Robert Constantinescu Jan 2020

New Insights Into The 2070calyrbp Pyroclastic Currents At El Misti Volcano (Peru) From Field Investigations, Satellite Imagery And Probabilistic Modeling, Sylvain J. Charbonnier, J.-C. Thouret, Valentin Gueugneau, Robert Constantinescu

School of Geosciences Faculty and Staff Publications

Pyroclastic currents (PCs) are the most challenging volcanic hazards for disaster planners in populated areas around volcanoes. “El Misti” volcano (5,825 m above sea level), located only 17 km from the city center of Arequipa (>1.1 million inhabitants), South Peru, has produced small-to-moderate volume (<1 km3) PCs with a frequency of 2,000–4,000 years over the past 50 kyr. The most recent Plinian eruption dated at 2070 cal yr BP (VEI 4) has been selected as one of the reference events for the hazard assessment and risk mitigation plan of Arequipa. Associated pumice- and lithic-rich PC deposits were emplaced …


Estimating Dispersal And Evolutionary Dynamics In Diploporan Blastozoans (Echinodermata) Across The Great Ordovician Biodiversification Event, Adriane R. Lam, Sarah L. Sheffield, Nicholas J. Matzke Jan 2020

Estimating Dispersal And Evolutionary Dynamics In Diploporan Blastozoans (Echinodermata) Across The Great Ordovician Biodiversification Event, Adriane R. Lam, Sarah L. Sheffield, Nicholas J. Matzke

School of Geosciences Faculty and Staff Publications

Echinoderms make up a substantial component of Ordovician marine invertebrates, yet their speciation and dispersal history as inferred within a rigorous phylogenetic and statistical framework is lacking. We use biogeographic stochastic mapping (BSM; implemented in the R package BioGeoBEARS) to infer ancestral area relationships and the number and type of dispersal events through the Ordovician for diploporan blastozoans and related species. The BSM analysis was divided into three time slices to analyze how dispersal paths changed before and during the great Ordovician biodiversification event (GOBE) and within the Late Ordovician mass extinction intervals. The best-fit biogeographic model incorporated jump dispersal, …