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Surface Deformation And Induced Seismicity Due To Fluid Injection And Oil And Gas Extraction In Western Texas, Fanghui Deng, Timothy H. Dixon, Surui Xie May 2020

Surface Deformation And Induced Seismicity Due To Fluid Injection And Oil And Gas Extraction In Western Texas, Fanghui Deng, Timothy H. Dixon, Surui Xie

School of Geosciences Faculty and Staff Publications

Texas is experiencing increasing seismicity, likely related to the oil and gas production process. We used satellite InSAR (Interferometric Synthetic Aperture Radar) to monitor surface deformation at three study sites in western Texas with similar geologic characteristics. The deformation data were compared to earthquake distribution, groundwater changes, volumes of produced and injected fluid, and calculated pore pressure change and Coulomb failure stress change to assess causes of deformation and seismicity. Site 1 experienced surface uplift due to fluid injection but no increase in seismicity. The average media properties were estimated based on the deformation using a poroelastic model. Site 2 …


Resolution Of Lava Tubes With Ground Penetrating Radar: The Tubex Project, Sanaz Esmaeili, Sarah Kruse, Sajad Jazayeri, P. Whelley, E. Bell, J. Richardson, W. B. Garry, K. Young May 2020

Resolution Of Lava Tubes With Ground Penetrating Radar: The Tubex Project, Sanaz Esmaeili, Sarah Kruse, Sajad Jazayeri, P. Whelley, E. Bell, J. Richardson, W. B. Garry, K. Young

School of Geosciences Faculty and Staff Publications

Remote sensing surveys of the Moon and Mars show evidence of lava tubes, which are potential safe havens for human crews and their equipment. Ground penetrating radar (GPR) can be used to map tubes because the void/rock interface at tube ceilings and floors strongly reflects radar pulses. We have tested the capacity of GPR to sense lava tube geometry at Lava Beds National Monument in California, USA. GPR and detailed light detection and ranging (LiDAR) data are presented for two tubes: Skull Cave, with a few meters of overburden, diameter ~10–20 m, and a rubbly floor; and Valentine Cave, with …


Biogenic Silica And Organic Carbon Records In Zhoushan Coastal Sea Over The Past One Hundred Years And Their Environmental Indications, Hao Xu, Shangwei Jiang, Jialin Li, Ruiliang Pu, Jia Wang, Wanghai Jin, Longbin Sha, Dongling Li May 2020

Biogenic Silica And Organic Carbon Records In Zhoushan Coastal Sea Over The Past One Hundred Years And Their Environmental Indications, Hao Xu, Shangwei Jiang, Jialin Li, Ruiliang Pu, Jia Wang, Wanghai Jin, Longbin Sha, Dongling Li

School of Geosciences Faculty and Staff Publications

The influence of terrestrial and marine input has dramatically changed eutrophication in coastal seas over the past 100 years. In this study, Zhoushan coastal sea (ZCS) is taken as a study area. We studied ZCS as it is a sink of the temporal and spatial variation of primary productivity, dominant species of algae, and the variation of provenance in this area over the past 100 years. We performed analysis using three sediment cores and the carbon and silicon deposition records. The analysis results demonstrate that: (1) The primary productivity in the northern area of the ZCS close to the Yangtze …


Evaluating The Influences Of Harvesting Activity And Eutrophication On Loss Of Aquatic Vegetations In Taihu Lake, China, Juhua Luo, Ruiliang Pu, Hongtao Duan, Ronghua Ma, Zhigang Mao, Yuan Zeng, Linsheng Huang, Qitao Xiao May 2020

Evaluating The Influences Of Harvesting Activity And Eutrophication On Loss Of Aquatic Vegetations In Taihu Lake, China, Juhua Luo, Ruiliang Pu, Hongtao Duan, Ronghua Ma, Zhigang Mao, Yuan Zeng, Linsheng Huang, Qitao Xiao

School of Geosciences Faculty and Staff Publications

A rapid degradation of aquatic vegetations in Taihu Lake has roused a wide attention in recent years. Giving large-scale harvesting activity on aquatic vegetation since 2012, whether water eutrophication or the human harvest activity induced the degradation remains controversial and unclear. In this study, based on Landsat and HJ-CCD data acquired from 1984 to 2016 and a 12-year field observation (2005–2016) of water quality, a method was proposed to quantitatively assess impacts of harvesting activity and water quality change on degradations of both floating-leaved aquatic vegetation (FAV) and submerged aquatic vegetation (SAV) in Taihu Lake. First, areas of FAV and …


Modeling The Contribution Of Poroelastic Deformation To Postseismic Geodetic Signals, Kimberly Mccormack, Marc A. Hesse, Timothy H. Dixon, Rocco Malservisi Apr 2020

Modeling The Contribution Of Poroelastic Deformation To Postseismic Geodetic Signals, Kimberly Mccormack, Marc A. Hesse, Timothy H. Dixon, Rocco Malservisi

School of Geosciences Faculty and Staff Publications

To constrain the poroelastic component of postseismic deformation, we model the subsurface hydrologic response to the Mw 7.6 subduction zone earthquake that occurred on the plate interface beneath the Nicoya peninsula in Costa Rica on 5 September 2012. The model shows that poroelastic relaxation occurs on multiple time scales and the associated deformation can be up to 2 cm for the trench‐perpendicular component. By modeling the time‐dependent deformation associated with poroelastic relaxation, we can begin to remove its contribution from the observed geodetic signal. Inversions for after slip that ignore poroelastic deformation have errors of 10–20% overall and up …


Estimation Of Aboveground Biomass Of Robinia Pseudoacacia Forest In The Yellow River Delta Based On Uav And Backpack Lidar Point Clouds, Jinbo Lu, Hong Wang, Shuhong Qin, Lin Cao, Ruiliang Pu, Guilin Li, Jing Sun Apr 2020

Estimation Of Aboveground Biomass Of Robinia Pseudoacacia Forest In The Yellow River Delta Based On Uav And Backpack Lidar Point Clouds, Jinbo Lu, Hong Wang, Shuhong Qin, Lin Cao, Ruiliang Pu, Guilin Li, Jing Sun

School of Geosciences Faculty and Staff Publications

Forest plantations are an important source of terrestrial carbon sequestration. The forest of Robinia pseudoacacia in the Yellow River Delta (YRD) is the largest artificial ecological protection forest in China. However, more than half of the forest has appeared different degrees of dieback and even death since the 1990s. Timely and accurate estimation of the forest aboveground biomass (AGB) is a basis for studying the carbon cycle of forests. Light Detecting and Ranging (LiDAR) has been proved to be one of the most powerful methods for forest biomass estimation. However, because of an irregular and overlapping shape of the broadleaved …


Quantifying Rates Of “Rifting While Drifting” In The Southern Gulf Of California: The Role Of The Southern Baja California Microplate And Its Eastern Boundary Zone, Paul J. Umhoefer, C. Plattner, Rocco Malservisi Feb 2020

Quantifying Rates Of “Rifting While Drifting” In The Southern Gulf Of California: The Role Of The Southern Baja California Microplate And Its Eastern Boundary Zone, Paul J. Umhoefer, C. Plattner, Rocco Malservisi

School of Geosciences Faculty and Staff Publications

The southern Baja California (Mexico) microplate has been rapidly moving away from the North America plate since ca. 12 Ma. This relative motion toward the northwest developed an oblique-divergent plate boundary that formed the Gulf of California. The rift-drift hypothesis postulates that when a continent ruptures and seafloor spreading commences, rifting on the plate margins ceases, and the margins start to drift, subside, and accumulate postrift sediments, eventually becoming a passive margin. In contrast to this hypothesis, the southern part of the Baja California microplate (BCM), and in particular its actively deforming eastern boundary zone, has continued significant rifting for …


A Hydrologic Landscapes Perspective On Groundwater Connectivity Of Depressional Wetlands, Brian P. Neff, Donald O. Rosenberry, Scott G. Leibowitz, Dave M. Mushet, Heather E. Golden, Mark C. Rains, J. R. Brooks, Charles R. Lane Jan 2020

A Hydrologic Landscapes Perspective On Groundwater Connectivity Of Depressional Wetlands, Brian P. Neff, Donald O. Rosenberry, Scott G. Leibowitz, Dave M. Mushet, Heather E. Golden, Mark C. Rains, J. R. Brooks, Charles R. Lane

School of Geosciences Faculty and Staff Publications

Research into processes governing the hydrologic connectivity of depressional wetlands has advanced rapidly in recent years. Nevertheless, a need persists for broadly applicable, non-site-specific guidance to facilitate further research. Here, we explicitly use the hydrologic landscapes theoretical framework to develop broadly applicable conceptual knowledge of depressional-wetland hydrologic connectivity. We used a numerical model to simulate the groundwater flow through five generic hydrologic landscapes. Next, we inserted depressional wetlands into the generic landscapes and repeated the modeling exercise. The results strongly characterize groundwater connectivity from uplands to lowlands as being predominantly indirect. Groundwater flowed from uplands and most of it was …


The Prebiotic Provenance Of Semi-Aqueous Solvents, Jennifer L. Lago, Bradley T. Burcar, Nicholas V. Hud, Rio Febrian, Christopher A. Mehta, Paul J. Bracher, Zachary D. Atlas, Matthew A. Pasek Jan 2020

The Prebiotic Provenance Of Semi-Aqueous Solvents, Jennifer L. Lago, Bradley T. Burcar, Nicholas V. Hud, Rio Febrian, Christopher A. Mehta, Paul J. Bracher, Zachary D. Atlas, Matthew A. Pasek

School of Geosciences Faculty and Staff Publications

The numerous and varied roles of phosphorylated organic molecules in biochemistry suggest they may have been important to the origin of life. The prominence of phosphorylated molecules presents a conundrum given that phosphorylation is a thermodynamically unfavorable, endergonic process in water, and most natural sources of phosphate are poorly soluble. We recently demonstrated that a semi-aqueous solvent consisting of urea, ammonium formate, and water (UAFW) supports the dissolution of phosphate and the phosphorylation of nucleosides. However, the prebiotic feasibility and robustness of the UAFW system are unclear. Here, we study the UAFW system as a medium in which phosphate minerals …


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: …


Serpentinization As A Route To Liberating Phosphorus On Habitable Worlds, Matthew Pasek, Arthur Omran, Carolyn Lang, Maheen Gull, Josh Abbatiello, Tian Feng, Lyle Garong, Heather Abbott-Lyon Jan 2020

Serpentinization As A Route To Liberating Phosphorus On Habitable Worlds, Matthew Pasek, Arthur Omran, Carolyn Lang, Maheen Gull, Josh Abbatiello, Tian Feng, Lyle Garong, Heather Abbott-Lyon

School of Geosciences Faculty and Staff Publications

Planetary habitability is in part governed by nutrient availability, including the availability of the element phosphorus. The nutrient phosphorus plays roles in various necessary biochemical functions, and its biogeochemical cycling has been proposed to be extremely slow due to a strong coupling to the rock cycle via mineral weathering. Here we show a route to P liberation from water-rock reactions that are thought to be common throughout the Solar System. We report the speciation of phosphorus in serpentinite rocks to include the ion phosphite (HPO32- with P3+) and show that reduction of phosphate to phosphite is predicted from thermodynamic models …


F1.1 Permanent Upland Streams, R. T. Kingsford, R. Mac Nally, P. S. Giller, Mark C. Rains, M. Kelly-Quinn, A. H. Arthington, D. A. Keith Jan 2020

F1.1 Permanent Upland Streams, R. T. Kingsford, R. Mac Nally, P. S. Giller, Mark C. Rains, M. Kelly-Quinn, A. H. Arthington, D. A. Keith

School of Geosciences Faculty and Staff Publications

No abstract provided.


F1.2 Permanent Lowland Rivers, R. T. Kingsford, R. Mac Nally, G. S. Giller, Mark C. Rains, A. H. Arthington, D. A. Keith Jan 2020

F1.2 Permanent Lowland Rivers, R. T. Kingsford, R. Mac Nally, G. S. Giller, Mark C. Rains, A. H. Arthington, D. A. Keith

School of Geosciences Faculty and Staff Publications

No abstract provided.


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.


Tf1.3 Permanent Marshes, R. T. Kingsford, J. A. Catford, Mark C. Rains, B. J. Robson, D. A. Keith Jan 2020

Tf1.3 Permanent Marshes, R. T. Kingsford, J. A. Catford, Mark C. Rains, B. J. Robson, D. A. Keith

School of Geosciences Faculty and Staff Publications

No abstract provided.


Factors Affecting The 2019 Atlantic Hurricane Season And The Role Of The Indian Ocean Dipole, Kimberly M. Wood, Philip J. Klotzbach, Jennifer M. Collins, Louis-Philippe Caron, Ryan E. Truchelut, Carl J. Schreck Jan 2020

Factors Affecting The 2019 Atlantic Hurricane Season And The Role Of The Indian Ocean Dipole, Kimberly M. Wood, Philip J. Klotzbach, Jennifer M. Collins, Louis-Philippe Caron, Ryan E. Truchelut, Carl J. Schreck

School of Geosciences Faculty and Staff Publications

The 2019 Atlantic hurricane season exhibited above‐average Accumulated Cyclone Energy—60% of which was produced by Hurricanes Dorian and Lorenzo. Most tropical cyclone (TC) activity was concentrated in a ~6‐week period from late August to early October. During the early part of the season, relatively TC‐unfavorable conditions persisted in the main development region (MDR). The MDR environment became largely favorable in September, followed by an abrupt shift back to less conducive conditions in October coincident with a strongly positive Indian Ocean Dipole (IOD). The IOD produced an El Niño‐like teleconnection pattern observed through 200‐hPa velocity potential anomalies. In the subtropical Atlantic, …


Utilizing Ecological Niche Modelling To Predict Habitat Suitability Of Eastern Equine Encephalitis In Florida, Claire Burch, Rebecca Loraamm, Thomas R. Unnasch, Joni A. Downs Jan 2020

Utilizing Ecological Niche Modelling To Predict Habitat Suitability Of Eastern Equine Encephalitis In Florida, Claire Burch, Rebecca Loraamm, Thomas R. Unnasch, Joni A. Downs

School of Geosciences Faculty and Staff Publications

Eastern Equine Encephalitis virus (EEEV) is a virus found predominantly east of the Mississippi River in the United States that can be fatal to both equines and humans. The disease has previously been most prolific in states like Florida, but there has been an increase in the prevalence in other states further up north on the east coast of the United States in recent years. The purpose of this research is to use the ecological niche modelling program Maxent to model EEEV habitat suitability probability. This research utilized data of fatality incidence in equine hosts, versus sentinel chicken infection data, …


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 …


Late Holocene Droughts And Cave Ice Harvesting By Ancestral Puebloans, Bogdan P. Onac, Steven M. Baumann, Dylan S. Parmenter, Eric Weaver, Tiberiu B. Sava Jan 2020

Late Holocene Droughts And Cave Ice Harvesting By Ancestral Puebloans, Bogdan P. Onac, Steven M. Baumann, Dylan S. Parmenter, Eric Weaver, Tiberiu B. Sava

School of Geosciences Faculty and Staff Publications

Water availability for Native Americans in the southwestern United States during periods of prolonged droughts is poorly understood as regional hydroclimate records are scant or contradicting. Here, we show that radiocarbon-dated charcoal recovered from an ice deposit accumulated in Cave 29, western New Mexico, provide unambiguous evidence for five drought events that impacted the Ancestral Puebloan society between ~ AD 150 and 950. The presence of abundant charred material in this cave indicates that they periodically obtained drinking water by using fire to melt cave ice, and sheds light on one of many human–environment interactions in the Southwest in a …


Uncovering Host-Microbiome Interactions In Global Systems With Collaborative Programming: A Novel Approach Integrating Social And Data Sciences [Version 1; Peer Review: Awaiting Peer Review], Jenna Oberstaller, Swamy Rakesh Adapa, Guy Dayhoff Ii, Justin Gibbons, Gregory S. Herbert Jan 2020

Uncovering Host-Microbiome Interactions In Global Systems With Collaborative Programming: A Novel Approach Integrating Social And Data Sciences [Version 1; Peer Review: Awaiting Peer Review], Jenna Oberstaller, Swamy Rakesh Adapa, Guy Dayhoff Ii, Justin Gibbons, Gregory S. Herbert

School of Geosciences Faculty and Staff Publications

Microbiome data are undergoing exponential growth powered by rapid technological advancement. As the scope and depth of microbiome research increases, cross-disciplinary research is urgently needed for interpreting and harnessing the unprecedented data output. However, conventional research settings pose challenges to much-needed interdisciplinary research efforts due to barriers in scientific terminologies, methodology and research-culture. To breach these barriers, our University of South Florida OneHealth Codeathon was designed to be an interactive, hands-on event that solves real-world data problems. The format brought together students, postdocs, faculty, researchers, and clinicians in a uniquely cross-disciplinary, team-focused setting. Teams were formed to encourage equitable distribution …


F2.3 Seasonal Freshwater Lakes, R. T. Kingsford, R. Mac Nally, Mark C. Rains, B. J. Robson, K. Irvine, D. A. Keith Jan 2020

F2.3 Seasonal Freshwater Lakes, R. T. Kingsford, R. Mac Nally, Mark C. Rains, B. J. Robson, K. Irvine, D. A. Keith

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 …


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 …


Optimizing Arbovirus Surveillance Using Risk Mapping And Coverage Modelling, Joni A. Downs, Mehrdad Vaziri, George Deskins, William Kellner, Kristi M. Miley, Thomas R. Unnasch Jan 2020

Optimizing Arbovirus Surveillance Using Risk Mapping And Coverage Modelling, Joni A. Downs, Mehrdad Vaziri, George Deskins, William Kellner, Kristi M. Miley, Thomas R. Unnasch

School of Geosciences Faculty and Staff Publications

Diseases carried by mosquitoes and other arthropods endanger human health globally. Though costly, surveillance efforts are vital for disease control and prevention This paper describes an approach for strategically configuring targeted disease surveillance sites across a study area. The methodology combines risk index mapping and spatial optimization modelling. The risk index is used to identify demand for surveillance, and the maximum covering location problem is used to select a specified number of candidate surveillance sites that covers the maximum amount of risk. The approach is demonstrated using a case study where optimal locations for sentinel surveillance sites are selected for …


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 …


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, …


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 …


Tf1.4 Seasonal Floodplain Marshes, D. A. Keith, R. T. Kingsford, R. Mac Nally, B. J. Robson, C. A. Catford, Mark C. Rains, K. Irvine, K. M. Rodriguez-Clark, A. Etter Jan 2020

Tf1.4 Seasonal Floodplain Marshes, D. A. Keith, R. T. Kingsford, R. Mac Nally, B. J. Robson, C. A. Catford, Mark C. Rains, K. Irvine, K. M. Rodriguez-Clark, A. Etter

School of Geosciences Faculty and Staff Publications

No abstract provided.