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Articles 181 - 210 of 524
Full-Text Articles in Geophysics and Seismology
Uas-Based Tracking Of The Santiaguito Lava Dome, Guatemala, Edgar U. Zorn, Thomas R. Walter, Jeffrey B. Johnson, René Mania
Uas-Based Tracking Of The Santiaguito Lava Dome, Guatemala, Edgar U. Zorn, Thomas R. Walter, Jeffrey B. Johnson, René Mania
Geosciences Faculty Publications and Presentations
Imaging growing lava domes has remained a great challenge in volcanology due to their inaccessibility and the severe hazard of collapse or explosion. Changes in surface movement, temperature, or lava viscosity are considered crucial data for hazard assessments at active lava domes and thus valuable study targets. Here, we present results from a series of repeated survey flights with both optical and thermal cameras at the Caliente lava dome, part of the Santiaguito complex at Santa Maria volcano, Guatemala, using an Unoccupied Aircraft System (UAS) to create topography data and orthophotos of the lava dome. This enabled us to track …
Joint Inversion Of Gpr And Er Data, Diego Domenzain
Joint Inversion Of Gpr And Er Data, Diego Domenzain
Boise State University Theses and Dissertations
Imaging the subsurface can shed knowledge on important processes needed in a modern day human's life such as ground-water exploration, water resource monitoring, contaminant and hazard mitigation, geothermal energy exploration and carbon dioxide storage. As computing power expands, it is becoming ever more feasible to increase the physical complexity of Earth's exploration methods, and hence enhance our understanding of the subsurface.
We use non-invasive geophysical active source methods that rely on electromagnetic fields to probe the depths of the Earth. In particular, we use Ground penetrating radar (GPR) and Electrical resistivity (ER). Both methods are sensitive to electrical conductivity while …
Rayleigh-Wave Multicomponent Crosscorrelation-Based Estimation Of Phase Velocities And Ambient Seismic Source Distributions, Zongbo Xu
Boise State University Theses and Dissertations
One uses seismic interferometry (SI) to recover Green’s functions (i.e. impulse response) from ambient seismic recordings and estimate surface-wave phase velocities to investigate subsurface structure. This method has been commonly used in the last 20 years because this method only utilizes ambient seismic recordings from seismic stations/sensors and does not rely on traditional seismic sources (e.g. earthquakes or active sources). SI assumes that the ambient seismic wavefield is isotropic, but this assumption is rarely met in practice. We demonstrate that, with linear-array spatial sampling of an anisotropic ambient seismic wavefield, SI provides a better estimate of Rayleigh-wave phase velocities than …
Hydraulic Tomography: 3d Hydraulic Conductivity, Fracture Network, And Connectivity In Mudstone, Claire R. Tiedeman, Warren Barrash
Hydraulic Tomography: 3d Hydraulic Conductivity, Fracture Network, And Connectivity In Mudstone, Claire R. Tiedeman, Warren Barrash
CGISS Publications and Presentations
We present the first demonstration of hydraulic tomography (HT) to estimate the three‐dimensional (3D) hydraulic conductivity (K) distribution of a fractured aquifer at high‐resolution field scale (HRFS), including the fracture network and connectivity through it. We invert drawdown data collected from packer‐isolated borehole intervals during 42 pumping tests in a wellfield at the former Naval Air Warfare Center, West Trenton, New Jersey, in the Newark Basin. Five additional tests were reserved for a quality check of HT results. We used an equivalent porous medium forward model and geostatistical inversion to estimate 3D K at high resolution (K …
Dynamic Magma Storage At Near-Ridge Hot Spots: Evidence From New Galápagos Gravity Data, Z. Cleary, D. M. Schwartz, E. Mittelstaedt, K. Harpp
Dynamic Magma Storage At Near-Ridge Hot Spots: Evidence From New Galápagos Gravity Data, Z. Cleary, D. M. Schwartz, E. Mittelstaedt, K. Harpp
Geosciences Faculty Publications and Presentations
A morphological dichotomy exists between the active western and older (>1–2.5 Ma) eastern volcanoes of the Galápagos Archipelago. All of the young shield volcanoes in the west have calderas, but none are present on the older volcanoes in the east. This striking difference suggests that there has been a change in volcanic construction and magmatic supply processes, a finding dissimilar to the prevailing Hawaiian model of hot spot evolution. Bouguer anomaly highs (30–50 mGal) consistent with dense cumulate bodies are measured over these calderas. In contrast, we present new gravity data from Santa Cruz and San Cristóbal islands that …
Constraints On The Shallow Deformation Around The Main Frontal Thrust In Central Nepal From Refraction Velocities, Yixiang Liu, Judith Hubbard, Rafael V. Almeida, Anna Foster, Lee Liberty, Ying Sin Lee, Soma Nath Sapkota
Constraints On The Shallow Deformation Around The Main Frontal Thrust In Central Nepal From Refraction Velocities, Yixiang Liu, Judith Hubbard, Rafael V. Almeida, Anna Foster, Lee Liberty, Ying Sin Lee, Soma Nath Sapkota
Geosciences Faculty Publications and Presentations
The youngest fault system in the Himalayan orogeny is the Main Frontal Thrust (MFT), the frontal ramp of the Main Himalayan Thrust, which is expected to host the largest and most damaging earthquakes in Nepal. We characterize the upper few hundred meters below the surface across two MFT fault strands using ten high-resolution seismic profiles that we acquired in 2014 and 2015 with a 6-tonne Vibroseis source. We use first arrival picks from 625,416 seismic traces to derive P-wave seismic velocity models using a wavepath eikonal traveltime inversion method, and derive estimates of alluvium thickness and water table depth across …
Orogenic Link ∼41°N–46°N: Collisional Mountain Building And Basin Closure In The Cordillera Of Western North America, Keith D. Gray, V. Isakson, D. Schwartz, Jeffrey D. Vervoort
Orogenic Link ∼41°N–46°N: Collisional Mountain Building And Basin Closure In The Cordillera Of Western North America, Keith D. Gray, V. Isakson, D. Schwartz, Jeffrey D. Vervoort
Geosciences Faculty Publications and Presentations
Polyphase structural mapping and mineral age dating across the Salmon River suture zone in west-central Idaho (Riggins region; ∼45°30′N, ∼117°W–116°W) support a late Mesozoic history of penetrative deformation, dynamothermal metamorphism, and intermittent magmatism in response to right-oblique oceanic-continental plate convergence (Farallon–North America). High-strain linear-planar tectonite fabrics are recorded along an unbroken ∼48 km west-to-east transect extending from the Snake River (Wallowa intra-oceanic arc terrane; eastern Blue Mountains Province) over the northern Seven Devils Mountains into the lower Salmon River Canyon (ancestral North America; western Laurentia). Given the temporally overlapping nature (ca. 145–90 Ma) of east-west contraction in the Sevier fold-and-thrust …
Co-Eruptive Tremor From Bogoslof Volcano: Seismic Wavefield Composition At Regional Distances, Matthew M. Haney, David Fee, Kathleen F. Mckee, John J. Lyons, Robin S. Matoza, Aaron G. Wech, Gabrielle Tepp, Cheryl Searcy, T. Dylan Mikesell
Co-Eruptive Tremor From Bogoslof Volcano: Seismic Wavefield Composition At Regional Distances, Matthew M. Haney, David Fee, Kathleen F. Mckee, John J. Lyons, Robin S. Matoza, Aaron G. Wech, Gabrielle Tepp, Cheryl Searcy, T. Dylan Mikesell
Geosciences Faculty Publications and Presentations
We analyze seismic tremor recorded during eruptive activity over the course of the 2016–2017 eruption of Bogoslof volcano, Alaska. Only regional recordings of the tremor wavefield exist for Bogoslof, making it a challenge to place the recordings in context with other eruptions that are normally captured by local seismic data. We apply a technique of time-frequency polarization analysis to three-component seismic data to reveal the wavefield composition of Bogoslof eruption tremor.We find that at regional distances, the tremor is dominated by P-waves in the band from 1.5 to 10 Hz. Using this information, along with an enriched Bogoslof earthquake catalog, …
High-Velocity Surface Layer Effects On Rayleigh Waves: Recommendations For Improved Shear-Wave Velocity Modeling, Gabriel Gribler, Lee M. Liberty, T. Dylan Mikesell
High-Velocity Surface Layer Effects On Rayleigh Waves: Recommendations For Improved Shear-Wave Velocity Modeling, Gabriel Gribler, Lee M. Liberty, T. Dylan Mikesell
Geosciences Faculty Publications and Presentations
Soil stiffness estimates are critical to geologic hazard and risk assessment in urban centers. Multichannel analysis of surface-wave (MASW) data collection along city streets is now a standard, cost-effective, and noninvasive soil stiffness approximation tool. With this approach, shear-wave velocities (VS) are derived from Rayleigh-wave signals. Although the current MASW practice is to neglect the effect of a high-velocity road layer on soil VS estimates, our models show measurable impacts on Rayleigh-wave amplitudes and phase velocities when seismic data are acquired on a road surface. Here, we compare synthetic models with field MASW and downhole V …
Mapping Snowmelt Progression In The Upper Indus Basin With Synthetic Aperture Radar, Jewell Lund, Richard R. Forster, Summer B. Rupper, Elias J. Deeb, H.P. Marshall, Muhammad Zia Hashmi, Evan Burgess
Mapping Snowmelt Progression In The Upper Indus Basin With Synthetic Aperture Radar, Jewell Lund, Richard R. Forster, Summer B. Rupper, Elias J. Deeb, H.P. Marshall, Muhammad Zia Hashmi, Evan Burgess
Geosciences Faculty Publications and Presentations
The Indus River is a vital resource for food security, ecosystem services, hydropower, and economy for millions of people living in Pakistan, India, China, and Afghanistan. Glacier and snowmelt from the high altitude Himalaya, Karakoram, and Hindu Kush mountain ranges are the largest drivers of discharge in the upper Indus Basin (UIB), and contribute significantly to Indus flows. Complex climatology and topography, coupled with the challenges of field study and meteorological measurement in these rugged ranges, elicit notable uncertainties in predicting seasonal runoff as well as cryospheric response to changes in climate. Here we utilize Sentinel-1 synthetic aperture radar (SAR) …
Early Triassic Conchostracans From The Tiryakh-Kobyume Section (Southern Verkhoyansk Region, Republic Of Sakha (Yakutia)), V. V. Zharinova, F. Scholze, V. I. Davydov, R. V. Kutygin
Early Triassic Conchostracans From The Tiryakh-Kobyume Section (Southern Verkhoyansk Region, Republic Of Sakha (Yakutia)), V. V. Zharinova, F. Scholze, V. I. Davydov, R. V. Kutygin
Geosciences Faculty Publications and Presentations
Conchostracans (Crustacea) from the Induan deposits of the Tiryakh-Kobyume section (southern Verkhoyansk region) were studied. We identified the following seven conchostracan species belonging to five genera: Pseudestheria Raymond, 1946; Euestheria Deperet et Mezeran, 1912; Sphaerestheria Novojilov, 1954; Lioestheria Deperet et Mezeran, 1912; Wetlugites Novojilov, 1958. Most of the previously identified species in the Tiryakh-Kobyume region (“Pseudestheria sibirica”, “Ps. tumaryana”, “Ps. kashirtzevi”, and “Sphaerestheria aldanensis”) were described in the middle of the 20th century from the basal Triassic in the western Verkhoyansk region (Balbuk section). Revision of these species with the use …
The Community Outreach Model Of Service-Learning: A Case Study Of Active Learning And Service-Learning In A Natural Hazards, Vulnerability, And Risk Class, Brittany D. Brand, Kara Brascia, Margaret Sass
The Community Outreach Model Of Service-Learning: A Case Study Of Active Learning And Service-Learning In A Natural Hazards, Vulnerability, And Risk Class, Brittany D. Brand, Kara Brascia, Margaret Sass
Geosciences Faculty Publications and Presentations
The popularity of service learning is increasing, especially at a time when college students want to make a greater impact in their communities. However, service learning has not been extensively assessed in courses based in science, technology, engineering, and mathematics. This article provides a case study of how incorporating service learning through a community outreach project can increase student engagement, enhance the depth of understanding of a given topic, build communication and teamwork skills, and contribute meaningfully to the students' community. This article shares how the instructor of a natural hazards, vulnerability, and risk course implements service-learning through a community …
Crevasse Initiation And History Within The Mcmurdo Shear Zone, Antarctica, Lynn Kaluzienski, Peter Koons, Ellyn Enderlin, Gordon Hamilton, Zoe Courville, Steven Arcone
Crevasse Initiation And History Within The Mcmurdo Shear Zone, Antarctica, Lynn Kaluzienski, Peter Koons, Ellyn Enderlin, Gordon Hamilton, Zoe Courville, Steven Arcone
Geosciences Faculty Publications and Presentations
While large-scale observations of intensified fracture and rifting can be observed through remote-sensing observations, understanding crevasse initiation may best be achieved with small-scale observations in which crevasses can be directly observed. Here we investigate the kinematic drivers of crevasse initiation in the McMurdo Shear Zone (MSZ), Antarctica. We delineated 420 crevasses from ∼95 km of 400 MHz frequency ground-penetrating radar data and compared these data with kinematic outputs derived from remotely-sensed ice surface velocities to develop a statistical method to estimate crevasse initiation threshold strain rate values. We found the MSZ to be dominated by simple shear and that surface …
Informing Field Management Decisions To Enhance Alfalfa Seed Production Using Remote Sensing, Thomas V. Van Der Weide
Informing Field Management Decisions To Enhance Alfalfa Seed Production Using Remote Sensing, Thomas V. Van Der Weide
Boise State University Theses and Dissertations
The development rate of alfalfa seed crop depends on both environmental conditions and management decisions. Crop management decisions, such as determining when to release pollinators to optimize pollination, can be informed by the identification of plant development stages from remote sensing data. I first identify what electromagnetic wavelengths are sensitive to alfalfa plant development stages using hyperspectral data. A Random Forest regression is used to determine the best Vegetation Index (VI) to monitor how much of the plant is covered in flower. The results indicate that Blue, Green, and Near-Infrared are the important electromagnetic wavelengths for the VI. Imagery collected …
Developing And Optimizing Shrub Parameters Representing Sagebrush (Artemisia Spp.) Ecosystems In The Northern Great Basin Using The Ecosystem Demography (Edv2.2) Model, Karun Pandit, Hamid Dashti, Nancy F. Glenn, Alejandro N. Flores
Developing And Optimizing Shrub Parameters Representing Sagebrush (Artemisia Spp.) Ecosystems In The Northern Great Basin Using The Ecosystem Demography (Edv2.2) Model, Karun Pandit, Hamid Dashti, Nancy F. Glenn, Alejandro N. Flores
Geosciences Faculty Publications and Presentations
Ecosystem dynamic models are useful for understanding ecosystem characteristics over time and space because of their efficiency over direct field measurements and applicability to broad spatial extents. Their application, however, is challenging due to internal model uncertainties and complexities arising from distinct qualities of the ecosystems being analyzed. The sagebrush-steppe ecosystem in western North America, for example, has substantial spatial and temporal heterogeneity as well as variability due to anthropogenic disturbance, invasive species, climate change, and altered fire regimes, which collectively make modeling dynamic ecosystem processes difficult. Ecosystem Demography (EDv2.2) is a robust ecosystem dynamic model, initially developed for tropical …
Recent Precipitation Decrease Across The Western Greenland Ice Sheet Percolation Zone, Hans-Peter Marshall, Tate Meehan
Recent Precipitation Decrease Across The Western Greenland Ice Sheet Percolation Zone, Hans-Peter Marshall, Tate Meehan
Geosciences Faculty Publications and Presentations
The mass balance of the Greenland Ice Sheet (GrIS) in a warming climate is of critical interest in the context of future sea level rise. Increased melting in the GrIS percolation zone due to atmospheric warming over the past several decades has led to increased mass loss at lower elevations. Previous studies have hypothesized that this warming is accompanied by a precipitation increase, as would be expected from the Clausius–Clapeyron relationship, compensating for some of the melt-induced mass loss throughout the western GrIS. This study tests that hypothesis by calculating snow accumulation rates and trends across the western GrIS percolation …
Exploring The Law Of Detrital Zircon: La-Icp-Ms And Ca-Tims Geochronology Of Jurassic Forearc Strata, Cook Inlet, Alaska, Usa, Trystan M. Herriott, James L. Crowley, Mark D. Schmitz, Marwan A. Wartes, Robert J. Gillis
Exploring The Law Of Detrital Zircon: La-Icp-Ms And Ca-Tims Geochronology Of Jurassic Forearc Strata, Cook Inlet, Alaska, Usa, Trystan M. Herriott, James L. Crowley, Mark D. Schmitz, Marwan A. Wartes, Robert J. Gillis
Geosciences Faculty Publications and Presentations
Uranium-lead (U-Pb) geochronology studies commonly employ the law of detrital zircon: A sedimentary rock cannot be older than its youngest zircon. This premise permits maximum depositional ages (MDAs) to be applied in chronostratigraphy, but geochronologic dates are complicated by uncertainty. We conducted laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) and chemical abrasion-thermal ionization mass spectrometry (CA-TIMS) of detrital zircon in forearc strata of southern Alaska (USA) to assess the accuracy of several MDA approaches. Six samples from Middle–Upper Jurassic units are generally replete with youthful zircon and underwent three rounds of analysis: (1) LA-ICP-MS of ∼115 grains, with one date per …
Spatially Extensive Ground‐Penetrating Radar Snow Depth Observations During Nasa's 2017 Snowex Campaign: Comparison With In Situ, Airborne, And Satellite Observations, Hans-Peter Marshall
Spatially Extensive Ground‐Penetrating Radar Snow Depth Observations During Nasa's 2017 Snowex Campaign: Comparison With In Situ, Airborne, And Satellite Observations, Hans-Peter Marshall
Geosciences Faculty Publications and Presentations
Seasonal snow is an important component of Earth's hydrologic cycle and climate system, yet it remains challenging to consistently and accurately measure snow depth and snow water equivalent (SWE) across the range of diverse snowpack conditions that exist on Earth. The NASA SnowEx campaign is focused on addressing the primary gaps in snow remote sensing in order to gain an improved spatiotemporal understanding of this important resource and to further efforts toward a future satellite‐based snow remote sensing mission. Ground‐penetrating radar (GPR) is an efficient and mature approach for measuring snow depth and SWE. We collected ~1.3 million GPR snow …
Snow Depth Variability In The Northern Hemisphere Mountains Observed From Space, Hans-Peter Marshall
Snow Depth Variability In The Northern Hemisphere Mountains Observed From Space, Hans-Peter Marshall
Geosciences Faculty Publications and Presentations
Accurate snow depth observations are critical to assess water resources. More than a billion people rely on water from snow, most of which originates in the Northern Hemisphere mountain ranges. Yet, remote sensing observations of mountain snow depth are still lacking at the large scale. Here, we show the ability of Sentinel-1 to map snow depth in the Northern Hemisphere mountains at 1 km² resolution using an empirical change detection approach. An evaluation with measurements from ~4000 sites and reanalysis data demonstrates that the Sentinel-1 retrievals capture the spatial variability between and within mountain ranges, as well as their inter-annual …
The Alleghanian Isthmus As The Trigger Of The Onset Of The Bashkirian Glaciation: Constraints From Warm-Water Benthic Foraminifera, Vladimir I. Davydov, Pedro Cózar
The Alleghanian Isthmus As The Trigger Of The Onset Of The Bashkirian Glaciation: Constraints From Warm-Water Benthic Foraminifera, Vladimir I. Davydov, Pedro Cózar
Geosciences Faculty Publications and Presentations
The timing of the final collision and particularly the disappearance of the gateway between the Rheic and Tethyan oceans is quite controversial and poorly established. The accurate timing on the gateway closure is vitally important for the understanding of global sea-level fluctuations, ocean circulation, regional and global environments, salinity and reorganization of the thermohaline circulation, enhanced deep water organic carbon production in the western Tethys and the overall decline of atmospheric CO2 concentrations. Here we present a new approach by applying warm-water benthic foraminifera (WWBF) data to precisely constraint the Rheic-Tethys gateway (RTG) closure, utilizing taxonomic and statistical methods. …
Melpf Version 1: Modeling Error Learning Based Post-Processor Framework For Hydrologic Models Accuracy Improvement, Rui Wu, Lei Yang, Chao Chen, Sajjad Ahmad, Sergiu M. Dascalu, Frederick C. Harris Jr.
Melpf Version 1: Modeling Error Learning Based Post-Processor Framework For Hydrologic Models Accuracy Improvement, Rui Wu, Lei Yang, Chao Chen, Sajjad Ahmad, Sergiu M. Dascalu, Frederick C. Harris Jr.
Geosciences Faculty Publications and Presentations
This paper studies how to improve the accuracy of hydrologic models using machine-learning models as post-processors and presents possibilities to reduce the workload to create an accurate hydrologic model by removing the calibration step. It is often challenging to develop an accurate hydrologic model due to the time-consuming model calibration procedure and the nonstationarity of hydrologic data. Our findings show that the errors of hydrologic models are correlated with model inputs. Thus motivated, we propose a modeling-error-learning-based post-processor framework by leveraging this correlation to improve the accuracy of a hydrologic model. The key idea is to predict the differences (errors) …
Regional Scale Dryland Vegetation Classification With An Integrated Lidar-Hyperspectral Approach, Hamid Dashti, Nancy F. Glenn, Nayani Ilangakoon, Josh Enterkine, Alejandro N. Flores
Regional Scale Dryland Vegetation Classification With An Integrated Lidar-Hyperspectral Approach, Hamid Dashti, Nancy F. Glenn, Nayani Ilangakoon, Josh Enterkine, Alejandro N. Flores
Geosciences Faculty Publications and Presentations
The sparse canopy cover and large contribution of bright background soil, along with the heterogeneous vegetation types in close proximity, are common challenges for mapping dryland vegetation with remote sensing. Consequently, the results of a single classification algorithm or one type of sensor to characterize dryland vegetation typically show low accuracy and lack robustness. In our study, we improved classification accuracy in a semi-arid ecosystem based on the use of vegetation optical (hyperspectral) and structural (lidar) information combined with the environmental characteristics of the landscape. To accomplish this goal, we used both spectral angle mapper (SAM) and multiple endmember spectral …
High-Precision Radioisotopic Ages For The Lower Midian (Upper Wordian) Stage Of The Tethyan Time Scale, Shigeyasu Quarry, Yamaguchi Prefecture, Japan, V. I. Davydov, M. D. Schmitz
High-Precision Radioisotopic Ages For The Lower Midian (Upper Wordian) Stage Of The Tethyan Time Scale, Shigeyasu Quarry, Yamaguchi Prefecture, Japan, V. I. Davydov, M. D. Schmitz
Geosciences Faculty Publications and Presentations
Global correlation of strata to the Guadalupian Series (Permian Period) of the International Geologic Time Scale remains provisional due to a lack of the sufficient biostratigraphically constrained radioisotopic ages. Five new high-precision U–Pb radioisotopic ages were obtained from tuffs in the lower Midian (upper Wordian) volcano-siliciclastic succession of the Akiyoshi Plateau, southwestern Japan. Two undisturbed and continuous tuffs occur within fusulinid-bearing laminated limestone turbidites, with precise biostratigraphic control. The Colania douvillei and Lepidolina shiraiwensis fusulinid Zones in the Akiyoshi succession provide an early Midian age in the Tethyan provincial time scale. The range of ages (267.46 ± 0.04 Ma to …
Ionoseis: A Package To Model Coseismic Ionospheric Disturbances, Thomas Dylan Mikesell, Lucie Rolland, Rebekah F. Lee, Florian Zedek, Pierdavide Coïsson, Jean-Xavier Dessa
Ionoseis: A Package To Model Coseismic Ionospheric Disturbances, Thomas Dylan Mikesell, Lucie Rolland, Rebekah F. Lee, Florian Zedek, Pierdavide Coïsson, Jean-Xavier Dessa
CGISS Publications and Presentations
We present the framework of the modeling package IonoSeis. This software models Global Navigation Satellite System (GNSS) derived slant total electron content (sTEC) perturbations in the ionosphere due to the interaction of the neutral atmosphere and charged particles in the ionosphere. We use a simplified model to couple the neutral particle momentum into the ionosphere and reconstruct time series of sTEC perturbations that match observed data in both arrival time and perturbation shape. We propagate neutral atmosphere disturbances to ionospheric heights using a three-dimensional ray-tracing code in spherical coordinates called Windy Atmospheric Sonic Propagation (WASP3D), which works for a …
Comparing Aerial Lidar Observations With Terrestrial Lidar And Snow-Probe Transects From Nasa's 2017 Snowex Campaign, Zach Uhlmann, Lucas Spaete, Nancy F. Glenn
Comparing Aerial Lidar Observations With Terrestrial Lidar And Snow-Probe Transects From Nasa's 2017 Snowex Campaign, Zach Uhlmann, Lucas Spaete, Nancy F. Glenn
Geosciences Faculty Publications and Presentations
NASA's 2017 SnowEx field campaign at Grand Mesa, CO, generated Airborne Laser Scans (ALS), Terrestrial Laser Scans (TLS), and snow‐probe transects, which allowed for a comparison between snow depth measurement techniques. At six locations, comparisons between gridded ALS and TLS observations, at 1‐m resolution, had a median snow depth difference of 5 cm, root‐mean‐square difference of 16 cm, mean‐absolute difference of 10 cm, and 3‐cm difference in standard deviation. ALS generally had greater but similar snow depth values to TLS, and results were not sensitive to the gridded cell size between 0.5 and 5 m. The greatest disagreements were where …
Approximating Input Data To A Snowmelt Model Using Weather Research And Forecasting Model Outputs In Lieu Of Meteorological Measurements, Scott Havens, Danny Marks, Katelyn Fitzgerald, Matt Masarik, Alejandro N. Flores, Patrick Kormos, Andrew Hedrick
Approximating Input Data To A Snowmelt Model Using Weather Research And Forecasting Model Outputs In Lieu Of Meteorological Measurements, Scott Havens, Danny Marks, Katelyn Fitzgerald, Matt Masarik, Alejandro N. Flores, Patrick Kormos, Andrew Hedrick
Geosciences Faculty Publications and Presentations
Forecasting the timing and magnitude of snowmelt and runoff is critical to managing mountain water resources. Warming temperatures are increasing the rain–snow transition elevation and are limiting the forecasting skill of statistical models relating historical snow water equivalent to streamflow. While physically based methods are available, they require accurate estimations of the spatial and temporal distribution of meteorological variables in complex terrain. Across many mountainous areas, measurements of precipitation and other meteorological variables are limited to a few reference stations and are not adequate to resolve the complex interactions between topography and atmospheric flow. In this paper, we evaluate the …
Leveraging Environmental Research And Observation Networks To Advance Soil Carbon Science, Alejandro N. Flores
Leveraging Environmental Research And Observation Networks To Advance Soil Carbon Science, Alejandro N. Flores
Geosciences Faculty Publications and Presentations
Soil organic matter (SOM) is a critical ecosystem variable regulated by interacting physical, chemical, and biological processes. Collaborative efforts to integrate perspectives, data, and models from interdisciplinary research and observation networks can significantly advance predictive understanding of SOM. We outline how integrating three networks—the Long‐Term Ecological Research with a focus on ecological dynamics, the Critical Zone Observatories with strengths in landscape/geologic context, and the National Ecological Observatory Network with standardized multiscale measurements—can advance SOM knowledge. This integration requires improved data dissemination and sharing, coordinated data collection activities, and enhanced collaboration between empiricists and modelers within and across networks.
Tsunamigenic Splay Faults Imply A Long‐Term Asperity In Southern Prince William Sound, Alaska, L. M. Liberty, D. S. Brothers, P. J. Haeussler
Tsunamigenic Splay Faults Imply A Long‐Term Asperity In Southern Prince William Sound, Alaska, L. M. Liberty, D. S. Brothers, P. J. Haeussler
CGISS Publications and Presentations
Coseismic slip partitioning and uplift over multiple earthquake cycles is critical to understanding upper‐plate fault development. Bathymetric and seismic reflection data from the 1964 Mw9.2 Great Alaska earthquake rupture area reveal sea floor scarps along the tsunamigenic Patton Bay/Cape Cleare/Middleton Island fault system. The faults splay from a megathrust where duplexing and underplating produced rapid exhumation. Trenchward of the duplex region, the faults produce a complex deformation pattern from oblique, south‐directed shortening at the Yakutat‐Pacific plate boundary. Spatial and temporal fault patterns suggest that Holocene megathrust earthquakes had similar relative motions and thus similar tsunami sources as in …
First-Order Estimates Of Coastal Bathymetry In Ilulissat And Naajarsuit Fjords, Greenland, From Remotely Sensed Iceberg Observations, Jessica Scheick, Ellyn M. Enderlin, Emily E. Miller, Gordon Hamilton
First-Order Estimates Of Coastal Bathymetry In Ilulissat And Naajarsuit Fjords, Greenland, From Remotely Sensed Iceberg Observations, Jessica Scheick, Ellyn M. Enderlin, Emily E. Miller, Gordon Hamilton
Geosciences Faculty Publications and Presentations
Warm water masses circulating at depth off the coast of Greenland play an important role in controlling rates of mass loss from the Greenland Ice Sheet through feedbacks associated with the melting of marine glacier termini. The ability of these warm waters to reach glacier termini is strongly controlled by fjord bathymetry, which was unmapped for the majority of Greenland’s fjords until recently. In response to the need for bathymetric measurements in previously uncharted areas, we developed two companion methods to infer fjord bathymetry using icebergs as depth sounders. The main premise of our methods centers around the idea that …
Permeability Prediction In Rocks Experiencing Mineral Precipitation And Dissolution: A Numerical Study, Qifei Niu, Chi Zhang
Permeability Prediction In Rocks Experiencing Mineral Precipitation And Dissolution: A Numerical Study, Qifei Niu, Chi Zhang
Geosciences Faculty Publications and Presentations
In this study, we focus on the electrical tortuosity-based permeability model k = reff2/8F (reff is an effective pore size, and F is the formation factor) and analyze its applicability to rocks experiencing mineral precipitation and dissolution. Two limiting cases of advection-dominated water-rock reactions are simulated, that is, the reaction-limited and transport-limited cases. At the pore scale, the two precipitation/dissolution patterns are simulated with a geometrical model and a phenomenological model. The fluid and electric flows in the rocks are simulated by directly solving the linear Stokes equation and Laplace equation on the representative …