Preprints
Filtering by Subject: Physical Sciences and Mathematics
The El Niño – La Niña cycle and recent trends in supply and demand of net primary productivity in African drylands
Published: 2019-04-24
Subjects: Climate, Environmental Sciences, Geography, Nature and Society Relations, Oceanography and Atmospheric Sciences and Meteorology, Physical and Environmental Geography, Physical Sciences and Mathematics, Remote Sensing, Social and Behavioral Sciences
The role of El Niño-Southern Oscillation (ENSO) in the balance between supply and demand of net primary productivity (NPP) over Africa is unclear. Here, we analyze the impact of ENSO on this balance in a spatially explicit framework using gridded population data from the WorldPop project, satellite-derived data on NPP supply, and statistical data from the United Nations. Our analyses demonstrate [...]
Anomalous structure of MgCO3 liquid and the buoyancy of carbonatite melts
Published: 2019-04-23
Subjects: Earth Sciences, Geochemistry, Mineral Physics, Physical Sciences and Mathematics
MgCO3 is one of the most important components of mantle-derived carbonatite melts, and yet also one of the most difficult to study experimentally. Attempts to constrain its thermodynamic properties are hampered by decarbonation, which occurs at only ~500 °C, far below its metastable 1 bar melting temperature. Molecular dynamic simulations, however, can predict the thermodynamic properties of the [...]
Field and LiDAR data observations of erosion on anthropogenic valley fills and associated landscape produced by mountaintop removal/valley fill coal mining in Central Appalachia
Published: 2019-04-19
Subjects: Earth Sciences, Geomorphology, Physical Sciences and Mathematics
Mountaintop removal/valley fill coal mining (MTR/VF) in Central Appalachia has buried an estimated 4000 km of headwater streams, but the geomorphic implications of the constructed anthropogenic valley fills and associated mined landscape have been studied very little. This landscape requires no maintenance in perpetuity once reclamation is considered to be complete. The first ever field-based [...]
High-angular resolution electron backscatter diffraction as a new tool for mapping lattice distortion in geological minerals
Published: 2019-04-18
Subjects: Earth Sciences, Geology, Mineral Physics, Physical Sciences and Mathematics
Analysis of distortions of the crystal lattice within individual mineral grains is central to the investigation of microscale processes that control and record tectonic events. These distortions are generally combinations of lattice rotations and elastic strains, but a lack of suitable observational techniques has prevented these components being mapped simultaneously and routinely in earth [...]
Route Schematization With Polygonal Landmarks
Published: 2019-04-18
Subjects: Geographic Information Sciences, Geography, Physical Sciences and Mathematics, Social and Behavioral Sciences
GPS-based navigation devices use large-scale visualizations of the route, where the focus lies on turn instructions. Although efficient on the wayfinding task, this approach does not support survey knowledge acquisition, which is essential for the user to build up a cognitive map and obtain orientation. Another visualization option is the small-scale topographic overview of the route. However, [...]
A Scalable Algorithm for Cross-correlations of Compressed Ambient Seismic Noise
Published: 2019-04-17
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Companies and academic geophysicists are increasingly collecting continuous seismic data on denser arrays, and are looking to a variety of lossy compression methods to store and quickly access this data. Some researchers turn to ambient noise interferometry for low-cost near-surface imaging to avoid to cost and permitting required for active source experiments, but the computation can be very [...]
Deeply buried ancient volcanoes control hydrocarbon migration in the South China Sea
Published: 2019-04-17
Subjects: Earth Sciences, Physical Sciences and Mathematics, Volcanology
Buried volcanoes are increasingly identified in the sedimentary basins both on lands and continental margins. However, their roles on the post-eruption fluid flows are still poorly understood, which greatly influence the estimate of seal integrity and increase the hydrocarbon exploration/production risks. Here we use high-resolution 3D seismic reflection and borehole data from the northern South [...]
Decomposition of Amino Acids in Water with Application to In-Situ Measurements of Enceladus, Europa and Other Hydrothermally Active Icy Ocean Worlds
Published: 2019-04-17
Subjects: Astrophysics and Astronomy, Physical Sciences and Mathematics, Planetary Biogeochemistry, Planetary Geochemistry, Planetary Sciences, The Sun and the Solar System
To test the potential of using amino acid abundances as a biosignature at icy ocean worlds, we investigate whether primordial amino acids (accreted or formed by early aqueous processes) could persist until the present time. By examining the decomposition kinetics of amino acids in aqueous solution based on existing laboratory rate data, we find that all fourteen proteinogenic amino acids [...]
Finite frequency inversion of cross-correlation amplitudes for ambient noise source directivity estimation
Published: 2019-04-15
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
We present a new method for determining the azimuthal variation of ambient seismic noise sources, that combines the computational speed and simplicity of traditional approaches with the rigour of waveform-inversion-based approaches to noise-source estimation. This method is based on a previously developed theoretical framework of sensitivity kernels for cross-correlation amplitudes. It performs a [...]
Efficient 3D large-scale forward-modeling and inversion of gravitational fields in spherical coordinates with application to lunar mascons
Published: 2019-04-11
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
An efficient forward modeling algorithm for calculation of gravitational fields in spherical coordinates is developed for 3D large‐scale gravity inversion problems. 3D Gauss‐Legendre quadrature (GLQ) is used to calculate the gravitational fields of mass distributions discretized into tesseroids. Equivalence relations in the kernel matrix of the forward‐modeling are exploited to decrease storage [...]
Explaining long-range fluid pressure transients caused by oilfield wastewater disposal using the hydrogeologic principle of superposition
Published: 2019-04-11
Subjects: Earth Sciences, Hydrology, Physical Sciences and Mathematics
Injection-induced earthquakes are now a regular occurrence across the midcontinent United States. This phenomenon is primarily caused by oilfield wastewater disposal into deep geologic formations, which induces fluid pressure transients that decrease effective stress and trigger earthquakes on critically stressed faults. It is now generally accepted that the cumulative effects of multiple [...]
Are Detected Trends in Flood Magnitude and Shifts in the Timing of Floods of A Major River Basin in India, Linked To Anthropogenic Stressors?
Published: 2019-04-10
Subjects: Applied Statistics, Civil and Environmental Engineering, Earth Sciences, Engineering, Hydraulic Engineering, Hydrology, Mathematics, Physical Sciences and Mathematics, Statistics and Probability
Analyzing of trends in flood magnitude and the timing of the dates of flood occurrences of large river basins across the globe are essential for understanding changes in water availability (high or low flows) and assessing the fidelity of global hydrological models. Our research is motivated by the recent six major consecutive floods in Mahanadi (years: 2001, 2003, 2006, 2008, 2011 and 2013) [...]
The stratigraphic evolution of onlap in siliciclastic deep-water systems: Autogenic modulation of allogenic signals
Published: 2019-04-09
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy
Seafloor topography affects the sediment gravity flows that interact with it. Understanding this interaction is critical for accurate predictions of sediment distribution, paleogeography, and structural reconstructions of deep-water basins. The effects of seafloor topography can be seen from the bed scale, through facies transitions toward intra-basinal slopes, to the basin scale, where onlap [...]
Characterising strong force networks produced during granular shear using percolation methods: Revealing the bridge between local grain scale processes and macroscopic sliding
Published: 2019-04-08
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Other Earth Sciences, Physical Sciences and Mathematics, Physics, Tectonics and Structure
Faults, landslides and subglacial till often contain accumulations of granular debris. Their macroscopic motion is at least to some extent determined by the processes operating in this sheared granular material. A valid question in these environments is how the local behaviour at the individual granular contacts actually sums up to influence macroscopic sliding. Laboratory experiments and [...]
What has Global Sensitivity Analysis ever done for us? A systematic review to support scientific advancement and to inform policy-making in earth system modelling
Published: 2019-04-08
Subjects: Civil and Environmental Engineering, Computer Sciences, Earth Sciences, Engineering, Environmental Sciences, Life Sciences, Mathematics, Medicine and Health Sciences, Physical Sciences and Mathematics, Risk Analysis, Statistics and Probability
Computer models are essential tools in the earth system sciences. They underpin our search for understanding of earth system functioning and support decision- and policy-making across spatial and temporal scales. To understand the implications of uncertainty and environmental variability on the identification of such earth system models and their predictions, we can rely on increasingly powerful [...]