Preprints
There are 4724 Preprints listed.
Geodynamic, geodetic, and seismic constraints favour deflated and dense-cored LLVPs
Published: 2021-06-18
Subjects: Cosmochemistry, Earth Sciences, Geochemistry, Geophysics and Seismology, Mineral Physics, Physical Sciences and Mathematics
Two continent-sized features in the deep mantle, the large low-velocity provinces (LLVPs), influence Earth's supercontinent cycles, mantle plume generation, and its geochemical budget. Seismological advances have steadily improved LLVP imaging, but several fundamental questions remain unanswered, including: What is their vertical extent? And, are they purely thermal anomalies, or are they also [...]
Past terrestrial hydroclimate driven by Earth System Feedbacks
Published: 2021-06-17
Subjects: Physical Sciences and Mathematics
Geologic evidence suggests drastic reorganizations of subtropical terrestrial hydroclimate during past warm intervals, including the mid-Piacenzian Warm Period (MP, 3.3 to 3.0 Ma). Despite having a similar to present-day atmospheric CO2 level (pCO2), MP featured moist subtropical conditions with high lake levels in Northern Africa, and mesic vegetation and sedimentary facies in subtropical [...]
Generation of Earth’s Early Continents From a Relatively Cool Archean Mantle
Published: 2021-06-17
Subjects: Physical Sciences and Mathematics
Several lines of evidence suggest that the Archean (4.0–2.5 Ga) mantle was hotter than today’s potential temperature (TP ) of 1350 ýC. However, the magnitude of such di erence is poorly constrained, with TP estimation spanning from 1500 ýC to 1600 ýC during the Meso-Archean (3.2-2.8 Ga). Such di erences have major implications for the interpreted mechanisms of continental crust generation on [...]
Fluid invasion dynamics in porous media with complex wettability and connectivity
Published: 2021-06-17
Subjects: Chemical Engineering, Complex Fluids, Earth Sciences, Fluid Dynamics, Hydrology, Materials Science and Engineering, Other Materials Science and Engineering, Petroleum Engineering, Transport Phenomena
Multiphase flow is important for many natural and engineered processes in subsurface geoscience. Pore-scale multiphase flow dynamics are commonly characterized by an average balance of driving forces. However, significant local variability in this balance may exist inside natural, heterogeneous porous materials, such as rocks and soils. Here, we investigate multiphase flow in heterogeneous rocks [...]
Impact of injection rate ramp-up on nucleation and arrest of dynamic fault slip
Published: 2021-06-17
Subjects: Engineering
Fluid injection into underground formations reactivates preexisting geological discontinuities such as faults or fractures. In this work, we investigate the impact of injection rate ramp-up present in many standard injection protocols on the nucleation and potential arrest of dynamic slip along a planar pressurized fault. We assume a linear increasing function of injection rate with time, up to a [...]
Two-fluid single-column modelling of Rayleigh-Bénard convection as a step towards multi-fluid modelling of atmospheric convection
Published: 2021-06-17
Subjects: Atmospheric Sciences
Multi-fluid models have recently been proposed as an approach to improving the representation of convection in weather and climate models. This is an attractive framework as it is fundamentally dynamical, removing some of the assumptions of mass-flux convection schemes which are invalid at current model resolutions. However, it is still not understood how best to close the multi-fluid equations [...]
Channel, dune and sand sheet architectures of strait-adjacent deltas, Rifian Corridor, Morocco
Published: 2021-06-17
Subjects: Earth Sciences, Geology, Sedimentology, Stratigraphy
Sea strait geographies amplify tidal currents, which can result in the formation of tidal strait deposits with a symmetrical facies arrangement. It can be problematic to distinguish such confined tidal strait deposits from strait systems that developed in less constricted settings. To push a more robust differentiation between the confined tidal strait model and a model for less constricted tidal [...]
Microstructure and fluid flow in the vicinity of basin bounding faults in rifts – the Dombjerg Fault, NE Greenland rift system
Published: 2021-06-17
Subjects: Earth Sciences, Geology, Sedimentology, Tectonics and Structure
Faults commonly form loci for high fluid flux in sedimentary basins, where fluids, rocks and deformation processes frequently interact. Here, we elucidate the interaction of fluid flow, diagenesis and deformation near basin-bounding faults in sedimentary basins through a study in the vicinity (0-3.5 km) of the Dombjerg Fault in the NE Greenland rift system. Due to fault-controlled fluid [...]
OpenOBS: Open-source, low-cost optical backscatter sensors for water quality and sediment-transport research
Published: 2021-06-17
Subjects: Environmental Monitoring, Fluid Dynamics, Fresh Water Studies, Geomorphology, Oceanography, Sedimentology, Water Resource Management
Optical backscatter sensors (OBSs) are commonly used to measure the turbidity, or light obscuration, of water in fresh and marine environments and various industrial applications. These turbidity measurements are commonly calibrated to yield total suspended solids (TSS) or suspended sediment concentration (SSC) measurements for water quality, sediment transport, and diverse other research and [...]
Matchup Characteristics of Sea Surface Salinity using a High-resolution Ocean Model
Published: 2021-06-16
Subjects: Oceanography
Sea surface salinity (SSS) satellite measurements are validated using in situ observations usually made by surfacing Argo floats. Validation statistics are computed using matched values of SSS from satellites and floats. This study explores how the matchup process is done using a high-resolution numerical ocean model, the MITgcm. One year of model output is sampled as if the Aquarius and Soil [...]
Will it float? Rising and settling velocities of common macroplastic foils
Published: 2021-06-15
Subjects: Environmental Engineering, Hydraulic Engineering
Plastic accumulates in the environment because of insufficient waste handling and the materials' high durability. Better understanding of plastic behaviour in the aquatic environment is needed to estimate transport and accumulation, which can be used for monitoring strategies, prevention measures, and plastic clean-up activities. Plastic transport models benefit from accurate description of [...]
An Outsized Role for the Labrador Sea in the Multidecadal Variability of the Atlantic Overturning Circulation
Published: 2021-06-15
Subjects: Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Climate models are essential tools for investigating intrinsic North Atlantic variability related to variations in the Atlantic meridional overturning circulation (AMOC), but recent observations have called into question the fidelity of models that emphasize the importance of Labrador Sea processes. A multi-century pre-industrial climate simulation that resolves ocean mesoscale eddies has a [...]
A new tropical cyclone surge index incorporating the effects of coastal geometry, bathymetry and storm information
Published: 2021-06-14
Subjects: Earth Sciences, Oceanography and Atmospheric Sciences and Meteorology, Risk Analysis
This study presents a new storm surge hazard potential index (SSHPI) for estimating tropical cyclone (TC) induced maximum surge levels at a coast. The SSHPI incorporates parameters that are often readily available at real-time: intensity in 10-minute maximum wind speed, radius of 50-kt wind, translation speed, coastal geometry, and bathymetry information. The inclusion of translation speed and [...]
Turbulent flow effects in hydraulic fracture propagation in permeable rock
Published: 2021-06-14
Subjects: Fluid Dynamics, Hydraulic Engineering, Hydrology, Numerical Analysis and Scientific Computing, Oil, Gas, and Energy
This chapter considers a model for a radial hydraulic fracture propagation in a permeable, linear elastic rock formation driven by a point source fluid injection. The linear elastic fracture mechanics theory controls the quasi-static propagation. The hydraulic fracturing fluid is slickwater -- pure water solution with polymeric additives which allow reducing the fluid flow friction in the [...]
Remote bed-level change and overwash observation with low-cost ultrasonic distance sensors
Published: 2021-06-13
Subjects: Earth Sciences, Geomorphology, Physical Sciences and Mathematics
Few datasets exist of high-frequency, in situ measurements of storm overwash, an essential mechanism for the subaerial maintenance of barrier islands and spits. Here we describe a new sensor platform for measuring bed-level change and estimating overwash inundation depths. Our MeOw (Measuring Overwash) stations consist of two ultrasonic distance sensors, a microprocessor board, and a camera and [...]