Preprints
There are 5726 Preprints listed.
Towards a new geological time scale: A template for improved rock-based subdivision of pre-Cryogenian time
Published: 2020-10-22
Subjects: Physical Sciences and Mathematics
Four first-order (Hadean, Archean, Proterozoic and Phanerozoic eon) and nine second-order (Paleoarchean, Mesoarchean, Neoarchean, Paleoproterozoic, Mesoproterozoic, Neoproterozoic, Paleozoic, Mesozoic and Cenozoic era) units continue to provide intuitive subdivision of geological time. Major transitions in Earth’s tectonic, biological and environmental history occurred at approximately 2.5-2.3, [...]
An explanation to the Nusselt-Rayleigh discrepancy in naturally convected porous media
Published: 2020-10-22
Subjects: Engineering, Physical Sciences and Mathematics
We model hydrothermal convection using a partial differential equation formed by Darcy velocity and temperature - the velocity formulation. Using the Elder problem as a benchmark, we found that the velocity formulation is a valid model of hydrothermal convection. By performing simulations with Rayleigh numbers in the non-oscillatory regime, we show that multiple quasi-steady-state solutions can [...]
Sedimentological and stratigraphic criteria to distinguish between basin-floor and slope mudstones: Implications for the delivery of mud to deep-water environments
Published: 2020-10-22
Subjects: Physical Sciences and Mathematics
Deep-water mudstones overlying basin-floor and slope sandstone-prone deposits are widely interpreted as hemipelagic drapes deposited during extended periods of sand starvation. However, the processes of mud transport and deposition, and the resulting facies and sedimentary architecture of mudstones in different deep-water environments, remain poorly understood. This study documents the [...]
Assessing streamflow sensitivity to precipitation variability in karst-influenced catchments with unclosed water balance
Published: 2020-10-22
Subjects: Physical Sciences and Mathematics
Karst hydrological models are widely used for simulating groundwater dynamics at the aquifer scale. However, modeling streamflow of a topographic catchment that is partially covered by karst is rarely reported. This is due to difficulties of properly considering the strong differences of karstic and non-karstic hydrodynamics and the widespread occurrence of unclosed water balances in karstic [...]
Structure-from-Motion on shallow reefs and beaches: potential and limitations of consumer-grade drones to reconstruct topography and bathymetry
Published: 2020-10-22
Subjects: Civil Engineering, Engineering, Environmental Engineering, Environmental Monitoring, Environmental Studies, Fluid Dynamics, Fresh Water Studies, Geographic Information Sciences, Hydraulic Engineering, Other Civil and Environmental Engineering, Other Environmental Sciences, Remote Sensing
Reconstructing the topography of shallow underwater environments using Structure-from-Motion – Multi View Stereo (SfM-MVS) techniques applied to aerial imagery from Unmanned Aerial Vehicles (UAVs) is a challenging problem, as it involves non-linear distortions caused by water refraction. This study presents an experiment with aerial photographs collected with a consumer-grade UAV on the [...]
The International Sedimentary Geosciences Congress (ISGC) 2021 – An Opportunity to Shape the Future of Sedimentary Geosciences
Published: 2020-10-22
Subjects: Physical Sciences and Mathematics
The 1st International Sedimentary Geosciences Congress (ISGC) was conceived a few years ago as a unique opportunity for the broad sedimentary geosciences community to come together in a time of transformations. The aim of the congress is to allow the community to express, plan and implement what we all know are necessary changes to progress into the new decades with new motivations, ideas and [...]
Modulation of riverine concentration-discharge relationships by changes in the shape of the water transit time distribution
Published: 2020-10-21
Subjects: Geochemistry, Hydrology
The concentrations of weathering-derived solutes in rivers and their co-variance with discharge are thought to reflect reactive-transport processes in hillslopes and to reveal the sensitivity of solute fluxes to climatic change. It is expected that discharge-driven changes in water transit times play some role in setting concentration-discharge (C-Q) relationships, but knowledge gaps remain. To [...]
Pangeo Benchmarking Analysis: Object Storage vs. POSIX File System
Published: 2020-10-21
Subjects: Computer Sciences, Earth Sciences, Physical Sciences and Mathematics
Pangeo is a community of scientists and software developers collaborating to enable Big Data Geoscience analysis interactively in the public cloud and on high-performance computing (HPC) systems. At the core of the Pangeo software stack is (1) Xarray, which adds labels to metadata such as dimensions, coordinates and attributes for raw array-oriented data, (2) Dask, which provides parallel [...]
River Planform Extraction From High-Resolution SAR Images Via Generalised Gamma Distribution Superpixel Classification
Published: 2020-10-21
Subjects: Computer Engineering, Electrical and Computer Engineering, Engineering, Geology, Geomorphology, Hydrology
The extraction of river planforms from remotely sensed satellite images is a task of crucial importance to many applications such as land planning, water resource monitoring or flood prediction. In this paper we present a novel framework for the extraction of rivers from Synthetic Aperture Radar (SAR) images, based on superpixel segmentation and subsequent classification. Superpixel segmentation [...]
Seismic energy radiation and along-strike heterogeneities of shallow tectonic tremors at the Nankai Trough and Japan Trench
Published: 2020-10-21
Subjects: Geophysics and Seismology
Shallow slow earthquakes have been documented along shallow plate interfaces near trenches. Recent geophysical observation networks located offshore of Japan enable us to analyze shallow tremors in the Nankai Trough and the Japan Trench. Onshore seismic stations are also important for detecting shallow very low frequency earthquakes (VLFEs) and for evaluating their seismicity prior to the [...]
Relative humidity gradients as a key constraint on terrestrial water and energy fluxes
Published: 2020-10-21
Subjects: Earth Sciences, Physical Sciences and Mathematics
Earth’s climate and water cycle are highly dependent on the latent heat flux (LE) associated with terrestrial evapotranspiration. While the widely-used Penman-Monteith LE model is useful to explore vegetative controls on LE, land-atmosphere interactions are difficult to interpret due to the complex role of biological controls on underlying physical processes. Here, we present a novel LE model [...]
The importance of the study of igneous rocks and compositions to constrain the martian planetary evolution
Published: 2020-10-21
Subjects: Physical Sciences and Mathematics
This white paper summarizes the scientific importance of studying igneous compositions in meteorites, surface samples, and through orbital analyses to better constrain the geology of Mars as a whole and better understand the geological processes that have shaped Mars in the past and present. In support of martian igneous studies, we strongly advocate for the following in the upcoming [...]
The Paradox of Increasing Initial Oil Production but Faster Decline Rates in Fracking the Bakken Shale: Implications for Long Term Productivity of Tight Oil Plays
Published: 2020-10-21
Subjects: Oil, Gas, and Energy, Petroleum Engineering
In the US, tight oil is the largest source of liquid hydrocarbons and has driven the country to become the world’s largest oil producer. Eventually many countries will likely be producing very large quantiles of tight oil. However, how robust is tight oil production? The answer to this question will have an impact on the future geographic spread of oil production and will have geopolitical [...]
Dynamical analysis of a reduced model for the North Atlantic Oscillation
Published: 2020-10-21
Subjects: Applied Mathematics, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
The dynamics of the North Atlantic Oscillation (NAO) are analyzed through a data-driven model obtained from atmospheric reanalysis data. We apply a regularized vector autoregressive clustering technique to identify recurrent and persistent states of atmospheric circulation patterns in the North Atlantic sector (110W-0E, 20N-90N). In order to analyze the dynamics associated with the resulting [...]
Downhole distributed acoustic sensing reveals the wave field structure of the coastal microseisms
Published: 2020-10-21
Subjects: Engineering, Physical Sciences and Mathematics
Ocean-generated seismic waves are omnipresent in passive seismic records around the world and present both a challenge for earthquakes observations and an input signal for interferometric methods for characterisation of the Earth's interior. Understanding of these waves requires the knowledge of the depth-dependence of the oceanic noise at the transition into continent. To this end, we examine 80 [...]