Preprints
Filtering by Subject: Physical Sciences and Mathematics
Hydro-morphodynamics 2D modelling using a discontinuous Galerkin discretisation
Published: 2020-01-09
Subjects: Applied Mathematics, Computer Sciences, Earth Sciences, Geomorphology, Numerical Analysis and Computation, Partial Differential Equations, Physical Sciences and Mathematics, Sedimentology
The development of morphodynamic models to simulate sediment transport accurately is a challenging process that is becoming ever more important because of our increasing exploitation of the coastal zone, as well as sea-level rise and the potential increase in strength and frequency of storms due to a changing climate. Morphodynamic models are highly complex given the non-linear and coupled nature [...]
Lessons learned from monitoring of turbidity currents and guidance for future platform designs
Published: 2020-01-09
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics
Turbidity currents transport globally significant volumes of sediment and organic carbon into the deep-sea and pose a hazard to critical infrastructure. Despite advances in technology, their powerful nature often damages expensive instruments placed in their path. These challenges mean that turbidity currents have only been measured in a few locations worldwide, in relatively shallow water depths [...]
Detection of VLF attenuation in the Earth-ionosphere waveguide caused by X-class solar flares using a global lightning location network
Published: 2020-01-09
Subjects: Astrophysics and Astronomy, Earth Sciences, Geophysics and Seismology, Other Physics, Physical Sciences and Mathematics, Physics, The Sun and the Solar System
Solar flares, energetic particles and Earth-impacting coronal mass ejections enhance ionization in the lower ionosphere, inhibiting radio wave propagation in the Earth-ionosphere waveguide (EIWG). This enhanced ionization is observed locally by ionosondes and GPS/GNSS receivers, but spatial coverage of these observations is limited by receiver location. VLF propagation studies have previously [...]
Impact of nested moisture cycles on coastal chalk cliff failure revealed by multi seasonal seismic and topographic surveys
Published: 2020-01-09
Subjects: Earth Sciences, Geomorphology, Physical Sciences and Mathematics
Cliff failure is a fundamental process shaping many coastlines worldwide. Improved insight into direct links between cliff failure and forcing mechanisms requires precise information on the timing of individual failures, which is difficult to obtain with conventional observation methods for longer stretches of coastline. Here we use seismic records and auxiliary data spanning 25 months to [...]
Uncertainty in the response of sudden stratospheric warmings and stratosphere-troposphere coupling to quadrupled CO2 concentrations in CMIP6 models
Published: 2020-01-09
Subjects: Atmospheric Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Major sudden stratospheric warmings (SSWs), vortex formation and final breakdown dates are key highlight points of the stratospheric polar vortex. These phenomena are relevant for stratosphere-troposphere coupling, which explains the interest in understanding their future changes. However, up to now, there is not a clear consensus on which projected changes to the polar vortex are robust, [...]
Magnetite biomineralization in ferruginous waters and early Earth evolution
Published: 2020-01-09
Subjects: Biogeochemistry, Earth Sciences, Geochemistry, Physical Sciences and Mathematics
Burial of large quantities of magnetite (Fe(II)Fe(III)2O4) in iron formations (IFs) likely contributed to the protracted oxidation of Earth’s surface during the Precambrian Eons. Magnetite can form through a diversity of biological and abiotic pathways and its preservation in IFs may thus be variably interpreted as the result of some combination of these processes. Such interpretations thus give [...]
Modelling the ecological impacts of tidal energy barrages
Published: 2020-01-09
Subjects: Environmental Sciences, Physical Sciences and Mathematics
Tidal energy has the potential to form a key component of the energy mix of a number of countries, including the UK. Nonetheless, the deployment of tidal energy systems is associated with potential environmental impacts as prime resource sites often coincide with unique ecosystems inhabited by sensitive organisms. Preceding studies have generally focused on the hydrodynamic impact of tidal energy [...]
Feedback between drought and deforestation in the Amazon
Published: 2020-01-09
Subjects: Atmospheric Sciences, Climate, Earth Sciences, Environmental Sciences, Hydrology, Natural Resources and Conservation, Natural Resources Management and Policy, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Sustainability
Deforestation and drought are among the greatest environmental pressures on the Amazon rainforest, possibly destabilizing the forest-climate system. Deforestation in the Amazon reduces rainfall regionally, while this deforestation itself has been reported to be facilitated by droughts. Here we quantify the interactions between drought and deforestation spatially across the Amazon during the early [...]
Distributed Acoustic Sensing of Microseismic Sources and Wave Propagation in Glaciated Terrain
Published: 2020-01-09
Subjects: Earth Sciences, Environmental Sciences, Glaciology, Physical Sciences and Mathematics
Records of Alpine microseismicity are a powerful tool to study landscape-shaping processes and warn against hazardous mass movements. Unfortunately, seismic sensor coverage in Alpine regions is typically insufficient. Here we show that distributed acoustic sensing (DAS) bridges critical observational gaps of seismogenic processes in Alpine terrain. Dynamic strain measurements in a 1 km long fiber [...]
Coastal flooding will disproportionately impact people on river deltas
Published: 2020-01-09
Subjects: Earth Sciences, Environmental Studies, Geography, Physical and Environmental Geography, Physical Sciences and Mathematics, Social and Behavioral Sciences
Climate change is intensifying tropical cyclones, accelerating sea-level rise, and increasing coastal flooding. Coastal flooding will not affect all environments equally, and river deltas are especially vulnerable because of their low elevations, densely populated cities, and river channels that propagate coastal floods inland. Yet, we do not know how many people live on deltas and their exposure [...]
A web application for hydrogeomorphic flood hazard mapping
Published: 2020-01-08
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Hydraulic Engineering, Hydrology, Physical Sciences and Mathematics
A detailed delineation of flood-prone areas over large regions represents a challenge that cannot be easily solved with today’s resources. The main limitations lie in algorithms and hardware, but also costs, scarcity and sparsity of data and our incomplete knowledge of how inundation events occur in different river floodplains. We showcase the implementation of a data-driven web application for [...]
The mixology of precursory strain partitioning approaching brittle failure in rocks
Published: 2020-01-08
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure
We examine the strain accumulation and localization process throughout twelve triaxial compression experiments on six rock types deformed in an X-ray transparent apparatus. In each experiment, we acquire 50-100 tomograms of rock samples at differential stress steps during loading, revealing the evolving 3D distribution of X-ray absorption contrasts, indicative of density. Using digital volume [...]
Paleotsunami record of the past 4300 years in the complex coastal lake system of Lake Cucao, Chiloé Island, south central Chile
Published: 2020-01-08
Subjects: Earth Sciences, Physical Sciences and Mathematics, Sedimentology
In CE 1960, Lake Cucao on Chiloé Island in south central Chile was inundated by the tsunami of the Great Chilean Earthquake (Mw 9.5). The area of what is now the lake basin has been submerged since the end of the rapid postglacial sea-level rise and has recorded tsunami inundations in its sediment record since then. This study reconstructs the tsunami history of Lake Cucao. Reflection-seismic [...]
Ge and Si isotope behavior during intense tropical weathering and ecosystem cycling
Published: 2020-01-03
Subjects: Biogeochemistry, Earth Sciences, Physical Sciences and Mathematics
Chemical weathering of volcanic rocks in warm and humid climates contributes disproportionately to global solute fluxes. Geochemical signatures of solutes and solids formed during this process can help quantify and reconstruct volcanic weathering intensity in the past. Here, we measured silicon (Si) and germanium (Ge) isotope ratios of the soils, clays, and fluids from a tropical lowland [...]
The Origin of Continental Carbonates in Andean Salars: A Multi-Tracer Geochemical Approach in Laguna Pastos Grandes (Bolivia)
Published: 2020-01-03
Subjects: Earth Sciences, Geochemistry, Hydrology, Physical Sciences and Mathematics
In continental volcanic settings, abundant carbonate precipitation can occur with atypical facies compared to marine settings. The (bio-)chemical processes responsible for their development and early diagenesis are typically complex and not fully understood. In the Bolivian Altiplano, Laguna Pastos Grandes hosts a 40-km2 carbonate platform with a great diversity of facies and provides an ideal [...]