Preprints
There are 7994 Preprints listed.
Causation of Late Quaternary Rapid-increase Radiocarbon Anomalies
Published: 2019-05-08
Subjects: Astrophysics and Astronomy, Cosmochemistry, Earth Sciences, Physical Sciences and Mathematics
Brief (<100 y) rapid-increase anomalies in the Earth’s atmospheric 14C production have previously been attributed to either gamma photon radiation from supernovae or to cosmic ray particle radiation from exceptionally large solar flares. Analysis of distances and ages of nearby supernovae (SNe) remnant surveys, the probable gamma emissions, the predicted Earth-incident radiation, and the [...]
Terrestrial environmental change across the onset of the PETM and the associated impact on biomarker proxies: a cautionary tale
Published: 2019-04-29
Subjects: Biogeochemistry, Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics
The Paleocene-Eocene Thermal Maximum (PETM; ~ 56 million years ago (Ma) is the most severe carbon cycle perturbation event of the Cenozoic. Although the PETM is associated with warming in both the surface (~up to 8°C) and deep ocean (~up to 5°C), there are relatively few terrestrial temperature estimates from the onset of this interval. The associated response of the hydrological cycle during the [...]
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 [...]
A long-term, high-latitude record of Eocene hydrological change in the Greenland region
Published: 2019-04-26
Subjects: Biogeochemistry, Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics
A range of proxy approaches have been used to reconstruct short-term changes to Earth’s hydrological cycle during the early Eocene hyperthermals. However, little is known about the response of Earth’s hydrological and biogeochemical systems to long-term Cenozoic cooling, which began following the Early Eocene Climatic Optimum (53.3 – 49.4 million years ago; Ma). Here, we use the molecular [...]
Application of multivariate statistical methods to hydrogeological property parameterisation from geotechnical and geophysical data
Published: 2019-04-26
Subjects: Earth Sciences, Environmental Sciences, Geology, Hydrology, Other Earth Sciences, Physical Sciences and Mathematics, Water Resource Management
Hydrogeological data sets are often relatively sparse compared to the scale of investigation, resulting in degrees of uncertainty which, although constrained, may be considered as not acceptable for achieving the desired precision in numerical modelling. The potential use of multivariate statistical methods in identifying correlations between geotechnical properties of the rock mass and hydraulic [...]
Influence of dissolution on frictional properties of carbonate faults
Published: 2019-04-25
Subjects: Civil and Environmental Engineering, Civil Engineering, Earth Sciences, Engineering, Geophysics and Seismology, Physical Sciences and Mathematics
Velocity stepping experiments have been performed on a simulated calcite gouge using an annular shear apparatus to investigate the effect of dissolution on the frictional properties of a carbonate fault. The tested material was put in contact with hydrochloric acid at different concentration in order to dissolve the grains. Particle size analysis shows that the small grains tend to disappear due [...]
A heuristic model inversion for coupled thermo-hydro-mechanical modeling of triaxial experiments
Published: 2019-04-25
Subjects: Applied Mathematics, Civil and Environmental Engineering, Engineering, Geotechnical Engineering, Physical Sciences and Mathematics
As multiphysics geomechanical models get developed, their increasing complexity and number of parameters make it particularly difficult to calibrate against experimental data. In this contribution, we present a heuristic workflow to invert for parameters of a coupled Thermo-Hydro-Mechanical (THM) model in a way that helps the theoretical modellers refine their definition of the underlying [...]
Radiation Hazard evaluation and spatial dose rate mapping in mineralized region of Siwaliks: A case study from Una, Kangra and Hamirpur distt, Himachal Pradesh, India.
Published: 2019-04-25
Subjects: Environmental Health and Protection, Environmental Sciences, Physical Sciences and Mathematics
The following work is a part of wider uranium prospecting programme of the Atomic Mineral Directorate for Exploration and Research (AMD) for mapping radioactive anomalies in mineralized regions of Siwalik, Himachal Pradesh. This study reports the analysis of average activity concentration, potential radiological hazards; radium equivalent activity (Raeq), external hazard index (Hex), internal [...]
Dispersion, accumulation and the ultimate fate of microplastics in deep-marine environments: A review and future directions
Published: 2019-04-04
Subjects: Earth Sciences, Environmental Health and Protection, Environmental Indicators and Impact Assessment, Environmental Monitoring, Environmental Sciences, Natural Resources and Conservation, Physical Sciences and Mathematics, Sustainability
An estimated 8.3 billion tonnes of non-biodegradable plastic has been produced over the last 65 years. Much of this is not recycled and is disposed into the sedimentary system, has a long environmental residence time and accumulates in sedimentary systems worldwide, posing a threat to important ecosystems and potentially human health. We synthesise existing knowledge of seafloor microplastic [...]
A physics-based approach of deep interseismic creep for viscoelastic strike-slip earthquake cycle models
Published: 2019-04-25
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Most geodetic inversions of surface deformation rates consider the depth distribution of interseismic fault slip-rate to be time invariant. However, some numerical simulations show down-dip penetration of dynamic rupture into regions with velocity-strengthening friction, with subsequent up-dip propagation of the locked-to-creeping transition. Recently, Bruhat & Segall (2017) developed a new [...]
Bayesian parameter estimation for space and time interacting earthquake rupture model using historical and physics-based simulated earthquake catalogs
Published: 2019-04-25
Subjects: Civil and Environmental Engineering, Civil Engineering, Earth Sciences, Engineering, Geophysics and Seismology, Physical Sciences and Mathematics, Risk Analysis
This paper presents a robust parameter estimation technique for a probabilistic earthquake hazard model that captures time and space interactions between earthquake mainshocks. The approach addresses the existing limitations of parameter estimation techniques by developing a Bayesian formulation and leveraging physics-based simulated synthetic catalogs to expand the limited datasets of historical [...]
Stratigraphy of Architectural Elements of a Buried Monogenetic Volcanic System and Implications for Geoenergy Exploration
Published: 2019-04-26
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics
Large volumes of magma emplaced and deposited within sedimentary basins can have an impact on their architectural style and geological evolution. Over the last decade, continuous improvement in techniques such as seismic volcano-stratigraphy and 3D seismic visualization of igneous rocks buried in sedimentary basins has helped increase knowledge about these “volcanic basins”. Here, we unravel the [...]
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 [...]