Preprints
Filtering by Subject: Earth Sciences
Observational estimates of dynamic topography through space and time
Published: 2021-01-24
Subjects: Biogeochemistry, Cosmochemistry, Earth Sciences, Geochemistry, Geology, Geomorphology, Geophysics and Seismology, Paleobiology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy, Tectonics and Structure, Volcanology
Earth's mantle undergoes convection on million-year timescales as heat is transferred from depth to the surface. Whilst this flow has long been linked to the large-scale horizontal forces that drive plate tectonics and supercontinent cycles, geologists are increasingly recognising the signature of convection through transient vertical motions in the rock record, known as "dynamic topography". A [...]
Carbon dioxide removal through enhanced weathering of basalt on agricultural land –Assessing the potential in Austria
Published: 2021-01-22
Subjects: Earth Sciences, Environmental Sciences
Enhanced weathering through basalt application on agricultural land represents a proposed strategy for the removal of carbon dioxide from the atmosphere. It has been shown that enhanced weathering is principally feasible on a global scale, but it remains unclear whether it can be implemented on a local level. This information is however vital, to evaluate, if enhanced weathering should be further [...]
Evidence confirms an anthropic origin of Amazonian Dark Earths
Published: 2021-01-22
Subjects: Biogeochemistry, Earth Sciences, Geochemistry, Geomorphology, Physical Sciences and Mathematics, Soil Science
First described over 120 years ago in Brazil, Amazonian Dark Earths (ADEs) are expanses of dark soil that are exceptionally fertile and contain large quantities of archaeological artefacts. The elevated fertility of the dark and often deep A horizon of ADEs is widely regarded as an outcome of pre-Columbian human influence. Controversially, in their recent paper Silva et al.2argue that the higher [...]
The building blocks of igneous sheet intrusions: insights from 3D seismic reflection data
Published: 2021-01-19
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure, Volcanology
The propagating margins of igneous sills (and other sheet intrusions) may divide into laterally and/or vertically separated sections, which later inflate and coalesce. These components elongate parallel to and thus record the magma flow direction, and can form either due to fracture segmentation (i.e., ‘segments’) or brittle and/or non-brittle deformation of the host rock (i.e., ‘magma fingers’). [...]
Earthquake rupture on multiple splay faults and its effect on tsunamis
Published: 2021-01-16
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Detailed imaging of accretionary wedges reveals splay fault networks that could pose a significant tsunami hazard. However, the dynamics of multiple splay fault activation during megathrust earthquakes and the consequent effects on tsunami generation are not well understood. We use a 2-D dynamic rupture model with complex topo-bathymetry and six curved splay fault geometries constrained from [...]
Integrated magnetotelluric and petrological analysis of felsic magma reservoirs: Insights from Ethiopian rift volcanoes
Published: 2021-01-16
Subjects: Earth Sciences, Geochemistry, Geophysics and Seismology, Volcanology
Geophysical and petrological probes are key to understanding the structure and the thermochemical state of active magmatic systems. Recent advances in laboratory analyses, field investigations and numerical methods have allowed increasingly complex data-constraint models with new insights into magma plumbing systems and melt evolution. However, there is still a need for methods to quantitatively [...]
Time to Depth Seismic Reprocessing of Vintage Data: a Case Study in the Otranto Channel (South Adriatic Sea)
Published: 2021-01-14
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Physical Sciences and Mathematics
In this chapter, we present a case study focused on the reprocessing of marine seismic line MS-29, acquired in 1971 in the Otranto Channel, in the South Adriatic Sea (Italy). This line crosses the channel between South Italy and Albania, a key location for understanding the geodynamics of the North Adria Plate. The work is divided into two steps. The first step consists of a modern broadband [...]
Proximal to distal grain-size distribution of basin-floor lobes: A study from the Battfjellet Formation, Central Tertiary Basin, Svalbard
Published: 2021-01-14
Subjects: Earth Sciences, Physical Sciences and Mathematics
The grain-size distribution of sediment particles is an important aspect of the architecture of submarine fans and lobes. It governs depositional sand quality and reflects distribution of particulate organic carbon and pollutants. Documenting the grain-size distribution of these deep-marine sedimentary bodies can also offer us an insight into the flows that deposited them. Submarine lobes are [...]
Dynamic recrystallization by subgrain rotation in olivine revealed by electron backscatter diffraction
Published: 2021-01-12
Subjects: Earth Sciences
We document how dynamic recrystallization by subgrain rotation (SGR) develops in natural olivine-rich rocks deformed in extension to up to 50% bulk finite strain (1473 K, confining pressure of 300 MPa, and stresses between 115 and 180 MPa) using electron backscatter diffraction (EBSD) mapping. SGR occurs preferentially in highly deformed grains (well-oriented to deform by dislocation glide) [...]
Temporal monitoring of vast sand mining in NW Turkey: Implications on environmental/social impacts
Published: 2021-01-08
Subjects: Earth Sciences, Environmental Indicators and Impact Assessment, Environmental Monitoring, Environmental Sciences, Geomorphology, Natural Resources and Conservation, Sedimentology
Loose sand has a wide variety (over 200) of industrial usage where most of the sand is used in infrastructure. Due to its low cost / high benefit nature and international high demand, worldwide examples of excessive sand mining caused complete destruction of habitats and forcing natives change living practices or even to migrate. Sand mining is one of the most controversial and rapidly growing [...]
Assessing erosion and flood risk in the coastal zone through the application of the multilevel Monte Carlo method
Published: 2021-01-07
Subjects: Applied Mathematics, Earth Sciences, Geomorphology, Hydrology, Numerical Analysis and Computation, Risk Analysis, Statistics and Probability
The risk from erosion and flooding in the coastal zone has the potential to increase in a changing climate. The development and use of coupled hydro-morphodynamic models is therefore becoming an ever higher priority. However, their use as decision support tools suffers from the high degree of uncertainty associated with them, due to incomplete knowledge as well as natural variability in the [...]
Sea-level stability over geologic time owing to limited deep subduction of hydrated mantle
Published: 2021-01-06
Subjects: Earth Sciences
The presence of liquid water makes our planet unique. Its budget over geological timescales, i.e., the long-term global sea level, depends on the balance of water exchanges between the Earth's mantle and the surface through both volcanism (mantle degassing) and subduction of hydrous minerals (mantle regassing). Current estimates of subduction water fluxes predict that regassing exceeds degassing [...]
Structural controls on the emplacement and evacuation of magma from a sub-volcanic laccolith; Reyðarártindur Laccolith, SE Iceland
Published: 2021-01-06
Subjects: Earth Sciences, Geology, Higher Education, Physical Sciences and Mathematics, Science and Mathematics Education, Tectonics and Structure, Volcanology
Comments on “On the reported magnetic precursor of the 1989 Loma Prieta earthquake” by J.N. Thomas, J.J. Love, and M.J.S. Johnston
Published: 2021-01-06
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Thomas et al. (2009) (hereafter TLJ09) attempt to cast doubt upon the report by FraserSmith et al. (1990) (hereafter FS90) of unusual large-amplitude ultra-low frequency (ULF; f < 10 Hz) magnetic fields preceding the M ~7 Loma Prieta earthquake. TLJ09 suggest there are instrumental problems with FS90’s data that we, the designers, builders and long-term operators of the equipment, are presumed to [...]
2-D P-SV and SH spectral element modelling of seismic wave propagation in non-linear media with pore-pressure effects
Published: 2021-01-06
Subjects: Earth Sciences, Engineering, Geophysics and Seismology, Geotechnical Engineering
It has long been recognized that the effects of superficial geological layers, or site effects, can play a major role on the seismic ground motion at the free surface. In this study, we compute wave propagation in a 2-D asymmetrical basin considering both soil non-linearity and pore- pressure effects. Equations of elastodynamics of wave propagation are solved using the spectral element method [...]