Preprints
Filtering by Subject: Physical Sciences and Mathematics
‘Scallywag Bunkers’: Geophysical Investigations of WW2 Auxiliary Unit Operational Bases (OBs) in the UK
Published: 2020-02-05
Subjects: Earth Sciences, Education, Geography, Other Earth Sciences, Other Physical Sciences and Mathematics, Physical Sciences and Mathematics, Social and Behavioral Sciences
In 1940, with the fall of France imminent, Britain prepared for invasion. After Dunkirk, with most armour and transport lost, a defence ‘stop line’ (GHQ Line) was prepared. Local Defence Volunteers (later Home Guard) were raised to buy time for the Home Army to deploy. Secret ‘Auxiliary Units’ were also formed, tasked with ‘Scallywagging’ – guerrilla activities ––in the invading army’s rear. 4-8 [...]
Centrifugal and symmetric instability during Ekman adjustment of the bottom boundary layer
Published: 2020-02-04
Subjects: Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Flow along isobaths of a sloping lower boundary generates an across-isobath Ekman transport in the bottom boundary layer. When this Ekman transport is down the slope it causes convective mixing --- much like a downfront wind in the surface boundary layer --- destroying stratification and potential vorticity. In this manuscript we show how this can lead to the development of a forced centrifugal [...]
A new model for fault growth during syn-kinematic deposition
Published: 2020-02-04
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
Constraining the mechanisms of fault growth is essential for understanding extensional tectonics. In these dynamic systems the propagation of existing faults through recent syn-kinematic depositions is a poorly understood yet critical process. To understand how underlying structures influence faulting, we examine fault growth in a 10 kyr magmatically-resurfaced region of the Krafla fissure swarm, [...]
Fault rupture during the December 26, 2018, Mw 4.9 Fleri earthquake (Mt. Etna): surface faulting in a volcano-tectonic environment
Published: 2020-02-04
Subjects: Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure, Volcanology
On December 26, 2018, the largest instrumental earthquake ever recorded in Mt. Etna (Sicily, southern Italy) shook the eastern flank of the volcano, with epicenter near the Fleri village along the right-lateral Fiandaca Fault (focal depth less than 1 km, Mw 4.9). The mainshock was accompanied by widespread surface faulting. We surveyed and mapped the coseismic ground ruptures and collected [...]
High-resolution surface velocities and strain for Anatolia from Sentinel-1 InSAR and GNSS data
Published: 2020-02-04
Subjects: Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure
Measurements of present-day surface deformation are essential for the assessment of long-term seismic hazard. The European Space Agencys Sentinel-1 satellites enable global, high-resolution observation of crustal motion from Interferometric Synthetic Aperture Radar (InSAR). We have developed new automated InSAR processing systems that exploit the first ~5 years of Sentinel-1 data to measure [...]
Developing a coral proxy system model to compare coral and climate model estimates of changes in paleo-ENSO variability
Published: 2020-02-04
Subjects: Climate, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Coral records of surface-ocean conditions extend our knowledge of interannual El Niño-Southern Oscillation (ENSO) variability into the pre-instrumental period. That said, the wide range of natural variability within the climate system as well as multiple sources of uncertainties inherent to the coral archive produce challenges for the paleoclimate community to detect forced changes in ENSO using [...]
Base Level Changes based on Basin Filling Modelling: a Case Study from the Paleocene Lishui Sag, East China Sea Basin
Published: 2020-02-04
Subjects: Earth Sciences, Physical Sciences and Mathematics, Sedimentology
Estimation of base level changes in geological records is an important topic for petroleum geologists. Taking the Paleocene Upper Lingfeng Member of Lishui Sag as an example, this paper conducted a base level reconstruction based on Basin Filling Modelling (BFM). The reconstruction was processed on the ground of a previously interpreted seismic stratigraphic framework with several assumptions and [...]
On the potential of linked-basin tidal power plants: an operational and coastal modelling assessment
Published: 2020-02-02
Subjects: Civil and Environmental Engineering, Computational Engineering, Engineering, Environmental Engineering, Hydraulic Engineering, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Single-basin tidal range power plants have the advantage of predictable energy outputs, but feature non-generation periods in every tidal cycle. Linked-basin tidal power systems can reduce this variability and consistently generate power. However, as a concept the latter are under-studied with limited information on their performance relative to single-basin designs. In addressing this, we [...]
A Shallow Water Model for Convective Self-Aggregation
Published: 2020-02-02
Subjects: Atmospheric Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Convective self-aggregation is proposed to be fundamental to the development of tropical cyclones and the Madden-Julian Oscillation, both of which are long-term mysteries in tropical meteorology. Therefore, understanding self-aggregation is key to deciphering how convection works in the tropical atmosphere. Here we present a 1D shallow water model that simulates the dynamics of the planetary [...]
Novel insights from Fe-isotopes into the lithological heterogeneity of Ocean Island Basalts and plume-influenced MORBs
Published: 2020-02-02
Subjects: Earth Sciences, Geochemistry, Physical Sciences and Mathematics, Volcanology
The extent of lithological heterogeneity in the Earth’s convecting mantle is highly debated. Whilst the presence of pyroxenite in the mantle source regions of Ocean Island Basalts (OIBs) has traditionally been constrained using the minor-element chemistry of olivine phenocrysts, recent studies have shown that the Ni and Mn contents of primitive olivines are influenced by the conditions of mantle [...]
Entangled external and internal controls on submarine fan evolution: an experimental perspective
Published: 2020-02-02
Subjects: Earth Sciences, Geology, Geomorphology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy
Submarine fans are formed by sediment-laden flows shed from continental margins into ocean basins. Their morphology represents the interplay of external controls such as tectonics, climate, and sea-level with internal processes including channel migration and lobe compensation. However, the nature of this interaction is poorly understood. We used physical modelling to represent the evolution of a [...]
Integrating suspended sediment flux in large alluvial river channels: Application of a synoptic Rouse-based model to the Irrawaddy and Salween rivers
Published: 2020-02-02
Subjects: Earth Sciences, Geochemistry, Geology, Geomorphology, Hydrology, Physical Sciences and Mathematics, Sedimentology
A large portion of freshwater and sediment is exported to the ocean by a small number of major rivers. Many of these mega-rivers are subject to substantial anthropogenic pressures, which are having a major impact on water and sediment delivery to deltaic ecosystems. Due to hydrodynamic sorting, sediment grain size and composition varies strongly with depth and across the channel in large rivers, [...]
Fate of organic compounds during transformation of ferrihydrite in iron formations
Published: 2020-01-30
Subjects: Biogeochemistry, Chemistry, Earth Sciences, Physical Chemistry, Physical Sciences and Mathematics
The absence of organic compounds from Precambrian iron formations (IF) challenges the hypothesis of the biogenic origin of IF. Here we address the fate of adsorbed organic compounds during transformation from ferrihydrite to hematite. We determined the binding energy between hematite and common molecular terminations found in extracellular polymeric substances and biofilms: carboxylic, hydroxyl [...]
Monitoring seasonal variations in seismic velocity and groundwater levels in Harvey, Western Australia using borehole ambient seismic noise interferometry
Published: 2020-01-30
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
In order to explore the relationships between environmental subsurface changes and seismic velocities, we use nearly four years (2015-2018) of continuous ambient seismic noise data recorded in a multi-level borehole sensor array to measure relative seismic velocity changes at the SW Hub CO2 Geosequestration Site in Harvey, Western Australia using seismic noise interferometry. We find a direct [...]
Sensitivity Analysis of a Conceptual, Lumped Model Using VARS-TOOL Applied to Western Ghats Catchments of India
Published: 2020-01-30
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Environmental Engineering, Environmental Sciences, Hydrology, Other Civil and Environmental Engineering, Physical Sciences and Mathematics, Water Resource Management
The present work considers the application of Variogram Analysis of Response Surfaces Toolbox (VARS-TOOL) to identify the sensitive parameters of a rainfall-runoff model in the Netravati river basin of Karnataka, India using the global sensitivity analysis method. The statistical bootstrapping method is used to obtain the confidence intervals around each of the sensitivity indices. The VARS-TOOL [...]