Preprints
Filtering by Subject: Physical Sciences and Mathematics
Temporal evolution of extensional fault-propagation folds
Published: 2017-11-23
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Stratigraphy, Tectonics and Structure
Integration of three-dimensional seismic and well data from the Upper Jurassic North Sea rift provides insights into the temporal evolution of fault-propagation folds in extensional settings. The hangingwall of the Oseberg fault zone is characterised by an asymmetric, fault-parallel syncline interpreted as the hangingwall portion of a breached monocline which formed in response to an [...]
BIOMEDIATION OF SEDIMENT GRAVITY FLOW DYNAMICS
Published: 2017-11-22
Subjects: Earth Sciences, Physical Sciences and Mathematics, Sedimentology
Sediment gravity flows (SGFs) are the primary process by which sediment and organic carbon are transported from the continental margin to the deep ocean. Forty percent of the total marine organic carbon pool is represented by cohesive extracellular polymeric substances (EPS) produced by marine benthic and pelagic micro-organisms. EPS research to date has focussed on coastal environments, where [...]
Comparison of 0-D, 1-D and 2-D model capabilities for tidal range energy resource assessments
Published: 2017-11-22
Subjects: Civil and Environmental Engineering, Computational Engineering, Earth Sciences, Electrical and Computer Engineering, Engineering, Environmental Sciences, Hydraulic Engineering, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Power and Energy
Tidal range energy projects present an attractive means for the predictable and large-scale generation of electricity from the marine environment. In particular, proposals are under consideration in UK waters, with their feasibility currently being under high levels of scrutiny. This is due to a combination of potential environmental and socio-economic impacts that are challenging to quantify in [...]
Numerical solution of a non-linear conservation law applicable to the interior dynamics of partially molten planets
Published: 2017-11-21
Subjects: Applied Mathematics, Computer Sciences, Earth Sciences, Fluid Dynamics, Geophysics and Seismology, Numerical Analysis and Computation, Numerical Analysis and Scientific Computing, Physical Sciences and Mathematics, Physics
The energy balance of a partially molten rocky planet can be expressed as a non-linear diffusion equation using mixing length theory to quantify heat transport by both convection and mixing of the melt and solid phases. Crucially, in this formulation the effective or eddy diffusivity depends on the entropy gradient, dS/dr, as well as entropy itself. First we present a simplified model with [...]
High curvatures drive river meandering
Published: 2017-11-21
Subjects: Earth Sciences, Geology, Geomorphology, Physical Sciences and Mathematics
One of the long- and widely held ideas about the dynamics of meandering rivers is that migration slows down in bends with higher curvatures. Identifying the radius of curvature at which migration is fastest is standard practice in field studies of meandering rivers. High-resolution measurements of local migration rates in time-lapse Landsat images from two rapidly migrating rivers in the Amazon [...]
Scientific and risk-reduction benefits of involving citizens in monitoring volcanic activity
Published: 2017-11-20
Subjects: Earth Sciences, Environmental Monitoring, Environmental Sciences, Geology, Physical Sciences and Mathematics, Volcanology
Citizen science involves volunteers, regardless of scientific background, in conducting scientific investigations. Although the extent of citizen involvement varies, the reported benefits of such activities include: the generation of new knowledge; increased public understanding of and confidence in science, and ‘real-time’ insights into rapidly evolving events such as natural hazards. In [...]
Seismic and structural characterization of a pre-salt rifted section: the Lagoa Feia Group, Campos Basin, offshore Brazil
Published: 2017-11-17
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics, Stratigraphy
The exploration of pre-salt offshore SE Brazil presents a multifaceted deep-water scenario that is bringing new challenges to seismic interpretation in offshore Brazilian exploration and production. Reservoirs in this domain are complex, heterogeneous with layered carbonates which makes accurate reservoir characterization very challenging. Our study here deals with the seismic characterization of [...]
Unravelling intrusion-induced forced fold kinematics and ground deformation using 3D seismic reflection data
Published: 2017-11-17
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics
Sills emplaced at shallow-levels are commonly accommodated by overburden uplift, producing forced folds. We examine ancient forced folds developed above saucer-shaped sills using 3D seismic reflection data from the Canterbury Basin, offshore SE New Zealand. Seismic-stratigraphic relationships indicate sill emplacement occurred incrementally over ~31 Myr between the Oligocene (~35–32 Ma) and Early [...]
Fault growth and interactions in a multiphase rift fault network: Horda Platform, Norwegian North Sea
Published: 2017-11-16
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
Physical models predict that multiphase rifts that experience a change in extension direction between stretching phases will typically develop non-colinear normal fault sets. Furthermore, multiphase rifts will display a greater frequency and range of styles of fault interactions than single-phase rifts. Although these physical models have yielded useful information on the evolution of fault [...]
The 1902-3 eruptions of the Soufrière, St Vincent: impacts, relief and response
Published: 2017-11-15
Subjects: Earth Sciences, Physical Sciences and Mathematics, Volcanology
Retrospective analysis of the contemporary colonial and scientific records of a major explosive eruption of the Soufrière of St Vincent from 1902-1903 reveals how this significant and prolonged event presented challenges to the authorities charged with managing the crisis and its aftermath. In a small-island setting vulnerable to multiple hazards, the spatial footprint of the volcanic hazard and [...]
Punctuated Sediment Discharge During Early Pliocene Birth of the Colorado River: Evidence from Regional Stratigraphy, Sedimentology, and Paleontology
Published: 2017-11-15
Subjects: Earth Sciences, Physical Sciences and Mathematics, Stratigraphy
The Colorado River in the southwestern U.S. provides an excellent natural laboratory for studying the origins of a continent-scale river system, because deposits that formed prior to and during river initiation are well exposed in the lower river valley and nearby basinal sink. This paper presents a synthesis of regional stratigraphy, sedimentology, and micropaleontology from the southern Bouse [...]
A new global mode of Earth deformation: seasonal cycle detected
Published: 2017-11-14
Subjects: Earth Sciences, Environmental Monitoring, Environmental Sciences, Geophysics and Seismology, Hydrology, Oceanography and Atmospheric Sciences and Meteorology, Other Earth Sciences, Other Environmental Sciences, Other Oceanography and Atmospheric Sciences and Meteorology, Other Physical Sciences and Mathematics, Physical Sciences and Mathematics
We have detected a global mode of Earth deformation that is predicted by theory. Precise positioning of GPS sites distributed worldwide reveals that in February to March the northern hemisphere compresses (and the southern hemisphere expands), such that sites near the North Pole move downward by 3.0 mm, and sites near the equator are pulled northwards by 1.5 mm. The opposite pattern of [...]
Choice of optimal averaging radii for temporal GRACE gravity solutions, a comparison with GPS and satellite altimetry
Published: 2017-11-14
Subjects: Earth Sciences, Environmental Monitoring, Environmental Sciences, Geophysics and Seismology, Glaciology, Hydrology, Other Earth Sciences, Other Environmental Sciences, Physical Sciences and Mathematics
One of the initial challenges of the GRACE mission is to validate the accuracy of the time-variable gravity fields. These gravity fields contain both spatially correlated (systematic) and random noise and hence spatial averaging needs to be implemented. Before the fields may be interpreted, optimum averaging radii need to be determined through comparison with independent data. We compare time [...]
A comparison of GPS, VLBI and model estimates of ocean tide loading displacements
Published: 2017-11-14
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Environmental Sciences, Geophysics and Seismology, Other Civil and Environmental Engineering, Other Earth Sciences, Physical Sciences and Mathematics
In recent years, Ocean Tide Loading Displacements (OTLD) have been measured using the Global Positioning System (GPS) and Very Long Baseline Interferometry (VLBI). This study assesses the accuracy of GPS measurements of OTLD by comparison with VLBI measurements and estimates derived from numerical ocean tide models. A daily precise point positioning (PPP) analysis was carried out on ~11 years of [...]
GPS sidereal filtering: coordinate- and carrier-phase-level strategies
Published: 2017-11-14
Subjects: Civil and Environmental Engineering, Civil Engineering, Earth Sciences, Engineering, Other Civil and Environmental Engineering, Other Earth Sciences, Other Physical Sciences and Mathematics, Physical Sciences and Mathematics
Multipath error is considered one of the major errors affecting GPS observations. One can benefit from the repetition of satellite geometry approximately every sidereal day, and apply filtering to help minimize this error. For GPS data at 1 second interval processed using a double-difference strategy, using the day-to-day coordinate or phase residual autocorrelation determined with a 10 hour [...]