Preprints
Filtering by Subject: Earth Sciences
Combined geophysical measurements provide evidence for unfrozen water in permafrost in the Adventdalen valley in Svalbard
Published: 2018-05-07
Subjects: Earth Sciences, Geophysics and Seismology, Hydrology, Other Earth Sciences, Physical Sciences and Mathematics
Quantifying the unfrozen water content of permafrost is critical for assessing impacts of surface warming on the reactivation of groundwater flow and release of greenhouse gasses from degrading permafrost. Unfrozen water content was determined along a ~12 km transect in the Adventdalen valley in Svalbard, an area with continuous permafrost, using surface nuclear magnetic resonance and controlled [...]
Identifying causes of ground-penetrating radar reflections using time-domain reflectometry and sedimentological analyses
Published: 2018-05-07
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics, Sedimentology
Ground-penetrating radar (GPR) is a geophysical technique widely used to study the shallow subsurface and identify various sediment features that reflect electromagnetic waves. However, little is known about the exact cause of GPR reflections because few studies have coupled wave theory to petrophysical data. In this study, a 100- and 200-MHz GPR survey was conducted on aeolian deposits in a [...]
Pre-existing basement thrusts influence rifting in the Taranaki Basin, New Zealand
Published: 2018-05-04
Subjects: Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure
Discrete structures (e.g. faults) or pervasive fabrics (e.g. foliation), which may occur in pre-rift sedimentary and/or crystalline basement rock, can control the growth and geometry of rift-related normal fault arrays. Previous studies examining how such structures/fabrics affect rift geometry typically rely only on plan-view correlations between the strike and dip of observed or, in some cases, [...]
EarthN: A new Earth System Nitrogen Model
Published: 2018-05-03
Subjects: Biogeochemistry, Earth Sciences, Physical Sciences and Mathematics
The amount of nitrogen in the atmosphere, oceans, crust, and mantle have important ramifications for Earth’s biologic and geologic history. Despite this importance, the history and cycling of nitrogen in the Earth system is poorly constrained over time. For example, various models and proxies contrastingly support atmospheric mass stasis, net outgassing, or net ingassing over time. In addition, [...]
Bedform migration in a mixed sand and cohesive clay intertidal environment and implications for bed material transport predictions
Published: 2018-05-03
Subjects: Earth Sciences, Physical Sciences and Mathematics, Sedimentology
Many coastal and estuarine environments are dominated by mixtures of non-cohesive sand and cohesive mud. The migration rate of bedforms, such as ripples and dunes, in these environments is important in determining bed material transport rates to inform and assess numerical models of sediment transport and geomorphology. However, these models tend to ignore parameters describing the physical and [...]
Volcanic ash generation mechanisms: Fingerprints in phase distribution highlighted by QEMSCAN particle mineralogical analysis
Published: 2018-05-03
Subjects: Earth Sciences, Physical Sciences and Mathematics, Volcanology
Volcanic ash particle properties depend upon their genetic fragmentation processes. Here, we introduce QEMSCAN particle mineralogical analysis (PMA) to quantify the phase distribution in two ash samples collected during activity at Santiaguito, Guatemala and assess the fingerprint of fragmentation mechanisms. Volcanic ash from a Vulcanian explosion and from a pyroclastic density current resulting [...]
Rainfall-Runoff modelling using Long Short-Term Memory (LSTM) networks
Published: 2018-05-01
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Environmental Engineering, Hydrology, Physical Sciences and Mathematics
Rainfall-runoff modelling is one of the key challenges in the field of hydrology. Various approaches exist, ranging from physically based over conceptual to fully data driven models. In this paper, we propose a novel data driven approach, using the Long-Short-Term-Memory (LSTM) network, a special type of recurrent neural networks. The advantage of the LSTM is its ability to learn long-term [...]
Late Pliocene marine pCO2 reconstructions from the Subarctic Pacific Ocean
Published: 2018-04-30
Subjects: Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics
The development of large ice-sheets across the Northern Hemisphere during the late Pliocene and the emergence of the glacial-interglacial cycles that punctuate the Quaternary mark a significant threshold in Earths climate history. Although a number of different mechanisms have been proposed to initiate this cooling and the onset of major Northern Hemisphere glaciation, reductions in atmospheric [...]
Structural Evolution of Salt-Influenced Fold-and-Thrust belts: A Synthesis and New Insights From Basins Containing Isolated Salt Diapirs
Published: 2018-04-30
Subjects: Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure
Lateral shortening is expressed in unique ways in salt basins, especially if pre-shortening diapirs are present. We present an overview and new 3-D conceptual models capturing the evolution of shortening structures formed in salt provinces dominated by precursor isolated diapirs (termed isolated-diapir provinces). In such provinces, isolated diapirs form only a minor volumetric component of a [...]
Rivers, reefs, and deltas; Geomorphological evolution of the Jurassic of the Farsund Basin, offshore southern Norway
Published: 2018-04-26
Subjects: Earth Sciences, Geology, Geomorphology, Physical Sciences and Mathematics, Tectonics and Structure
In many petroleum-bearing, data-poor ‘frontier’ basins, source, reservoir, and seal distribution is poorly constrained, making it difficult to identify petroleum systems and play models. However, 3D seismic reflection data provide an opportunity to directly map the three-dimensional distribution of key petroleum system elements, thereby supplementing typically sparse, one-dimensional sedimentary [...]
Tracking CO2 plumes in clay-rich rock by distributed fiber optic strain sensing (DFOSS): a laboratory demonstration
Published: 2018-04-25
Subjects: Earth Sciences, Environmental Monitoring, Environmental Sciences, Fluid Dynamics, Geology, Geophysics and Seismology, Hydrology, Mineral Physics, Oil, Gas, and Energy, Optics, Physical Sciences and Mathematics, Physics
Monitoring the migration of pore pressure, deformation, and saturation plumes with effective tools is important for the storage and utilization of fluids in underground reservoirs, such as geological stores of carbon dioxide (CO2) and natural gas. Such tools would also verify the security of the fluid contained reservoir–caprock system. Utilizing the swelling strain attributed to pressure [...]
Strain budget of the Ecuador-Colombia subduction zone: a stochastic view
Published: 2018-04-24
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
The 2016 Pedernales earthquake (Mw=7.8) ruptured a portion of the Colombia-Ecuador subduction interface where several large historical earthquakes have been documented since the great 1906 earthquake (M=8.6). Considering all significant ruptures that occurred in the region, it has been suggested that the cumulative moment generated co-seismically along this part of the subduction over the last [...]
Plants and Drought in a Changing Climate
Published: 2018-04-23
Subjects: Earth Sciences, Ecology and Evolutionary Biology, Life Sciences, Other Earth Sciences, Other Ecology and Evolutionary Biology, Physical Sciences and Mathematics
Purpose of review: Climate is changing in response to rising concentrations of atmospheric CO2 and it is commonly asserted that this will cause droughts to become more frequent and severe. However, different metrics of drought give diverging estimates of future impacts. I present a summary of the significant yet underappreciated influence that plant stomatal and growth responses to CO2 have on [...]
Controls on early‐rift geometry: new perspectives from the Bilila‐Mtakataka fault, Malawi
Published: 2018-04-23
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
This study investigates the controls to fault and rift geometry for a young rift system. Our case study is a large fault in southern Malawi. The geometry of the fault at the surface, the scarp, and structures within the rocks the fault cuts through, are measured. We also calculate the scarp height. The orientation and height of the fault scarp implies that local stresses influence its geometry, [...]
Bimodal or quadrimodal? Statistical tests for the shape of fault patterns
Published: 2018-04-23
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
Natural fault patterns, formed in response to a single tectonic event, often display significant variation in their orientation distribution. The cause of this variation is the subject of some debate: it could be ‘noise’ on underlying conjugate (or bimodal) fault patterns or it could be intrinsic ‘signal’ from an underlying polymodal (e.g. quadrimodal) pattern. In this contribution, we present [...]