Preprints
Filtering by Subject: Physical Sciences and Mathematics
Seismicity induced by hydraulic fracturing and wastewater disposal in the Appalachian Basin, USA - a review
Published: 2019-01-01
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Eastern Ohio is an area of North America where a significant increase in seismicity rate was noted in the early 2010s. This increase has been associated with intensification of unconventional gas extraction performed in the Appalachian Basin and has been directly linked to two processes: hydraulic fracturing and disposal of the associated wastewater. In this paper we review the recent seismicity [...]
Differential Depletion-Induced 3D Stress Modification in Fault-Bounded Reservoirs and Implications for Fault Stability in Three Faulting Regimes
Published: 2019-01-01
Subjects: Earth Sciences, Environmental Sciences, Oil, Gas, and Energy, Physical Sciences and Mathematics
Depletion-induced faulting has been documented in a number of hydrocarbon reservoirs. This type of faulting has mostly been attributed to poroelastic effects: in-situ horizontal stresses are coupled with a pore pressure change according to a certain coupling coefficient (known as the stress path), which is generally less than 1. For faults with certain orientations, if the stress path is [...]
Hydromechanical–Stochastic Modeling of Fluid-Induced Seismicity in Fractured Poroelastic Media
Published: 2019-01-01
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
We present a new method for modeling fluid-perturbation induced seismicity in a fluid-saturated poroelastic medium embedded with a dual network of fractures. The inter-seismic triggering is deterministically modeled using a quasi-static, nonlinear and fluid-solid fully coupled fracture-poro-mechanical approach that resolves only the large-scale fractures. The co-seismic dynamic rupture is not [...]
The Impact of Pre-salt Rift Topography on Salt Tectonics: a Discrete-Element Modelling Approach
Published: 2018-12-30
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
Gravity-driven salt tectonics along passive margins is commonly depicted as domains of updip extension and downdip contraction linked by an intermediate, broadly undeformed zone of translation. This study expands on recently published physical models by applying discrete-element modelling to demonstrate how salt-related translation over pre-salt rift structures produce complex deformation and [...]
Base-Salt Relief Controls on Salt-Tectonic Structural Style, São Paulo Plateau, Santos Basin, Brazil
Published: 2018-12-30
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
Base-salt relief influences salt flow, producing three-dimensionally complex strains and multiphase deformation within the salt and its overburden. Understanding how base-salt relief influences salt-related deformation is important to correctly interpret salt basin kinematics and distribution of structural domains, which have important implications to understand the development of key petroleum [...]
Exceptional retreat of Kangerlussuaq Glacier, east Greenland, between 2016 and 2018
Published: 2018-12-28
Subjects: Earth Sciences, Glaciology, Physical Sciences and Mathematics
Kangerlussuaq Glacier is one of Greenland’s largest tidewater outlet glaciers, accounting for approximately 5% of all ice discharge from the Greenland ice sheet. In 2018 the Kangerlussuaq ice front reached its most retreated position since observations began in 1932. We determine the relationship between retreat and: (i) ice velocity; and (ii) surface elevation change, to assess the impact of the [...]
Ice shelf stability and the brittle–ductile transition
Published: 2018-12-21
Subjects: Earth Sciences, Glaciology, Physical Sciences and Mathematics
Fracturing processes limit the ability of floating ice shelves to stabilize marine ice sheets. Here, I argue that ice shelves are most susceptible to fracture when their thickness is less than the brittle–ductile transition thickness H*?, defined as the depth at which the overburden pressure equals the local yield strength in tension. A fracture mechanical analysis, compared with time-lapse [...]
Comparing the Euro 2k reconstruction to a regional climate model simulation
Published: 2018-12-20
Subjects: Climate, Earth Sciences, Oceanography and Atmospheric Sciences and Meteorology, Other Earth Sciences, Physical Sciences and Mathematics
We do not expect simulations and reconstructions of past climate change to agree on the exact evolution of past climate variations. Simulations with sophisticated climate models present spatially discrete but complete estimates, which are consistent relative to the implemented physics and their uncertain forcing data. Reconstruction methods statistically infer past changes from natural archives [...]
Cyclic preservation of Fe/Mn-redox fronts in sediments of an oligotrophic, ventilated deep-water lake (Lago Fagnano, Tierra del Fuego)
Published: 2018-12-20
Subjects: Earth Sciences, Physical Sciences and Mathematics, Sedimentology
Changing redox conditions in lakes are captured in their sediments, and are often influenced by climate. Their study therefore allows tracing past climate change on (sub-) annual to longer time-scales. In Lago Fagnano (54°S Argentina/Chile), an oligotrophic and deep-ventilated soft-water lake, cyclic alternations of light grey clay and dark green to black laminae are preserved throughout the [...]
Different stacking patterns along an active fold-and thrust-belt—Acerenza Bay, Southern Apennines (Italy)
Published: 2018-12-19
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Sedimentology
Traditional sequence stratigraphic models provide limited understanding of internal complexity and variability when applied to mixed siliciclastic-carbonate strata accumulated in tectonically active settings. Coeval Lower Pleistocene (Gelasian) shallow-marine, mixed siliciclastic-carbonate depositional wedges accumulated within an active piggy-back basin along the southern Italy fold-and [...]
Land surface temperature estimation at the global scale using satellite observations
Published: 2018-12-19
Subjects: Ecology and Evolutionary Biology, Electrical and Computer Engineering, Engineering, Life Sciences, Physical Sciences and Mathematics
Aim of this paper is to offer a brief overview of satellite based LST estimation fundamentals, discuss the main design principles of the corresponding algorithms, present some examples of the global scale LST and land surface emissivity products from the literature that were derived using satellite observations, and finally highlight different challenges in the described measurement process. [...]
Report for the Yujiang Government on the China-UK Knowledge Exchange Project for the Red Soil Critical Zone
Published: 2018-12-19
Subjects: Environmental Sciences, Environmental Studies, Geography, Natural Resources Management and Policy, Nature and Society Relations, Physical Sciences and Mathematics, Social and Behavioral Sciences
Knowledge exchange (KE) has been increasingly used to translate the scientific findings to produce outputs that inform land users and policy makers to lead to the sustainable environmental management. As part of the wider China-UK Critical Zone (CZ) programme, a KE research project was conducted to help ensure research results can be more effectively delivered to those who need them. Following on [...]
Attributing Historical and Future Evolution of Radiative Feedbacks to Regional Warming Patterns using a Green’s Function Approach: The Preeminence of the Western Pacific
Published: 2018-12-18
Subjects: Climate, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Global radiative feedbacks have been found to vary in global climate model (GCM) simulations. Atmospheric GCMs (AGCMs) driven with historical patterns of sea-surface temperatures (SST) and sea-ice concentrations produce radiative feedbacks that trend toward more negative values, implying low climate sensitivity, over recent decades. Freely-evolving coupled GCMs driven by increasing CO2 produce [...]
Intensity-Duration-Frequency curves at the global scale
Published: 2018-12-18
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Environmental Sciences, Hydraulic Engineering, Hydrology, Meteorology, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Water Resource Management
Intensity-Duration-Frequency (IDF) curves usefully quantify extreme precipitation over various durations and return periods for engineering design. Unfortunately, sparse, infrequent or short observations hinder the creation of robust IDF curves in many locations. This paper presents the first global, multi-temporal (1 to 360 hours) dataset of Generalized Extreme Value (GEV) parameters at 31 km [...]
Can we relate the surface expression of dike-induced normal faults to subsurface dike geometry?
Published: 2018-12-14
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure, Volcanology
Dikes feed volcanic eruptions and drive crustal extension on Earth and other planetary bodies. Yet many dikes do not reach the surface, instead triggering normal faulting and graben formation in overlying rock. Whilst dike-induced faults provide a surficial and accessible record of active and ancient diking, unlocking these archives is difficult because we do not know how faults grow above or [...]