Preprints
There are 4725 Preprints listed.
Characterizing user-defined objects from outcrop and modern system interpretations for stochastic object-based reservoir modelling
Published: 2019-01-07
Subjects: Earth Sciences, Physical Sciences and Mathematics, Sedimentology
Outcrops and modern depositional environments are important analogues for subsurface hydrocarbon-, water- or CO2-sequestration reservoirs, as they supplement limited well- and seismic- data and provide information on connectivity of sandbodies observed in subsurface datasets. Object based modelling is one of a series of methods that is widely used for modelling subsurface facies architecture. A [...]
Structural evolution and medium-temperature thermochronology of central Madagascar: implications for Gondwana amalgamation
Published: 2019-01-06
Subjects: Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics, Tectonics and Structure
Madagascar occupied an important place in the amalgamation of Gondwana and preserves a record of several Neoproterozoic events that are linked to orogenesis of the East African Orogen. In this study, we integrate remote sensing, field data and thermochronology to unravel complex deformation in the Ikalamavony and Itremo domains of central Madagascar. The deformation sequence comprises a gneissic [...]
Buoyancy driven distributed chaos and ensemble weather forecasting
Published: 2019-01-04
Subjects: Atmospheric Sciences, Meteorology, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
It is shown, using results of direct numerical simulations, that strong thermal convection in horizontal layer and on a hemisphere can be well described by the distributed chaos approach with the stretched exponential kinetic energy spectrum. Two relevant cases: the vorticity and helicity dominated distributed chaos, have been considered. The results obtained with the Weather Research and [...]
Development of an inversion method to extract information on fault geometry from teleseismic data
Published: 2019-01-04
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Teleseismic waveforms contain information on fault slip evolution during an earthquake, as well as on the fault geometry. A linear finite-fault inversion method is a tool for solving the slip-rate function distribution under an assumption of fault geometry as a single or multiple-fault-plane model. An inappropriate assumption of fault geometry would tend to distort the solution due to Greens [...]
Impulsive source of the 2017, Mw =7.3, Ezgeleh, Iran, earthquake
Published: 2019-01-03
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
On November 12th 2017, a MW =7.3 earthquake struck near the Iranian town of Ezgeleh, close to the Iran-Iraq border. This event was located within the Zagros fold and thrust belt which delimits the continental collision between the Arabian and Eurasian Plates. Despite a high seismic risk, the seismogenic behaviour of the complex network of active faults is not well documented in this area due to [...]
Wet rice cultivation was the primary cause of the earthquake-triggered Palu landslides
Published: 2019-01-03
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics
The death toll and economic impact of an earthquake are greatly exacerbated when landslides are triggered by strong ground motion. These slides typically occur in two different contexts: localized failure of steep slopes that pose a major threat to life in areas below; and lateral spreading of nearly flat sediment plains due to shaking-induced liquefaction, which can damage large areas of [...]
Long-term and inter-annual mass changes in the Iceland ice cap determined from GRACE gravity
Published: 2019-01-03
Subjects: Earth Sciences, Glaciology, Physical Sciences and Mathematics
The Gravity Recovery and Climate Experiment (GRACE) satellites have measured anomalies in the Earth’s time-variable gravity field since 2002, allowing for the measurement of the melting of glaciers due to climate change. Many techniques used with GRACE data have difficulty constraining mass change in small regions such as Iceland, often requiring broad averaging functions in order to capture [...]
A New Method for Simultaneously Determining The Magnitude And Orientation of SHmax And Rock Strength Using Wellbore Failures in Deviated Wells
Published: 2019-01-03
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Forward constraining of the magnitude of SHmax on a stress polygon using wellbore failures observed from deviated wells requires the orientation of SHmax known a priori. This orientation can be separately determined from, e.g., wellbore failures in vertical/near-vertical wells. Unfortunately, in the case where image logs are available only in highly deviated wells, SHmax orientation cannot be [...]
A test case for application of convolutional neural networks to spatio-temporal climate data: Re-identifying clustered weather patterns
Published: 2019-01-01
Subjects: Applied Mathematics, Computer Sciences, Earth Sciences, Engineering, Environmental Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Planetary Sciences
Convolutional neural networks (CNNs) can potentially provide powerful tools for classifying and identifying patterns in climate and environmental data. However, because of the inherent complexities of such data, which are often spatio-temporal, chaotic, and non-stationary, the CNN algorithms must be designed/evaluated for each specific dataset and application. Yet to start, CNN, a supervised [...]
Methane bursts as a trigger for intermittent lake-forming climates on post-Noachian Mars
Published: 2019-01-01
Subjects: Astrophysics and Astronomy, Earth Sciences, Geology, Physical Sciences and Mathematics, The Sun and the Solar System
Lakes existed on Mars later than 3.6 billion years ago, according to sedimentary evidence for deltaic deposition. The observed fluvio-lacustrine deposits suggest that individual lake-forming climates persisted for at least several thousand years (assuming dilute flow). But the lake watersheds’ little weathered soils indicate a largely dry climate history, with intermittent runoff events. Here we [...]
Persistent or repeated surface habitability on Mars during the Late Hesperian - Amazonian
Published: 2019-01-01
Subjects: Astrophysics and Astronomy, Earth Sciences, Geology, Physical Sciences and Mathematics, The Sun and the Solar System
Large alluvial fan deposits on Mars record relatively recent habitable surface conditions (≲3.5 Ga, Late Hesperian – Amazonian). We find net sedimentation rate <(4-8) μm/yr in the alluvial-fan deposits, using the frequency of craters that are interbedded with alluvial fan deposits as a fluvial-process chronometer. Considering only the observed interbedded craters sets a lower bound of >20 [...]
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 [...]