Preprints
Filtering by Subject: Physical Sciences and Mathematics
Pore network model predictions of Darcy-scale multiphase flow heterogeneity validated by experiments
Published: 2019-11-07
Subjects: Earth Sciences, Hydrology, Physical Sciences and Mathematics
Small-scale heterogeneities in multiphase flow properties fundamentally control the flow of fluids from very small to very large scales in geologic systems. Inability to characterize these heterogeneities often limits numerical model descriptions and predictions of multiphase flow across scales. In this study, we evaluate the ability of pore network models (PNM) to characterize multiphase flow [...]
Growth, overprinting, and stabilization of Proterozoic Provinces in the southern Lake Superior region
Published: 2019-11-07
Subjects: Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics, Tectonics and Structure
New geochronologic data in the southern Lake Superior region provide key information on the timing and nature of tectonic activity that pre-and post-date initial Paleoproterozoic growth of Laurentia during the geon 18 Penokean orogeny. The obducted Pembine ophiolite formed along the edge of a Paleoproterozoic ocean basin at least 30 m.y. prior to Penokean island arc/microcontinent accretion [...]
Nowcasting submarine slope instability at local, margin, and global scales using machine learning
Published: 2019-11-07
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics
Submarine slope instability (SSI) is a broad term for events ranging from 100 km3 instantaneous open slope failures on continental margins to 0.001 km3 creeping mudflows on heavily sedimented river deltas. SSI events such as the 2018 Sunda Strait and 1929 Grand Banks submarine landslides extract high societal tolls, yet SSI predictive capability is limited. SSI observational studies are resource [...]
Chemical versus mechanical denudation in meta-clastic and carbonate bedrock catchments on Crete, Greece, and mechanisms for steep and high carbonate topography
Published: 2019-11-05
Subjects: Earth Sciences, Geomorphology, Physical Sciences and Mathematics
On Crete — as is common elsewhere in the Mediterranean — carbonate massifs form high mountain ranges whereas topography is lower in areas with meta-clastic rocks. This observation suggests that differences in denudational processes between carbonate-rich rocks and quartzofeldspathic units impart a fundamental control on landscape evolution. Here we present new cosmogenic basin-average denudation [...]
On the statistical significance of foreshock sequences in Southern California
Published: 2019-11-05
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Earthquake foreshocks may provide information that is critical to short-term earthquake forecasting. However, foreshocks are far from ubiquitously observed, which makes the interpretation of ongoing seismic sequences problematic. Based on a statistical analysis, Trugman & Ross (2019) suggested that as much as 72% of all mainshocks in Southern California is preceded by foreshock sequences. In [...]
Equifinality, Sloppiness, and emergent model structures of mechanistic soil biogeochemical models
Published: 2019-11-05
Subjects: Biogeochemistry, Earth Sciences, Environmental Sciences, Physical Sciences and Mathematics, Soil Science
Biogeochemical models increasingly consider the microbial control of car- bon cycling in soil. The major current challenge is to validate mechanistic descriptions of microbial processes and predicted system responses against experimental observations. We analyzed soil biochemical models of different complexity regarding parameter identifiability using information geometry, i.e. a model is [...]
The global lake area, climate, and population dataset
Published: 2019-11-05
Subjects: Environmental Monitoring, Environmental Sciences, Other Environmental Sciences, Physical Sciences and Mathematics
An increasing population in conjunction with a changing climate necessitates a detailed understanding of water abundance at multiple spatial and temporal scales. Remote sensing has provided massive data volumes to track fluctuations in water quantity, yet contextualizing water abundance with other local, regional, and global trends remains challenging by often requiring large computational [...]
Gulf Stream and Kuroshio Current are synchronized
Published: 2019-11-05
Subjects: Atmospheric Sciences, Climate, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Observational records show that sea surface temperatures along the Gulf Stream and Kuroshio tend to synchronize at decadal time scales. This synchronization, which we refer to as the Boundary Current Synchronization (BCS), is reproduced in global climate models with high spatial resolution. Both in observations and model simulations, BCS is associated with meridional migrations of the atmospheric [...]
Neogene-Recent Reactivation of Jurassic-age Faults in Southern Vietnam, with Implications for the Extrusion of Indochina
Published: 2019-11-02
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics
Onshore Vietnam contains a complex series of faults coupled with a diffuse igneous province that has been active since the mid-Miocene. However, there are several conflicting fault maps in the literature and no consensus concerning the relative age of mapped faults and Neogene basalt flows, which becomes problematic when trying to use structural data to distinguish between competing tectonic [...]
Detection and temperature estimation of gas flares with nocturnal Landsat OLI
Published: 2019-11-02
Subjects: Earth Sciences, Environmental Sciences, Oil, Gas, and Energy, Physical Sciences and Mathematics
Natural gas flaring is a worldwide polluting activity carried out during oil production. Satellite imagery has emerged as a low-cost, objective tool to measure and monitor gas flaring. Since 2012, hectometre-resolution infrared imagery from the Suomi NPP VIIRS sensor has been used to operationally monitor global gas flaring (Elvidge et al. 2016). Since 2013, nocturnal acquisitions of Landsat 8 [...]
The variation and visualisation of elastic anisotropy in rock-forming minerals
Published: 2019-10-31
Subjects: Earth Sciences, Geochemistry, Geology, Geophysics and Seismology, Mineral Physics, Physical Sciences and Mathematics, Tectonics and Structure
All minerals behave elastically, a rheological property that controls their ability to support stress, strain and pressure, the nature of acoustic wave propagation and influences subsequent plastic (i.e. permanent, non-reversible) deformation. All minerals are intrinsically anisotropic in their elastic properties – that is, they have directional variations that are related to the configuration [...]
A unique bacteriohopanetetrol stereoisomer of marine anammox
Published: 2019-10-31
Subjects: Biogeochemistry, Earth Sciences, Physical Sciences and Mathematics
Anaerobic ammonium oxidation (anammox) is a significant process for bioavailable nitrogen removal from marine systems. A bacteriohopanetetrol (BHT) isomer, with unknown stereochemistry, eluting later than BHT using high performance liquid chromatography (HPLC), was detected in ‘Ca. Scalindua profunda’ and proposed as a biomarker for anammox in marine paleo-environments. Four non-marine, [...]
The Earthquake Arrest Zone
Published: 2019-10-31
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Earthquake ruptures are generally considered to be cracks that propagate as fracture or frictional slip on preexisting faults. Crack models have been used to describe the spatial distribution of fault offset and the associated static stress changes along a fault, and have implications for friction evolution and the underlying physics of rupture processes. However, field measurements that could [...]
Pre-deliquescent water uptake in deposited nanoparticles observed with in situ ambient pressure X-ray photoelectron spectroscopy
Published: 2019-10-31
Subjects: Atmospheric Sciences, Chemistry, Oceanography and Atmospheric Sciences and Meteorology, Physical Chemistry, Physical Sciences and Mathematics
In this work we study the adsorption, or uptake, of water onto deposited inorganic sodium chloride and organic malonic acid and sucrose nanoparticles at low relative humidities from 0 to 16%. We employ the surface sensitive ambient pressure x-ray photoelectron spectroscopy technique, which has a detection sensitivity from parts per thousand. Our results show that water is adsorbed on sodium [...]
Deep Unsupervised 4D Seismic 3D Time-Shift Estimation with Convolutional Neural Networks
Published: 2019-10-30
Subjects: Applied Statistics, Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics, Statistics and Probability
We present a novel 3D warping technique for the estimation of 4D seismic time-shift. This unsupervised method provides a diffeomorphic 3D time shift field that includes uncertainties, therefore it does not need prior time-shift data to be trained. This results in a widely applicable method in time-lapse seismic data analysis. We explore the generalization of the method to unseen data both in the [...]