Preprints
There are 5496 Preprints listed.
Impact and rebound of near real-time United States fossil fuel carbon dioxide emissions from COVID-19 and large differences with global estimates
Published: 2021-04-20
Subjects: Social and Behavioral Sciences
The COVID-19 pandemic has altered energy use and greenhouse gas (GHG) emissions globally and continues to evolve in the U.S. as the politics of COVID-19 change. Here we report on a new near-real-time fuel consumption data-driven, week-resolved estimate of national U.S. fossil fuel carbon dioxide (FFCO2) emissions, Vulcan-NRT. We explore the impact and rebound from the COVID-19 pandemic in the US. [...]
Particulate PhozzyLogic Index for policy makers—an index for a more accurate and transparent identification of critical source areas
Published: 2021-04-20
Subjects: Environmental Sciences, Physical Sciences and Mathematics, Water Resource Management
This study presents an algorithm for the allocation of particulate phosphorus (PP) loads entering surface waters to their sources of origin, which is a basic requirement for the identification of critical PP source areas and in turn a cost-effective implementation of mitigation measures. Furthermore, it conducts a sensitivity analysis determining the impacts of storm drains, discharge frequencies [...]
Subdivide and Conquer: Adapting Non-manifold Subdivision Surfaces to Surface-Based Representation and Reconstruction of Complex Geological Structures
Published: 2021-04-20
Subjects: Earth Sciences, Geology, Mining Engineering
Methods from the field of Computer Graphics are the foundation for the representation of geological structures in the form of geological models. However, as many of these methods have been developed for other types of applications, some of the requirements for the representation of geological features may not be considered and the capacities and limitations of different algorithms are not always [...]
Reactivation Potential of Intraplate Faults in the Western Quebec Seismic Zone, Eastern Canada
Published: 2021-04-19
Subjects: Earth Sciences, Physical Sciences and Mathematics
The intraplate western Quebec seismic Zone (WQSZ) in eastern Canada experiences moderate seismicity that mainly results from reactivation of inherited structures under the present-day, NE-striking regional stress field and, possibly to a minor extent, through stress perturbations in response to glacio-isostatic adjustments. This work comprises the first numerical stress simulation-based study [...]
Comparison of Machine Learning Approaches for Tsunami Forecasting from Sparse Observations
Published: 2021-04-19
Subjects: Physical Sciences and Mathematics
We have explored various different machine learning (ML) approaches for forecasting tsunami amplitudes at a set of forecast points, based on hypothetical short-time observations at one or more observation points. As a case study, we chose an observation point near the entrance of the Strait of Juan de Fuca, and two forecast points in the Salish Sea, one in Discovery Bay and the other in Admiralty [...]
The effect of water and pressure on fabric development in olivine
Published: 2021-04-18
Subjects: Physical Sciences and Mathematics
Water has a very strong effect on both the strength and fabric development of forsterite but the mechanism of this effect is unclear. In the paper we use Density Functional Theory Peierls-Nabarro modelling to examine the effect of water on the Peierls stress of different forsterite slip systems. We find that water in Mg vacancies will weaken [100](010) slip and thus produce A fabrics while [...]
Controls on the distribution of hydrous defects in forsterite from a thermodynamic model
Published: 2021-04-16
Subjects: Physical Sciences and Mathematics
The distribution of hydrogen across different crystallographic sites and point defects in forsterite is important because it determines how many properties, such as rheology, conductivity, diffusion and elemental partitioning are affected by water. In this study we use lattice dynamics and Density Functional Theory (DFT) to build a thermodynamic model of H-bearing defects that incorporates both [...]
Source region geochemistry from unmixing downstream sedimentary elemental compositions
Published: 2021-04-15
Subjects: Earth Sciences, Geochemistry, Physical Sciences and Mathematics
The geochemistry of river sediments is routinely used to obtain information about geologic and environmental processes occurring upstream. For example, downstream samples are used to constrain chemical weathering and physical erosion rates upstream, as well as the locations of mineral deposits or contaminant sources. Previous work has shown that, by assuming conservative mixing, the geochemistry [...]
A global hydrothermal reactor triggered prebiotic synthesis on Earth
Published: 2021-04-15
Subjects: Biogeochemistry, Earth Sciences, Geochemistry, Geology, Planetary Geology
Biosignatures in the rock record limit the time available for life to start on Earth to 600-800 million years1 (4.5-3.7 Ga; Hadean-Archean). Whether the conditions for the synthesis of complex organic molecules were unique to this time or remain present today is unclear, but understanding these conditions is essential for the search of life on other planets. The outer portion of the Hadean Earth [...]
Stress and Strain during Shock Metamorphism
Published: 2021-04-15
Subjects: Geology, Planetary Geology, Planetary Geophysics and Seismology, Tectonics and Structure
Shock metamorphism is the process by which rocks, and the minerals within them, transform during the passage of a shock wave. Shock effects, such as shatter cones, are critical for the identification of impact structures and have commonly been used to infer mechanical and structural information on the cratering process. To make these inferences, the mechanics of shock wave behavior must be [...]
Structure and Stress Field of the Lithosphere between Pamir and Tarim
Published: 2021-04-15
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure
The Pamir plateau protrudes ~300 km between the Tajik- and Tarim-basin lithosphere of Central Asia. Whether its salient location and shape are caused by forceful indentation of a promontory of Indian mantle lithosphere is debated. We present a new local-seismicity and focal-mechanism catalog, and a P-wave velocity model of the eastern part of the collision system. The data suggest a [...]
Microstructural differences between naturally-deposited and laboratory beach sands
Published: 2021-04-15
Subjects: Civil and Environmental Engineering, Civil Engineering, Earth Sciences, Engineering, Geophysics and Seismology, Geotechnical Engineering, Physical Sciences and Mathematics, Sedimentology
The orientation of and contacts between grains of sand reflect the processes that deposit the sands. Grain orientation and contact geometry also influence mechanical properties. Quantifying and understanding sand microstructure thus provide an opportunity to understand depositional processes better and connect microstructure and macroscopic properties. We compare naturally-deposited beach sands [...]
Evaluation of satellite precipitation products for water allocation studies in the Sio-Malaba-Malakisi River Basin of East Africa
Published: 2021-04-15
Subjects: Physical Sciences and Mathematics
Study region: Sio Malaba Malakisi river basin, East Africa. Study Focus: Poor rain-gauge density is a limitation to comprehensive hydrological studies in Sub-Saharan Africa. Consequently, Satellite precipitation products (SPPs) provide an alternative source of data for possible use in hydrological modelling. However, there is need to test their reliabilities across varied hydro-climatic and [...]
The morphology, evolution and seismic visibility of partial melt at the core-mantle boundary: Implications for ULVZs
Published: 2021-04-15
Subjects: Geophysics and Seismology
Seismic observations indicate that the lowermost mantle above the core-mantle boundary is strongly heterogeneous. Body waves reveal a variety of ultra-low velocity zones (ULVZs), which extend not more than 100 km above the core-mantle boundary and have shear velocity reductions of up to 30%. While the nature and origin of these ULVZs remain uncertain, some have suggested they are evidence of [...]
Probing the DPRK nuclear test-site down to low seismic magnitude
Published: 2021-04-15
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
On 3 September 2017, the Democratic People’s Republic of Korea (DPRK) carried out its sixth declared underground nuclear test (NK6) at the Punggye‐ri test site. With body‐wave magnitude 6.1, this explosion was significantly larger than any of the previous five explosions, and it has been followed by numerous smaller seismic events. The explosion generated seismic waves dominated by significantly [...]