Preprints

Filtering by Subject: Physics

Extreme curvature of shallow magma pathways controlled by competing stresses

Timothy Davis, Marco Bagnardi, Paul Lundgren, Eleonora Rivalta

Published: 2020-10-30
Subjects: Earth Sciences, Physics

To feed off-summit eruptions at volcanoes, magma moves by creating and passing through cracks that can propagate many kilometres downslope. Typically, these cracks are vertical (dykes). Here we show the propagation of a flat-lying magma-filled crack (sill) at Sierra Negra volcano, Galápagos Islands, using space-borne radar interferometric data spanning the 2018 eruption. This sill propagated [...]

An analytical solution to the Navier–Stokes equation for incompressible flow around a solid sphere

Ahmad Talaei, Timothy J. Garrett

Published: 2020-08-25
Subjects: Applied Mathematics, Earth Sciences, Engineering, Fluid Dynamics, Mechanical Engineering, Other Mechanical Engineering, Partial Differential Equations, Physical Sciences and Mathematics, Physics, Special Functions

This paper is concerned with obtaining a formulation for the flow past a sphere in a viscous and incompressible fluid, building upon previously obtained well-known solutions that were limited to small Reynolds numbers. Using a method based on a summation of separation of variables, we develop a general analytical solution to the Navier--Stokes equation for the special case of axially symmetric [...]

Isotropic and Azimuthally Anisotropic Rayleigh Wave Dispersion Across the Juan de Fuca and Gorda Plates and U.S. Cascadia from Earthquake Data and Ambient Noise Two- and Three-Station Interferometry

Shane Zhang, Hongda Wang, Mengyu Wu, Michael H. Ritzwoller

Published: 2020-08-08
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics, Physics

We use data from the Cascadia Initiative (CI) amphibious array and the USArray Transportable Array to construct and compare Rayleigh wave isotropic and azimuthally anisotropic phase speed maps across the Juan de Fuca and Gorda Plates extending onto the continental northwestern U.S. Results from both earthquakes (28--80~s) as well as ambient noise two- and three-station interferometry (10--40~s) [...]

Sedimentary structures discriminations with hyperspectral imaging on sediment cores

Kévin Jacq, Rapuc William, Benoit Alexandre, Coquin Didier, Fanget Bernard, Yves Perrette, Pierre Sabatier, Wilhelm Bruno, Debret Maxime, Fabien Arnaud

Published: 2020-07-17
Subjects: Analytical Chemistry, Chemistry, Earth Sciences, Environmental Chemistry, Environmental Monitoring, Environmental Sciences, Multivariate Analysis, Optics, Physical Sciences and Mathematics, Physics, Sedimentology, Statistical Models, Statistics and Probability

Hyperspectral imaging (HSI) is a non-destructive high-resolution sensor, which is currently under significant development to analyze geological areas with remote devices or natural samples in a laboratory. In both cases, the hyperspectral image provides several sedimentary structures that need to be separated to temporally and spatially describe the sample. Sediment sequences are composed of [...]

Rapid heat discharge during deep-sea eruptions generates megaplumes and disperses tephra

Samuel Pegler, David Ferguson

Published: 2020-07-16
Subjects: Earth Sciences, Fluid Dynamics, Geology, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Other Physical Sciences and Mathematics, Physical Sciences and Mathematics, Physics, Volcanology

Deep-marine volcanism drives Earth’s most energetic transfers of heat and mass between the crust and the oceans. Seafloor magmatic activity has been correlated in time with the appearance of massive enigmatic plumes of hydrothermal fluid, known as megaplumes, yet little is known of the primary source and intensity of the hydrothermal energy release that occurs during [...]

Fracture mechanics of rate-and-state faults and fluid injection induced slip

Dmitry Garagash

Published: 2020-07-08
Subjects: Earth Sciences, Engineering, Environmental Sciences, Geophysics and Seismology, Oil, Gas, and Energy, Physical Sciences and Mathematics, Physics

Propagation of a slip transient on a fault with rate-and-state dependent friction resembles a fracture which near tip region is characterized by large departure of the slip velocity and fault strength from the steady-state sliding. We develop a near tip solution to describe this unsteady dynamics, and obtain the fracture energy Gc, dissipated in overcoming strength-excursion away from [...]

Deep spatial transformers for autoregressive data-driven forecasting of geophysical turbulence

Ashesh Kumar Chattopadhyay, Mustafa Mustafa, Pedram Hassanzadeh, Karthik Kashinath

Published: 2020-07-05
Subjects: Artificial Intelligence and Robotics, Atmospheric Sciences, Climate, Computer Sciences, Dynamical Systems, Earth Sciences, Environmental Sciences, Fluid Dynamics, Geophysics and Seismology, Mathematics, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Physics

A deep spatial transformer based encoder-decoder model has been developed to autoregressively predict the time evolution of the upper layers stream function of a two-layered quasi-geostrophic (QG) system without any information about the lower layers stream function. The spatio-temporal complexity of QG flow is comparable to the complexity of 500hPa Geopotential Height (Z500) of fully coupled [...]

Dislocation interactions in olivine control postseismic creep of the upper mantle

David Wallis, Lars Hansen, Angus J. Wilkinson, Ricardo A. Lebensohn

Published: 2020-06-29
Subjects: Condensed Matter Physics, Earth Sciences, Geology, Mineral Physics, Physical Sciences and Mathematics, Physics, Tectonics and Structure

Changes in stress applied to mantle rocks, such as those imposed by earthquakes, induce a period of evolution in viscosity and microstructure. This transient creep is often modelled based on stress transfer among slip systems due to grain interactions. However, recent experiments have demonstrated that the intragranular accumulation of stresses among dislocations is the dominant cause of strain [...]

Seismological Expression of the Iron Spin Crossover in Ferropericlase in the Earth’s Lower Mantle

Grace E. Shephard, Christine Houser, John Hernlund, Juan J. Valencia-Cardona, Reidar Trønnes, Renata Wentzkovitch

Published: 2020-06-29
Subjects: Earth Sciences, Geochemistry, Geophysics and Seismology, Mineral Physics, Physical Sciences and Mathematics, Physics, Quantum Physics, Tectonics and Structure

The two most abundant minerals on Earth which together make up over 90% of the Earth’s lower mantle are (Mg,Fe)O-ferropericlase (Fp) and (Mg,Fe)SiO3-bridgmanite (Bm). Iron in Fp undergoes a high-spin to low-spin (HS-LS) crossover that influences density, viscosity, elasticity, thermal conductivity, and elemental partitioning, however, the predicted effects of this transition are not apparent in [...]

Nonlinear stochastic dissipation in turbulent geophysical flows

Jean-Michel Brankart

Published: 2020-06-19
Subjects: Earth Sciences, Fluid Dynamics, Physical Sciences and Mathematics, Physics

The purpose of this study is to further investigate the assumption that geophysical flows can be described and simulated by direct sampling from a dynamically constrained probability distribution, with a reversible formulation of dissipation. This is done by making the probability of the flow decrease with the deviation of the Lagrangian with respect to local equilibrium, and by assuming that [...]

Sampling geophysical flows from a dynamically constrained probability distribution

Jean-Michel Brankart

Published: 2020-06-19
Subjects: Earth Sciences, Fluid Dynamics, Physical Sciences and Mathematics, Physics

The purpose of this study is to further investigate the problem of explicitly simulating uncertainties in geophysical models. Rather than introducing stochastic processes in forward-in-time partial differential equations, this is done here by reformulating the dynamical equations governing the time evolution of the flow as a probability distribution. Flows can then be drawn directly from the [...]

Increasing economic drought impacts in Europe with anthropogenic warming

Gustavo Naumann, Carmelo Cammalleri, Lorenzo Mentaschi, Luc Feyen

Published: 2020-05-13
Subjects: Climate, Earth Sciences, Environmental Sciences, Hydrology, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Physics

While climate change will alter the distribution in time and space of water, quantifications of drought risk in view of global warming remain little explored. Here, we show that in Europe drought damages could strongly increase with global warming and cause a strong regional imbalance in future drought impacts. In the absence of climate action (4°C in 2100 and no adaptation) annual drought losses [...]

Constraining global changes in temperature and precipitation from observable changes in surface radiative heating

Chirag Dhara

Published: 2020-04-30
Subjects: Climate, Earth Sciences, Environmental Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Physics

Changes in the atmospheric composition alter the magnitude and partitioning between the downward propagating solar and atmospheric longwave radiative fluxes heating the Earths surface. These changes are computed by radiative transfer codes in Global Climate Models and measured with high precision at surface observation networks. Changes in radiative heating signify changes in the global surface [...]

Interferometry with ALOS-2 full-aperture ScanSAR data

Cunren Liang, Eric Jameson Fielding

Published: 2020-04-14
Subjects: Aerospace Engineering, Civil and Environmental Engineering, Earth Sciences, Electrical and Computer Engineering, Engineering, Geology, Geophysics and Seismology, Glaciology, Mining Engineering, Other Engineering, Physical Sciences and Mathematics, Physics, Tectonics and Structure, Volcanology

Advanced Land Observing Satellite-2 (ALOS-2) is designed to routinely acquire both scanning synthetic aperture radar (ScanSAR) and stripmap data. In this paper, we present a special multiband bandpass filter (MBF) to remove azimuth nonoverlap spectra for the interferometric processing of ALOS-2 full-aperture ScanSAR product. As required by the MBF, we estimate the important ScanSAR system [...]

Estimating Azimuth Offset With Double-Difference Interferometric Phase: The Effect of Azimuth FM Rate Error in Focusing

Cunren Liang, Eric Jameson Fielding, Mong-Han Huang

Published: 2020-04-06
Subjects: Aerospace Engineering, Civil and Environmental Engineering, Earth Sciences, Electrical and Computer Engineering, Engineering, Environmental Sciences, Geology, Geomorphology, Geophysics and Seismology, Glaciology, Hydrology, Mining Engineering, Other Earth Sciences, Physical Sciences and Mathematics, Physics, Tectonics and Structure, Volcanology

Estimating azimuth offset with double-difference interferometric (DDI) phase, which is called multiple-aperture interferometric synthetic aperture radar (InSAR) or spectral diversity, is increasingly used in recent years to measure azimuth deformation or to accurately coregister a pair of InSAR images. We analyze the effect of frequency modulation (FM) rate error in focusing on the DDI phase with [...]

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