Preprints

Filtering by Subject: Physics

Three-dimensional fluid-driven stable frictional ruptures

Alexis Sáez, Brice Lecampion, Pathikrit Bhattacharya, et al.

Published: 2021-09-13
Subjects: Earth Sciences, Engineering, Environmental Sciences, Geophysics and Seismology, Oil, Gas, and Energy, Physical Sciences and Mathematics, Physics

We investigate the quasi-static growth of a fluid-driven frictional shear crack that propagates in mixed mode (II+III) on a planar fault interface that separates two identical half-spaces of a three-dimensional solid. The fault interface is characterized by a shear strength equal to the product of a constant friction coefficient and the local effective normal stress. Fluid is injected into the [...]

Modeling P waves in seismic noise correlations: Application to fault monitoring using train traffic sources

Korbinian Sager, Victor C. Tsai, Yixiao Sheng, et al.

Published: 2021-06-19
Subjects: Applied Mathematics, Earth Sciences, Geophysics and Seismology, Physics

The theory of Green's function retrieval essentially requires homogeneously distributed noise sources. Even though these conditions are not fulfilled in nature, low-frequency (<1 Hz) surface waves generated by ocean-crust interactions have been used successfully to image the crust with unprecedented spatial resolution. In contrast to low-frequency surface waves, high-frequency (>1 Hz) body waves [...]

Yield estimation of the 2020 Beirut explosion using open access waveform and remote sensing data

Christoph Pilger, Patrick Hupe, Peter Gaebler, et al.

Published: 2020-12-22
Subjects: Applied Statistics, Earth Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Physics, Statistics and Probability

We report on a multi-technique analysis using publicly available data for investigating the huge, accidental explosion that struck the city of Beirut, Lebanon, on August 4, 2020. Its devastating shock wave led to thousands of injured with more than two hundred fatalities and caused immense damage to buildings and infrastructure. Our combined analysis of seismological, hydroacoustic, infrasonic [...]

Anatomy of Strike Slip Fault Tsunami-genesis

Ahmed Elbanna, Mohamed Abdelmeguid, Xiao Ma, et al.

Published: 2020-12-13
Subjects: Earth Sciences, Engineering, Fluid Dynamics, Geophysics and Seismology, Physical Sciences and Mathematics, Physics

Tsunami generation from earthquake induced seafloor deformations has long been recognized as a major hazard to coastal areas. Strike-slip faulting has generally been believed as insufficient for triggering large tsunamis, except through the generation of submarine landslides. Herein, we demonstrate that ground motions due to strike-slip earthquakes can contribute to the emergence of large [...]

Extreme curvature of shallow magma pathways controlled by competing stresses

Timothy Davis, Marco Bagnardi, Paul Lundgren, et al.

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

Eruptions at shield volcanoes often occur from radially aligned linear fissures fed by blade-like magma-filled cracks (dykes). The fissures of the 2018 Sierra Negra eruption were scattered on the flank of the volcano. Space-borne radar interferometric data (InSAR) revealed that, unexpectedly, part of the eruption was fed by a 15 km long, tortuous and flat-lying crack (sill). Here we develop a [...]

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, et al.

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 north- western United States. Results from both earthquakes (28–80 s) as well as ambient noise two- and three-station interferometry [...]

Sedimentary structures discriminations with hyperspectral imaging on sediment cores

Kévin Jacq, Rapuc William, Benoit Alexandre, et al.

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, et al.

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, et al.

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, et al.

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 [...]

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