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Preprints

Filtering by Subject: Geophysics and Seismology

Towards a widely applicable earthquake detection algorithm for fibreoptic and hybrid fibreoptic-seismometer networks

Thomas Samuel Hudson, Sara Klaasen, Olivier Fontaine, et al.

Published: 2024-08-29
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics

Distributed Acoustic Sensing (DAS) is a promising technology for providing dense (metre-scale) sampling of the seismic wavefield. However, harnessing this potential for earthquake detection with accurate phase picking and associated localisation remains challenging. Single-channel algorithms are limited by individual channel noise, while machine learning and semblance methods are typically [...]

Frictional Properties of Simulated Fault Gouges subject to Normal Stress Oscillation and Implications for Induced Seismicity

Bowen Yu, Jianye Chen, Christopher Spiers, et al.

Published: 2024-08-24
Subjects: Geophysics and Seismology, Oil, Gas, and Energy, Risk Analysis

Under critical conditions where experimental fault slip exhibits self-sustained oscillation, effects of normal stress oscillation (NSO) on fault strength and stability remain poorly understood, as do potential effects of NSO on natural and induced seismicity. In this study, we employed double direct shear testing to investigate the frictional behavior of a synthetic, slightly velocity-weakening [...]

Array-based seismic measurements of OSIRIS-REx's re-entry

Benjamin Fernando, Constantinos Charalambous, Nicholas Schmerr, et al.

Published: 2024-08-23
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics, Planetary Sciences

The return home of the OSIRIS-REx spacecraft in September 2023 marked only the fifth time that an artificial object entered the Earth's atmosphere at interplanetary velocities. Although rare, such events serve as valuable analogues for natural meteoroid re-entries; enabling study of hypersonic dynamics, shockwave generation, and acoustic-to-seismic coupling. Here, we report on the signatures [...]

Complex and confined laboratory ruptures explain scaling of the critical slip distance for earthquake faulting

Srisharan Shreedharan, Luc Lavier, Chris Marone

Published: 2024-08-22
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure

Earthquake sequences in nature are complex, exhibiting a range of magnitudes and slip behaviors. In contrast, earthquake-like instabilities generated on frictional faults in the laboratory and in continuum numerical models are usually quasi-periodic with a smaller range of magnitudes and durations. The discrepancy, especially apparent for cm-sized samples used in lab friction experiments, has [...]

Partial ruptures governed by the complex interplay between geodetic slip deficit, rigidity, and pore fluid pressure in 3D Cascadia dynamic rupture simulations

Jonatan Glehman, Alice-Agnes Gabriel, Thomas ULRICH, et al.

Published: 2024-08-14
Subjects: Geophysics and Seismology

Physics-based simulations are crucial to assessing the seismic hazard in the Cascadia subduction zone (CSZ), requiring assumptions about fault stress and material properties. Geodetic slip deficit models (SDMs) may inform the initial stresses governing megathrust earthquake dynamics. We present a unified workflow linking SDMs to 3D dynamic rupture simulations, and 22 rupture scenarios to unravel [...]

Constraining Earth's core composition from inner core nucleation.

Alfred Wilson, Chris Davies, Andrew Walker, et al.

Published: 2024-08-02
Subjects: Earth Sciences, Geophysics and Seismology, Mineral Physics, Physical Sciences and Mathematics, Planetary Geophysics and Seismology, Planetary Mineral Physics, Planetary Sciences

Mesoscale fractures control the scale dependences of seismic velocity and fluid flow in subduction zones

Yuya Akamatsu, Hanaya Okuda, Manami Kitamura, et al.

Published: 2024-07-27
Subjects: Geophysics and Seismology

Natural geological systems contain porosity structures of various scales that play different roles in geophysical properties, fluid flow, and geodynamics. To understand seismic activity associated with high pore-fluid pressure and fluid migration in subduction zones, it is necessary to explore the scale dependence of geophysical properties such as seismic velocity and permeability. Here, we [...]

Tomotectonics of Cordilleran North America since Jurassic times: double-sided subduction, archipelago collisions, and Baja-BC translation

Karin Sigloch, Mitchell G. Mihalynuk

Published: 2024-07-27
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure

 Tomotectonics hindcasts paleo-trenches, through the spatiotemporal superposition of subducted lithosphere (slabs imaged in the earth’s mantle) with plate reconstructions (constrained by seafloor isochrons). The two geophysical datasets are linked through the tomotectonic null hypothesis, that oceanic lithosphere sinks vertically down after entering in the mantle. This linkage permits simple and [...]

Volcanic arc structure controlled by liquid focusing from the slab — evidence from boron isotopes and trace elements

Stephen J Turner, Ivan Savov, Tamsin Mather, et al.

Published: 2024-07-16
Subjects: Earth Sciences, Geochemistry, Geology, Geophysics and Seismology, Physical Sciences and Mathematics, Volcanology

The rates and pathways of material transport from subducting plates to arc volcanoes control the long-term chemical evolution of the atmosphere, continents, and mantle. Arc magma compositions are commonly used as proxies for the state of the slab directly below a volcanic vent, under the assumption of vertical transport from the slab to the surface. Here, we present new boron (B) isotope and [...]

Rupture directivity from energy envelope deconvolution: theory and application to 69 Ridgecrest M 3.5–5.5 earthquakes

Zhe Jia, Peter M. Shearer, Wenyuan Fan

Published: 2024-07-12
Subjects: Geophysics and Seismology

Earthquake rupture directivity impacts ground motions and provides important insights on fault zone properties and earthquake physics. However, measuring directivity of small earthquakes is challenging due to their compact rupture sizes and complex path and site effects at high frequencies. Here, we develop a new approach that deconvolves energy envelopes of the S-coda waves to remove path and [...]

Bridging the gap between SOLA and Deterministic Linear Inferences in the context of seismic tomography

Adrian Marin Mag, Christophe Zaroli, Paula Koelemeijer

Published: 2024-07-12
Subjects: Geophysics and Seismology

Seismic tomography is routinely used to image the Earth's interior using seismic data. However, in practice, data limitations lead to discretised inversions or the use of regularisations, which complicates tomographic model interpretations. In contrast, Backus-Gilbert inference methods make it possible to infer properties of the true Earth, providing useful insights into the internal structure of [...]

Quantifying relationships between fault parameters and rupture characteristics associated with thrust and reverse fault earthquakes.

Kristen Chiama, William Bednarz, Robb Moss, et al.

Published: 2024-07-11
Subjects: Geology, Geomorphology, Geophysics and Seismology, Geotechnical Engineering, Risk Analysis, Tectonics and Structure

We investigate the influence of earthquake source characteristics and geological site parameters on fault scarp morphologies for thrust and reverse fault earthquakes using geomechanical models. We performed a total of 3,434 distinct element method (DEM) model experiments to evaluate the impact of the sediment depth, density, homogeneous and heterogeneous sediment strengths, fault dip, and the [...]

Fast and full characterization of large earthquakes from prompt elastogravity signals

Kévin Juhel, Quentin Bletery, Andrea Licciardi, et al.

Published: 2024-07-11
Subjects: Geophysics and Seismology

Prompt ElastoGravity Signals (PEGS) are light-speed gravity-induced signals recorded by seismometers before the arrival of seismic waves. They have raised interest for early warning applications but their weak amplitudes, close to the background seismic noise even for large earthquakes, have questioned PEGS actual potential for operational use. A deep-learning model has recently demonstrated its [...]

A non-equilibrium slurry model for planetary cores with application to Earth’s F-layer

Andrew Walker, Chris Davies, Alfred Wilson, et al.

Published: 2024-07-09
Subjects: Earth Sciences, Fluid Dynamics, Geophysics and Seismology, Mineral Physics

Slurry regions may exist in the cores of several terrestrial bodies and are expected to influence the dynamics of deep planetary interiors and the viability of maintaining global magnetic fields. Here we develop a two-component slurry model of the lowermost outer core of the Earth (the F-layer). In contrast to most previous models of slurries in planetary cores, we explicitly model the [...]

The sensitivity of lowermost mantle anisotropy to past mantle convection

James A Ward, Andrew Walker, Andy Nowacki, et al.

Published: 2024-06-20
Subjects: Geophysics and Seismology, Mineral Physics

It is widely believed that seismic anisotropy in the lowermost mantle is caused by the flow-induced alignment of anisotropic crystals such as post-perovskite. What is unclear, however, is whether the anisotropy observations in the lowermost mantle hold information about past mantle flow, or if they only inform us about the present-day flow field. To investigate this, we compare the general and [...]

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