From slow to fast faulting: recent challenges in earthquake fault mechanics

Nielsen, S. B.

doi:10.1098/rsta.2016.0016

Cited by 20 publications

(15 citation statements)

References 98 publications

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“…This movement, that is, the very faulting, takes place either as creep: stable, slow sliding, or in the form of a series of earthquakes: unstable, fast slip intertwined with long periods of no motion. Faults thus accommodate strain on a momentous range of dimensions: on a spatial scale, from millimeters to hundreds of kilometers (for major plate boundaries), while also the time intervals range widely from seconds to minutes of earthquake slip, to years of slow, aseismic slip, and to millions of years of intermittent activity (e.g., Nielsen, 2017; Sibson, 2003). The textures and structures that develop in fault rocks depend on the amount and rate of shearing, and the physical conditions, that is, temperature and pressure, under which the shearing occurred.…”

Section: Formation Of Fault Rocks and Processes During Faultingmentioning

confidence: 99%

Faulting Processes Unveiled by Magnetic Properties of Fault Rocks

Yang

Chou

Ferré

et al. 2020

Reviews of Geophysics

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As iron-bearing minerals-ferrimagnetic minerals in particular-are sensitive to stress, temperature, and presence of fluids in fault zones, their magnetic properties provide valuable insights into physical and chemical processes affecting fault rocks. Here, we review the advances made in magnetic studies of fault rocks in the past three decades. We provide a synthesis of the mechanisms that account for the magnetic changes in fault rocks and insights gained from magnetic research. We also integrate nonmagnetic approaches in the evaluation of the magnetic properties of fault rocks. Magnetic analysis unveils microscopic processes operating in the fault zones such as frictional heating, energy dissipation, and fluid percolation that are otherwise difficult to constrain. This makes magnetic properties suited as a "strain indicator," a "geothermometer," and a "fluid tracer" in fault zones. However, a full understanding of faulting-induced magnetic changes has not been accomplished yet. Future research should focus on detailed magnetic property analysis of fault zones including magnetic microscanning and magnetic fabric analysis. To calibrate the observations on natural fault zones, laboratory experiments should be carried out that enable to extract the exact physicochemical conditions that led to a certain magnetic signature. Potential avenues could include (1) magnetic investigations on natural and synthetic fault rocks after friction experiments, (2) laboratory simulation of fault fluid percolation, (3) paleomagnetic analysis of postkinematic remanence components associated with faulting processes, and (4) synergy of interdisciplinary approaches in mineral-magnetic studies. This would help to place our understanding of the microphysics of faulting on a much stronger footing. Plain Language Summary The Earth's surface is riddled with faults that largely contribute to landscape evolution and human activities. Some of these faults produce earthquakes of different magnitudes including some with catastrophic consequences. Understanding faulting mechanisms benefits society when predictions about rupture are made. Fault zones preserve an excellent record of chemical and physical processes involved in failure. Among other analytical methods, magnetic studies prove to be an emergent and untapped source of information on these processes. These methods, focused on prefaulting, synfaulting, and postfaulting mineral changes, have resulted in significant advances in our understanding of the conditions of faulting. In this review, we present an extensive account of the state of knowledge and highlight current challenges and future avenues of fault magnetism research.

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Section: Formation Of Fault Rocks and Processes During Faultingmentioning

confidence: 99%

Faulting Processes Unveiled by Magnetic Properties of Fault Rocks

Yang

Chou

Ferré

et al. 2020

Reviews of Geophysics

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“…Multiple scales, multi-physics interactions and nonlinearities govern earthquake source processes, rendering the understanding of how faults slip a grand challenge of seismology [ 1 , 2 ]. Over the last decades, earthquake rupture dynamics have been commonly modelled as a sudden displacement discontinuity across a simplified (potentially heterogeneous) surface of zero thickness in the framework of elastodynamics [ 3 ].…”

Section: Introductionmentioning

confidence: 99%

A unified first-order hyperbolic model for nonlinear dynamic rupture processes in diffuse fracture zones

Gabriel

Chiocchetti

et al. 2021

Phil. Trans. R. Soc. A.

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Earthquake fault zones are more complex, both geometrically and rheologically, than an idealized infinitely thin plane embedded in linear elastic material. To incorporate nonlinear material behaviour, natural complexities and multi-physics coupling within and outside of fault zones, here we present a first-order hyperbolic and thermodynamically compatible mathematical model for a continuum in a gravitational field which provides a unified description of nonlinear elasto-plasticity, material damage and of viscous Newtonian flows with phase transition between solid and liquid phases. The fault geometry and secondary cracks are described via a scalar function ξ ∈ [0, 1] that indicates the local level of material damage. The model also permits the representation of arbitrarily complex geometries via a diffuse interface approach based on the solid volume fraction function α ∈ [0, 1]. Neither of the two scalar fields ξ and α needs to be mesh-aligned, allowing thus faults and cracks with complex topology and the use of adaptive Cartesian meshes (AMR). The model shares common features with phase-field approaches, but substantially extends them. We show a wide range of numerical applications that are relevant for dynamic earthquake rupture in fault zones, including the co-seismic generation of secondary off-fault shear cracks, tensile rock fracture in the Brazilian disc test, as well as a natural convection problem in molten rock-like material. This article is part of the theme issue ‘Fracture dynamics of solid materials: from particles to the globe’.

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“…[13]. Detailed geological and experimental study of fracture processes in rock massifs has shown that the fundamental tribological patterns of creep or stick-slip sliding can be successfully used to determine the causes and mechanisms of strong earthquakes in fault segments [14,15].…”

Section: Methodological Basismentioning

confidence: 99%

A New Method for Seismically Safe Managing of Seismotectonic Deformations in Fault Zones

Ruzhich

Shilko

2020

Springer Tracts in Mechanical Engineering

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The authors outline the results of long-term interdisciplinary research aimed at identifying the possibility and the methods of controlling tangential displacements in seismically dangerous faults to reduce the seismic risk of potential earthquakes. The studies include full-scale physical and numerical modeling of P-T conditions in the earth’s crust contributing to the initiation of displacement in the stick-slip regime and associated seismic radiation. A cooperation of specialists in physical mesomechanics, seismogeology, geomechanics, and tribology made it possible to combine and generalize data on the mechanisms for the formation of the sources of dangerous earthquakes in the highly stressed segments of faults. We consider the prospect of man-caused actions on the deep horizons of fault zones using powerful shocks or vibrations in combination with injecting aqueous solutions through deep wells to manage the slip mode. We show that such actions contribute to a decrease in the coseismic slip velocity in the fault zone, and, therefore, cause a decrease in the amplitude and energy of seismic vibrations. In conclusion, we substantiate the efficiency of the use of combined impacts on potentially seismically hazardous segments of fault zones identified in the medium-term seismic prognosis. Finally, we discuss the importance of the full-scale validation of the proposed approach to managing the displacement regime in highly-stressed segments of fault zones. Validation should be based on large-scale tests involving advanced technologies for drilling deep multidirectional wells, injection of complex fluids, and localized vibrational or pulse impacts on deep horizons.

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From slow to fast faulting: recent challenges in earthquake fault mechanics

Cited by 20 publications

References 98 publications

Faulting Processes Unveiled by Magnetic Properties of Fault Rocks

Faulting Processes Unveiled by Magnetic Properties of Fault Rocks

A unified first-order hyperbolic model for nonlinear dynamic rupture processes in diffuse fracture zones

A New Method for Seismically Safe Managing of Seismotectonic Deformations in Fault Zones

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