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Jara J, Bruhat L, Thomas MY, Antoine SL, Okubo K, Rougier E, Rosakis AJ, Sammis CG, Klinger Y, Jolivet R, Bhat HS. Signature of transition to supershear rupture speed in the coseismic off-fault damage zone. Proc Math Phys Eng Sci 2021; 477:20210364. [PMID: 35153594 PMCID: PMC8595990 DOI: 10.1098/rspa.2021.0364] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 10/21/2021] [Indexed: 11/17/2022] Open
Abstract
Most earthquake ruptures propagate at speeds below the shear wave velocity within the crust, but in some rare cases, ruptures reach supershear speeds. The physics underlying the transition of natural subshear earthquakes to supershear ones is currently not fully understood. Most observational studies of supershear earthquakes have focused on determining which fault segments sustain fully grown supershear ruptures. Experimentally cross-validated numerical models have identified some of the key ingredients required to trigger a transition to supershear speed. However, the conditions for such a transition in nature are still unclear, including the precise location of this transition. In this work, we provide theoretical and numerical insights to identify the precise location of such a transition in nature. We use fracture mechanics arguments with multiple numerical models to identify the signature of supershear transition in coseismic off-fault damage. We then cross-validate this signature with high-resolution observations of fault zone width and early aftershock distributions. We confirm that the location of the transition from subshear to supershear speed is characterized by a decrease in the width of the coseismic off-fault damage zone. We thus help refine the precise location of such a transition for natural supershear earthquakes.
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Affiliation(s)
- Jorge Jara
- Laboratoire de Géologie, Département de Géosciences, École Normale Supérieure, CNRS, UMR 8538, PSL Université, Paris, France
| | - Lucile Bruhat
- Laboratoire de Géologie, Département de Géosciences, École Normale Supérieure, CNRS, UMR 8538, PSL Université, Paris, France
| | - Marion Y. Thomas
- Institut des Sciences de la Terre de Paris, Sorbonne Université, CNRS, UMR 7193, Paris, France
| | - Solène L. Antoine
- Université de Paris, Institut de Physique du Globe de Paris, CNRS, Paris 75005, France
| | - Kurama Okubo
- National Research Institute for Earth Science and Disaster Resilience, 3-1 Tennnodai, Tsukuba, Ibaraki 305-0006, Japan
| | - Esteban Rougier
- EES-17–Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Ares J. Rosakis
- Graduate Aerospace Laboratories, California Institute of Technology, Pasadena, CA 91125, USA
| | - Charles G. Sammis
- Department of Earth Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Yann Klinger
- Université de Paris, Institut de Physique du Globe de Paris, CNRS, Paris 75005, France
| | - Romain Jolivet
- Laboratoire de Géologie, Département de Géosciences, École Normale Supérieure, CNRS, UMR 8538, PSL Université, Paris, France
- Institut Universitaire de France, 1 rue Descartes, Paris 75005, France
| | - Harsha S. Bhat
- Laboratoire de Géologie, Département de Géosciences, École Normale Supérieure, CNRS, UMR 8538, PSL Université, Paris, France
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Gabriel AA, Li D, Chiocchetti S, Tavelli M, Peshkov I, Romenski E, Dumbser M. A unified first-order hyperbolic model for nonlinear dynamic rupture processes in diffuse fracture zones. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2021; 379:20200130. [PMID: 33715407 PMCID: PMC8059614 DOI: 10.1098/rsta.2020.0130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 09/28/2020] [Indexed: 06/12/2023]
Abstract
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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Affiliation(s)
- A.-A. Gabriel
- Ludwig-Maximilians-Universität München, Theresienstr. 41, 80333 München, Germany
| | - D. Li
- Ludwig-Maximilians-Universität München, Theresienstr. 41, 80333 München, Germany
| | - S. Chiocchetti
- Laboratory of Applied Mathematics, University of Trento, Via Mesiano, 77, 38123 Trento, Italy
| | - M. Tavelli
- Laboratory of Applied Mathematics, University of Trento, Via Mesiano, 77, 38123 Trento, Italy
| | - I. Peshkov
- Laboratory of Applied Mathematics, University of Trento, Via Mesiano, 77, 38123 Trento, Italy
| | - E. Romenski
- Sobolev Institute of Mathematics, 4 Acad. Koptyug Avenue, 630090 Novosibirsk, Russia
- Laboratory of Applied Mathematics, University of Trento, Via Mesiano, 77, 38123 Trento, Italy
| | - M. Dumbser
- Laboratory of Applied Mathematics, University of Trento, Via Mesiano, 77, 38123 Trento, Italy
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