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Graham CC, Harrington JF. Stress field disruption allows gas-driven microdeformation in bentonite to be quantified. Sci Rep 2024; 14:788. [PMID: 38191782 PMCID: PMC10774314 DOI: 10.1038/s41598-023-41238-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 08/23/2023] [Indexed: 01/10/2024] Open
Abstract
Geological disposal of radioactive waste is being planned by many countries. Bentonite clay is often included in facility design, providing a barrier to radionuclide migration. Gas, generated by the waste or corrosion of waste canisters, may disrupt the properties of the bentonite. Robust prediction of this interaction is, therefore, necessary to demonstrate safe facility evolution. In some cases, gas may deform the clay, resulting in localised flow; however, the nature of this deformation has been widely debated. Accurate numerical representation of this behaviour has been limited by a shortage of information on the degree/distribution of deformation. Using experimental data from gas injection tests in bentonite, we show that first order fluctuations in the stress field can provide this information. We show that hundreds of microdeformation events can be detected, with similar characteristics to established fracturing phenomena, including earthquakes and acoustic emissions. We also demonstrate that stress field disruption (i) is spatially localised and (ii) has characteristics consistent with gas pathway 'opening' and 'closure' as gas enters and exits the clay, respectively. This new methodology offers fundamental insight and a new opportunity to parameterise and constrain gas advection models in clays and shales, substantially improving our capacity for safe facility design.
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Affiliation(s)
- Caroline C Graham
- British Geological Survey, Nicker Hill, Keyworth, Nottinghamshire, NG12 5GG, UK.
| | - Jon F Harrington
- British Geological Survey, Nicker Hill, Keyworth, Nottinghamshire, NG12 5GG, UK
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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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Hussain E, Wright TJ, Walters RJ, Bekaert DPS, Lloyd R, Hooper A. Constant strain accumulation rate between major earthquakes on the North Anatolian Fault. Nat Commun 2018; 9:1392. [PMID: 29643366 PMCID: PMC5895838 DOI: 10.1038/s41467-018-03739-2] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 03/09/2018] [Indexed: 11/09/2022] Open
Abstract
Earthquakes are caused by the release of tectonic strain accumulated between events. Recent advances in satellite geodesy mean we can now measure this interseismic strain accumulation with a high degree of accuracy. But it remains unclear how to interpret short-term geodetic observations, measured over decades, when estimating the seismic hazard of faults accumulating strain over centuries. Here, we show that strain accumulation rates calculated from geodetic measurements around a major transform fault are constant for its entire 250-year interseismic period, except in the ~10 years following an earthquake. The shear strain rate history requires a weak fault zone embedded within a strong lower crust with viscosity greater than ~1020 Pa s. The results support the notion that short-term geodetic observations can directly contribute to long-term seismic hazard assessment and suggest that lower-crustal viscosities derived from postseismic studies are not representative of the lower crust at all spatial and temporal scales.
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Affiliation(s)
- Ekbal Hussain
- COMET, School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, UK.
| | - Tim J Wright
- COMET, School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, UK
| | - Richard J Walters
- COMET, Department of Earth Sciences, Durham University, Durham, DH1 3LE, UK
| | - David P S Bekaert
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Ryan Lloyd
- COMET, School of Earth Sciences, University of Bristol, Bristol, BS8 1TH, UK
| | - Andrew Hooper
- COMET, School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, UK
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Hu Y, Wang K. Spherical-Earth finite element model of short-term postseismic deformation following the 2004 Sumatra earthquake. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2012jb009153] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Freed AM, Hirth G, Behn MD. Using short-term postseismic displacements to infer the ambient deformation conditions of the upper mantle. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011jb008562] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Pollitz FF, Thatcher W. On the resolution of shallow mantle viscosity structure using postearthquake relaxation data: Application to the 1999 Hector Mine, California, earthquake. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2010jb007405] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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