The closure of microcracks under pressure: inference from elastic wave velocity and electrical conductivity in granitic rocks
Abstract Measurements of elastic wave velocity and electrical conductivity were conducted on brine-saturated granitic rocks under confining pressure to quantitatively characterize the closure of cracks. The number of contacting asperities and radius ratio of contact over crack were estimated. Contac...
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SpringerOpen
2024-11-01
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| Series: | Earth, Planets and Space |
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| Online Access: | https://doi.org/10.1186/s40623-024-02103-7 |
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| author | Tohru Watanabe Arina Tomioka Kenta Yoshida |
| author_facet | Tohru Watanabe Arina Tomioka Kenta Yoshida |
| author_sort | Tohru Watanabe |
| collection | DOAJ |
| description | Abstract Measurements of elastic wave velocity and electrical conductivity were conducted on brine-saturated granitic rocks under confining pressure to quantitatively characterize the closure of cracks. The number of contacting asperities and radius ratio of contact over crack were estimated. Contacting asperities were assumed to deform elastically and/or plastically. The number of contacts increases steeply at low pressure (< 10 MPa) and decreases gradually at higher pressure, while the radius ratio of contact over crack linearly increases. Though the area fraction of contacts increases to no more than 30% even at the highest confining pressure (150 MPa), the stiffness of the solid phase is recovered, and the connectivity of fluid is maintained in a crack. Cracks under pressure are closed for elastic properties, but open for transport properties. The effective aperture is of the order of 100 nm at atmospheric pressure, and steeply decreases at low pressure (< 10 MPa) and then gradually at higher pressure. Observed seismic velocity and electrical conductivity in the crust should be interpreted by considering contacts in cracks. Microstructures of closing cracks should be further investigated to seek relationships between structural parameters and effective pressure. Graphical abstract |
| format | Article |
| id | doaj-art-7eea5d68c8024c3998d9c3cfe6b68b8b |
| institution | Kabale University |
| issn | 1880-5981 |
| language | English |
| publishDate | 2024-11-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | Earth, Planets and Space |
| spelling | doaj-art-7eea5d68c8024c3998d9c3cfe6b68b8b2024-12-01T12:13:45ZengSpringerOpenEarth, Planets and Space1880-59812024-11-0176112210.1186/s40623-024-02103-7The closure of microcracks under pressure: inference from elastic wave velocity and electrical conductivity in granitic rocksTohru Watanabe0Arina Tomioka1Kenta Yoshida2Department of Earth System Science, University of ToyamaGraduate School of Science and Engineering, University of ToyamaResearch Institute for Marine Geodynamics, Japan Agency for Marine-Earth Science and TechnologyAbstract Measurements of elastic wave velocity and electrical conductivity were conducted on brine-saturated granitic rocks under confining pressure to quantitatively characterize the closure of cracks. The number of contacting asperities and radius ratio of contact over crack were estimated. Contacting asperities were assumed to deform elastically and/or plastically. The number of contacts increases steeply at low pressure (< 10 MPa) and decreases gradually at higher pressure, while the radius ratio of contact over crack linearly increases. Though the area fraction of contacts increases to no more than 30% even at the highest confining pressure (150 MPa), the stiffness of the solid phase is recovered, and the connectivity of fluid is maintained in a crack. Cracks under pressure are closed for elastic properties, but open for transport properties. The effective aperture is of the order of 100 nm at atmospheric pressure, and steeply decreases at low pressure (< 10 MPa) and then gradually at higher pressure. Observed seismic velocity and electrical conductivity in the crust should be interpreted by considering contacts in cracks. Microstructures of closing cracks should be further investigated to seek relationships between structural parameters and effective pressure. Graphical abstracthttps://doi.org/10.1186/s40623-024-02103-7Seismic velocityElectrical conductivityFluidCrackAsperity |
| spellingShingle | Tohru Watanabe Arina Tomioka Kenta Yoshida The closure of microcracks under pressure: inference from elastic wave velocity and electrical conductivity in granitic rocks Earth, Planets and Space Seismic velocity Electrical conductivity Fluid Crack Asperity |
| title | The closure of microcracks under pressure: inference from elastic wave velocity and electrical conductivity in granitic rocks |
| title_full | The closure of microcracks under pressure: inference from elastic wave velocity and electrical conductivity in granitic rocks |
| title_fullStr | The closure of microcracks under pressure: inference from elastic wave velocity and electrical conductivity in granitic rocks |
| title_full_unstemmed | The closure of microcracks under pressure: inference from elastic wave velocity and electrical conductivity in granitic rocks |
| title_short | The closure of microcracks under pressure: inference from elastic wave velocity and electrical conductivity in granitic rocks |
| title_sort | closure of microcracks under pressure inference from elastic wave velocity and electrical conductivity in granitic rocks |
| topic | Seismic velocity Electrical conductivity Fluid Crack Asperity |
| url | https://doi.org/10.1186/s40623-024-02103-7 |
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