Improvement on spatial resolution of a coseismic slip distribution using postseismic geodetic data through a viscoelastic inversion
Abstract Obvious crustal deformation is observed during a postseismic period as well as a coseismic period associated with a large earthquake. Major mechanisms of transient postseismic deformation are known as afterslip and viscoelastic relaxation. Since the viscoelastic relaxation occurs as a respo...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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SpringerOpen
2020-06-01
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| Series: | Earth, Planets and Space |
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| Online Access: | http://link.springer.com/article/10.1186/s40623-020-01207-0 |
| _version_ | 1819091963246280704 |
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| author | Fumiaki Tomita Takeshi Iinuma Yusaku Ohta Ryota Hino Motoyuki Kido Naoki Uchida |
| author_facet | Fumiaki Tomita Takeshi Iinuma Yusaku Ohta Ryota Hino Motoyuki Kido Naoki Uchida |
| author_sort | Fumiaki Tomita |
| collection | DOAJ |
| description | Abstract Obvious crustal deformation is observed during a postseismic period as well as a coseismic period associated with a large earthquake. Major mechanisms of transient postseismic deformation are known as afterslip and viscoelastic relaxation. Since the viscoelastic relaxation occurs as a response to a coseismic slip, postseismic deformation provides information on coseismic deformation through the viscoelastic response. However, most previous studies have not thoroughly utilized postseismic geodetic observational data for revealing coseismic slip behaviors. In this study, we developed a slip inversion method that simultaneously estimates coseismic slip and postseismic slip distributions from coseismic and postseismic geodetic observational data using viscoelastic Green’s function (viscoelastic inversion method). We investigated the performance of the viscoelastic inversion method via two synthetic tests: one assumed a strike–slip event along an inland fault, while the other assumed a dip–slip event along a plate interface in a subduction zone. Both synthetic tests demonstrated that when extensive postseismic observational data were given, the viscoelastic inversion method provided a superior spatial resolution of coseismic slip distributions compared to conventional elastic inversion distributions. We also applied the viscoelastic inversion method to co- and post-seismic deformations associated with the 2011 Tohoku-oki earthquake. The seafloor geodetic observational network of the off-Tohoku region has been widely extended after the occurrence of the mainshock. Using this extended seafloor geodetic observational data, we successfully improved the spatial resolution of the coseismic slip distribution through the viscoelastic inversion method. Furthermore, using the seafloor observational data during the postseismic period, our inversion method enables us to obtain high spatial resolution of the coseismic slip in the offshore area and a reasonable coseismic slip distribution even if seafloor observational data during the coseismic period are unavailable. These results clarify the importance of deploying a geodetic observational network even after large coseismic events to assess past coseismic slip behaviors by considering the viscoelasticity of the Earth. |
| first_indexed | 2024-12-21T22:48:04Z |
| format | Article |
| id | doaj.art-3283143e2be94e04a868d327d344ed9b |
| institution | Directory Open Access Journal |
| issn | 1880-5981 |
| language | English |
| last_indexed | 2024-12-21T22:48:04Z |
| publishDate | 2020-06-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | Earth, Planets and Space |
| spelling | doaj.art-3283143e2be94e04a868d327d344ed9b2022-12-21T18:47:39ZengSpringerOpenEarth, Planets and Space1880-59812020-06-0172112410.1186/s40623-020-01207-0Improvement on spatial resolution of a coseismic slip distribution using postseismic geodetic data through a viscoelastic inversionFumiaki Tomita0Takeshi Iinuma1Yusaku Ohta2Ryota Hino3Motoyuki Kido4Naoki Uchida5Research Institute for Marine Geodynamics, Japan Agency for Marine-Earth Science and TechnologyResearch Institute for Marine Geodynamics, Japan Agency for Marine-Earth Science and TechnologyGraduate School of Science, Tohoku UniversityGraduate School of Science, Tohoku UniversityInternational Research Institute of Disaster Science, Tohoku UniversityGraduate School of Science, Tohoku UniversityAbstract Obvious crustal deformation is observed during a postseismic period as well as a coseismic period associated with a large earthquake. Major mechanisms of transient postseismic deformation are known as afterslip and viscoelastic relaxation. Since the viscoelastic relaxation occurs as a response to a coseismic slip, postseismic deformation provides information on coseismic deformation through the viscoelastic response. However, most previous studies have not thoroughly utilized postseismic geodetic observational data for revealing coseismic slip behaviors. In this study, we developed a slip inversion method that simultaneously estimates coseismic slip and postseismic slip distributions from coseismic and postseismic geodetic observational data using viscoelastic Green’s function (viscoelastic inversion method). We investigated the performance of the viscoelastic inversion method via two synthetic tests: one assumed a strike–slip event along an inland fault, while the other assumed a dip–slip event along a plate interface in a subduction zone. Both synthetic tests demonstrated that when extensive postseismic observational data were given, the viscoelastic inversion method provided a superior spatial resolution of coseismic slip distributions compared to conventional elastic inversion distributions. We also applied the viscoelastic inversion method to co- and post-seismic deformations associated with the 2011 Tohoku-oki earthquake. The seafloor geodetic observational network of the off-Tohoku region has been widely extended after the occurrence of the mainshock. Using this extended seafloor geodetic observational data, we successfully improved the spatial resolution of the coseismic slip distribution through the viscoelastic inversion method. Furthermore, using the seafloor observational data during the postseismic period, our inversion method enables us to obtain high spatial resolution of the coseismic slip in the offshore area and a reasonable coseismic slip distribution even if seafloor observational data during the coseismic period are unavailable. These results clarify the importance of deploying a geodetic observational network even after large coseismic events to assess past coseismic slip behaviors by considering the viscoelasticity of the Earth.http://link.springer.com/article/10.1186/s40623-020-01207-0Geodetic slip inversionCoseismic deformationPostseismic deformationViscoelastic relaxationSeismic cycle2011 Tohoku-oki earthquake |
| spellingShingle | Fumiaki Tomita Takeshi Iinuma Yusaku Ohta Ryota Hino Motoyuki Kido Naoki Uchida Improvement on spatial resolution of a coseismic slip distribution using postseismic geodetic data through a viscoelastic inversion Earth, Planets and Space Geodetic slip inversion Coseismic deformation Postseismic deformation Viscoelastic relaxation Seismic cycle 2011 Tohoku-oki earthquake |
| title | Improvement on spatial resolution of a coseismic slip distribution using postseismic geodetic data through a viscoelastic inversion |
| title_full | Improvement on spatial resolution of a coseismic slip distribution using postseismic geodetic data through a viscoelastic inversion |
| title_fullStr | Improvement on spatial resolution of a coseismic slip distribution using postseismic geodetic data through a viscoelastic inversion |
| title_full_unstemmed | Improvement on spatial resolution of a coseismic slip distribution using postseismic geodetic data through a viscoelastic inversion |
| title_short | Improvement on spatial resolution of a coseismic slip distribution using postseismic geodetic data through a viscoelastic inversion |
| title_sort | improvement on spatial resolution of a coseismic slip distribution using postseismic geodetic data through a viscoelastic inversion |
| topic | Geodetic slip inversion Coseismic deformation Postseismic deformation Viscoelastic relaxation Seismic cycle 2011 Tohoku-oki earthquake |
| url | http://link.springer.com/article/10.1186/s40623-020-01207-0 |
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