Insight into poroelastic rebound deformation following the tohoku earthquake
K. Wang, Hu, and He (2012) proposed 3 primary processes that dominate the deformation following an earthquake at subduction zones; (1) afterslip, (2) viscoelastic relaxation, (3) re-locking of subduction fault. However, if the upper crust was saturated by fluid, the crust must be treat as a fluid...
| Main Authors: | , |
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| Format: | Conference or Workshop Item |
| Language: | English |
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2016
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| Online Access: | https://repository.ugm.ac.id/276582/1/JPGU%202016%20Hidayat.pdf |
| _version_ | 1797037091348021248 |
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| author | Panuntun, Hidayat Miyazaki, Shinichi |
| author_facet | Panuntun, Hidayat Miyazaki, Shinichi |
| author_sort | Panuntun, Hidayat |
| collection | UGM |
| description | K. Wang, Hu, and He (2012) proposed 3 primary processes that dominate the deformation following an
earthquake at subduction zones; (1) afterslip, (2) viscoelastic relaxation, (3) re-locking of
subduction fault. However, if the upper crust was saturated by fluid, the crust must be treat as a
fluid-saturated poroelastic medium instead of elastic medium. Coseismic stress change disrupt pore
fluid equilibrium and cause fluid migration from high pressure to zone of low pressure. Fluid
migration drive transient surface deformation which is known as poroelastic rebound. Pore fluid
flow induced by coseismic stress change is usually ignored due to the fact that; (1) this effect
occurs in short time at early postseismic deformation just around the rupture area, (2) and no
clear evidence of fluid-rich existence in the upper crust of the rupture. Due to the fluids-rich
existence detected in the upper crust (Z. Wang, Huang, Zhao, & Pei, 2012; Yamamoto, Obana, Kodaira,
Hino, & Shinohara, 2014; Zhao, Huang, Umino, Hasegawa, & Kanamori, 2011), pore fluid flow induced
by coseismic stress change can produce contribution to the surface deformation.
Therefore, poroelastic rebound should be included in the analysis of early postseismic deformation
following the Tohoku earthquake. Previous modeling studies in poroelastic rebound used various
values for undrained and drained Poisson’s ratio (e.g., Peltzer, Rosen, Rogez, and Hudnut (1998);
Jonsson, Segall, Pedersen, and Bjornsson (2003)). Instead of just assuming the values of drained
and undrained Poisson’s ratio, we use grid search to estimate undrained and drained Poisson’s ratio
value by combining forward calculation of poroelastic rebound and afterslip inversion of inland and
offshore GPS data. In total, we build 400 poroelastic rebound model with different combination of
undrained and drained Poisson’s ratio. Grid search approach obtained optimum value of 0.23 and 0.29
for drained and undrained Poisson’s ratio, respectively. Poroelastic rebound produced by the
optimum value of drained and undrained Poisson’s ratio estimated horizontal displacement up to 0.28
m in the rupture area. Majority of large uplift due to poroelastic rebound occurred in and around
the vicinity of the rupture area where maximum uplift estimated up to 0.37 m around the maximum
slip area of the mainshock. |
| first_indexed | 2024-03-13T23:57:37Z |
| format | Conference or Workshop Item |
| id | oai:generic.eprints.org:276582 |
| institution | Universiti Gadjah Mada |
| language | English |
| last_indexed | 2024-03-13T23:57:37Z |
| publishDate | 2016 |
| record_format | dspace |
| spelling | oai:generic.eprints.org:2765822021-02-04T06:14:49Z https://repository.ugm.ac.id/276582/ Insight into poroelastic rebound deformation following the tohoku earthquake Panuntun, Hidayat Miyazaki, Shinichi Tectonics Geophysics Geodesy K. Wang, Hu, and He (2012) proposed 3 primary processes that dominate the deformation following an earthquake at subduction zones; (1) afterslip, (2) viscoelastic relaxation, (3) re-locking of subduction fault. However, if the upper crust was saturated by fluid, the crust must be treat as a fluid-saturated poroelastic medium instead of elastic medium. Coseismic stress change disrupt pore fluid equilibrium and cause fluid migration from high pressure to zone of low pressure. Fluid migration drive transient surface deformation which is known as poroelastic rebound. Pore fluid flow induced by coseismic stress change is usually ignored due to the fact that; (1) this effect occurs in short time at early postseismic deformation just around the rupture area, (2) and no clear evidence of fluid-rich existence in the upper crust of the rupture. Due to the fluids-rich existence detected in the upper crust (Z. Wang, Huang, Zhao, & Pei, 2012; Yamamoto, Obana, Kodaira, Hino, & Shinohara, 2014; Zhao, Huang, Umino, Hasegawa, & Kanamori, 2011), pore fluid flow induced by coseismic stress change can produce contribution to the surface deformation. Therefore, poroelastic rebound should be included in the analysis of early postseismic deformation following the Tohoku earthquake. Previous modeling studies in poroelastic rebound used various values for undrained and drained Poisson’s ratio (e.g., Peltzer, Rosen, Rogez, and Hudnut (1998); Jonsson, Segall, Pedersen, and Bjornsson (2003)). Instead of just assuming the values of drained and undrained Poisson’s ratio, we use grid search to estimate undrained and drained Poisson’s ratio value by combining forward calculation of poroelastic rebound and afterslip inversion of inland and offshore GPS data. In total, we build 400 poroelastic rebound model with different combination of undrained and drained Poisson’s ratio. Grid search approach obtained optimum value of 0.23 and 0.29 for drained and undrained Poisson’s ratio, respectively. Poroelastic rebound produced by the optimum value of drained and undrained Poisson’s ratio estimated horizontal displacement up to 0.28 m in the rupture area. Majority of large uplift due to poroelastic rebound occurred in and around the vicinity of the rupture area where maximum uplift estimated up to 0.37 m around the maximum slip area of the mainshock. 2016 Conference or Workshop Item NonPeerReviewed application/pdf en https://repository.ugm.ac.id/276582/1/JPGU%202016%20Hidayat.pdf Panuntun, Hidayat and Miyazaki, Shinichi (2016) Insight into poroelastic rebound deformation following the tohoku earthquake. In: Japan Geoscience Union Meeting, 2016, Chiba. |
| spellingShingle | Tectonics Geophysics Geodesy Panuntun, Hidayat Miyazaki, Shinichi Insight into poroelastic rebound deformation following the tohoku earthquake |
| title | Insight into poroelastic rebound deformation following the tohoku earthquake |
| title_full | Insight into poroelastic rebound deformation following the tohoku earthquake |
| title_fullStr | Insight into poroelastic rebound deformation following the tohoku earthquake |
| title_full_unstemmed | Insight into poroelastic rebound deformation following the tohoku earthquake |
| title_short | Insight into poroelastic rebound deformation following the tohoku earthquake |
| title_sort | insight into poroelastic rebound deformation following the tohoku earthquake |
| topic | Tectonics Geophysics Geodesy |
| url | https://repository.ugm.ac.id/276582/1/JPGU%202016%20Hidayat.pdf |
| work_keys_str_mv | AT panuntunhidayat insightintoporoelasticrebounddeformationfollowingthetohokuearthquake AT miyazakishinichi insightintoporoelasticrebounddeformationfollowingthetohokuearthquake |