2024-03-28T13:24:20Z
https://nagoya.repo.nii.ac.jp/oai
oai:nagoya.repo.nii.ac.jp:00025028
2023-01-16T04:15:40Z
488:489:490
Transient rheology of the oceanic asthenosphere following the 2012 Indian Ocean Earthquake inferred from geodetic data
Pratama, Cecep
Ito, Takeo
Sasajima, Ryohei
Tabei, Takao
Kimata, Fumiaki
Gunawan, Endra
Ohta, Yusaku
Yamashina, Tadashi
Ismail, Nazli
Nurdin, Irwandi
Sugiyanto, Didik
Muksin, Umar
Irwan, Meilano
open access
© 2017. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/
Asthenosphere
Lithosphere
Viscosity
Transient rheology
GNSS
Postseismic motion in the middle-field (100–500 km from the epicenter) geodetic data resulting from the 2012 Indian Ocean earthquake exhibited rapid change during the two months following the rupture. This pattern probably indicates multiple postseismic deformation mechanisms and might have been controlled by transient rheology. Therefore, the relative contribution of transient rheology in the oceanic asthenosphere and afterslip in the oceanic lithosphere should be incorporated to explain short- and long-term transitional features of postseismic signals. In this study, using two years of post-earthquake geodetic data from northern Sumatra, a three-dimensional spherical-earth finite-element model was constructed based on a heterogeneous structure and incorporating transient rheology. A rheology model combined with stress-driven afterslip was estimated. Our best-fit model suggests an oceanic lithosphere thickness of 75 km with oceanic asthenosphere viscosity values of 1 × 10^17 Pa s and 2 × 10^18 Pa s for the Kelvin and Maxwell viscosity models, respectively. The model results indicate that horizontal landward motion and vertical uplift in northern Sumatra require viscoelastic relaxation of the oceanic asthenosphere coupled with afterslip in the lithosphere. The present study demonstrates that transient rheology is essential for reproducing the rapidly changing motion of postseismic deformation in the middle-field area.
Elsevier
2017-10-01
eng
journal article
AM
http://hdl.handle.net/2237/27250
https://nagoya.repo.nii.ac.jp/records/25028
https://doi.org/10.1016/j.jseaes.2017.07.049
1367-9120
JOURNAL OF ASIAN EARTH SCIENCES
147
50
59
https://nagoya.repo.nii.ac.jp/record/25028/files/2017_JAES_OPEN_REPOSITORY.pdf
application/pdf
22.9 MB
2019-10-01