DOI: 10.1016/j.epsl.2019.116031
论文题名: Spatio-temporal variations of afterslip and viscoelastic relaxation following the Mw 7.8 Gorkha (Nepal) earthquake
作者: Tian Z. ; Freymueller J.T. ; Yang Z.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2020
卷: 532 语种: 英语
中文关键词: afterslip
; Gorkha earthquake
; GPS postseismic deformation
; viscoelastic relaxation
英文关键词: Deformation
; Earthquakes
; Viscosity
; afterslip
; Elastic lithosphere
; Integrated modeling
; Postseismic deformation
; Spatio-temporal variation
; Steady state viscosity
; Viscoelastic deformation
; Viscoelastic relaxation
; Viscoelasticity
; deformation
; Gorkha earthquake 2015
; GPS
; postseismic process
; rheology
; slip rate
; spatial variation
; temporal variation
; viscoelasticity
; China
; Gandaki
; Gorkha
; Nepal
; Xizang
英文摘要: We use 4 years of 3D GPS data from Nepal and southern Tibet to investigate the postseismic deformation caused by the 2015 Mw 7.8 Gorkha (Nepal) earthquake. We first model afterslip and viscoelastic relaxation separately, but find that this approach results in an overestimate of the total postseismic deformation. We then use an integrated model to simultaneously extract the contributions from afterslip and viscoelastic relaxation by assessing the misfit between observed and simulated displacements during different periods. The results show that the near-field postseismic displacements are dominated by downdip afterslip during the first 2 years, and then viscoelastic relaxation plays the leading role in the following years. In the far-field, however, the observed deformation is mainly controlled by viscoelastic mechanism throughout the postseismic period. The best model supports a laterally heterogeneous rheology: the Tibetan lower crust is viscoelastic with a transient viscosity 5×1017 Pa s, steady-state viscosity 5×1018 Pa s; we assume in our model that India has an elastic lithosphere 50 km thick with a high viscosity upper mantle (1020 Pa s), and that the same mantle viscosity applies beneath Tibet. We further predict that viscoelastic deformation will be observed in the near-field for ∼12 years and the displacements caused by afterslip for ∼6 years. Given the afterslip following the earthquake and the possible untapped strain inherited from historical events, the regions to the west and south of Kathmandu have the potential to suffer a large earthquake rupture in the future. © 2019 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/165313
Appears in Collections: 气候变化与战略
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作者单位: School of Geology Engineering and Geomatics, Chang'an University, Xi'an, China; Department of Earth and Environmental Sciences, Michigan State UniversityMI, United States
Recommended Citation:
Tian Z.,Freymueller J.T.,Yang Z.. Spatio-temporal variations of afterslip and viscoelastic relaxation following the Mw 7.8 Gorkha (Nepal) earthquake[J]. Earth and Planetary Science Letters,2020-01-01,532