Early Postseismic Deformation of the 2010 Mw 6.9 Yushu Earthquake and Its Implication for Lithospheric Rheological Properties

Abstract We used the 250‐day postseismic displacements derived from Global Positioning System data to explore various postseismic deformation processes of the 14 April 2010 Mw 6.9 Yushu earthquake, including the afterslip of the fault, viscoelastic relaxation in the lower crust and upper mantle, and...

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Bibliographic Details
Main Authors: Yunguo Chen, Yan Hu, Liang Qian, Guojie Meng
Format: Article
Language:English
Published: Wiley 2022-08-01
Series:Geophysical Research Letters
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Online Access:https://doi.org/10.1029/2022GL098942
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Summary:Abstract We used the 250‐day postseismic displacements derived from Global Positioning System data to explore various postseismic deformation processes of the 14 April 2010 Mw 6.9 Yushu earthquake, including the afterslip of the fault, viscoelastic relaxation in the lower crust and upper mantle, and the poroelastic rebound. The preferred model shows that the afterslip of the fault decays rapidly with time. Viscoelastic relaxation in the lower crust and upper mantle decays slower with time but affects a broader area. Our results show that the range of the steady‐state viscosity in the lower crust is 0.3–2 × 1019 Pa s. The optimal steady‐state viscosity in the lower crust is ∼5 × 1018 Pa s. We simulate the deformation due to the poroelastic rebound in the top 10 km upper crust. Model results indicate that the poroelastic rebound only produces a few millimeters surface deformation and may be a secondary‐order postseismic process.
ISSN:0094-8276
1944-8007