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Title: Characteristics of viscoelastic crustal deformation following a megathrust earthquake: discrepancy between the apparent and intrinsic relaxation time constants
Authors: Fukahata, Yukitoshi  kyouindb  KAKEN_id  orcid (unconfirmed)
Matsu’ura, Mitsuhiro
Author's alias: 深畑, 幸俊
Keywords: Viscoelastic relaxation
Maxwell time
megathrust earthquake
postseismic deformation
Issue Date: Feb-2018
Publisher: Springer Nature
Journal title: Pure and Applied Geophysics
Volume: 175
Issue: 2
Start page: 549
End page: 558
Abstract: The viscoelastic deformation of an elastic–viscoelastic composite system is significantly different from that of a simple viscoelastic medium. Here, we show that complicated transient deformation due to viscoelastic stress relaxation after a megathrust earthquake can occur even in a very simple situation, in which an elastic surface layer (lithosphere) is underlain by a viscoelastic substratum (asthenosphere) under gravity. Although the overall decay rate of the system is controlled by the intrinsic relaxation time constant of the asthenosphere, the apparent decay time constant at each observation point is significantly different from place to place and generally much longer than the intrinsic relaxation time constant of the asthenosphere. It is also not rare that the sense of displacement rate is reversed during the viscoelastic relaxation. If we do not bear these points in mind, we may draw false conclusions from observed deformation data. Such complicated transient behavior can be explained mathematically from the characteristics of viscoelastic solution: for an elastic–viscoelastic layered half-space, the viscoelastic solution is expressed as superposition of three decaying components with different relaxation time constants that depend on wavelength.
Rights: This is a post-peer-review, pre-copyedit version of an article published in Pure and Applied Geophysics. The final authenticated version is available online at:
This is not the published version. Please cite only the published version.
DOI(Published Version): 10.1007/s00024-017-1735-3
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