Post-earthquake relaxation using a spectral element method: 2.5-D case

Geophysical Journal International



The computation of quasi-static deformation for axisymmetric viscoelastic structures on a gravitating spherical earth is addressed using the spectral element method (SEM). A 2-D spectral element domain is defined with respect to spherical coordinates of radius and angular distance from a pole of symmetry, and 3-D viscoelastic structure is assumed to be azimuthally symmetric with respect to this pole. A point dislocation source that is periodic in azimuth is implemented with a truncated sequence of azimuthal order numbers. Viscoelasticity is limited to linear rheologies and is implemented with the correspondence principle in the Laplace transform domain. This leads to a series of decoupled 2-D problems which are solved with the SEM. Inverse Laplace transform of the independent 2-D solutions leads to the time-domain solution of the 3-D equations of quasi-static equilibrium imposed on a 2-D structure. The numerical procedure is verified through comparison with analytic solutions for finite faults embedded in a laterally homogeneous viscoelastic structure. This methodology is applicable to situations where the predominant structure varies in one horizontal direction, such as a structural contrast across (or parallel to) a long strike-slip fault.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Post-earthquake relaxation using a spectral element method: 2.5-D case
Series title Geophysical Journal International
DOI 10.1093/gji/ggu114
Volume 198
Issue 1
Year Published 2014
Language English
Publisher Blackwell Science
Contributing office(s) Earthquake Science Center
Description 19 p.
First page 308
Last page 326
Online Only (Y/N) N
Additional Online Files (Y/N) N