Perturbational and nonperturbational inversion of Rayleigh-wave velocities

Geophysics
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Abstract

The inversion of Rayleigh-wave dispersion curves is a classic geophysical inverse problem. We have developed a set of MATLAB codes that performs forward modeling and inversion of Rayleigh-wave phase or group velocity measurements. We describe two different methods of inversion: a perturbational method based on finite elements and a nonperturbational method based on the recently developed Dix-type relation for Rayleigh waves. In practice, the nonperturbational method can be used to provide a good starting model that can be iteratively improved with the perturbational method. Although the perturbational method is well-known, we solve the forward problem using an eigenvalue/eigenvector solver instead of the conventional approach of root finding. Features of the codes include the ability to handle any mix of phase or group velocity measurements, combinations of modes of any order, the presence of a surface water layer, computation of partial derivatives due to changes in material properties and layer boundaries, and the implementation of an automatic grid of layers that is optimally suited for the depth sensitivity of Rayleigh waves.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Perturbational and nonperturbational inversion of Rayleigh-wave velocities
Series title Geophysics
DOI 10.1190/geo2016-0397.1
Volume 82
Issue 3
Year Published 2017
Language English
Publisher Society of Exploration Geophysicists
Contributing office(s) Volcano Science Center
Description 14 p.
First page F15
Last page F28