Mapping the Mechanical Anisotropy of the Lithosphere using a 2D Wavelet Coherence, and its Applicaton to Australia

We develop a new method for imaging the spatial variations of the anisotropy of the flexural response of the lithosphere, and apply it to recent topographic and gravity data sets over Australia. The method uses two-dimensional Morlet wavelet transforms, superposed in a strictly controlled geometry,...

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Main Authors: Kirby, Jon, Swain, Christopher
Format: Journal Article
Published: Elsevier 2006
Subjects:
Online Access:http://hdl.handle.net/20.500.11937/23914
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author Kirby, Jon
Swain, Christopher
author_facet Kirby, Jon
Swain, Christopher
author_sort Kirby, Jon
building Curtin Institutional Repository
collection Online Access
description We develop a new method for imaging the spatial variations of the anisotropy of the flexural response of the lithosphere, and apply it to recent topographic and gravity data sets over Australia. The method uses two-dimensional Morlet wavelet transforms, superposed in a strictly controlled geometry, to estimate the auto- and cross-spectra of the two data sets in a number of different directions. The resulting wavelet coherence is a function of scale, or wavelength, as well as orientation, and is inverted, at each spatial location, for the three parameters of an anisotropic, thin elastic plate model, i.e., maximum and minimum flexural rigidities and the orientation of the maximum. Extensive tests of the method on synthetic anisotropic, but uniform, data sets, show that it retrieves the amplitude and orientation of the anisotropy with useful accuracy. The results for Australia west of 143oE show a strong correlation with the shallower layers (75-175 km) of a recent model of seismic SV wave azimuthal anisotropy. The 'weak' axes (i.e., of minimum flexural rigidity) in most cases are approximately at right angles to the fast axes of the seismic anisotropy, implying that, for Precambrian Australia, they arise from the same source. This is most likely deformation resulting from the most recent episode of orogeny.
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spelling curtin-20.500.11937-239142019-02-19T05:35:05Z Mapping the Mechanical Anisotropy of the Lithosphere using a 2D Wavelet Coherence, and its Applicaton to Australia Kirby, Jon Swain, Christopher Anisotropy Lithosphere Australia Wavelets Isostasy We develop a new method for imaging the spatial variations of the anisotropy of the flexural response of the lithosphere, and apply it to recent topographic and gravity data sets over Australia. The method uses two-dimensional Morlet wavelet transforms, superposed in a strictly controlled geometry, to estimate the auto- and cross-spectra of the two data sets in a number of different directions. The resulting wavelet coherence is a function of scale, or wavelength, as well as orientation, and is inverted, at each spatial location, for the three parameters of an anisotropic, thin elastic plate model, i.e., maximum and minimum flexural rigidities and the orientation of the maximum. Extensive tests of the method on synthetic anisotropic, but uniform, data sets, show that it retrieves the amplitude and orientation of the anisotropy with useful accuracy. The results for Australia west of 143oE show a strong correlation with the shallower layers (75-175 km) of a recent model of seismic SV wave azimuthal anisotropy. The 'weak' axes (i.e., of minimum flexural rigidity) in most cases are approximately at right angles to the fast axes of the seismic anisotropy, implying that, for Precambrian Australia, they arise from the same source. This is most likely deformation resulting from the most recent episode of orogeny. 2006 Journal Article http://hdl.handle.net/20.500.11937/23914 10.1016/j.pepi.2006.03.022 Elsevier fulltext
spellingShingle Anisotropy
Lithosphere
Australia
Wavelets
Isostasy
Kirby, Jon
Swain, Christopher
Mapping the Mechanical Anisotropy of the Lithosphere using a 2D Wavelet Coherence, and its Applicaton to Australia
title Mapping the Mechanical Anisotropy of the Lithosphere using a 2D Wavelet Coherence, and its Applicaton to Australia
title_full Mapping the Mechanical Anisotropy of the Lithosphere using a 2D Wavelet Coherence, and its Applicaton to Australia
title_fullStr Mapping the Mechanical Anisotropy of the Lithosphere using a 2D Wavelet Coherence, and its Applicaton to Australia
title_full_unstemmed Mapping the Mechanical Anisotropy of the Lithosphere using a 2D Wavelet Coherence, and its Applicaton to Australia
title_short Mapping the Mechanical Anisotropy of the Lithosphere using a 2D Wavelet Coherence, and its Applicaton to Australia
title_sort mapping the mechanical anisotropy of the lithosphere using a 2d wavelet coherence, and its applicaton to australia
topic Anisotropy
Lithosphere
Australia
Wavelets
Isostasy
url http://hdl.handle.net/20.500.11937/23914