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Constraining crustal and sedimentary structure of Southeast Australia with Rayleigh wave ellipticity

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posted on 29.03.2022, 00:59 by Haoming Wu
Ambient noise tomography has been widely applied in seismic studies to invert for crustal and upper mantle structure, but has limited resolution for the near surface layer. A recent method involves measuring the ellipticity or ZH ratio of Rayleigh waves to further constrain shallow sedimentary structure. We apply this method to South-East Australia, using multicomponent ambient noise data obtained from the WOMBAT array. We present a shear wave velocity model, derived from the joint inversion of Rayleigh wave ZH ratio and phase velocities measured at short periods (2-10s). At shallow depth, our shear wave velocity model showed strong spatial correlation with the known surface geology. High velocities were associated with the Gawler craton and the eastern subprovince of the Lachlan Orogen. This contrasted with anomalously low velocities featured prominently in the locations of the Central Murray basin, Sydney Basin and the Northern Curnamona province at 1km depth. A low velocity, shallow layer of 0.5-2km thickness was detectable across study region, which was found to be thicker beneath sedimentary basins. We evaluate the strengths and limitations of the ZH ratio method for the South-East Australia dataset.

History

Table of Contents

1. Introduction -- 2. Methodology -- 3. Results -- 4. Discussion -- 5. Conclusions.

Notes

Theoretical thesis. Bibliography: pages 50-52

Awarding Institution

Macquarie University

Degree Type

Thesis MRes

Degree

MRes, Macquarie University, Faculty of Science and Engineering, Department of Earth and Planetary Sciences

Department, Centre or School

Department of Earth and Planetary Sciences

Year of Award

2018

Principal Supervisor

Yingjie Yang

Rights

Copyright Haoming Wu 2018 Copyright disclaimer: http://mq.edu.au/library/copyright

Language

English

Extent

1 online resource (vi, 52 pages : maps)

Former Identifiers

mq:70737 http://hdl.handle.net/1959.14/1267238