University of Tasmania
Browse

File(s) under permanent embargo

Structural controls on localized intraplate deformation and seismicity in Southern Australia: Insights from local earthquake tomography of the Flinders Ranges

journal contribution
posted on 2023-05-17, 21:03 authored by Pilia, S, Rawlinson, N, Nicholas DireenNicholas Direen, Cummins, PR, Balfour, N
Data from an array of 24 seismometers are used to image the crust beneath the Flinders Ranges, southeast Australia, with the goal of improving our understanding of crustal structure, rheology, and the mechanism responsible for the localized intraplate deformation that characterizes this region. A subset of P- and S-wave traveltimes is inverted to jointly recover earthquake hypocenters, P-wave velocity structure and v(p)/v(s) anomalies. The P-wave velocity model reveals a spatial correlation between major negative velocity perturbations and concentrations of seismicity. In particular, a cluster of seismicity is observed within a distinct low velocity region between the Archean-Mesoproterozoic Gawler Craton and the Palaeo-Mesoproterozoic Curnamona Province, from 7 to 20km depth. We postulate that this may be associated with a pre-existing structural weakness in the crust that arises primarily from rifting between the Curnamona Province and the Gawler Craton. Another area characterized by a high level of seismicity overlies a major sequence of N-S trending Ross-Delamerian thrust faults, which correspond to a band of low v(p) and particularly v(p)/v(s). The lack of evidence for elevated heat flows in both of these seismogenic regions suggests that thermally induced weakness is unlikely to play a dominant role. Instead, the dynamic behavior of this intraplate region appears to be caused by a serendipitously oriented regional stress field, provided by far field forces that originate from the boundary between the Pacific and Australian plates, which acts upon preexisting structural weaknesses in the lithosphere.

Funding

Australian Research Council

Frog Tech Pty Ltd

GeoScience Victoria

Mineral Resources Tasmania

History

Publication title

Journal of Geophysical Research: Solid Earth

Volume

118

Issue

5

Pagination

2176-2190

ISSN

2169-9313

Department/School

School of Natural Sciences

Publisher

American Geophysical Union

Place of publication

2000 Florida Ave NW, Washington, DC 20009 USA

Rights statement

Copyright 2013 American Geophysical Union

Repository Status

  • Restricted

Socio-economic Objectives

Expanding knowledge in the earth sciences

Usage metrics

    University Of Tasmania

    Exports

    RefWorks
    BibTeX
    Ref. manager
    Endnote
    DataCite
    NLM
    DC