University of Tasmania
Browse

File(s) under permanent embargo

High-frequency ambient noise tomography of southeast Australia - New constraints on Tasmania's tectonic past

journal contribution
posted on 2023-05-17, 09:30 authored by Young, MK, Rawlinson, N, Arroucau, P, Anya ReadingAnya Reading, Tkalcic, H
The island of Tasmania, at the southeast tip of Australia, is an ideal natural laboratory for ambient noise tomography, as the surrounding oceans provide an energetic and relatively even distribution of noise sources. We extract Rayleigh wave dispersion curves from the continuous records of 104 stations with similar to 15 km separation. Unlike most passive experiments of this type, which observe very little coherent noise below a 5 s period, we clearly detect energy at periods as short as 1 s, thanks largely to the close proximity of oceanic microseisms on all sides. The main structural elements of the eastern and northern Tasmanian crust are revealed by inverting the dispersion curves (between 1 and 12 s period) for both group and phase velocity maps. Of particular significance is a pronounced band of low velocity, observed across all periods, that underlies the Tamar River Valley and continues south until dissipating in southeast Tasmania. Together with evidence from combined active source and teleseismic tomography and heat flow data, we interpret this region as a diffuse zone of strong deformation associated with the mid-Paleozoic accretion of oceanic crust along the eastern margin of Proterozoic Tasmania, which has important implications for the evolution of the Tasman Orogen of eastern Australia. In the northwest, a narrower low-velocity anomaly is seen in the vicinity of the Arthur Lineament, which may be attributed to local sediments and strong deformation and folding associated with the final phases of the Tyennan Orogeny.

History

Publication title

Geophysical Research Letters

Volume

38

Issue

13

Article number

L13313

Number

L13313

Pagination

1-6

ISSN

0094-8276

Department/School

School of Natural Sciences

Publisher

American Geophysical Union

Place of publication

2000 Florida Ave Nw, Washington, USA, Dc, 20009

Rights statement

Copyright 2011 by the 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