Linking mainland Australia and Tasmania using ambient seismic noise tomography: Implications for the tectonic evolution of the east Gondwana margin

S Pilia, N Rawlinson, N G Direen, A M Reading, R Cayley, L Pryer, P Arroucau, M Duffet

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)


For nearly half a century, a number of conflicting tectonic models have been postulated to explain the enigmatic geological relationship between Tasmania and Victoria, with a view to unifying our understanding of the evolution of the eastern margin of Gondwana in Australia. In this study, ambient noise data from an array of 24 broadband seismometers is used to produce a high-resolution 3-D crustal shear wave velocity model of Bass Strait, the key to understanding the missing link. We apply a novel transdimensional and hierarchical Bayesian inversion approach to construct group velocity maps in the period range of 2–30 s, and subsequently invert group velocity dispersion for 3-D shear wave velocity structure. This allows us to image, for the first time, the entire crust beneath Bass Strait in high detail and elucidate the geometry and position of key crustal features with corroboration from complementary datasets. The three sedimentary basins related to the failed rifting event associated with the Australia–Antarctica breakup, in particular Bass Basin, clearly emerge from the tomographic solution model. A key feature of the 3-D shear wavespeed model is a distinct mid-lower crustal NW–SE high velocity zone which extends from northwestern Tasmania to south-central Victoria, confirming a Proterozoic geological connection. We also image three north–south high velocity belts that appear to span Bass Strait, with some interruption from velocity variations possibly related to more recent tectonic events. These belts are consistent with recent gravity and magnetic maps, and may indicate the presence of an exotic Precambrian terrane (the Selwyn Block). The model also images the crustal velocity structure of the southern Stawell and Bendigo Zones, and their internal large-scale multi-layer characters, a legacy of their Early Paleozoic intra-oceanic origins. Another high velocity anomaly imaged in the mid-lower crust is an east–west lineament beneath the northern part of Bass Strait, which may be an intrusive feature associated with the failed rift.
Original languageEnglish
Pages (from-to)1212-1227
Number of pages16
JournalGondwana Research
Issue number3
Early online date22 Oct 2014
Publication statusPublished - Oct 2015

Bibliographical note

This work has benefitted from insightful discussions with David Moore and many other colleagues from the Australian National University, University of Tasmania, FROGTECH, Geological Survey of Victoria and Mineral Resources of Tasmania. Thomas Bodin is thanked for kindly providing the rj-McMC code and Mallory Young for helpful discussions about its implementation. The contribution of all project partners is greatly appreciated. Furthermore, the authors would like to thank the many people involved in the field deployment and pull out of the instruments. Major project support including that of SP was provided through the Australian Research Council grant LP110100256 as well as a PESA and a CSIRO scholarship. The authors are very grateful to Stewart Fishwick and an anonymous reviewer for their constructive reviews.

Calculations were performed on the Terrawulf II cluster, a computational facility supported through the AuScope Australian Geophysical Observing System (AGOS). AuScope is funded under the National Collaborative Research Infrastructure Strategy (NCRIS) and the Education investment Fund (EIF3), both Australian Commonwealth Government Programs.

MD publishes with the permission of the Director of Mines, Mineral Resources Tasmania.


  • Gondwana evolution
  • Australia
  • seismic imaging
  • seismic inversion
  • ambient noise tomography
  • Bass Strait
  • Bayesian inversion
  • East Gondwana
  • Selwyn Block
  • Tasmania


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