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

Pilia, Simone; Rawlinson, Nicholas; Direen, Nicholas G.; Reading, Anya M.; Cayley, R. A.; Pryer, Lynn; Arroucau, Pierre; Duffett, Mark

doi:10.1016/j.gr.2014.09.014

Cited by 18 publications

(19 citation statements)

References 91 publications

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“…We present the crustal structure beneath southeastern Australia via a series of period‐dependent phase velocity maps (Figure ), in which the orientation of the fast axes of anisotropy is superimposed onto the isotropic component of the wavefield. The regional pattern of isotropic phase velocity variations is similar to previous 2‐D and 3‐D isotropic tomographic models based on ambient noise recordings [ Young et al , , ; Pilia et al , , ]. This appears to suggest that the final isotropic tomographic models from southeastern Australia are not significantly affected by the addition of azimuthal anisotropy to the inversion process.…”

Section: Methods and Resultssupporting

confidence: 83%

Inherited crustal deformation along the East Gondwana margin revealed by seismic anisotropy tomography

Pilia¹,

Arroucau

Rawlinson

et al. 2016

Geophysical Research Letters

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The mechanisms of continental growth are a crucial part of plate tectonic theory, yet a clear understanding of the processes involved remains elusive. Here we determine seismic Rayleigh wave phase anisotropy variations in the crust beneath the southern Tasmanides of Australia, a Paleozoic accretionary margin. Our results reveal a complex, thick‐skinned pervasive deformation that was driven by the tectonic interaction between the proto‐Pacific Ocean and the ancient eastern margin of Gondwana. Stress‐induced effects triggered by the collision and entrainment of a microcontinent into the active subduction zone are evident in the anisotropy signature. The paleofracturing trend of failed rifting between Australia and Antarctica is also recorded in the anisotropy pattern as well as a tightly curved feature in central Tasmania. The observed patterns of anisotropy correlate well with recent geodynamic and kinematic models of the Tasmanides and provide a platform from which the spatial extent of deformational domains can be refined.

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Section: Methods and Resultssupporting

confidence: 83%

Inherited crustal deformation along the East Gondwana margin revealed by seismic anisotropy tomography

Pilia¹,

Arroucau

Rawlinson

et al. 2016

Geophysical Research Letters

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“…A representative model can be selected from the samples using a variety of statistical operations. Examples of representative models applied in previous studies include the mean [e.g., Pilia et al, 2015], median [e.g., Gehrmann et al, 2015], and maximum a posteriori model for the most probable number of layers [e.g., Steininger et al, 2013].…”

Section: Trans-dimensional Bayesian Inversion and Pseudo 3d Tomographymentioning

confidence: 99%

Upper crustal investigation of the Gulf of Saint Lawrence region, eastern Canada using ambient noise tomography

et al. 2017

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We studied the 3‐D shear wave velocity (Vs) structure in the Gulf of St. Lawrence (GSL) and adjacent onshore areas to 20 km depth by inverting Rayleigh wave dispersion extracted from the vertical components of continuous ambient seismic noise waveforms. The region is divided into three broad zones based on their Vs characteristics. In the northwest, the Grenville Province (i.e., the exposed edge of predominantly Middle‐Proterozoic Laurentian crust) is dominated by high Vs, except for well‐known anorthosite sites, which are characterized by relatively lower Vs. In contrast, the central segment of the GSL region corresponds to a belt with generally low Vs at upper crustal levels. In the southeastern part of the GSL, prominent low Vs in the uppermost crust are found to coincide with locations of subsidiary basins of the Canadian Maritime Basin, while higher Vs characterize the accreted Appalachian terranes where they are exposed on land. The Grenville Province is wedged out at depth by the Red Indian Line, which is the suture between composite Laurentia and peri‐Godwanan Ganderia in the Canadian Appalachians. The geometry and Vs characteristics of the south‐easternmost peri‐Gondwanan terranes of Avalonia and Meguma suggest that they may be fully or partially structurally overlying a basement with distinct seismic characteristics, which could be a vestige of the West African craton that was underthrust beneath composite Laurentia during the terminal Alleghenian continent‐continent collision. In the middle of the GSL, the 3‐D geometry of the Canadian Maritimes sedimentary basins overlying the Appalachian terranes shows that the depth to the top of basement is in excess of 8 km.

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“…The phase velocity field is subsequently discretized into 1,186 evenly spread grid points from which Rayleigh wave phase velocities are extracted from each period-dependent map to generate a pseudo 1-D phase velocity dispersion curve. To invert for 1-D shear wave speed profiles, we adopt the rj-McMC and assume that the number, position, and velocity of the layers are all unknown during the inversion; the posterior is then a transdimensional function and can be sampled with the rj-McMC algorithm (Bodin et al, 2012;Crowder et al, 2019;Pilia et al, 2014Pilia et al, , 2015. More details of the methods are given in the supporting information.…”

Section: Methodsmentioning

confidence: 99%

The Southern Zagros Collisional Orogen: New Insights From Transdimensional Trees Inversion of Seismic Noise

Pilia

Jackson

Hawkins

et al. 2020

Geophysical Research Letters

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Imaging and resolving the lateral continuity of 3‐D crustal structures enhance our ability to interpret seismicity and to understand how orogens are created. We apply a Bayesian, hierarchical inversion approach based on a transdimensional trees‐structured wavelet parameterization to recover phase velocity maps at 2–40 s periods. We then invert phase velocity dispersion to constrain a 3‐D shear velocity model of the crust beneath south‐central Iran. Together with accurate earthquake centroid depths and focal mechanisms, the pattern of 3‐D velocity variations supports recent suggestions that most large earthquakes in the Zagros occur within the lower sedimentary cover or close to the sediment‐basement interface. Furthermore, we find evidence for Arabian basement underthrusting beneath central Iran, although only in one location does it appear to generate earthquakes. Our new 3‐D tomographic model clarifies and throws new light on the crustal structure of the SE Zagros and its relation to seismicity and active faulting.

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

Cited by 18 publications

References 91 publications

Inherited crustal deformation along the East Gondwana margin revealed by seismic anisotropy tomography

Inherited crustal deformation along the East Gondwana margin revealed by seismic anisotropy tomography

Upper crustal investigation of the Gulf of Saint Lawrence region, eastern Canada using ambient noise tomography

The Southern Zagros Collisional Orogen: New Insights From Transdimensional Trees Inversion of Seismic Noise

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