Crustal structure of the east Gondwana margin in southeast Australia revealed by transdimensional ambient seismic noise tomography

摘要

Ambient seismic noise data from the ongoing WOMBAT transportable seismic array in southeast Australia, the largest deployment of its kind in the Southern Hemisphere, are used to produce a high-resolution 3-D shear wave velocity model of the region. We apply a two-stage, transdimensional, hierarchical Bayesian inversion approach to recover phase velocity maps at periods of 1-20 s and then invert phase velocity dispersion for 3-D shear wave velocity structure to the base of the crust. Data uncertainty is propagated through the sequence of inversions, ensuring that model complexity is justified by the quality and quantity of the measurements. The pattern of 3-D velocity variations helps elucidate the geometry and position of key crustal features - such as the Torrens Hinge Zone - associated with the transition from Paleozoic eastern Australia to Precambrian central and western Australia that formed along the proto-Pacific margin of east Gondwana. Key Points Large ambient noise dataset reveals new insight into east Gondwana margin Bayesian transdimensional tomography achieves superior results Candidate for the Tasman Line separating east and west Australia revealed.