Western Australia is one of the oldest continental regions in the world, with a complex, lengthy geological history. It contains the Yilgarn craton, a long-lived, ancient piece of continental crust that has remained stable for over 2 billion years.
Rigid continental plates record their deformation history in large-scale rock fabric that alters the directional dependence of seismic wave speed: a property known as seismic anisotropy. Current deformation occurring beneath plates as the mantle flows also contributes to seismic anisotropy.
I am using shear-wave splitting to measure seismic anisotropy in the south-western area of Western Australia. Our results emphasise the complexity of the Earth’s interior beneath this region. We find that seismic anisotropy likely reflects past deformation events fossilised into the lithosphere. These events could potentially be linked to the formation of the craton itself.