On the resolving power of (an)isotropic tomography: a seismo-geodynamics
approach
Abstract
Seismic anisotropy is key to constrain mantle flow, but it is
challenging to image and interpret it. To better understand the
robustness of anisotropy tomography, we create a 2-D ridge-to-slab
geodynamic model and compute the associated fabrics. Using the resulting
21 elastic constants we compute seismic waveforms, which are inverted
for isotropic and radially anisotropic structure. We test the effects of
different data coverage and levels of regularisation on the resulting
images and on their geodynamical interpretation. The retrieved isotropic
images exhibit substantial artificial slab thickening and loss of the
slab’s high velocity signature below ~100 km depth. Our
results also show that regularisation and data coverage strongly control
the characteristics of the retrieved depth-age dependency of anisotropy,
leading to an artificial flat depth-age trend shown in existing
anisotropy tomography models. Greater data coverage and additional
complementary data types are needed to improve the resolution of
(an)isotropic tomography models.