On the resolving power of (an)isotropic tomography: a seismo-geodynamics approach

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.