Two anisotropic layers in the Slave craton

Four years of recording global earthquakes using a broadband seismometer located at the Ekati diamond mine revealed variations with earthquake azimuth in the arrival of SKS phases. These variations can be modeled assuming two distinct layers of anisotropy in the lithosphere. The lower layer probably lies in the mantle, and the anisotropy aligns with both North American plate motion and the strike of mantle structures identified by previous conductivity and geochemical analyses, at ~N50°E. The upper layer is hypothesized to result from regional structures in the uppermost mantle and the crust; these trends are distinct from the mantle trends.