Orateur
Description
The lower mantle of the Earth is home to a variety of anomalous structures with different scales. This includes two large-scale, continent-sized structures called large low shear velocity provinces which are consistently observed across the existing three-dimensional tomographic models. Conversely, small- to meso-scale structures such as a ultralow-velocity zone (ULVZ) or mega-ULVZ are often beyond the current resolution of those tomographic models but studied by using seismic wavefield simulations with various seismic phases which have been scattered or multipathed by such heterogeneities in the core-mantle boundary region. Although the origin and nature of these structures are still largely unknown, recent studies suggest that they are capable of hosting primordial geochemical reservoirs and are therefore intimately tied to important geological processes and evolution that entail interactions between contrasting materials for the mantle and core, possibly aided by deep-seated mantle plumes. In my presentation, I will provide a brief summary of seismological constraints pertaining to the lower mantle structures of the Earth.
