Subduction from top to bottom - Insights from linear and non-linear numerical geodynamic simulations DUARTESILVIA SALVADOR 2019 Subduction represents the process by which old oceanic lithosphere is recycled into the mantle, and is commonly associated with high intensity and high frequency seismicity regions. Thus, it is important to continuously further our knowledge in this field. This thesis investigated how subducting plates initiate and interact with the Earth mantle using numerical simulations. These simulations allow to relate and quantify how plate-mantle interactions at great depths influence tectonic plates behaviour at the surface. Moreover, the simulations revealed a novel subduction mode in which upper mantle is recycled into the deep lower mantle, with consequences for global mantle convection.