Terra-Neo Integrated Co-Design of an Exascale Earth Mantle Modeling Framework. Mantle convection is a vital component of the Earth system. The relentless deformation taking place in the mantle by viscous creep has a far greater impact on our planet than might be immediately evident. Immense forces are at work in mantle convection cells: continuously reshaping Earth’s surface, the mantle provides the enormous driving forces necessary to support large scale horizontal motion, in the form of plate tectonics and associated earthquake and mountain building activity. At the same time the mantle induces substantial vertical motion in the form of dynamically maintained topography through lateral pressure gradients beneath tectonic plates. This vertical motion is perhaps the most spectacular manifestation of mantle convection - and its most defining and enduring impact upon the entire Earth system. ..