ChEESE is a new initiative to integrate HPC and data across Solid Earth related disciplines in Europe. One of its main goals is to prepare ten flagship codes for exascale environments. These codes cover fields of study highly relevant for urgent computing, probabilistic hazard assessment and data science, such as computational seismology, magnetohydrodynamics, physical volcanology, and tsunami modeling. POP conducted performance assessments of all these https://register.gotowebinar.com/register/4651760320227892225pcodes at the start of the project and will do so again at the end. We will look in more detail at one of these, a physical volcanology code called Fall3D and will explain how work conducted within ChEESE, aided by insights provided by the POP assessment, has led to a 10x improvement in scalability in a fairly short period of time.