The goal of the Townhall was to engage the subduction zone and wider geodynamics community (both modelers and observationalists) to review the current state of affairs of the MCS-RCN and MCS planning and get feedback on emergent plans for a potential MCS implementation. Specifically, the goal was to evaluate which of the envisioned MCS’s core capabilities are of the highest priority to the community and start the discussion of a proposed organizational structure for a future Modeling Collaboratory for Subduction Zone Science.