The community discussion which began under the theme of subduction zone observatory (SZO) has evolved to become the SZ4D Initiative, which aims to capture the four dimensional (4D) evolution, in space and time, of subduction processes that create geohazards and drive the evolution of the solid Earth and its surface. The SZ4D Initiative seeks to move subduction science from describing static snapshots to fully capturing and modeling key phenomena as they evolve both in real time and through geological time. SZO-like capabilities may form a valuable piece of SZ4D, providing a comprehensive suite of onshore and offshore observations to understand the entire subduction zone system. This website serves as one potential forum to stimulate further development of the idea amongst a wide range of disciplines, engage the international community, and identify strategies to move these concepts forward.