On 18 May 1980, Mount St. Helens erupted catastrophically, spawning a cascade of events having legacies that continue to affect and influence both science and society some four decades later. This landmark eruption not only changed recognition, perceptions and understanding of many volcanic processes—such as volcano deformation, sector collapse, PDC processes, lahars, and magma dynamics—but also ushered in innovation and modernization of volcano monitoring techniques, hazards assessments and communication, and emergency management. It also underscored the need for interdisciplinary coordination and collaboration to respond to and mitigate volcano crises. Furthermore, it was seminal event for several disciplines such as ecology, forestry, hydrology, geomorphology, engineering, mechanics, health sciences, and social science. This session highlights the sweeping scientific legacy of Mount St. Helens, lingering societal issues, and some of the transformative (and ongoing) scientific advances that can be linked directly to its 1980 (and later) eruption.

• EP - Earth and Planetary Surface Processes
• GH - GeoHealth
• V - Volcanology, Geochemistry and Petrology