The hazard isn't the event; the hazard is the sequence. Disaster risk is usually assessed event by event, yet many of the most damaging outcomes arise when hazards follow one another. Earthquakes alter drainage, slopes and sediment supply before the next flood or monsoon; floods weaken structures before the next earthquake; wildfires change how catchments respond to rainfall. Two examples show how one event changes the conditions under which the next unfolds. The 2015 Gorkha earthquake in Nepal was followed by increased landsliding in the monsoons that came after it. The 2023 Kahramanmaraş earthquakes in Türkiye were followed by flooding in the Asi (Orontes) catchment in 2026. Understanding such sequences means connecting physical processes to the people, buildings and institutions that experience them.

This session invites inter- and transdisciplinary contributions on sequential and cascading hazards and their consequences. Topics include field evidence and reconnaissance of hazard sequences; modelling of how earlier events change hazard, exposure and vulnerability, including damage accumulation; health, housing and indoor-environment outcomes in multi-hazard settings; governance, accountability and responsibility for multi-hazard risk; and methods for transferring lessons across hazards, regions and institutional contexts. We welcome geoscientists, engineers, public health researchers, social scientists and practitioners, and particularly encourage early-career researchers and colleagues from affected regions. The session complements multi-hazard assessment sessions in NH by bringing physical and societal perspectives on hazard sequences into one conversation.