1. Introduction

As social, technical and economic hubs, and as centers of industry and infrastructure, cities are particularly frequently affected by technology-related disasters, political and social conflicts, and hazards such as pandemics, extreme natural events and terrorist attacks, as numerous events in recent years have made clear. The protection of urban areas and their population is associated with numerous challenges, such as the supply and possible evacuation of many people in high-density urban areas in the event of an accident at a nearby nuclear power plant. Dealing with vulnerable groups affected by catastrophic events, such as financially weak families, immigrants, or elderly people living alone, is also a particular challenge, making effective and timely risk communication increasingly important, as was evident and confirmed in the Corona pandemic (2020/2021).