Multi-hazard impacts and recovery: A global assessment using Nighttime Light Satellite Data

Multiple disasters that occur simultaneously or in short succession, with impacts that overlap in space and time, are referred to as multi-hazard events. Such events can create societal impacts that can be significantly worse than the sum of the individual events, due to the dynamics and interconnected nature of the disasters. Additionally, response and recovery become more complex, for instance due to depletion of financial and human resources and damaged infrastructure. Quantitative, large-scale studies that assess systematic differences between single- and multi-hazard events remain limited due to the lack of  suitable, consistent, and scalable data. There are a few studies that do provide more quantitative generalized comparisons between single and multi-hazard impacts on a large scale, using disaster impact databases like EMDAT and DESINVENTAR, but these are not able to assess the dynamic changes in impact and recovery that occur after the event. 

In this study, we use consistent Visible Infrared Imaging Radiometer Suite Nighttime Light (VIIRS NTL) daily Black Marble data as a satellite-based data proxy for disaster impact and recovery. We provide a global-scale analysis of different geological, meteorological, and hydrological hazards between 2012-2019, comparing areas affected by a single hazard to areas affected by multiple disaster events with a time lag of 14 and 28 days. The results reveal systematic differences in impact and recovery profiles between single- and multi-hazard events. These findings demonstrate the potential of satellite-based proxies for generalisable, large-scale assessments of disaster impacts and recovery dynamics, supporting policymakers, humanitarian organisations, and risk assessment studies in anticipating emerging challenges in a future where increasingly frequent and intense hazards increase the likelihood of consecutive disasters.