Addressing the 'Black Hole' amidst Sediment Connectivity and Multi-Hazards

‘Sediment Connectivity’ and ‘Multi-Hazard’ – two booming topics over the last decade; have experienced intensive methodological and conceptual developments. Research so far has acknowledged their interrelationships and established sediment connectivity as a crucial component in the framework of hazard and risk research, but mostly through the so called ‘single-hazard’ approaches. Sediment connectivity referring to the entire assemblage of connectivity network would by definition occupy a significant amount of space, which may often accommodate multiple interactive and interrelated hazards, making a single-hazard approach fairly inadequate and thus leaving a crucial research gap.

The primary aim of this study is to draw the attention of future research on this gap while attempting to address it through developing a new perspective to look into multi-hazard events. In line of that we propose a semi-quantitative index based on the classification of hazard events and their interactions through an inverse event tree approach – assuming a cascading process flow. The event classification is based on the type of interactions (e.g. process-process, triggering, impeding, structure-process, etc.) to facilitate the understanding and inclusion of the connectivity concept. The index would assess each step and the interlinkages of such cascading events and assign weights to them based on their significance from a sediment connectivity viewpoint. Furthermore, it would also address how these weights may alter the probabilities across the event tree. Overall, this study proposes a novel perspective into the inter-connectedness of geomorphic/sediment connectivity and multi-hazard events, in line with the ‘Gaia’ and ‘Systems’ theories.