Iris van Zelst , Silvia Brizzi, Elenora van Rijsingen, Francesca Funiciello, Ylona van Dinther

Tsunamigenic earthquakes pose a large hazard in subduction zones, but it is currently unclear in which - if any - tectonic setting they preferentially occur. Here, we compile the global Subduction Nature & Interconnected Tsunamigenic earthquake Characteristics (SNITCH) database with parameters on subduction geometry and tectonics, megathrust seismicity, and tsunami characteristics of tsunamis caused by earthquakes in subduction zones. We first use a bivariate regression analysis to reveal correlations between the normalised number of tsunamigenic earthquakes and the megathrust seismicity and tectonic parameters characterising a subduction zone. Considering the scarcity of tsunami data, we then employ the more robust multivariate Fisher analysis on the tectonic parameters to see which combination of parameters best distinguishes subduction zone segments in which relatively many and few tsunamis occur. The most important parameters in these combinations are consistently the type of margin (i.e., erosional or accretionary), the trench-normal component of the subduction and convergence velocity, the amount of trench sediments and the roughness of the incoming plate. Our results therefore suggest that tsunamigenic earthquakes may be more prone to occur in tectonic settings where plates subduct relatively fast beneath a sediment-starved, erosional margin with a complex, shallow subduction interface, characterised by multiple faults and fractures.