The TSUSY Database: a global database of historical tsunami events and a tsunami-occurrence criterion based on historical earthquakes

Abstract. Tsunamis are high-impact natural disasters capable of causing significant social, economic, and environmental losses. Despite advances in tsunami warning systems, accurately predicting tsunami occurrence remains a challenge due to the uncertainty associated with seismic rupture characteristics. This study develops a methodology that integrates historical earthquake records, numerical modelling and statistical analysis to derive a tsunami-occurrence criterion, expressed as a binary labelling threshold for identifying whether an earthquake generates a tsunami. As part of this methodology, a global simulation-based database (TSUSY Database) was constructed using earthquake focal mechanism data from the USGS database and validated against tsunami records from the NOAA catalogue, covering events from 1976 to 2023. Through numerical simulations, maximum wave heights were estimated for each event as the maximum value within the entire simulation domain, and used to define thresholds that label earthquakes as tsunamigenic or non-tsunamigenic, with the aim of balancing missed events and unnecessary alerts. By providing a simulation-based criterion for tsunami occurrence, the methodology supports the development of decision tools for real-time tsunami assessment and has been incorporated into an operational tsunami decision-support system that can assist Tsunami Warning Centres in their warning procedures.