Real-time contribution of ship-based GNSS contribution to tsunami warning

Tracking changes in sea-surface height with ship-based GNSS can be used to detect tsunamis in the open ocean. In the North Eastern Atlantic and Mediterranean region case studies based on historical events show that regardless of the tsunami source (seismic, volcanic, landslide or a multi-combination), ships are likely to be in position to be among the first sensors reached. Similar results are found in the Pacific region and worldwide as ships have an excellent spatial and temporal coverage of the most active tsunamigenic zone. A network of ships, based on voluntary participation of cargo and tanker vessels could then contribute to tsunami warning, augmenting the existing systems, which are mostly constituted by tide gauges and DART. To further analyze the potential contribution of a ship-based GNSS tsunami detection network, we have implemented an automatic process that is launched for each ongoing potential tsunami event. It generates a map with a tsunami amplitude model, based on the inferred earthquake source source, and calculates the number of ships and the number of tide gauges and DART sites  projected to be reached by the tsunami function of time. In all cases, ships make a significant contribution to the rapid and accurate characterization of a tsunami event as they provide observations from otherwise unsampled locations. This system could be particularly impactful in the Mediterranean and south-west Pacific regions, where many countries and islands have no direct instrumentation for tsunami detection, but the global nature of GNSS and ship routes make this technique a promising, low-cost approach, to augment tsunami detection everywhere.