Feasibility study of an integrated Earthquake and Tsunami Early Warning System

Tsunami Early Warning Systems should issue the first alert for a potential tsunami within a few minutes after the origin of a seismic event, based on the earthquake source parameters obtained from teleseismic and regional seismic data. This time could be significantly reduced by using local seismic data, increasing in this way the lead time for evacuation and other risk reduction measures, which is crucial for coastal areas in the near field of the tsunamigenic source. In this study, we explored the possibility to integrate the earthquake magnitude and location estimations from the QuakeUp software, used in a Earthquake Early Warning System, into the tsunami forecasting procedure for a Tsunami Early Warning System. We analyzed the trade-off between earliness and accuracy of the seismic parameters estimations and of the tsunami forecast based on them. We considered as a first case study the 2020 M w 7.0 Aegean Sea earthquake occurred offshore Samos Island, Greece. This event generated a tsunami that hit the coasts of Samos Island and the southern coast of the İzmir province, Türkiye, within ten minutes after the earthquake’s origin time. In a hind-casting experiment, our workflow retrieved in about 40 s after the origin time stable hypocenter and magnitude, consistent with those obtained a few minutes later with the Early-Est software, adopted by some Tsunami Service Providers in the Mediterranean Sea. The rapid earthquake characterization was used to run a Probabilistic Tsunami Forecasting workflow, whose results compare reasonably well to the observed tsunami. We also simulated 150 sets of seismograms for events of moment magnitude between 6 and 7 in the Messina Strait (in southern Italy). Also in that case, the workflow confirmed its capacity to provide robust earthquake parameters estimations in less than one minute. This is a first example of the feasibility of a double-risk mitigation integrated approach for the coasts located near to tsunamigenic faults. Plain Language Summary