Feasibility study of an integrated earthquake and tsunami early warning system

Current Tsunami Early Warning Systems (TEWS) aim to issue an initial alert within minutes after a seismic event, relying on rapid estimates of earthquake source parameters derived from teleseismic and regional seismic data. For coastal areas located in the near-distance range of a tsunamigenic source, reducing this alert time is critical to increase evacuation lead-time and enhance risk mitigation actions. In this study, we evaluate the integration of earthquake magnitude and location estimations from QuakeUp, an impact-based earthquake early warning system (EEWS), into a tsunami early warning system (TEWS) workflow. We investigate the trade-off between earliness and accuracy of the seismic source parameters and their impact on Probabilistic Tsunami Forecasting (PTF). A hindcast of the 30 October 2020 M_w7.0 Aegean Sea earthquake, whose tsunami reached nearby coasts within ~ 10 min demonstrated that QuakeUp can deliver stable and accurate hypocenter and magnitude estimates within ~ 40 s from origin time, comparable to those obtained by the Early-Est software within minutes, used operationally in the Mediterranean area. These rapid parameter estimates were used to run a PTF procedure, yielding runup predictions in reasonable agreement with observations. A second scenario, based on 150 simulated seismogram sets for Mw 6-7 earthquakes in the Messina Strait (Southern Italy) confirmed the ability of the integrated workflow to provide robust source estimates within one minute. This work represents the first demonstration of a combined EEWS-TEWS approach for near-field tsunamigenic earthquakes, highlighting its potential for dual risk mitigation.