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Earthquake early warning for Portugal: part 1 - Where does it matter?
Peer-reviewed
In the last five centuries, Portugal was affected by several earthquakes of strong magnitude (M > 7) that caused widespread destruction and a significant death toll. Due to the geographical distribution of moderate-to-strong magnitude events along the Tagus Valley and Southwest of the country, an earthquake early warning system might potentially provide precious warning time ahead of the arrival of the destructive seismic waves. We used a probabilistic seismic hazard model to generate a large stochastic event set for the country, and evaluated the probability of triggering correct and false alerts considering different ground shaking thresholds. We propagated the aleatory variability related to the estimation of the location and event magnitude, as well as the variability in the ground shaking across the Portuguese territory. For the events for which a correct alert would be expected, we estimated the warning time for each district, considering various sources of latency. These analyses were performed considering the current seismic network of the country, as well as the potential installation of submarine sensors as part of the forthcoming renewal of the communication cables between mainland Portugal and the archipelagos of Azores and Madeira. The results indicate that for the districts located in the Southwest of the country, an earthquake early warning system might provide sufficient warning time for risk mitigation measures to be followed.
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