Toward the next generation of earthquake early warning systems

Aldo ZOLLO, Université de Naples Federico II | 10 septembre 2015

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The concept of Earthquake Early Warning System (EEWS) today is becoming more and more popular in the seismological and engineering communities, as an effective real-time strategy to mitigate the earthquake damage, through individual or automatic safety actions to undertake during the earthquake emergency. EEW means the rapid detection and source characterization of an ongoing earthquake rupture and the alert broadcasting to a wide target area, before the late arrival of potential damaging waves. During the last three decades, EEWS experienced a sudden improvement both in technologies and real-time signal processing methodologies, leading to their wide diffusion in many active seismic regions worldwide. The underlying assumption of current Early Warning methods is that the rapid and automatic analysis of the initial P-wave signal can bring information about the final earthquake size and its potential damage effects. Such a simplifying hypothesis has revealed to be not consistent with post-event analysis of large to huge earthquakes (M>7.5), and in particular for the 2011 M9, Tohoku-Oki earthquake. In the recent years, new concepts and ideas have been set forward to overcome the limitations of actual EEWS, either by expanding the observational window along seismograms or including contemporary measurements of different physical quantities, such as the displacement from high frequency continuous GPS or ground motion acceleration/velocity from strong motion instruments. In this perspective, the very recent observations of a different rupture initiation between small and large earthquakes provide new insights about the earthquake nucleation processes and lead to new real-time signal processing methods to rapidly discriminate the earthquake size and rupture extent. We will explore these new research directions and review the new methods and technologies which are now being set up to build the next generation of earthquake early warning systems.

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