One-Second-Lead Earthquake Warning and Impact Assessment at Campi Flegrei

Rapid dissemination of earthquake information during seismic crises is crucial for mitigating the impact of earthquakes, particularly in densely populated volcanic areas, such as the Campi Flegrei caldera (Southern Italy). This region is affected by recurrent bradyseism and shallow seismicity, with recent events up to Md 4.6, very well perceived by the local inhabitants and increasing concern among the local community. In such small-extent areas, conventional Earthquake Early Warning (EEW) systems face physical limitations, due to the short duration and relatively small magnitude of earthquakes. Here we propose and calibrate a hybrid, impact-based, on-site EEW system capable of providing rapid estimates of the earthquake size and expected impact (PGV, PGA), within one second after the P-wave detection. In addition, the proposed system extends the classical concept of an on-site EEW system, introducing the idea of an “area of competence” around each seismic station that can benefit from the local warning.The proposed methodology is easily transferable to other volcanic or seismically active regions and might represent a step toward low-latency, impact-based earthquake alert systems designed to enhance community resilience.