Abstract The intense May 2024 geomagnetic storm provided an opportunity to conduct the first analysis of geoelectric hazards in Italy. Data from three geomagnetic observatories and a magnetotelluric station were analyzed to examine the spatiotemporal evolution of storm‐induced variations. Our results establish the horizontal magnetic field time derivative as a robust, large‐scale proxy for the geoelectric field in southern Italy, with the east‐west component reaching amplitudes of 100 mV/km during the storm's sudden impulse. Time‐frequency analysis reveals a fundamental transition in geophysical response: at periods longer than 100 s, and maintain a stable, phase‐locked relationship, indicating regionally coherent forcing. Below 50 s, this coherence deteriorates, demonstrating that the geoelectric field becomes dominated by local subsurface conductivity structure. During the storm's recovery phase, intermittent Pc3–Pc5 pulsations generated coherent signatures in both field types, representing an additional mechanism for sustained geoelectric activity. This study provides a significant first step in understanding storm‐induced geoelectric effects in Italy, bridging geoelectric field observations and first‐order estimates of GIC hazard, and highlighting potential implications for the resilience of critical ground‐based infrastructure.
Pignatiello et al. (Thu,) studied this question.