The impact of the geospace environment on earthquake preparation processes. Case studies for M>6 in Italy for 1980-2016

We discuss the potential impact of the Geospace environment on the significant earthquake preparation processes. In this work, we investigate the response of major seismic activity to geomagnetic storms with a joint analysis of solar wind, geomagnetic field, and earthquake catalog. As a test case, we processed the seven strongest earthquakes in Italy for the period  1980 - 2016:  Amatrice M6.2 of Aug 24, 2016; Visso M6.1 of 26 Oct 2016; Norcia M6.6 of 30 Oct 2016; Emilia-Romagnia M6 of May 20, 2012;  L’Aquila M6.3 of Apr 6, 2009;  Foligno M6 of Sep 26,1997  and  Irpina of M6.9 of 23 Nov 1980. All of the seismic events were preceded by geomagnetic storms, which satisfied a given criterion: at the time of geomagnetic storm onset, the high-latitude part of the longitudinal region, where in the future an earthquake occur, was located under the polar cusp, where the solar wind plasma would directly access the Earth’s environment [Ouzounov and Khachikyan, 2024]. The number of preceded storms varied for different earthquakes from two to five. This results in different time delays between the day of the magnetic storm onset and the day of earthquake occurrence; it ranges between 9-80 days. Because of the existing delay between a shocked solar wind arrival and earthquake occurrence up to some months, this may suggest that solar wind energy does not trigger earthquakes immediately (as it is believed at present); instead, it may accelerate the processes of lithosphere dynamics, such as fluid and gas upwelling, which are active participants in tectonic earthquakes. For comparison, we present the results of the same analysis applied to other territories of the Mediterranean region: the Anatolian Plate (Turkey) and Crete Island (Greece), which look strikingly similar.