A long term geomagnetic deep sounding analysis from a two-dimensional magnetometer array in Central Italy

Following the Mw 6.3 earthquake that hit the city of L'Aquila (Central Italy) on the 6th April 2009, a scientific project was proposed with the aim of investigating the Abruzzo area by means of different disciplinary approaches including geological, seismic, and physical studies. Electromagnetic field monitoring in the 0.01–500 mHz frequency band was implemented for the investigation of electromagnetic signals in the Earth's crust. Three measurement stations were installed in a tectonically active area with a radius of about 10 km. Each site was equipped with a fluxgate magnetometer with a 1 Hz sampling rate. This paper describes a long term geomagnetic deep sounding analysis for each site, aimed at investigating the dimensionality of the electrical structure of the subsurface in the area involved in the survey. According to a very simplified RL circuit model, some electrical properties of subsurface are also deduced.