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.