A Magnetovariational Survey at Lampedusa Island for Investigating the Ambient Noise and the Subsoil Electrical Conductivity

Abstract We conducted a magnetovariational field investigation at Lampedusa island (Italy), in the proximity to the geomagnetic observatory of Lampedusa. Data were collected from March 19 to March 23, 2022, using vector fluxgate magnetometers, configured in different spatial arrangements for two main purposes: (a) estimating the spatial distribution of potential anthropogenic noise; (b) identifying different conductivity structures beneath the observatory’s surroundings. The results obtained by means of the 1-D gradient method on simultaneous measurements indicate a very low ambient noise level, likely originating north of the geomagnetic observatory. Hypothetical event analysis, combining data from eleven sites with temporary magnetometer installations, reveals the presence of at least three distinct strata in the crust: a highly conductive layer positioned between two more resistive layers, located west of the observatory.