GNGTS 2023 - Atti del 41° Convegno Nazionale

Session 1.2 - POSTER GNGTS 2023 Fig. 1 – Left: relief map of Vulcano Island and location of the two surveyed areas (A and B). Right: anomaly map of the total magnetic field measured in the study area “A” located in the lower southwestern flank of the cone. Data and method The magnetic survey was performed with the device G-858G produced by Geometrics Inc. The magnetometer was set in gradiometric configuration with the two sensors 2.0 m apart. The magnetometer is equipped with a GPS that provides the position and the time for each magnetic measure, taken every 0.5 s. The data processing consists in the removal of spikes and in a running average over 50 samples acting as a low-pass filter. The filter attenuates the shorter wavelength component related to the shallower anomalies, enhancing the components with larger wavelength. The areas at the southwestern base of the cone (area A) is where the seismic investigation by Bruno and Castiello (2009) revealed a velocity anomaly interpreted as a possible fault zone. In this area we performed more than 40,000 measurements in back-and-forward profiles. The average spacing between two consecutive measures is about 0.5 m. The data, reduced with respect to the International Geomagnetic Reference Field (IGRF), have been interpolated by kriging on a 20x20 m grid (Fig. 1, right). In the area of Spiaggia di Levante (area B), we performed about 6,000 magnetic measurements in the same configuration as previously described. Moreover, a thermal survey by means of an Unmanned Aircraft System (UAS) has been performed to better investigate the fumarole field of this area. In particular, this survey consisted of a DJI Phantom 4 Pro UAS platform, equipped with FLIR Vue Pro R 640 (FLIR Systems, USA), a small sized radiometric thermal sensor designed for UAV integration and data collection. The thermal sensor was equipped with a 9 mm lens, producing images with 640X512 pixels and a spectral response in the range of 7.5-13.5 μ m. The camera was mounted to the drone by a 3D-printed camera mount in a nadir view position to the ground. Infrared flights were realized before sunrise to minimize distortions like irregular surface heating