The drone-borne magnetic survey as the optimal strategy for high-resolution investigations in presence of extremely rough terrains: The case study of the Taverna San Felice quarry dike

In the Taverna San Felice limestone active quarry (Italy) excavation has progressively exposed a magmatic dikeembedded in a calcareous succession. The dike outcrops are scattered among the high vertical steps of the quarry,whereas outside the excavated area the steep mountain slope covered by a dense bush vegetation make directinspection and geological mapping a challenging task. To map the areal extension of the dike and to define itsdirection and its relationship with tectonic lines over an area larger than the quarry, a magnetic survey wasperformed. Given the above-mentioned extremely rugged terrain, a UAV-based magnetic survey was thepreferred acquisition strategy. Data were acquired by rigidly fixing the magnetometer to the UAV landing sled,using a sensor with a very high-frequency (1000 Hz) acquisition rate. The acquisition strategy and some simpleprocessing steps resulted in a detailed drone-borne total field anomaly map. This dataset allowed for a mappingof the dike outside the quarry area and the identification of a vent fed by the dike. The 2D forward modelling ofthe magnetic data was constrained by a field estimation of the intensity of the total magnetization and by thedepth to the dike's top, in places where it is outcropping.