GNGTS 2024 - Atti del 42° Convegno Nazionale

Session 1.2 GNGTS 2024 Figure 2 - Magnetc anomaly map of Martgnano Lake displayed using a nonlinear intensity color scale and contour lines. Leters denote magnetc anomalies discussed in the main text. Red lines indicate survey lines from the 2008 aeromagnetc survey of the Sabatni Volcanic District (Nicolosi et al., 2019). During the echosounder survey, numerous gas emission fares were observed across the entre lake botom surface. A concentrated area with higher fare density was identfed (FL, Fig. 3). This area coincides with a local magnetc anomaly minimum oriented in the N-S directon, with its southern boundary corresponding to the magnetc anomaly minimum G depicted in Fig. 2. Gas and fuid circulaton might serve as an additonal factor contributng to the reducton in magnetzaton propertes of volcanic products. In this partcular area, a submarine ROV was deployed to capture images of the emission sources originatng from the lakebed. The acquired images depict an extensive feld of gas sources emerging from small pockmarks and craters excavated in the mud due to gas efux. The lack of signifcant local magnetc dipolar anomalies within the crater perimeter suggests the absence of intrusions of dikes and lava efusions from the Martgnano diatreme system. The intense dipolar anomalies situated on the western border of the lake ( E, F in Fig. 2) are associated with local lava outcrops whereas anomaly C is atributed to the presence of a bathymetric rock spur. This spur can be interpreted as a remnant of the fused crater rims resultng