GNGTS 2014 - Atti del 33° Convegno Nazionale

GPR surveys were carried out using GSSI SIR-2000 Instruments equipped with the two high-frequency antenna 40 and 400 MHz, characterized by different resolution and investigation depth. The two antennas were used to investigate the lake shores to find possible areas affected by sinkhole phenomena. For this purposes, on the south lake shore, two long acquisition profiles (about 180 m) were performed (Fig. 1): 400 MHz antenna: red line composed by F1÷F11 segments in ���� ���� ���� ������������ ������� �� ��� �������� �� ���� ���� ���� �������� ���� ���� ���� ������������ ������� �� ��� �������� �� ���� ���� ���� �������� step mode with survey-wheel coupled to the antenna; 40 MHz: blue line composed by F12÷F15 segments �� ���������� ����� �� ���������� ����� in continuous mode. The raw-data acquired in field without gain and other filters were processed in order to, compensate the attenuation of GPR signal, eliminate noise and associate the GPR information with the real depth of reflectors after an assessment of electromagnetic velocity propagation (migration). Finally, self-potential measurements (for a total of 226 points) were acquired ����� ������ along closed loops, around the lake shores and the surrounding areas, by alternating the leading and following Fig. 2 – Electrical resistivity and GPR profiles acquired with 400 (red line) and 40 MHz antennas (blu line) carried out both on water covered area and lake shores. 146 GNGTS 2014 S essione 3.2