Geoelectrical and EMI Studies at an Urban Site in Buenos Aires, Argentina, for Localizing an Old Tunnel.

BONGIOVANNI M. V.; DE LA VEGA M.; MARTINELLI H. P. ; GRÜNHUT V.; BONOMO, N.

Oporto

Congreso; 24º European Meeting of Environmental and Engineering Geophysics; 2018

European Association of Geoscientist and Engineers

We performed a geophysicalstudy in a historical site in Buenos Aires, Argentina. The main objective wasto localize and characterize an old tunnel. Considering the complexcharacteristics of the buried structure and the urban localization of thestudied area, we performed prefeasibility studies to determine the usefulnessof different geophysical methods. We first applied the EMI method then theelectrical resistivity tomography (ERT) method. The EMI results showed alarge amount of anomalies associated to varied facilities that helped us not todo false interpretations in the ERT results. Regarding ERT results, inthree lines a resistive anomaly was found. These anomalies were aligned in thepresumed direction of the tunnel. The joint inversion acquired with fourdifferent electrode spacings (a = 1, 2, 3 and 4 m) provided good lateral andvertical resolutions, as well as enough penetration depth, in which thecontours of the anomaly associated to the tunnel appear fairlywell delimited.