GNGTS 2017 - 36° Convegno Nazionale

GNGTS 2017 S essione 3.2 655 The electrical resistivity values range between 10 to 2000 Ohm*m and the image highlights four Electrical Layers (EL): • EL1- a shallow high resistivity layer (>800 Ohm*m) with a depth around 10 to 40 m; • EL2- a deep very conductive electrical layer(< 50 Ohm*m) with a thickness around 20 to 70 m; • EL3- a third electrical layer with electrical resistivity values between 600 Ohm*m to 200 Ohm*m is visible. It is located between the shallow high resistivity layer (EL1) and the conductive one (EL2), with a thickness ranging from a few meters up to 10 m; • EL4- the last relative high resistive layer (> 200 Ohm*m) is observed in depth (between x=240 to the end of the profile). From a geological/hydrogeological point of view, the EL1 electro-layer should be associated to Upper Coralline Limestone, the EL2 to Blue Clay formation, the EL3 to Upper Coralline Limestone with water (shallow aquifer). Finally, the last deep layer (EL4) should be associated to the saturated Globigerina Limestone. Acknowledgements The authors acknowledge the European Cost Action TU1208, that has supported this works thought a short term scientific mission STSM. Moreover, the work is part of MARCAN project, that is funded by the European Research Council under the European Union’s Horizon 2020 Programme (grant agreement n° 677898). References Constable S.C., Parker R.L., Constable C.G. 1987. Occam’s inversion: a practical algorithm for generating smooth models from electromagnetic sounding data. Geophysics, 52, 289-300 Giampaolo, V., Capozzoli, L., Grimaldi, S., Rizzo, E., Sinkhole risk assessment by ERT: The case study of sirino lake (Basilicata, Italy), Geomorphology (2016), 253, 1-9 doi: 10.1016/j.geomorph.2015.09.028 Maillet G., Rizzo E., Revil A., Vella C. (2005) High resolution ERT applied in sand-bed channel mouth infilling. The test site of Pégoulier channel in the Rhône Delta, France. Marine Geophysical Research , 26, 2-4, 317-328 Marquardt, D.W., 1963, An algorithm for least squares estimation of nonlinear parameters: J. Soc. Indust. Appl. Math., 11, 431-441. MRA, 2005. Initial Characterisation of the Groundwater Bodies within the Maltese Water Catchment District under the Water Policy Framework Regulations, 2004, Malta: Malta Resources Authority. Oil Exploration Directorate, 1993. Geological map of the Maltese Islands. ������ �� ��� ����� ��������� ��������� Office of the Prime Minister, Valletta. Rizzo E., Colella, A., Lapenna, V. and Piscitelli, S. (2004). ���������������� ������ �� ��� ����� ���������� ���� ���� “High-resolution images of the fault controlled High Agri Valley basin (Southern Italy) with deep and shallow Electrical Resistivity Tomographies”. Physics and Chemistry of the Earth, 29, 321-327. Sub-bottom and GPR surveys over two puzzling lakes within the Ivrea Morainic Amphitheatre (NW Italy) L. Sambuelli 1 , S. Piro 2 , A. Fiorucci 1 , C. Comina 3 , C. Colombero 3 1 DIATI - Politecnico Di Torino, Italy 2 ITABC - CNR - Roma, Italy 3 DST - Università di Torino, Italy Introduction. Lake sediments, including those of the peri-alpine and pro-glacial lakes, are well known records of the past climate and environments (e.g. Carrivick and Tweed, 2013). Extensive studies have been devoted to the evaluation of sedimentation rates and correlated climatic conditions as an important factor controlling the preservation of inland waters. This is even more relevant over lakes with no inflows, where the only factors governing sedimentation rates are related to the external environment. Several literature papers (Tab. 1) report on quite