En jämförelse mellan markbundna resistivitetsmätningar och helikopterburen Sky-TEM i Skåne
Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
Access to groundwater of good quality may in some places be limited. The Geological Surveyof Sweden (SGU) has for the first time in Sweden used Sky-TEM (Danish developed systemfor measurements with Transient Electromagnetic by helicopter) in an area of Skåne tomeasure the resistivity of the ground and thus identify areas with saline groundwater. Thisthesis has its basis in the comparison between those Sky-TEM measurements and fieldworkwith geoelectrical measurements (electrical resistivity measurement with a multi-electrodesystem)The geoelectrical measurements were carried out along two profiles in the area of theprivios Sky-TEM measurements. One of the profiles (Annero) in an area where the depthdown to the saline groundwater were interpreted to be large, and the other (Lillevångsgatan)in an area where the depth was interpreted to be small.The interpretations of Sky-TEM and geoelectrical measurements were not entirely inagreement with each other. They both showed a greater depth to the saline groundwater atAnnero and a smaller depth at Lillevång, but also that measurements with Sky-TEMsystematically pointed to a greater depth to the saline groundwater compared to thegeoelectrical. It could be derived from that TEM works best at low resistivities (<100 ohm-m)and electrical resistivity measurements are good at detecting contrasts between differentresistivities. The saline groundwater has a low resistivity (<10 ohm-m) and its surface createsno clear contrast. It is thus likely that the interpretation of the Sky-TEM measurements liesclosest to the truth.Measurements with Sky TEM provide good overall data but not as good detailed data.Many smaller geological formations and shifts are lost in interpretations of Sky-TEM data,these can however be more effectively detect the geoelectrical method. Sky-TEM is a goodmethod when large areas need to be examined and when the data does not have to be toodetailed. The geoelectrical method is good for smaller areas where more detailed informationis required. To get a good interpretation of how the ground looks like in the area requires acombination of both Sky-TEM measurements and geoelectrical measurements.
Place, publisher, year, edition, pages
2013. , 59 p.
Teknik, Resistivitet, grundvatten
IdentifiersURN: urn:nbn:se:ltu:diva-43992Local ID: 1cd827c9-180f-410b-8cd3-f80d3f5d2976OAI: oai:DiVA.org:ltu-43992DiVA: diva2:1017266
Subject / course
Student thesis, at least 30 credits
Natural Resources Engineering, master's
Validerat; 20131216 (global_studentproject_submitter)2016-10-042016-10-04Bibliographically approved