A First geophysical survey to investigate the Telóes basin

Along the major geological fault of Penacova-Régua-Verin, FPRV, (north Portugal, fig. 1) there are several tectonic depressions that have been interpreted as the result of recent reactivation of the fault. On the other hand these depressions are very important for water exploitation in a region where water resources are scarce. Generally, these basins are filled with undifferentiated sedimentary materials of unknown thickness. The “Telões Basin”, a grabben structurally controlled by the FPRV, is a typical and important economical example and its 3D study comprises a comprehensive geophysical project including Electromagnetic Mapping, Resistivity Imaging, Seismic Refraction and Gravity Mapping. Here in an account will be given of the Electromagnetic and part of the resistivity survey (Lourenço, 1997) that were the basis for the planification of the other geophysical techniques to be used.