Subaquatic electrical measurements

A prototype subaquatic resistivity system was developed at the Universidade de Aveiro in order to perform resistivity measurements in sea water environments. Literature states that the first tests date from the 60' s (OrelIana, 1982) and until nowadays underwater measurements are limited to pass electrical current and measure electrical potentials at sediment/water interface (Kermovant,1989). In sea water environments resistivity values are very low and thus potential measurements are difficult to undertake. On the other hand the sea water bypasses the injected current and therefore little sediment characterisation is achieved. The developed prototype includes a resistive rubber shield (I x2m) covering copper/salt water/ceramic electrodes (Fig. I).