Patent ID: 7132831

Claim:
Device for resistivity soundings on water covered subsurfaces ( 3 ) comprising a multi-channel towing cable ( 1 ), which tows along a water covered subsurface ( 3 ), with an array of electrodes including a first current electrode ( 9 ), a second current electrode ( 11 ) and at least three voltage electrodes positioned between the first and second current electrodes ( 9 , 11 ), whereby neighboring voltage electrodes ( 14 and 15 , 15 and 18 , 18 and 19 , 19 and 20 ) are separated from each other by distances ( 21 , 22 , 23 , 24 ) along the cable ( 1 ) that decrease from the first current electrode ( 9 ) towards the second current electrode ( 11 ), whereby the first current electrode ( 9 ) is separated from a neighboring first voltage electrode ( 14 ) by a distance ( 16 ) that is at least equal to the distance ( 17 ) between the second current electrode ( 11 ) and a second voltage electrode ( 15 ) that is located between the first voltage electrode ( 14 ) and the second current electrode ( 11 ) and, whereby further voltage electrodes ( 18 , 19 , 20 ) are located between the second voltage electrode ( 15 ) and the second current electrode ( 11 ), whereby the voltage electrodes ( 14 , 15 , 18 , 19 and 20 ) are connected to each other such that a voltage gradient can be measured across at least two pairs of neighboring voltage electrodes ( 14 and 15 , 15 and 18 , 18 and 19 , 19 and 20 ) forming pairs of neighboring voltage electrodes having one voltage electrode ( 15 , 18 , 19 ) in common.