SPOCK (Self Potential and CSEM Receiver Kit) is our inhouse developed successor to the deep-towed VULCAN receivers by the SCRIPPS Institute in San Diego. The electric field is measured with electrode pairs in 3 spatial directions and recorded with a multi-channel data logger inside the SPOCK tow body. Altimeter and attitude sensors provide the orientation in the water. In addition, the magnetic field is measured with a broadband magnetometer, which is located in the tube for attaching the rear electrode.
SPOCK has so far been used in the INDEX project for passive self potential measurements to detect and characterize massive sulphide deposits. For this purpose, SPOCK is towed at a distance of approx. 50 m above the seabed behind HOMESIDE or ULLA, which provide the acoustic positioning, commanding and data connection. In principle, one or more SPOCKs can also be used as a receiver chain for active CSEM measurements in conjunction with a CSEM source and a transmitting dipole.