Patent ID: 7224641

Claim:
Arrangement for use for seismic surveys of geological formations in a seabed, where a plurality of such arrangements are placed on the seabed for collecting pressure waves and shear waves reflected from the geological formations, and are adapted to transfer seismic data to a surface receiver placed on a vessel, an offshore installation, or an onshore installation, each arrangement comprising: a sensor unit; a carrier for holding the sensor unit; a cylindrical skirt-shaped structure adapted to be connected to the sensor unit and to be led down into the seabed, and where each sensor unit comprises at least one geophone, wherein the carrier comprises a holder for the cylindrically skirt-shaped structure, which structure shall penetrate down into the seabed, this holder being adapted to be moved between a lower position and an upper position, to be able to move away from and be mechanically released from the skirt-shaped structure.