Abstract: A measuring device for measuring the elastic properties of a surface structure (3), comprising a probe (2) arranged within a housing (1), a transmitter and at least one receiver, the transmitter transmitting acoustic pulses and the receiver picking up the propagation behavior of the acoustic pulses in the surface structure (3), a control means (16) for generating acoustic pulses and an evaluating means (18) for the measuring signals received by the receiver, at least two adjacent measuring tips (4, 6) being connected as transmitting and receiving elements, the measuring tips being adapted to be set onto the surface structure (3) and having strip-shaped bi-morph elements (12, 14) carried by a holder (8, 10), wherein the measuring tips (4,6) are formed by the holders (8, 10) of the bi-morph elements (12, 14) and the strip-shaped elements (12, 14) have one side of one of their ends fastened to the holder (8, 10).

Abstract: A method and apparatus for the sounding of waters, particularly suitable for depth (and the like) sounding of Arctic waters, comprises shooting an energetic projectile at the water or ice surface from, say, a helicopter which has suspended close to the waters surface a suitably housed microphone for receiving the echo energizing from the waters. By measuring elapsed time between firing of the projectile and reception of the echo, and knowing all distances except the depth of the reflecting boundary (be it the bottom or a submarine), the unknown depth is easily determined.

Abstract: A method and apparatus for improved detection of reflected seismic energy through detection of air pressure variations in air above an air/earth surface interface. One form of apparatus suitable for detection in air of seismic energy waves emanating from beneath the earth surface consists of supporting a collecting reflecting member over a designated earth surface site and detecting air pressure variations at a focal point within the reflector member; and, thereafter, transmitting or conducting the reflected seismic energy indications for processing in accordance with the seismic energy source requirements to obtain seismic energy reflection data for the particular locale.

Abstract: A seismic exploration system for use on ice-covered waters is disclosed. The system comprises a housing which contains equipment such as an engine, a compressor, means for boring holes in the ice, and acoustic signal generating means that can be lowered into the water through holes in the ice. The housing is sufficiently lightweight that it easily can be transported from one location to another by helicopter or other aircraft. The heat generated by the engine is sufficient to provide a comfortable working environment for personnel within said housing and helps prevent freezing of equipment located within said housing.