Abstract: The geological gyrocompass is an accurate, portable instrument useful for geologic mapping and surveying which employs an aircraft gyrocompass, strike reference bars, a pair of sights and leveling devices for horizontally leveling the instrument. A clinometer graduated in degrees indicates the dip of the surface being measured.

Abstract: A method wherein a light emitting device, such as a laser, is used to precisely measure strike measurements of planar geologic features; for example, bedding planes, fractures, or fold axes. A pre-existing survey line between two spads is first located on a plan view map of the mine. A tape measure is placed between the two located spads in the mine. A laser is then placed on the planar surface to be measured, and the instrument leveled. The laser unit in the instrument is activated and the beam located at its intersection with the tape measure. The location point of the laser unit on the wall of the mine is marked on a mine map, the point on the tape where the beam intersects the tape is marked on a mine map, and a line is drawn between the two points. This line defines the strike of the planar feature relative to the survey line.

Abstract: A geophone is hung from a ball bearing in a pendular fashion so that it is free to swing in any direction. Because it is weighted, it will assume the correct positioning for operation. A clamp, carried with the pendular geophone in a seismometer designed for use on the ocean floor, fixes the geophone in a rigid position when a solenoid is actuated. After the seismometer is deployed on the sea bottom, it is desired to clamp the geophone into its assumed position. The solenoid is fired upon command causing the ball to be clamped. When the seismometer is recovered the angle of inclination with respect to the vertical it assumed at the time when the geophone was clamped can be determined by measuring the angle formed by the clamped geophone and a surface known to be vertical when the seismometer rests on a flat, horizontal surface.

Abstract: A device for determining angle relationships of or between planes, such as in geological structures, having a first member having on a planar surface thereof a family of concentric circles indicative of angles from the range 0.degree. to 90.degree., the circles each being indicative of an angle that is the complement of the half-angle of a respective one of a family of notional right circular cones of equal height based on the surface concentrically of the circles and having a diameter corresponding to that of its circle; and means mounted on and extending across the surface, the means being rotatable with respect to the circles to permit correlation between (a) the angle of inclination of a plane in one direction as indicated by a circle and (b) the inclination of that plane in another direction, or another direction in which a particular inclination of the plane occurs.