Dip is the angle between that horizontal plane and the inclined surface (such as a geological contact between tilted layers) measured perpendicular to the strike line down to the inclined surface. A useful way to think about strike and dip is to look at the roof of a house (Figure 1).

Dip is the inclination of a given feature, and is measured from the steepest angle of descent of a tilted bed or feature relative to a horizontal plane. [5] [6] True dip is always perpendicular to the strike. It is written as a number (between 0° and 90°) indicating the angle in degrees below horizontal.

This cross-section shows seven tilted sedimentary layers (a to g), a fault, and a steeply dipping dyke. Place strike and dip symbols on the map to indicate the orientations of the beds shown, the fault, and the dyke. Then answer the questions.

The orientation of a planar feature, such as a bed of sedimentary rock, can be described with two values. The strike of the bed is the compass orientation of a horizontal line on the surface of the bed. The dip is the angle at which the surface tilts down from the horizontal (Figure 13.35).

The line of strike is represented by the water line when a lake intersects with the rock along the shoreline (Figure 8.7). The dip angle for the beds is measured from the horizontal surface to the uppermost dipping bed, perpendicular to the strike line. Figure 8.7 | Strike and dip for tilted sedimentary beds. Water provides a horizontal surface.