Dear reader we will discuss about fault geometry to make smooth understanding topics of fault activity, fault movement and also moment magnitude scale for measuring earthquake.
Specific geologic notations are used to define orientation of fault with some approximation. A large fault have surface of much irregularity (usually) but are assumed that the surface is plane over small distance.
This is a horizontal line that is generated by intersection of horizontal plane with fault plane.
Dip angle is used to define slope of fault plane (obviously downward) and is defined as angle created by horizontal plane with fault plane which is measured normal to strike.
Azimuth of strike is used to define orientation of fault relative to north, say N 60° E.
When a fault have vertical surface the dip angle will be 90°.