ANDERSONIAN FAULTS

E M Anderson (1951) divided all faults into three principal types depending upon whether the maximum principal compressive stress,s 1 intermediate principal compressive stress s2 or least principal compressive stress s3 was in the earth's gravitational field. If the maximum principal compressive stress is vertical, grabens result and the crust is extended. When this is horizontal but the least principal compressive stress is vertical, crustal thickening and shortening occurs and thrust faults are generated as in most of the orogenic belts. However, if both maximum and minimum principal stresses are horizontal or tangential to the earth's surface and intermediate principal stress vertical, then there is no appreciable extension or shortening of the earth's crust and transcurrent faults or strike slip faults are generated.