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Faults and Fractures |
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| Structural geologists are interested in figuring out faults "kinematic", in other word they want to found out the relative sense of motion of blocks on either side of faults, as well as in the orientation and amplitude of the slip. The slip along a fault is characterized by a vector called the net slip (the red vector on the sketches). Its direction is that of the slip and its length is the amplitude of the slip. On a fault plane the direction of the net slip is often given by striae (friction mark). The net slip can be decomposed into either 1/ two orthogonal components on the fault plane (strike-slip and dip slip components); or 2/ two orthogonal components in the vertical plane that contains the net slip (horizontal heave and vertical throw), or 3/ three orthogonal components in the geographic system (strike slip, heave, and vertical throw). |
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The "kinematic plane" is the plane which is perpendicular to the fault plane and parallel to the net slip vector (ie the striae). For newly form faults the kinematic plane contains two of the 3 principal stress axis: σ1 and σ2 |
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