Fracture frequency is defined as the number of natural fractures per unit length of core recovered.

$\text{FF=}\frac{\text{number of natural fractures}}{\text{total length of core recovered}}$

The fracture frequency can be determined for the entire length of a core run, or for a smaller segment of core. As is the case with

RQD

, artificial fractures or mechanical breaks created during drilling or core handling should be neglected when calculating fracture frequency.