FROM SHEAR STRUCTURES TO FRICTION LAW - SIMILARITY OF NATURAL STRESS TENSOR IN BRITTLE TECTONICS

The determination of the natural stress tensor is a major step in the reconstruction of the conditions that prevailed during a tectonic even t, taking the palaeo-depth into account. Assuming that the tension gas hes associated with fault slip are parallel to the applied stresses mo dified by friction, and based on the simple measurements, we determine two parameters of the friction law: the slope of the friction line an d the proportionality ratio between the principal stress magnitudes. T he reduced stress tensor was also determined, thus the similarity rati o of the natural stress tensor was determinable through a simple calib ration constrained by a threshold value of the shear stress, the tensi le strength of the rock, or the depth of overburden.