The state of stress in the Earth's crust as based on measurements in mines and on geophysical data

Measurements of stress carried out in mines suggest that much of the Earth's crust is in a state of horizontal compression. The average of the two principal horizontal stresses usually exceeds the hydrostatic (geostatic) pressure and fits N. Hast's empirical relationship of increasing excess compressive stress with depth. High compressive stresses are usually aligned perpendicular to the trends of young, folded mountain ranges and to axes of positive and negative gravity anomalies.