ABSTRACT
Geostress is a natural stress that exists in the strata. Knowledge of Geo-stress is very important in many problems related to rocks in civil and mining engineering. Hydro-fracturing stress measurements for determining in situ stresses are used in different areas such as mine and tunnel construction, earthquake prediction, and oil and gas source designing all over the world (Goodman 1989, Cardy & Brown 1993, Ziaie et al. 2012, Haimson & Fairhust 1970, Haimson & Rummel 1970, Hubbert & Willis 1957, Shadizadeh et al. 2009).
