Revisiting the risk concept in Geotechnics: qualitative and quantitative methods

Abstract In this paper, the concept of risk is discussed with focus on its use in geotechnics. The authors focalize the operational definition of risk, giving special emphasis to the concept of risk scenarios. Concepts of hazard, vulnerability and susceptibility are focalized because they appear in the literature in place of the concept of risk. Examples are presented. It is concluded that quantitative methods to evaluate risks are associated with non-equations elucidating the cultural, phenomenal and environmental dimensions of the risk concept. Index approach qualitative methods are associated with a compression of risk concept expressed through equations that evaluate risk as a sole number. This apparent paradox in risk analyses - equations associated to qualitative methods - is responsible for most of problems in measuring and communicating risk.