Surface fault rupture can be a complex phenomenon involving brittle fracture and closely associated deformation. In order to characterize the hazard to structures from surface rupture it is the task of the geologist to identify where rupture and related deformation have occurred as well as the style and magnitude of past displacements and to interpret these data so as to anticipate future fault rupture. To extrapolate this information from the data that are preserved or discovered in investigations requires an appreciation of the variety of surface rupture processes and expression. This paper looks at the problem in terms of three questions one must ask: 1) Where should fault rupture and deformation be anticipated?; 2) How much slip, and in what sense, should be anticipated?; and 3) How should the hazard be addressed when data are incomplete? It is concluded that there will remain a number of uncertainties in the assessment of future fault rupture and that mitigation strategies must include a sufficient margin of safety to accommodate these uncertainties.