The stratigraphic separation diagram (SSD) is an often neglected tool of fault analysis, which assists with the interpretation of both the fault-surface geometry and the mechanism of faulting. As the SSD needs to evaluate displacement or separation along the fault, this particular method can be used only in areas with well-documented stratigraphic sequences. This paper presents details of some common patterns obtained when using SSDs and also discusses some real examples of two apparently similar faults found in the Barrandian area in the Czech Republic. Although both the Prague and the Tachlovice faults in the Barrandian area seem to be of the same character (the same strike, remarkable stratigraphic separation, similar localization in the Prague Synform), the SSDs of these two faults demonstrate the difference in fault surface geometries and consequently a very distinct mechanism of origin. The Tachlovice Fault is one of the main thrusts in the Prague Synform. It has ramp-flat geometry and is associated with fault-related folds. The Prague Fault, on the other hand, was formed later, after the initial folding, and belongs to a group of steep translatory faults. It is shown how SSDs are practical, effective tools for the analysis of these types of faults and associated stratigraphies without the need of 3D seismics or boreholes. Copyright © 2010 John Wiley & Sons, Ltd.