Fault-slip calculation from separations

A computer program to calculate the slip vector of a fault from either: (1) the separations of two marker planes, or (2) the separation of a marker plane and the slip direction of the fault, measured at an outcrop, was revised in order to calculate the error range of the slip vector under given error ranges of the measured separations and directions. In some cases a small error range in the original data gives rise to large error ranges in the calculated slip direction and magnitude, and therefore it is very important to accurately assess the error range of data. The use of the program to solve some structural problems is also discussed.