A Pascal Program for Determining Slip-Vector Orientations on Fault Planes

Abstract

I have written a Pascal program which provides a method for calculating the slip vector and the shear stress to normal stress ratio on an arbitrarily oriented fault plane situated within a stress field of varying principal stress magnitudes. The orientation of a fault plane relative to the principal stress axes and the magnitudes of the greatest (σ1) and least (σ3) compressive principal stresses are given. The magnitude of the intermediate principal stress (σ2) is initially set equal to σ3 and then increased in a specified number of equal steps until it is equal in magnitude to σ1. At each value of σ2, the total stress vector acting upon the fault plane is calculated and resolved into a maximum shear stress direction within the fault plane. The ratio of the shear to normal stresses acting upon the fault plane are also calculated to determine whether the fault plane would experience slip under realistic geological conditions. The program can be used as a teaching tool and in the development of synthetic da...