An analysis using stereographic projection or its mathematical equivalent to determine the attitude of the causative fault and its direction of slip from the radiation pattern of seismic waves using earthquake records at many stations. The analysis most commonly uses the direction of first motion of P waves and yields two possible orientations for the fault rupture and the direction of seismogenic slip. From these data, inferences can be made concerning the principal axes of stress in the region of the earthquake. The principal stress axes determined in this method are the compressional axis (also called the P-axis, the axis of greatest compression, or s1), the tension axis (also known as the T-axis, axis of least compression, or s3), and the intermediate stress axis ( s2)