Abstract: This invention relates to a method for determining direction and relative magnitude of maximum horizontal stress in sedimentary basins within Earth's crust. In particular the method uses seismic reflection data in determining the direction and magnitude of stresses. The method involves identifying from seismic data faults which cut the upper continental crust and uses those faults in conjunction with globally simultaneous compressional structures such as anticline to map the horizontal stresses. The invention has a particular application in the hydrocarbon exploration and production industry and has the advantage of providing the results pre-drill.