Principal stresses, that is vertical, maximum horizontal and minimum horizontal stresses, and elastic moduli related to rock brittleness, like Young's modulus and Poisson's ratio, can be estimated from wide-angle, wide-azimuth seismic data. This is established using a small 3D seismic survey over the Colorado shale gas play of Alberta, Canada. It is shown that this information can be used to optimize the placement and direction of horizontal wells and hydraulic fracture stimulations.