We derive Carleman estimates with two large parameters for a general partial di erential operator of second order under explicit su cient global conditions of pseudo-convexity on the weight function. We use these estimates to derive the most natural Carleman type estimates for the anisotropic system of elasticity with residual stress. Also, we give applications to uniqueness and stability of the continuation, observability, and identi cation of the residual stress from boundary measurements.