Dynamic models of elastic structures are derived using approximations of linear three dimensional elasticity. A model for the three dimensional motion of a nonsymmetric structure that is of use for applications to health monitoring for buildings is obtained. The symmetric version of the model is validated using laboratory acceleration data. Narrow plate equations whose derivation is based on similar consideration but with plate thinness assumptions are used in a probabilistic inversion for elastic and mass properties from acceleration data. Finally, predictions of structural behavior based on the information from the inversion problem are made.