Summary: The boundary control problem for the dynamical Lame system (isotropic elasticity model) is considered. The continuity of the {``input \(\to \) state''} map in \(L_2\)-norm is established. The structure of the reachable sets for arbitrary \(T>0\) is studied. In the general case, only the first component \(u(\cdot ,T)\) of the complete state \(\{ u(\cdot ,T),u_t(\cdot ,T)\}\) may be controlled, an approximate controllability occurring in the subdomain filled with the shear (slow) waves. The controllability results are applied to the problem of the boundary data continuation. If \(T_0\) exceeds the time needed for shear waves to fill the entire domain, then the response operator ({``input \(\to \) output''} map) \(R^{2T_0}\) uniquely determines \(R^T\) for any \(T>0\). A procedure recovering \(R^\infty \) via \(R^{2T_0}\) is also described.