SUMMARYWe extend the abstract time-dependent scattering theory of C.H. Wilcox to the case of elastic waves. Most of the results are proved with the minimal assumption that the obstacle satisÿes the energy local compactness condition (ELC Notations: Let us ÿrst explain the notations which are used throughout the text. The space R 3 is endowed with the canonical basis {e 1 ; e 2 ; e 3 }, the origin O and the coordinate system (x 1 ; x 2 ; x 3 ). The canonical scalar product of R 3 is denoted by a dot. By a '·' we mean the contracted product of tensors. Vectors and matrices are typed in bold style.I is the identity map or matrix or tensor. When we want more precision, we use the notation id X for the identity map in the space X . For a matrix or a map A; t A means the transpose. For any open set ⊆ R 3 , we introduce the classical spaces of scalar complex functions: 3 . * = − curlcurl + ( + ) graddiv is the Lamà e operator, ; are the Lamà e constants, c 1 = + 2 ; c 2 = √ are the speeds of the longitudinal and shear waves and we set c jl = c j =c l ; k j (!) = c j =! are wave numbers. T(u; n) = 2 (9u=9n) + n div u + n ∧ curl u is the traction vector at the boundary point where the normal is n.