We study the homogenization of the elastic system submitted to a strong oscillating magnetic field. We prove that oscillations in time or space make increase the effective mass. More generally, oscillations in time and space produce a new term in the limit equation which can be considered as a nonlocal Lorentz force, the range of which is limited to light cone at each point. We also consider the case of soft inclusions where we prove that the magnetic field induces a viscoelastic behavior.