  Magnetoelastic measurements in the piezomagnetic antiferromagnet UO$_{2}$
were performed via the fiber Bragg grating method in magnetic fields up to
$150\,\mathrm{T}$ generated by a single-turn coil setup. We show that in short
timescales, order of a few micro seconds, pulsed-magnetic fields excite
mechanical resonances at temperatures ranging from $10\,\mathrm{K}$ to
$300\,\mathrm{K}$, in the paramagnetic as well as within the robust
antiferromagnetic state of the material. These resonances, which are barely
attenuated within the 100 ms observations, are attributed to the strong
magnetoelastic coupling in UO$_{2}$ combined with the high crystallographic
quality of the single crystal samples. They compare well with mechanical
resonances obtained by a resonant ultrasound technique and superimpose on the
known non-monotonic magnetostriction background. A clear phase-shift of $\pi$
in the lattice oscillations is, unexpectedly, observed in the antiferromagnetic
state when the magnetic field overcomes the piezomagnetic switch-field $H_c
\simeq -18\,\mathrm{T}$. We further present simulations and a theoretical
argument to explain the observed phenomena.
