  The velocity-space distribution of the solar neighbourhood stars shows
complex substructures. Most of the previous studies use static potentials to
investigate their origins. Instead we use a self-consistent $N$-body model of
the Milky Way, whose potential is asymmetric and evolves with time. In this
paper, we quantitatively evaluate the similarities of the velocity-space
distributions in the $N$-body model and that of the solar neighbourhood, using
Kullback-Leibler divergence (KLD). The KLD analysis shows the time evolution
and spatial variation of the velocity-space distribution. The KLD fluctuates
with time, which indicates the velocity-space distribution at a fixed position
is not always similar to that of the solar neighbourhood. Some positions show
velocity-space distributions with small KLDs (high similarities) more
frequently than others. One of them locates at $(R,\phi)=(8.2\;\mathrm{kpc},
30^{\circ})$, where $R$ and $\phi$ are the distance from the galactic centre
and the angle with respect to the bar's major axis, respectively. The detection
frequency is higher in the inter-arm regions than in the arm regions. In the
velocity maps with small KLDs, we identify the velocity-space substructures,
which consist of particles trapped in bar resonances. The bar resonances have
significant impact on the stellar velocity-space distribution even though the
galactic potential is not static.
