  Until now, observations have caught up only a handful of galaxies in ongoing
buckling action. Interestingly, N-body simulations over the past several
decades show that almost every bar buckles or vertically thickens as soon as it
reaches its peak strength during its evolution and leads to box$/$ peanut$/$ x
(BPX) shapes. In order to understand the effect of multiple buckling events on
the observable properties of galactic bar and disk, we perform an N-body
simulation of a Milky Way-type disk. The axisymmetric galaxy disk forms a bar
within a Gyr of its evolution and the bar undergoes two successive buckling
events. We report that the time spans of these two buckling events are 220 Myr
and 1 Gyr which have almost similar strengths of the bending modes. As a result
of these two buckling events, the sizes of BPX shapes are around 5.8 kpc and
8.6 kpc which are around two-thirds of the bar length at the end of each
buckling event. We find that the first buckling occurs at a smaller scale
(radius less than 3 kpc) with a shorter time span affecting the larger length
scales of the disk which is quantified in terms of changes in $m$ =2 and $m$ =
4 Fourier modes. While the second buckling occurs at larger scales (radius of
around 6 kpc) affecting the inner disk the most. Finally, we provide observable
kinematic signatures (for example quadrupolar patterns of the line-of-sight
velocities) which can potentially differentiate the successive buckling events.
