  We studied the dynamics of the solar atmosphere in the region of a large
quiet-Sun filament, which erupted on 21 October 2010. The filament eruption
started at its northern end and disappeared from the H$\alpha$ line-core
filtergrams line within a few hours. The very fast motions of the northern leg
were recorded in ultraviolet light by AIA.
  We aim to study a wide range of available datasets describing the dynamics of
the solar atmosphere for five days around the filament eruption. This interval
covers three days of the filament evolution, one day before the filament growth
and one day after the eruption. We search for possible triggers that lead to
the eruption of the filament.
  The surface velocity field in the region of the filament were measured by
means of time-distance helioseismology and coherent structure tracking. The
apparent velocities in the higher atmosphere were estimated by tracking the
features in the 30.4 nm AIA observations. To capture the evolution of the
magnetic field, we extrapolated the photospheric line-of-sight magnetograms and
also computed the decay index of the magnetic field.
  We found that photospheric velocity fields showed some peculiarities. Before
the filament activation, we observed a temporal increase of the converging
flows towards the filament's spine. In addition, the mean squared velocity
increased temporarily before the activation and peaked just before it, followed
by a steep decrease. We further see an increase in the average shear of the
zonal flow component in the filament's region, followed by a steep decrease.
The photospheric l.o.s. magnetic field shows a persistent increase of induction
eastward from the filament spine. The decay index of the magnetic field at
heights around 10 Mm shows a value larger than critical at the connecting point
of the northern filament end.
