  Filaments, the dense cooler plasma floating in the solar corona supported by
magnetic fields, generally exhibit certain activations before they erupt. In
our previous study (Seki et al. 2017 ), we observed that the standard deviation
of the line-of-sight (LOS) velocities of the small-scale motions in a filament
increased prior to its eruption. However, because that study only analyzed one
event, it is unclear whether such an increase in the standard deviation of LOS
velocities is common in filament eruptions. In this study, 12 filaments that
vanished in H{\alpha} line center images were analyzed in a manner similar to
the one in our previous work; these included two quiescent filaments, four
active region filaments, and six intermediate filaments. We verified that in
all the 12 events, the standard deviation of the LOS velocities increased
before the filaments vanished. Moreover, we observed that the quiescent
filaments had approximately 10 times longer duration of an increase in the
standard deviation than the other types of filaments. We concluded that the
standard deviation of the LOS velocities of the small-scale motions in a
filament can potentially be used as the precursor of a filament eruption.
