Parametrically forced gravity waves in axisymmetric mode in a circular cylinder filled with FC-72 with large liquid depth have been studied numerically. The instability threshold and wave breaking thresholds are plotted from the simulated results which show good agreement with the reported experimental and theoretical results. A notable observation is the presence of different time scales of wave amplitude modulations at different regimes. The wave amplitude response exhibits amplitude modulations, period tripling and period quadrupling without breaking of waves. Inertial collapse of the wave trough causes a high velocity jet ejection has also been observed when forcing amplitude crosses the breaking limit. © Published under licence by IOP Publishing Ltd.