During the eruption of the Kizimen volcano in 2010-2013. There was a uniform squeezing of the viscous lava flow. Simultaneously with its movement, earthquakes with an unusual quasi-periodicity were recorded, the drumbeats mode. In this work, we show that these earthquakes were generated by the movement of the flow front, which was observed for the first time in the practice of volcanological research. We represent the movement of the flow as an intermittent slip with the inclusion of the stick-slip mechanism with the initiation of a self-oscillating process. The plausibility of the phenomenological model at the qualitative level is confirmed by the mathematical model of a fractional nonlinear oscillator.