At many volcanoes, low-frequency earthquakes have often been associated with the state of a volcanic system and have been employed for eruption prediction. Several models attempt to explain the generation of such earthquakes, but fail to describe their clustering in tight spatial swarms and their highly repetitive nature. We present a new model that not only explains the generation of a single event, but also accounts for the swarm behavior and cyclic activity. By considering magma rupture as a source mechanism of seismic events, we demonstrate that a change in conduit geometry is the most plausible cause for their generation. Our model matches the observed spatial and temporal behavior of low-frequency seismicity and contributes to the understanding necessary to provide estimates of magma ascent rates.