Volcanic eruptions are one of the most hazardous natural disasters on Earth. With the increasing rate of development of areas on and around volcanoes, more people and property are at risk of volcanic activity. Thankfully, volcanoes exhibit precursory unrest that, if detected and analyzed in time, it may be possible to anticipate eruptions and forewarn communities at risk. Volcanic eruptions often occur along with earthquakes and/or tremor. Seismology, together with other geophysical and geochemical studies, can help our understanding of the eruption process because seismicity within a volcanic system can provide evidence of an impending eruption or sources for tracking the movement of magma. One of the various types of seismic signals produced are volcano-tectonic earthquakes, which are so named because they share features with typical tectonic earthquakes, which allow them to be detected and located using similar approaches in automatic processing systems. High-precision earthquake relocations can be obtained by applying more sophisticated techniques, including waveform cross-correlation, though this is not routinely applied to volcanic areas.