Earthquakes with clear P waves and S waves occurring beneath volcanoes. They are indistinguishable from normal shallow tectonic earthquakes. In the original definition by Minakami (1961), it was contrasted to the B-type earthquake attributed to an extremely shallow focal depth. In recent years the contrast has been attributed to the source process, and it is more often called volcano-tectonic (VT), or high-frequency (HF) earthquake (see Chapter 13 of this Manual)