parasitic volcano; lateral volcano
A smaller volcanic vent or cone on the flank of a larger volcano, formed by eruptions branching off from the main conduit. Used in geology and volcanology.
Mount Fuji has many parasitic volcanoes.
Activity of parasitic volcanoes is often related to eruptions of the main volcano.
Compound of 側 (そく, 'side') + 火山 (かざん, 'volcano'). The reading そっかざん results from a regular sound change (sokuon) when 側 is combined with 火山.