Where an earthquake reflects foundational instability and a tornado reflects fast external chaos, a volcano is more specific: it represents pressure building internally toward an eventual, and often overdue, release.
Watching a volcano about to erupt
This common version usually appears during periods of suppressed frustration or anger — a situation where you've been containing a reaction that's building toward a point where it will eventually need to come out.
The volcano erupting
If the dream progresses to actual eruption, it can reflect either a recent moment when suppressed feelings finally surfaced, or an anxiety about what will happen when they do.
Living near a dormant volcano
A more chronic version of the same theme — this often reflects an ongoing situation (a relationship, work environment) where you're aware of unresolved tension that hasn't erupted yet but could.