Violent disruption (8)
I believe the answer is:
upheaval
'violent disruption' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for upheaval that I've seen before include "A pH value? (anag)" , "At university, books are taken in to cure" , "Violent or sudden disturbance" , "Disturbance that brings about great disruption" , "Great disturbance and disorder" .)