Raising of part of the earth's crust alters a pH value (8)
I believe the answer is:
upheaval
'raising of part of the earth's crust' is the definition.
'upheaval' can be an answer for 'raising' (thesaurus). I am unsure of the 'of part of the earth's crust' bit.
'alters a ph value' is the wordplay.
'alters' is an anagram indicator.
'a'+'ph'+'value'='aphvalue'
'aphvalue' anagrammed gives 'UPHEAVAL'.
Can you help me to learn more?
(Other definitions for upheaval that I've seen before include "Disorder, turmoil" , "Major disturbance" , "Great disturbance and disorder" , "Violent change or disturbance" , "Disturbance that brings about great disruption" .)