Relating to earth's crust and its movements (8)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
tectonic
(Other definitions for tectonic that I've seen before include "Pertaining to the structure or movement of the earth's crust" , "associated with global movement" , "Resulting from distortions in earth's crust - in cot etc (anag)" , "Concerned with construction" , "Relating to movements or distortion within the earth's crust" .)