A hitch, with landmass quaking in Pacific territory (7,7)

I believe the answer is:

chatham islands

I'm a little stuck... Click here to teach me more about this clue!

'a hitch with landmass quaking in pacific' is the definition.
I don't know anything about this answer so I cannot tell whether this works.

'territory' is the wordplay.
I cannot really understand how this works, but
'territory' could be 'island' (I have seen 'detached territory' mean 'island' so perhaps 'territory' could also mean 'island') and 'island' is found in the answer.
This may be the basis of the clue (or it may be nonsense).

Can you help me to learn more?

I've seen this clue in The Independent.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.