Talking, I think, about a shift of the axis compared with where it would have been without the quake. Earth isn’t all solid, it is also mush and liquid. When that uneven mass gets jiggled around, so does the angle of the axis of the planet’s spin in space.
Yes. Do a google search on Earth Orientation Parameters or Polar Motion...NGA and USNO have the best resources, though you may find simpler explanations elsewhere.
I would help more but I am on my way out for the day.
FRegards,