Roger,

There are many forces that constantly affect the surface of the Earth. The Solid Earth Tide causes the surface to move up and down and around four times a day like a cork on an ocean wave

I am not certain about this. But I would expect that the twist and tilt of the Earth's surface from the Earth Tide by itself would be something that astronomers would need to compensate for when they focus on some object in space for more than a few minutes.

Twists and tilts in the Earth's surface associated with approaching earthquakes should probably also affect their focus I would expect, depending on where their observatories are located. Some locations should be more strongly affected than others.

This might be a good question to ask people in the Astro Newsgroups. And I think that I will give that a try one of these days.