ok, looks like the earths gravity field is affected by
earth seismic events , lots of reading on the subject.

https://duckduckgo.com/?q=is+earths+gravity+field+affected+by+earthquakes

unless the ligo machines have some type of anti gravity
field built in to remove the effects of earths gravity
field on the laser then the earths gravity field would
cause the laser to bend and tremble during a seismic event
occurring on the earth.

but having anti gravity built into the ligo would defeat the purpose of the ligo wouldn't it.

3/4 inch of dust build up on the moon in 4.527 billion years,LOL and QM is fantasy science.