@cleeds , always a pleasure. Having owned two Linns I can certify that the AR XA is more stable than the Linn. The Linn is not tricky to set up at all. You set it up just like any other turntable. You just have to put it in a bullet proof situation, a very stable platform. The problem is that there is no reasonable platform stable enough. I sold the first Linn in frustration but back then I did not know near as much as I do now. After several other turntables it became obvious that the Linn sounded better than other turntables of the day so I wound up getting another one. I sold #2 in 1980 or so when I got my first Sota. What a breath of fresh air.
There are plenty of videos showing an earthquake wave traveling along the ground. Obviously seismology is not your subject. Earthquakes are not happening on a continuous basis but they are happening all the time. Most of them so mild you do not feel them. Really big earthquakes, above Richter 5 are fortunately not frequent.
Many audiophiles tap around their turntables to determine the level of isolation. Michael Fremer does this occasionally. Is a hammer excessive? Not if you want a turntable that is totally immune to everything. You may not want this but I do and there may be a few other nut jobs out there like me who want it also. I mention it just to let people know it is possible. I can bump into my turntable, drop the dust cover, run into the cabinet, etc and not only will it not skip but you can not hear a twitter through the system with the volume maxed out. The result is a dead quiet turntable. Is this excessive? Given that the background noise on the record is magnitudes higher, it probably is. It certainly is for you.