Glad to see your Shake working. I'm a bit north of you in S.Central Ohio (SD07C) with a 3D. Setup looks good. Never tried a weight on the Shake, but I did put a weight (aka brick...) on my power and Ethernet cables just short of the Shake, in case vibrations find their way in that way.
You’ll find that your Shake will also detect lots of other things…Cars (broadband vertical “hashmarks” in your Shake DataView (still in beta but works well), refrigerator, aircraft, particularly helicopters, who’s rotors make a whole lot of “shaking”.
Looking at your data in Data View (bottom frequency display), I do see something that has puzzled me for quite some time now…if you look carefully at the “sonogram” of your z-axis, I think I see a signal at about 42 hz and about 45 hz. They occur at the same time and the duration is pretty much 5 minutes. They happen at irregular intervals and some days you won’t see them, other days they seem to happen one after the other. They are stronger in the Horizontal Axis. I’ve mentioned the “mystery signal” here before,but no response. My “Pet Theory” since they do not appear to be generated in our own setups, might be “Seismic Military Communications”, good as any I suppose…