Also another thing-
Hugh your first post really reminded me something I should do this summer also- earthquake proof my tank stand. Right now it is on a nice table, but a table with some rather skinny iron legs... It has too many degrees of freedom and in the chance of a quake would most likely buckle one of the legs and cause hell...
.. especially since it's in my 2nd story bedroom.
Here's a pic of part of it- it is all I have... from when I was taking pics of my new speakers on either side of it. The stand is that oak tabletop, with 4 bend rod iron legs under the black curtain, masking a bunch of junk..