< The best computer shelves I've found were sold in the SF bay area at Orc < supply hardware. The brand name was "Gorilla Rack". They're heavy, and < need a hammer to put them together but the shelf supports are about 14 < guage steel angle 2 1/2 inches by an inch quarter inch pressboard on top < The whole assembly weighs 50 or 60 pounds unloaded, but I've got a pc, < it's monitor, a scanner, a laser printer, a box of cassette tapes, and a < on the one I have. It still has room and shows no signs of strain. < < I've seen these at Home Depot under another name. Yes, same here. A simple addition is plywood 1fx2f or 1fx4f (rough size) scred inside the angle steel that form the uprights to form a 3 sided box around the shelf, then one of those cargo nets used for pickup trucks in the front. Properly secured this will hold ANYTHING. RE: earthquake zones. Assuming no fire, racks like that or standard equipment racks can support amazing amounts of weight such that if the "roof" should cave there is support to protect the equipment between and in the racks. Also if racks cannot be tied to the wall, then back to back works or in groups of four with a two back to back and one at each end bolted together as one large unit. The idea is to increase the effective size of the footprint. FYI most equipment racks should have anti tip foot (extensions to the front) to keep their center of gravity from toppling them. Most also have skid feet that were designed to support the rack off the casters, minimally then should be adjusted down so they touch as that will allow sliding but provide better support. Again multiple racks bolted together will provide a very strong unit capable of holding up immense weights. Another disaster trick is if the top of the rack is covered water draining down can't easily get in. Small things can protect the hardware from significant damage. Allison