Two identical 60 gallon glass tanks are filled with water and placed side-by-side on an earthquake simulation platform.  One tank is secured to the wall with furniture straps while the other is left freestanding.  Flip on the switch and you can probably guess what happens next. The most obvious lesson is to secure your aquarium to your wall.  Aquarium joints are also surprisingly strong (even mass-produced 60 gallons with thin glass).