There are many speculations of what's go wrong. Looking at your tank, there are no big rocks that can fall or unusual conditions that can cause failure except that it is an uncommon 30 inch tall big tank. The stand is made to support the tank on the perimeter so styrofoam is not needed. Tall tanks are notorious leakers as the water pressure is proportional to the height of tank. I would not trust any glass tanks over 24 inch high, besides, it is hard to work with tanks taller than my arm can reach. So I believe it is just a design deficiency that the bottom glass is not thick enough to withstand the pressure.
Could it be a Deep Blue tank? I heard bad reputation about Deep Blue tanks which can fail with no reason due to design and construction deficiencies.