I'm not sure what your options are, but the best safety features would be ones suited for earthquakes, particularly violent earthquakes if they are close enough to a transform boundary to be concerned about safety. Things like a reinforced floor (to prevent splitting), wall ties (for large things like cabinets or displays), and other large items bolted to the floor would be helpful, along with a reinforced roof and lots of things to hide under should an earthquake occur. Basically, things that will prevent people from getting crushed or plummeting into a hole if the quake leaves a big enough split in the floor. Also, earthquake survival kits placed in all the shops, etc would be helpful if the quake traps people for any amount of time.
I hope this helps you out with what you were looking for!