Is "buildings should be made according to ground" thing valid only for soft ground?

[The Grandeur]

Is buildings should be made according to ground" thing valid only for soft ground?

If a building is designed for soft ground but made on hard ground, it is not a problem for earthquake?

[K'ledgeBldr]

The science and engineering for building in "Seismic Zones" is rather complicated due to many factors.

But, to answer the jest of your question- A building that is built to withstand seismic conditions in a zone that is not seismically active would do well... the problem? Why would you spend twice as much money for a building that can withstand seismic conditions that it will most likely never see?