Why do we still tolerate buildings that are Unsafe in Earthquakes?

Earthquakes continue to kill thousands of people and make hundreds of thousands homeless. Within a few seconds, they destroy infrastructure that was developed over decades. To a degree, we have the means and knowledge to stop this happening. But, painfully, we are unable to do this because we tolerate unsafe buildings. In this paper, we explore why we are unable to stop this - from both engineering and socio-cultural/ economic perspectives. We look into both issues together, because these are related from a seismic safety point of view.

Not tolerating unsafe building means having a sound engineering definition and a sound implementation strategy. From an engineering perspective, we looked at the common concepts/ terminology we use in engineering to describe safe buildings and the procedures we use to satisfy ourselves as designers that we are doing the right thing. However, we find there are many paradoxes (i.e., conflicts with expectations) in our common procedures and explanations when we try to define safe. These are because interpretations vary between people and cultures. We authors (each coming from a very different culture) have debated over many years our appreciation of risk. It is clear that a definition of safe depends both on how we define risk, and on how much risk we are prepared to accept.