Human history had been punctuated by catastrophes, and human being had to face many disasters like Santorin's eruption (-1500 BC), Constantinople's earthquake (557), Seine's flooding, Sumatra's tsunami (2004), hurricane Katrina (2005) or the Japan's “triple disaster” (2011). These disasters had different origins and could appear as a single event or more often as a combination of events. They could affect local population or impact at the international scale, and they could generate major economic consequences. However, natural disaster fascinates, by the event suddenness, its strength and what it implies on a scientific purpose.

Nowadays, human pressure is so important, that many people are currently living on a territory that is exposed to different type of disasters, most of time not only one but many of them, without knowing that they are exposed. It is therefore essential to obtain an overview of the risk. That is why it is important to study these events from a physical point of view, in order to understand the mechanisms that created those natural hazards, and ideally to be able to predicting them; and from a human point of view, by studying the territory and the exposed issues. It is that second point that is interesting us here. To do so, we are going to deal with some notions, mainly with the vulnerability and the resilience, which are key concepts on natural hazard studies.