Numerous recent disasters, in several parts of the world, should alert us to the fact that people are going to be trapped under buildings and other structures. The very nature of our technologically sophisticated and "growing taller" society continually increases the likelihood that this sort of calamity will occur. Current construction trends and population increases seem to continually expand the risks as people move further up from the ground. With the advent of the “High-Rise" buildings comes the very real concern of a "building collapse". The building can collapse in two ways i.e. either by an explosion or by an implosion.
In the case of explosion, either caused by an outward rush of force caused by natural (as during earthquake or an explosion in the building), or chemical forces, the building will collapse in an "outward" direction. A tornado or hurricane can "scatter" building parts for several hundred meters or even farther, when it causes a building(s) to collapse.
With implosion, the building will collapse into itself. It is a technique that is used by demolition specialists to minimize the spread of debris when purposely demolishing buildings. This type of collapse is likely to be caused when interior weight bearing elements of structures fail. Such a situation may arise during a major fire, heavy rains or explosion in the adjoining building.