## 1 Introduction
### Negative Effects of Air Blast Wave  
The air blast wave is an undesirable side effect that occurs in any explosive detonation and consequently has to be studied. The study of the air blast wave due to explosive detonation has been carried out in the last decades from two points of view.  
One is the safety point of view, and the other is the environmental impact. The air blast wave is studied from the safety point of view because it has a great destructive effect within a radius that depends on the amount of explosive detonated.  
During the second half of the 20 th century, a considerable number of experimental and theoretical studies were conducted to understand the effects of blast on buildings and structures [3; 4; 5; 6; 7]. The aim was first to study the behavior of air blast waves including the determination of their characteristics and then to investigate the dominant factors influencing the incident waves. Another objective was to investigate the response of the building structure to blast loads [8; 9; 10; 11; 12; 13].  
The damage caused by the air waves on the structures depends on the overpressure, the impulse, and the formation of projectiles. The level of severity is also influenced by the orientation with respect to the direction of advance of the wave, the geometry of the structure (height/length ratio), and the construction materials. For emergency planning, it is interesting to consider inhabited buildings, due to the greater severity of the consequences.  
When a shock wave reaches a structure, it is reflected, with an overpressure at least double that of the incident wave. The wave continues its propagation, reaching a moment in which the entire structure is encompassed by the wave. The explosions produced on the surface cause practically horizontal loads on the structures that they find in their path (except on the roof).  
If the structure is small, with few openings, the load results in a homogeneous compression of it; if the structure is large, the load will be markedly different at the front and at the rear, with a greater potential for damage. The existence of openings or the breakage of some part of the structure will result in the homogenization of the pressure between the interior and the exterior of the structure. The calculation of the loads on a structure is carried out by combining the incident pressure and the dynamic pressure and their duration.  
Actually, the response of a structure depends not only on the incident overpressure but also on the impulse (which takes into account the duration of the pressure pulse).  
In the case of blasting in which the explosive is confined, it generates an air wave with a large proportion of low frequencies that can induce vibrations in buildings, although they are not heard because they are infrasonic. In any case, the effects of the air wave produced by a confined explosive are rarely harmful except in remote cases of glass breakage.  
On the other hand, the air blast wave has been extensively studied from the environmental protection point of view. The air blast wave, even of a small intensity, can produce negative effects near the blasting areas. It is very typical of blasting related to mining (quarries or open-pit mines) or civil works (excavation or demolition). For example, the air blast wave can negatively influence the wildlife, which is critical in the case of protected animal species. In the same way, the air blast wave can produce different negative effects on population, from complaints of the neighbors of a village, to small damages to buildings, such as glass breakage or displacement of some tiles on the roof.