The distructive earthquake of magnitude 6.0 in Afghanistan took place last night about 27 km from the city of Jalalabad it caused more than 800 victims and thousands of injurieswith unfortunately constantly updated numbers: this consequence, also, also daughter of the large damage that occurred to the buildingsespecially in the epicentral area. A scenario that follows situations already lived with strong earthquakes of the past and which still places the emphasis on how important knowledge and prevention towards seismic risk is.
The damage of the earthquake in Afghanistan: the analysis of buildings from images
From the images circulating on the net, an important state of damage to the existing constructions present is evident, with many partial and total collapses. However, it is tendentially low buildings2-3 floors maximum. The photographic material, combined with technical and sector literature studies in the field of seismic engineering, allow to trace a ranking of the Afghan build, grossly represented by two distinct categories:
- Urban areas and main cities show a lot of use of reinforced concrete as a building material. Some studies show how school buildings are made mainly in reinforced concrete. However, many sector studies emphasize the presence of works previously carried out for the application of more recent technical technical regulations.
- The most external areas At the heart of the main cities (such as those close to the epicenter in this case) identify themselves in a much more problematic construction from the point of view of structural robustness for seismic purposes. Especially in the current areas affected by the earthquake, the images show the high presence of buildings made of masonry blockslow height (few floors) and tendentially with wooden roofs. Realization quality and type of masonry often appear, from a first photographic analysis, relatively scarce.
Why is this a problem? The wall systems are very susceptible to earthquakesas they tend to be rigid buildings with important mass. This intrinsically generates a structural deficiency, because they tend to attract more amplified seismic actions, due to their natural dynamic behavior. Therefore, for events of important seismic intensity, it is not surprising that these are The first buildings to be affected by the effects of shaking.
There is, in addition in these structural types, one poor respect for modern construction standards And consequent anti -seismic precautions of the case: a situation that is actually not a specific photograph of this nation, but it is – relatively and proportionate – a problem that is usually found also, for example, in Italy.
Finally, it should be considered the fact that, both for the magnitude (currently estimated at 6.0) and for the superficiality of the hypocenter (about 8 km away), The seismic event contributed to emphasizing structural critical issues of the case and the damage consequently observed.
The seismic danger of Nangarhar in Afghanistan affected by the strong shocks
The event that occurred is not surprising the experts: it is in fact known that the Afghan territory has a high seismic danger, that is a high probability of recording earthquakes, even strong, within its territory. Among other things, the Nangarhar region – affected by the epicentral area of the recent seismic event – is to be in one of the highest dangerous areas of the whole nation. If to this is added the high vulnerability of the existing constructed, you can easily get to a high seismic risk, which is reflected punctually in these catastrophic events in terms of damage and loss of human lives.
Despite theirs rarityhigh magnitude earthquakes in areas with high seismic risk continue to identify themselves as events “shortly“, Meaning what who only worry a few days After their manifest. However, events like these should leave food for reflection related to seismic safety and why It is very important to act for prevention in high risk areas.
