Carlos Rosique |
Alicante (EFE) is prepared for an earthquake of this magnitude. The experts conclude that the south, because of how their homes are built, would hold it better.
The last major earthquake with casualties that occurred in Spain took place in May 2011 in Lorca (Murcia), when the earth trembled with a magnitude of 5.1 (2.8 less than this week’s tragic earthquake) and caused nine dead and 324 wounded.
“Building in Madrid is not the same as building in Granada”
In Spain there are areas that are prepared for an earthquake of this magnitude and others that are not, but both answers have their reason: “It is not the same to build in Madrid, where the risk of earthquake is very low, than to do it in Granada”, where, as in Murcia, Almería or Alicante, “it is possible to build to support values of up to 7”.
This is explained to EFE by the professor of Structures Salvador Ivorra, from the University of Alicante (UA), who has a Seismic Risk Unit specialized in detecting and studying these earthquakes.
Its director, José Delgado, highlights in this regard that when looking at a seismic map of Spain there are places like Murcia, Alicante, Granada, the western part of the Pyrenees or the Canary Islands that are more prone than in others, although the numbers they handle are far from reaching to a magnitude 7 earthquake like the one in Turkey and Syria.
However, that is why the houses in the southeast of the peninsula or the Canary Islands, where the movement of magma causes small movements, are designed to “bear” these natural events.
For this reason, Ivorra insists that building in Castilla-La Mancha or in Granada is “absolutely different”, since “greater actions will have to be considered when sizing the construction in Granada” and that it will imply that the pillars are larger or that they have different amounts of steel, “but also in the constructive typology, that is, the way in which it is built.”
“All the recommendations indicate the greatest possible symmetry both in plan and elevation,” highlights Ivorra, who states that “if this symmetry does not exist due to design criteria, other structural considerations will have to be made to be able to resist” an earthquake.
Next, the EFE Agency poses several questions to both experts:
Can there be an earthquake like the ones that occurred in Turkey and Syria?
For Delgado, “yes and no”, because although the peninsula “has a plate limit close by and there are faults that are moving and are producing earthquakes”, so that there can be earthquakes on that side, these faults have no Neither the size of those in Turkey nor their speed reaches those of the Asian country, so these earthquakes “should not be the size of those who have lived” there.
Asked if the fact that there are small earthquakes throughout the weeks in the south of the peninsula is positive so that there is not a bigger one, the director of the Unit of Seismic Risks of the UA explains that no, although these earthquakes , which at most reach a magnitude of 3.5, “allow us to know where the faults are, when they are moving and how they do it.”
“But having the hope of saying that -these movements are- like a container that has a small leak and that this leak means that it will never be clogged, no”, he highlights.
Thus, the director of this unit in which the Generalitat Valenciana and the Alicante Provincial Council collaborate points out that “a magnitude 5 earthquake releases approximately the same energy as 32 magnitude 4 earthquakes”, so small earthquakes do not allow one to be avoided. much older.
Is the current anti-seismic regulation for homes optimal?
Ivorra points out that the first anti-seism regulations date from the 1970s, but that they have been improving over time until reaching the 2002 regulation, “if it were properly complied with, all constructions after that date would be very well dimensioned”, he emphasizes.
“The most important thing is that when a structure is calculated, all these requirements are considered, although what we find is that there are homes prior to that publication, when these criteria did not exist, but with buildings from 20 years ago there should be no problem” , affects.
Can our building be upgraded to fight an earthquake?
The professor of Structures points out that it is difficult to give a clear yes, because in the first place it will be necessary to approach each construction, but he affirms that in most cases it can be done through reinforcements with steel, with carbon fibers or fibers of glass, which would help reduce material damage in an earthquake.
However, he warns that it is still necessary to “evaluate the cost-benefit” of the action, because if the building does not have historical value, “it is still cheaper to carry out another type of intervention”, although he concludes that practically all of it “does you can make a structural reinforcement to condition a building ».
How to act in the event of an earthquake?
Delgado assures that no matter how much it has been repeated, it is important to emphasize how to act in the event of an earthquake: “Find a safe place such as a table or the frame of a door” and when it is over, “get out of the building calmly towards a clear area.”
“Frequently, when a serious earthquake occurs, a short time later there are aftershocks that will act on the buildings,” insists Delgado, who recalls that these aftershocks will finish “cracking” the damaged structure of the buildings that has caused the main earthquake and will cause In many cases, landslides, so these areas must be avoided to prevent them from falling on people.