This Tuesday, 3 earthquakes with magnitudes between 2.9 and 4.8 on the Richter scale shook the province of Granada. Are European regulations on seismicity being fully applied in a risk area like this?
The European regulations should now be implemented throughout the national territory, as they distinguish dangerousness by area, and these days it is becoming clear that looking the other way does not make sense. Warned as we are, if personal misfortunes occur, criminal liability will have to be sought. In relation to the building stock of Granada, these days we have seen that the most modern ones, where at least the 2002 Spanish standard has been applied, have resisted better. As old buildings are still very numerous, it is only possible to audit all critical infrastructures and intensive public use, and obviously all buildings in which the slightest damage has been caused. We must understand this moderate earthquake as an opportunity to rectify and avoid that if one of 6 or 6.5 degrees arrives, the damage is unlimited. As we have seen these days in Granada, not only structural problems can cause personal injury, but also an inadequate design of the facades and their protrusions.
What happens with this European regulation? Why is it not being fully executed? What prevents it?
The Eurocodes are mandatory, but it turns out that they are not being implemented. There is internal resistance in the Ministry of Transport, which in the end becomes political. We are the only country in Europe where it does not apply. The only Secretary General of Land Transportation, Marta Serrano, who really took the bull by the horns, left. All the previous work had been done, including the administrative work, and suddenly it was left in a drawer again.
In any case, at present, it is impossible to predict when an earthquake will occur although the areas with seismic risk are perfectly known...
It is statistically impossible to predict. Yes we can say the density. In Japan we really forget, but if you bother to look, you will see that last week or the other there were earthquakes of significant intensity. What happens is that there are almost never deaths, but very recently there was one with deaths and it was no bigger than others. It was in an area where the buildings were a little older and, well, the thing is that there were deaths, which is a strange thing. In Spain, Murcia or Granada are seismic zones and it is a matter of time, if they are not within a year they will be within 15, one will come and it will be important. If we are not prepared, then things will happen.
So, what should we do to be better prepared? Because our housing stock is quite varied and there are many homes that were built several decades ago....
A forensic audit of critical infrastructure and buildings should be carried out. We are talking about hospitals, schools and public buildings that are widely used such as energy production plants and, of course, dams. These days I was reading that, in Colombia, a hospital had collapsed. It just can't be! A hospital has to be calculated specifically and if it is worth 5% more, which is the most it will cost, then it has to be because what is worth in a hospital is what is inside. The outside is "relatively" cheap. You need it to be a reference point and, in general, the critical infrastructures: if there is an earthquake it is very important to know that the children are at school and that this is a safe place, that it is well calculated.
I understand from your words that we should focus on critical and public infrastructures, not so much on private buildings...
The forensic audit is easy and would give us knowledge of where we are. And yes, we really are not particularly well and that is what happened in Lorca tells us, which was a large earthquake no greater than 6 degrees. It is important to know where we are and it is true that we will not be able to change entire towns, because they are already built, but the critical infrastructures - what is public - that has to be the place to take refuge. It is the refuge in the bombardment. It can also be made that buildings over 40 years old, as they comply, would have to carry out a minimum audit of their condition within a period of 2 years so that it would be attached to the certificates that they ask for at the notary when making sales. At least, in risk areas it would be good if they did a less extensive audit than that necessary for critical infrastructures, where the diagnosis has to be very fine and add proposals.
I suppose that the actions that the technicians would recommend would not come cheap in both cases...
Any work is worth money, while an audit can ultimately cost you 1 or 2% of the cost of the building. That of a renovation, since it is 5% of the cost of the building, and when we talk about public buildings, it is money. We would have to see what happens with the audit, what it allows you to do is be aware of reality. From there we see what it is worth, and that is why, so that it is not diluted, it is even important to do it in places with risk.
What exactly do you mean when you talk about a kind of "second" audit of buildings that turn 40 years old?
In the so-called 'architectural ITV' of 40-year-old buildings, in risk areas, it would be necessary to incorporate - it would be easier - a complementary analysis of what affects the earthquake resistance capacity. Simply at an initial informative level, because then it is a consolidated right. It would mean, for example, that a certain house in the event of an earthquake is really at high risk or not. If we incorporate it as a special addition it makes perfect sense and is simply an administrative approval to improve the efficiency of this ITV in seismic risk areas. This "ITV" is designed to be very cheap and the solutions are more difficult to provide. For example, lower silver should be braced, which would be the most sensitive. You could make a more or less standard recommendation and it would make sense.
