The 6.8 magnitude earthquake that shook the Marrakech region, in southern Morocco, "was not expected" because, although historically there have been earthquakes in the area, they had never before reached such strength, according to the seismologist from the Geographic Institute National (IGN), Carlos González.
"An earthquake could be expected there, but not so strong, at most magnitude 5," González told Efe, pointing out that what happened will have to be studied before conclusions can be drawn as to why it was so strong.
Apparently, the cause could be in a fault, called South Atlas, which is mapped but was not expected to exceed magnitudes of 6.4.
According to data collected by the National Geographic Institute (IGN), in Spain, the earthquake has been felt in Andalusia, Castilla-La Mancha, Extremadura, the Canary Islands, Ceuta and Melilla, although the data will have to be adjusted.
"The intensity of an earthquake is given to us by the questionnaires that citizens fill out and the damage it causes, and the magnitude is not given by the energy that the devices measure," added the seismologist.
The Richter seismological scale, which assigns a number to quantify the energy released by an earthquake, has no limits, he stressed, after explaining that, for example, in Japan or Chile, earthquakes of high magnitudes can be expected and that in those areas, the one hit by the Moroccan earthquake, "is not a big deal.
Regarding the damage that an earthquake can cause, he has detailed that its devastation capacity will depend, mainly, on the resistance of the construction, on whether or not they have been built to resist the seismic danger of the area; and the depth at which the earthquake is recorded.
If it is very deep, the waves are attenuated and the effects will be smaller, "while if it is superficial, if it is recorded at a shallow depth, as has been the case in Morocco (about 15 kilometers), the damage will be greater." The closer, the more damage," he stressed.
Regarding the possibility of an earthquake of these characteristics occurring in Spain, he wanted to make it clear that earthquakes "cannot be predicted as such" and no one can ever say when an earthquake is going to occur.
"What there is are hazard maps, which indicate where earthquakes can be expected and their characteristics."
In Spain, the maps produced by the IGN indicate that the areas with the greatest risk of significant earthquakes are the area between Alicante and Huelva, the Pyrenees and "a little bit" in Galicia.
"From Alicante to Huelva would be the most dangerous area, which means that it is more likely that there will be an earthquake there, although we cannot say when it will be," González pointed out, adding that these maps also indicate that although Madrid does not earthquakes can be ruled out, these would be of lower magnitude than in the southern area.
