Earthquakes in the Canary Islands are usually detected at about 30 or 40 kilometers deep, right in the channel that separates the islands of Gran Canaria and Tenerife and its strength does not usually exceed 3 mbLg. Finding out the reason for this high seismic activity is one of the objectives of the National Geographic Institute (IGN), hence an investigation is being carried out, with the objective of Solve the mystery of the origin of the earthquakes in the area.
The enigma has been going on for more than three decades without answer although there have been many hypotheses that have been made to try to explain it. Although due to the difficulties to access the area and the lack of stations, the seismologists insist that the location may have a margin of error.
different theories
There are several existing theories. One of them correlates earthquakes with the existence of a fault that separates both islands and causes earthquakes. “It has been theorized that perhaps a structure of this type exists as an extension of the Atlas”, says Itahiza Domínguez, IGN seismologist. But this theory does not have much support among the scientific community, and even less, after several analyzes of the area have found absolutely nothing. Among other things, as Domínguez explains, “because the distribution of earthquakes is not linear,” as usually happens in areas separated by a fault.
Another of the theories that the researchers are considering is the one that considers that the earthquakes are generated by the weight changes between the buildings of Tenerife and Gran Canaria that, moreover, are “one on top of the other”. It would be, as the IGN explains, a relative movement of approximation between the two islands due to the dismantling process of Gran Canaria and the growth of Tenerife and that could explain the existence of this seismicity. “But if that were the case, this would also have to happen on La Gomera and we are not seeing it,” says Domínguez.
the middle volcano
Then there is one of the most famous, that of the enmedio volcano, name with which the area has been popularly called. Between both islands rises an underwater colossus, 470 meters high, one of the largest volcanoes in the Canary Islands under the sea. The structure was discovered shortly after the strongest earthquake that the Canary Islands have suffered in its recent history. that of 1989. Scientists set out to try to discover what had caused such terrestrial movement. of that expedition the first “photograph” of the volcano emerged carried out by the Spanish Institute of Oceanography (IEO) in 1990 and, later, it began to be related to seismic movements.
This last theory explained that between the two islands there is a hot spot where the magma “has an easier way out” because the oceanic crust is thinner.
That would explain why there are so many “little cones” around the enmedio volcano and the very existence of the great colossus that rests on three and a half kilometers of land at its base (the size of Puerto de la Cruz). But this theory also raises doubts. “We do not believe that it is magmatic activity because the earthquakes we see are not intense or in the form of a swarm, as would be expected if they were of this type of origin,” Domínguez emphasizes.
With the project, researchers from IGN hope to get answersthat in two or three years they could finally solve one of the best-kept enigmas of the Canarian ocean.
