Earthquakes are detected every year in Gran Canaria, specifically in the same area where the earth trembled on Monday (22nd August 2011), just off the coast of San Bartolomé de Tirajana. However, it is the first time that it has reached a magnitude as large as this one, 3.4 degrees on the Richter scale. It was felt almost all over Gran Canaria. Earthquakes here normally never exceed 2.6 or 2.7 degrees on the Richter scale which, according to the centre responsible for seismic monitoring on the islands are considered “normal”. But the earthquake on Monday, which was located five kilometers from the coast of San Bartolomé de Tirajana, which reached a magnitude of 3.4 degrees, seven points above the maximum magnitude detected in the area, “is not normal,” according to Manuel Moreno, head of Seismology of the IGN in the Canaries. “Never before has there been an earthquake of such magnitude in the area,” he blamed the magnitude of the earthquake on “greater tension accumulated over the years in this area has led to a break, most likely by a landslide or settlement of material.”
The volcanic origin of the islands brings with it, over time, the accumulation of materials from successive eruptions in the past. The fact that there has been an earthquake of this magnitude does not mean that the seismic activity in the area has increased. “Several years ago we could detect between two and three earthquakes per month, now we will usually detect eight to ten, but the activity is the same, what happens is that the instrumentation with which we measure is more accurate and there are more stations” he explains. Gran Canaria has two permanent seismic stations, one in the Montana Guia and one at the Finca de Osorio.

Manuel Moreno believes that these two stations are “sufficient” to locate earthquakes occurring in Gran Canaria. He explains that if anything abnormal occurs on the island or an increase in activity is detected, more portable monitors would be installed on the island, as has happened this summer in El Hierro.