The North of the African continent, from its Atlantic part, in the Agadir area in Morocco, to its Mediterranean coastline, will continue to suffer earthquakes such as the one that occurred last Friday in the province of Al-Haouz. It is a situation that comes from two major seismological faults.
The African plate is moving very slowly northward, colliding with the Eurasian square. Seismologists know this perfectly. Africa is moving up and plate tectonics will continue to produce these large earthquakes.
The great French seismologist, the late Harun Terzieff, calculated that each year Africa moves upward by 5 to 6 centimeters; This seems trivial, but on a tectonic scale it is an important movement.
In Algiers, an earthquake measuring 6.8 on the Richter scale (the same intensity as this one in Al-Haouz) took place in May 2003, causing 2,266 deaths and 10,261 injuries. If the balance of what happened on Friday in Morocco will undoubtedly be higher, this is due to the fact that in the affected area most of the houses were made of clay, mud and bricks of little consistency.
It is unavoidable; The African plate will continue to move imperceptibly, but over billions of years, it will stick to the Eurasian plate and the Mediterranean Sea will practically disappear. Today that seems unimaginable, but it corresponds to a reality that must be accepted. The earth is suffering convulsions and will continue to suffer them. Japan, for example, is at the confluence of three major plates and a fourth minor one.
The Japanese archipelago suffers from the collisions of the Eurasian, Pacific and Philippine plates; and to a lesser extent, that of Okhotsk. In reality, the earthquakes that occur daily in several countries are multiple; They can reach 5,000 a year, but their intensities are not always perceptible by man.
As the African plate moves, earthquakes occur from South Africa to the Mediterranean. Tremors of considerable intensity have already occurred in South Africa and the Congo.
Sooner or later, a “big bang” earthquake, a high-intensity earthquake, will occur in California (USA), due to the gravitational instability of the San Andreas fault, 1,200 km long. What is expected is that one fault will ride on another. The last major earthquake on this fault occurred in April 1906 with a magnitude of 7.9 on the Richter scale. It lasted 60 seconds and the death toll was 700. The destruction of buildings was enormous.
In this case, the reason was the collision between the North American plate and the Pacific plate; a situation that will inevitably occur again, although it is impossible to calculate the approximate time it will take to arrive.
Terzieff pointed out that we must accept and, as far as possible, understand these upheavals of the earth. It is important to implement anti-seismic structures, but even that does not guarantee that earthquakes will be catastrophic. The earth is not inert and it is the one that dominates us.
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