This is certainly not the last time that this region, one of the most seismically risky in the world, is struck.
The Earth shook strongly in the night from Sunday to Monday in the south of Turkey, causing the death of more than a thousand people.
Several foreign countries, starting with France, Germany and the United States, have offered their help to Turkish and Syrian rescuers.
Most of Turkey is located on the Anatolian Plate.
It sits at the junction of several much larger tectonic plates, including the Eurasian one to the north and the Arabian one to the east.
This new earthquake with a very heavy toll occurred at the East Anatolian fault, that is to say at the junction between the Anatolian plate and the Arabian plate, about 700 km long.
This is a so-called "stripping" or "sliding" fault, that is to say that the two separate blocks slide horizontally relative to each other.
“What is important is the difference in speed.
The Arabian plate is going a little faster than the Anatolian plate towards the northeast, which leads to accumulations of forces at this level", describes the seismologist Florent Brenguier, from the Institute of Earth Sciences (ISTerre) in Grenoble. (Isere).
The fear of the “Big One”
The recorded magnitude reached 7.8, above 7 for the first time in this area.
“If we look at the historical map of seismicity, we had not yet had a major earthquake at the level of this fault.
But we know, thanks in particular to GPS observations, that it was at risk,” says Florent Brenguier.
Several aftershocks were recorded near the epicenter in the hours that followed, including one of magnitude 7.5.
VIDEO.
Violent earthquake in Turkey and Syria: hundreds dead, many buildings collapsed
Until now, the main earthquakes that have shaken Turkey have mainly taken place at the level of the North Anatolian fault, also called “stripping”, at the junction of the Anatolian and Eurasian plates.
On August 17, 1999, an earthquake of magnitude 7.8 (also) caused the death of more than 17,000 people in northwestern Turkey, around the epicenter near Izmit.
Many experts anticipate the emergence of a “Big One” in the coming decades, that is to say a mega-earthquake that would hit Istanbul, the most populous agglomeration in Turkey.
Enough to fear a very heavy human toll.
“In the worst case, the earthquake could reach a magnitude of 7.7.
Is Istanbul ready for this?
Unfortunately, no”, indicated in 2019 Sükrü Ersoy, earthquake specialist and teacher at the Technical University of Yildiz.
And “what happened last night has no effect on the probability of having an earthquake in Istanbul, the most risky region in all of Europe”, comments Florent Brenguier.
Difficult prediction
Science could make it possible to limit the human impact of such a natural event.
“With sensors located at seismic faults, we are now able to transmit alerts as soon as an earthquake occurs.
Seismic waves travel much slower than telephone waves, which allows time to take shelter”, describes Florent Bregnier.
The debate now focuses on the possibility, or not, of predicting large earthquakes a few hours or even a few days in advance.
“The question is whether there are warning signs, such as certain landslides.
This is the subject of much research,” concludes the seismologist.
