A magnitude 7.8 earthquake, the largest to hit the region in nearly 25 years, struck the border between Turkey and Syria on Monday (February 6th), killing more than 1,000 people in both countries and causing great damage.
A disaster that reminds us of the vulnerability of this territory, located in one of the most active seismic zones in the world.
>> Live: a violent aftershock of the earthquake in Turkey, international aid is organized
A region in a vice between three tectonic plates
Geologically, the region is indeed at the limit of three tectonic plates: the Arabian plate to the south, Eurasian to the north and Anatolian, in the middle, on which the vast majority of Turkish territory is located.
However, these plates are constantly moving, causing pressures at their limits.
In some places, these dynamics create mountains like the Zagros Mountains that cross Iran, Iraq and Turkey.
Elsewhere, soils can break, causing faults – prime locations for triggering earthquakes.
Turkey thus shelters, in the north, the North Anatolian fault which runs from Iraq to the Aegean Sea and which crosses Istanbul and, in the east, the East Anatolian fault.
"This Monday's earthquake occurred on the East Anatolian fault," confirms Martin Vallée, seismologist at the Globe Institute in Paris.
Occurred in the middle of the night, at 4:17 a.m. local time (1:17 a.m. GMT), according to the American seismological institute USGS, at a depth of about 17.9 kilometers, its epicenter is located in the district of Pazarcik, between the towns of Gaziantep and Kahramanmaras, about 60 km as the crow flies from the Syrian border.
Turkey, a country located on one of the most active seismic zones in the world.
© France 24
Some 70% of the country in an active seismic zone
"The question in Turkey is not whether there will be earthquakes but when," recalls Bilal Tarabey, international columnist for France 24. The figures speak for themselves: according to a report of the Disasters and Emergencies Authority (AFAD) published in November 2020, 70% of the country is located in an active seismic zone.
Eighteen earthquakes of magnitude greater than 7 on the Richter scale have been recorded there for 120 years and more than 75% of the losses and damages suffered by the country in the 20th century were due to earthquakes.
In October 2020, a magnitude 7 earthquake in the Aegean Sea left 114 dead and more than 1,000 injured in Turkey.
A few months earlier, in January 2020, a magnitude 6.7 earthquake struck the provinces of Elazig and Malatya (East), killing more than 40 people.
More recently, at the end of November, a magnitude 6.1 earthquake hit the northwest of the country, injuring around 50 people.
Located a few kilometers from the North Anatolian fault, Istanbul is preparing, for its part, to be hit by a massive earthquake within several years – a scenario deemed “inevitable” by seismologists.
"The former Ottoman capital has experienced many earthquakes in its history. In 1509, the city was devastated by an earthquake so powerful that the Ottomans named it the "Little apocalypse", reminded AFP in 2019 Sükrü Ersoy, earthquake specialist and teacher at Yildiz Technical University in Istanbul.
The fear of aftershocks
If earthquakes are thus expected, the earthquake which hit the country on Monday is however striking in its magnitude: it is the largest since that of August 17, 1999, which caused the death of 17,000 people, including a thousand in Istanbul.
"The earthquake has a magnitude of at least 7.8. This is very important for this fault", continues Martin Vallée.
"At least 100 km of fault are affected, probably more. The area of damage will therefore be very large and we do not yet have a complete vision of it."
"We must also expect aftershocks in the hours and days to come," he warns.
In the morning, fifty aftershocks had been recorded in Turkey, according to AFAD, including three of magnitude greater than 6 and eight of magnitude 5 and more.
The tremors were also felt in Lebanon and Cyprus, according to AFP, and as far as Greenland, according to the Danish geological institute.
A second earthquake, of magnitude 7.5, also struck southeastern Turkey on Monday, a few hours after the first, reported the American seismological institute USGS.
An unsurprising phenomenon: during an earthquake, the rupture of the fault propagates in the earth's crust.
If it releases tension in one place, it can create tension in others and lead to a chain reaction.
A region "marked by war"
"We cannot yet know the extent of the area of damage, in particular because we do not know precisely the number of towns affected", concludes Martin Vallée.
"But faced with this magnitude, the human and material damage will be massive."
On Monday morning, images of the affected areas quickly spread on social media from both sides of the border, showing many destroyed buildings and rescuers searching for survivors.
After the 1999 earthquake, which caused an electric shock, the Turkish authorities multiplied risk prevention measures: they created the AFAD, set up hospitals capable of withstanding violent tremors and provided for mechanisms providing for the shutdown automatic gas networks.
Despite this, the area affected on Monday remains very vulnerable to earthquakes.
"It is already greatly weakened by war and unrest," recalls Bilal Tarabey.
"Millions of people, including displaced Syrians, live there in precarious and fragile buildings, which could collapse at any time."
In Gaziantep, the governor of the province has called on residents to stay outside despite the cold, fearing the collapse of a chain of buildings.
The balance sheet, very provisional, should continue to increase, a very large number of people remaining trapped under the rubble.
The snow, which is falling in abundance and the drop in temperatures, expected in the evening and tomorrow, will also make the situation of people finding themselves homeless, as well as the work of the relief workers, even more difficult.
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