Turkey is one of the most seismically active countries in the world, It frequently experiences damaging earthquakes that cause extensive loss of life and property But why exactly does Turkey have so many earthquakes? There are several geological factors that contribute to Turkey’s high earthquake risk
Turkey’s Location on Active Fault Lines
The main reason for Turkey’s earthquake-prone nature is its location. Turkey sits on top of several active fault lines between three major tectonic plates – the Eurasian Plate, the Anatolian Plate, and the Arabian Plate. The boundaries between these plates are seismically active fault zones that frequently generate earthquakes.
The Anatolian Plate which makes up most of Turkey is being slowly squeezed from the north and south between the giant Eurasian and Arabian plates. This tectonic pressure builds up stress over time that is eventually released suddenly in the form of earthquakes when the plates slip past each other along fault lines.
The two main fault zones in Turkey are
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The North Anatolian Fault running along northern Turkey roughly from east to west. This transform boundary between the Anatolian and Eurasian plates moves about 2 cm per year.
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The East Anatolian Fault running along southeastern Turkey marking the boundary between the Anatolian and Arabian plates. It moves more slowly, between 5 mm to 1 cm per year.
A History of Devastating Earthquakes
Turkey’s vulnerable location at the intersection of major continental plates has resulted in a long history of catastrophic earthquakes over the centuries.
Some of the more destructive earthquakes that have hit Turkey in the last 100 years include:
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In 1939, an earthquake of magnitude 7.8 in eastern Turkey killed over 30,000 people.
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In 1999, a massive 7.4 magnitude quake struck near Istanbul killing over 17,000 people.
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The latest 7.8 earthquake in February 2023 in southeastern Turkey is the worst to strike the region since 1939, with over 40,000 fatalities.
Geologists say that we can expect similar intense seismic events to continue happening in Turkey in the future as the tectonic plates keep grinding against each other.
Unique Geology Amplifies Shaking
Turkey’s geology and ground conditions also play a role in why earthquake effects can be more severe.
The Turkish peninsula sits on thick sedimentary basins filled with soft sediments and loose soils. During an earthquake, these soft ground layers can amplify seismic shaking, increasing building damage.
Liquefaction of sandy soils from earthquake vibrations can cause additional structural failures. Many urban areas sit atop former river valleys and lakebeds prone to liquefaction.
High Population Exposure
Turkey has a large population concentrated in vulnerable urban areas near active fault zones. The 7.8 earthquake in February 2023 caused extensive damage in densely populated southeastern cities like Gaziantep, Şanliurfa, Diyarbakir, Adana, and Osmaniye.
With more people and buildings sitting on top of hazardous faults, the scale of devastation from any given earthquake is higher. Rapid urbanization in Turkey has put more people and property directly at risk.
Old Building Stock
A significant portion of Turkey’s building stock comprises older structures that lack modern seismic engineering and construction practices. Adherence to updated building codes is also poor in many areas.
When strong earthquakes hit, many vulnerable structures have collapsed, amplifying the death toll. Upgrading and retrofitting old buildings to withstand earthquake forces remains a challenge.
Cascading Earthquakes
The complex network of faults crisscrossing Turkey can lead to cascading sequences of earthquakes over time. Major earthquakes on one fault segment can load up pressure on adjoining faults, triggering further tremors.
For example, in the 20th century a series of 7+ magnitude quakes progressively moved westwards along the North Anatolian Fault over decades. Scientists worry the recent big quake could now load other nearby fault sections.
Turkey’s hazardous location at the junction of the Eurasian, Anatolian and Arabian plates ensures that destructive earthquakes will continue being a regular occurrence. The unique geology, high population exposure, vulnerable building stock, and possibility of cascading quakes further compounds Turkey’s earthquake vulnerability. Implementing strict building codes, retrofitting older structures, and improving emergency response will be vital to reduce future earthquake losses. While the fault lines cannot be changed, understanding and adapting to Turkey’s seismic reality is critical.
Earthquakes are common in Turkey and Syria
The Arabian Peninsula is part of a tectonic plate that is making its way north into the Eurasian Plate, and the entire nation of Turkey is getting squeezed aside.
“Arabia has slowly been moving north and has been colliding with Turkey, and Turkey is moving out of the way to the west,” says Michael Steckler of Columbia Universitys Lamont-Doherty Earth Observatory.
That tectonic shift has been behind earthquakes for millennia in the area, including one that flattened the Syrian city of Aleppo in 1138. More recent quakes, such as the 1999 one that struck the city of İzmit, have killed many thousands.
Mondays quake is believed to be the most powerful that Turkey has seen in more than 80 years.
This particular region was overdue for a big one
Most of the largest earthquakes in the past hundred years have been along the North Anatolian Fault.
But stress has been building along another major fault: the East Anatolian Fault. That fault has seen some big earthquakes in the past, says Patricia Martínez-Garzón, a seismologist at GFZ Potsdam, a research center in Germany. But more recently, there hasnt been as much activity.
“It was unusually quiet in the last century,” she says.
Some researchers had begun to suspect the fault was due for a major quake, according to Fatih Bulut, with the Kandilli Observatory and Earthquake Research Institute at Boğaziçi University in Istanbul. His research group and others had run computer models showing that this fault could have a magnitude 7.4 or greater earthquake.
“This is not a surprise for us,” Bulut tells NPR.
But that doesnt mean that seismologists could say exactly when a big one would hit, according to Ian Main, a seismologist at the University of Edinburgh in the United Kingdom. The time between big quakes on a fault can vary quite a bit in unpredictable ways, he says. “Theyre not like buses, they dont come along on a timetable.”
And not all the shaking has occurred on this one fault. The initial quake spilled over onto the Dead Sea Transform, another fault region where the Arabian, Anatolian and African plates converge. And a second, magnitude 7.5 quake took place hours later on a nearby fault that had been mapped but isnt part of the East Anatolian Fault.
“Its a pretty busy and complicated area with multiple fault systems,” Steckler says.
Turkey’s history of earthquakes…
FAQ
How often do earthquakes happen in Turkey?
Is Turkey on a fault line?
What country has the most earthquakes?
What caused the Turkey earthquake?
What happened in Turkey after a major earthquake?
A major earthquake struck southern Turkey early on Monday, causing extensive damage and killing thousands there and in neighboring Syria. Rescue workers have been searching the rubble of buildings for survivors, who face bitterly cold winter temperatures, as well as electricity and water outages—and the terror of continuing aftershocks.
Why is Turkey prone to earthquakes?
Turkey’s high propensity for earthquakes is due to its location at the crossroads of three different tectonic plates. These land masses, which make up the outermost shell of the Earth, are constantly moving and bumping into each other. Earthquakes most often occur at the plate’s fault lines, which are large fractures on the planet’s surface.
How strong are earthquakes in Syria & Turkey?
Earthquakes in Syria and Turkey are common, but the magnitude 7.8 that shook the region on 6 February at 4:17am local time is clearly impressive. To find earthquakes this strong on this particular fault, we would have to go back to the year 1114. Ten minutes after the strongest earthquake, an aftershock of magnitude 6.7 struck near the epicentre.
How powerful was a quake in Turkey?
The earthquake was powerful — especially for a quake that hit on land. Typically, very strong earthquakes occur underwater, Margarita Segou, a seismologist with the British Geological Survey, said. On top of that, the quake hit near heavily populated areas. The epicenter was near Gaziantep, a major city and provincial capital in Turkey.