Why Turkey’s earthquake is one of the deadliest this century

CNN
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More than 11,000 people are believed to have been killed and tens of thousands more injured by the devastating earthquake that shook Turkey and Syria on Monday.

Thousands of buildings have collapsed in both countries and aid agencies warn of ‘catastrophic’ repercussions in northwest Syria, where millions of vulnerable and displaced people were already relying on humanitarian aid .

Massive rescue efforts are underway with the global community offering assistance in search and recovery operations. Meanwhile, agencies have warned that the death toll from the disaster could rise dramatically.

Here’s what we know about the earthquake and why it was so deadly.

One of the strongest earthquakes to hit the region in a century jolted residents from their sleep in the early hours of Monday morning around 4am. The quake struck 23 kilometers (14.2 miles) east of Nurdagi in Turkey’s Gaziantep province at a depth of 24.1 kilometers (14.9 miles), the United States Geological Survey said ( USGS).

A series of aftershocks rippled through the area in the hours following the initial incident. A magnitude 6.7 aftershock followed 11 minutes after the first quake, but the largest quake, which measured 7.5 in magnitude, struck about nine hours later at 1:24 p.m., according to the USGS.

This magnitude 7.5 aftershock, which struck about 95 kilometers (59 miles) north of the initial quake, is the strongest of more than 100 aftershocks recorded so far.

Rescuers are now racing against time and the elements to pull survivors from the debris on both sides of the border. More than 5,700 buildings in Turkey have collapsed, according to the country’s disaster management agency.

Monday’s quake was also one of the strongest Turkey has seen in the past century – a 7.8 magnitude quake hit the east of the country in 1939, killing more than 30,000 people, according to the report. ‘USGS.

A number of factors contributed to making this earthquake so deadly. One of them is the time of day it happened. As the earthquake struck early in the morning, many people were in their beds when it struck and are now trapped under the rubble of their homes.

Additionally, with a cold and wet weather system sweeping through the region, poor conditions have made access to affected areas more difficult, and rescue and recovery efforts on both sides of the border much more difficult once the teams arrived.

Temperatures are already terribly low, but on Wednesday they were expected to drop several degrees below zero. An area of ​​low pressure is currently hovering over Turkey and Syria. As it moves away, it will bring “significantly cooler air” from central Turkey, according to CNN senior meteorologist Britley Ritz.

It was forecast to be -4 degrees Celsius (24.8 degrees Fahrenheit) in Gaziantep and -2 degrees in Aleppo on Wednesday morning. On Thursday, the forecast drops further to -6 degrees and -4 degrees respectively.

With scattered showers and snow in the area expected to continue, the elements are putting the lives of those trapped under the rubble – who have already gone days without food or water – at risk of hypothermia. Meanwhile, authorities have asked residents to leave the buildings for their own safety, fearing further aftershocks.

With so much damage in both countries, many are beginning to wonder about the role local building infrastructure might have played in the tragedy.

“The most striking thing is the type of collapse – what we call the pancake collapse – which is the type of collapse that we engineers don’t like to see,” Mustafa said. Erdik, professor of earthquake engineering at Istanbul Bogazici University. . “In such collapses, it is difficult – as you can see – and very tragic to save lives. This makes the operation of search and rescue teams very difficult.

Erdik told CNN that the images of widespread destruction and debris indicate “there are widely varying design and construction qualities.” He says the type of structural failures following an earthquake are usually partial collapses. “Total meltdowns are something you always try to avoid both in code and in actual design,” he added.

USGS structural engineer Kishor Jaiswal told CNN on Tuesday that Turkey has experienced significant earthquakes in the past, including a 1999 earthquake that struck southwestern Turkey. Turkey and killed more than 14,000 people. For this reason, he said, many regions in Turkey have regional building regulations to ensure construction projects can withstand these types of events.

But not all buildings were built to the modern Turkish seismic standard, Jaiswal said. Shortcomings in design and construction, particularly in older buildings, meant that many buildings could not withstand the severity of the shocks.

“If you don’t design these structures for the seismic intensity that they may face over their lifetime, these structures may not perform well,” Jaiswal said.

Erdik also said he believed many of the buildings that collapsed were likely “built before 1999 or…with older codes.” He said there have also been instances where some buildings were not up to code.

“Codes are very modern in Turkey, very similar to American codes, but again code compliance is an issue that we have tried to solve with legal and administrative procedures.” he explained. “We have the permits from the municipalities and controls for the design, controls for the construction. But again, there are things missing.

Despite mounting challenges, a structural engineer and humanitarian coordinator has urged rescuers not to give up hope as survivors could be found up to “weeks” after the massive earthquake hit the area. Kit Miyamoto, president of the nonprofit Miyamoto Global Disaster Relief, praised the Turkish community for coming together and “doing their part” after the earthquake.

“The community, the citizens, they’re actually the first line of defense,” he told CNN on Wednesday. “They dug up family, friends, neighbors.”

Earthquakes occur on every continent in the world – from the highest mountain peaks of the Himalayas to the lowest valleys, such as the Dead Sea, to the freezing regions of Antarctica. However, the distribution of these earthquakes is not random.

The USGS describes an earthquake as “the shaking of the ground caused by a sudden slip across a fault. Stresses in the earth’s outer layer push the sides of the fault together. Stress builds up and rocks suddenly slide , releasing energy in waves that travel through the earth’s crust and cause the tremors we feel during an earthquake.

Earthquakes are measured using seismographs, which monitor seismic waves passing through the Earth after an earthquake.

Many may recognize the term “Richter Scale” which scientists previously used for many years, but these days they generally follow the Modified Mercalli Intensity Scale (MMI), which is a more accurate measure of size. of an earthquake, according to the USGS.

The power of an earthquake is known as the magnitude. The intensity of the shaking may vary depending on the local geography and topography and the depth of the earthquake. On the magnitude scale, each increase of a whole number translates to 32 times more energy.

On this occasion, the tremors of the 7.8 magnitude earthquake in southern Turkey could be felt as far as Israel and Lebanon, hundreds of kilometers away.

Turkey is no stranger to strong earthquakes, as it is located along the boundaries of tectonic plates. Seven earthquakes of magnitude 7.0 or greater have struck the country in the past 25 years – but Monday’s was one of the strongest.

It is also the strongest earthquake to strike anywhere in the world since an 8.1 magnitude quake struck an area near the South Sandwich Islands in the southern Atlantic Ocean. in 2021, although the remote location of this incident caused little damage.

CNN meteorologist and extreme weather expert Chad Myers said, “We always talk about the epicenter, but in this case we should be talking about the epi-line.”

Two massive tectonic plates – the Arabian and the Eurasian – meet beneath Turkey’s southeastern provinces. Along this fault line, “about 100 miles from side to side, the earth slid,” Myers continued.

Seismologists call this event a “strike slip” — “where the plates touch each other and all of a sudden they slip sideways,” Myers said.

This is different from the Ring of Fire, which runs along the west coast of the United States. In this area, earthquakes and tsunamis are often caused by subduction – where one plate slides under another.

But in a “strike slip”, the plates move horizontally rather than vertically. “It’s important because buildings don’t want to come and go. And then the side waves start coming and going as well,” Myers added.

Due to the nature of this seismic event, aftershocks could last “weeks and months,” according to CNN meteorologist Karen Maginnis.

In comparison to other major earthquakes around the world, the 2011 earthquake and tsunami in Japan – in which more than 22,000 people were killed or missing – registered a magnitude of 9.1.

The incident left widespread destruction in its wake after walls of water engulfed entire towns, washed homes onto highways and caused the country’s worst nuclear disaster on record.

A year earlier, in 2010, a magnitude 7.0 earthquake in Haiti reportedly killed between 220,000 and 300,000 people. Another 300,000 people were injured and millions were displaced.

In 2004, an earthquake with an estimated magnitude of 9.1 hit the coast of Sumatra, Indonesia, causing a tsunami that left 227,898 dead or listed as missing and presumed dead.

The strongest earthquake on record was a magnitude 9.5 in Chile in 1960, according to the USGS.