Rescue workers and volunteers carry out search and rescue operations in the earthquake of a collapsed building in Diyarbakir, Turkey, following Monday’s magnitude 7.8 earthquake.
Ilyas Akengin/AFP via Getty Images
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Ilyas Akengin/AFP via Getty Images
Rescue workers and volunteers carry out search and rescue operations in the earthquake of a collapsed building in Diyarbakir, Turkey, following Monday’s magnitude 7.8 earthquake.
Ilyas Akengin/AFP via Getty Images
Scenes of thousands of buildings reduced to rubble in southern Turkey and northern Syria after Monday’s deadly 7.8 magnitude earthquake — and many aftershocks — it comes as no surprise to civil engineer Jonathan Stewart.
“We’ve seen this before,” says Stewart, an engineering professor at the University of California, Los Angeles who was part of an infrastructure assessment team sent to Turkey after a major earthquake struck the north of the country in 1999.
At that time, he says, “there was a great loss of life from pancaked buildings.”
Fast-forward to Monday, and video of destruction shows exactly this “pancaking” — the sudden collapse of a multi-story building as bystanders run for their lives.
The region is one of the most earthquake prone in the world, as it is located in an area where three tectonic plates meet. In addition to the 1999 earthquake that left more than 17,000 people dead, Turkey also experienced a major earthquake in 2011 that killed hundreds.
This time, the death toll already exceeds 3,400 in Turkey, with more than 1,500 dead in neighboring Syria, where the infrastructure was already crumbling after years of civil war.
In both countries, survivors may be under the rubble, but more bodies too — perhaps many more — are likely to be found in the coming days under the ruins of around 3,000 structures destroyed by the earthquake, according to an estimate preliminary from the Turks. officials.
Older buildings quickly fell apart when the shaking began
Why did so many buildings fall? Stewart says that for buildings in Turkey that are taller than about three stories, a usual construction technique is to use reinforced concrete.
“Typically, columns and beams are concrete,” he says. “And then there’s a kind of stone infill block inside these frames, which falls out very quickly when the shaking starts.”
Abbie Liel, an engineer and professor at the University of Colorado Boulder, says the assessment almost matches what she saw in the photos of the destruction in Turkey.
Rescuers search for victims and survivors in the rubble of a collapsed building in Aleppo, Syria, on Monday.
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Rescuers search for victims and survivors in the rubble of a collapsed building in Aleppo, Syria, on Monday.
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Instead of this kind of fragile construction, she says, engineering a building to withstand earthquakes means factoring in “capacity to deform.”
“It involves putting a lot of rebar in all the right places,” she says.
Kit Miyamoto, an expert in disaster resilience engineering who is preparing to go to Turkey as part of a team of engineers, says the building codes enacted after the 1999 earthquake near Izmit are good, but many structures are before those codes.
“Anything built before 2000 can be considered very dangerous,” he says. Also, even with the newest building codes, enforcement is “not very robust,” so even some of the latest construction isn’t necessarily up to standards.
“Quality control in the field is really important,” he says.
More steel equals more earthquake resistant structures
The amount of steel and types of concrete in a building can make the difference between structures still standing in an earthquake zone and those in ruins, says Alanna Simpson, senior specialist in disaster risk management at the World Bank based in Bucharest.
“Buildings made of steel actually respond quite well in earthquakes because they are a little flexible,” she says. “So the more steel reinforcement there is in a building, the better it’s likely to respond.”
She says building codes in Turkey were updated again in 2018. But the country’s “legacy buildings” are still vulnerable, and this is true for much of the rest of the world as well, she says. “It’s a global problem.”
It is also important to note that Monday’s earthquake was so large and shallow that “in almost every part of the world [where] a similar earthquake will happen, you will see substantial damage to old buildings,” says Simpson.
As for rebuilding a safer building, “it takes a lot longer than anyone would hope to rebuild after a major tragedy like this,” she says. “It’s expensive and requires a lot of coordination and public outreach.”
