Wednesday, March 29, 2023

The reasons why the earthquake in Turkey was so strong

(CNN Spanish) — Just after 4 a.m., when most people were asleep, a 7.8 magnitude earthquake struck Turkey.

The earthquake was so strong that it was also felt in other countries in the Middle East region, especially in northwestern Syria, which is near the epicenter (located 23 kilometers east of Noordagi, Gaziantep Province, Turkey).

The consequences of the earthquake – which is already believed to be the most powerful earthquake on Turkish soil in more than 80 years – have been devastating: as of 1 p.m. this Tuesday (Eastern Time), the death toll from the disaster in Turkey and Syria was Over 7,700 in both countries, the number of injured exceeded 35,000 and the number of collapsed buildings numbered in the thousands.

Why was the earthquake in Turkey so strong?

There are several factors that help us understand why this earthquake, which has caused at least 125 magnitude 4 or greater aftershocks, is so powerful and destructive.

This is the footprint of the deadly earthquake that shook the world 1:04

“complex area”

Doctor Carlos Miguel Valdés González, of the Seismology Department of the Institute of Geophysics of the National Autonomous University of Mexico (UNAM), explained that Turkey is in a complex region that is prone to earthquakes, because practically the country is surrounded by three plates. ,

“In the northern part, (Turkey) has the Eurasian Plate, in the southern part the African Plate and in the southeastern part the Arabian Plate,” Valdés commented in an interview with CNN en Español.

To make this more clear, let’s remember how earthquakes develop. According to the UNAM academic, the outermost part of the Earth where we live is known as the crust and which we can imagine as a circular puzzle. The pieces of this puzzle are the plates and they move in different directions from the internal heat of the planet. The point at which the plates contact each other is known as a fault.

On average, the plates move at a rate of 3 to 6 centimeters per year, which humans cannot detect, Valdés said. As they move, stress or energy accumulates at the points of contact (faults) of the plates. When the energy stored in faults is no longer resisted and the rocks break, an earthquake occurs, the magnitude of which will depend on the energy stored in the fault and the size of the crack.

So Turkey—which is between three plates—had a huge release of energy on a fault, which triggered the earthquake.

In particular, “the earthquake in the region of Turkey and Syria (…) is a phenomenon related to the East Anatolia Fault,” which passes through the epicenter Gaziantep in the southeast of the country, the academic explained.

Valdés said the earthquake had catastrophic consequences in part because the East Anatolian fault is located in highly populated areas, which can be seen in the thousands of people killed and injured so far. The disaster was exacerbated because the event was “shallow”, meaning it originated at a shallow surface depth (about 18 kilometres), allowing seismic waves to propagate more easily.

“The energy is known as surface waves, which are big waves, waves that also have a long period. It’s hard to talk about the duration of an earthquake, but I would estimate that some of it was for a magnitude of 7.8.” In places the earthquake (…) could have easily lasted more than a minute, hardly more than two minutes,” he said.

A similar release of energy may also occur in northern Turkey (for example, Istanbul, to the northwest), as the North Anatolian Fault runs through that region of the country, but when this will occur cannot be predicted.

In short, a nation that is vulnerable to earthquakes.

type of failure

The National Seismic Network (RSN) of Costa Rica states that there are mainly three types of faults that generate earthquakes: normal, lateral displacement and reverse.

In the case of the recent earthquake in Turkey, it’s a lateral displacement fault, Valdés pointed out. A famous fault of this type is the San Andreas fault, “which separates two large plates: the Pacific Plate and the North American Plate. These faults The city of San Francisco is on one side of the fault and Los Angeles on the other; while the first moves east, the second moves west, so the two cities are coming closer and closer together, and due to the accumulated energy in the San Andreas Fault, a large Earthquake may happen.

According to the expert, the Anatolian block (which includes the aforementioned faults to the east and north) also separates two large plates: the Arabian and the African.

The contact of the Anatolian Block caused the accumulation of energy in the East Fault and then the earthquake in Turkey.

Previously, Valdés noted, studies had already been done “on the potential risk of this fault, eastern Anatolia, and they had established that (the earthquake) could be between a magnitude of 6.5 to 7.7”, which is the most recent. Earthquake is close in magnitude.

It is possible to verify that the East Anatolian fault is a lateral displacement fault with an earthquake intensity map. It can be felt from very strong to severe in a large lateral or horizontal stripe where said fault passes.

external factors

The consequences of earthquakes have been even more devastating due to external factors.

The expert at UNAM’s Institute of Geophysics explained that the earthquake released energy close to that produced by 27,000 atomic bombs dropped on sites such as Hiroshima and Nagasaki, which is enough to cause significant destruction.

However, the damage caused by an earthquake is magnified by extreme weather conditions.

According to CNN meteorologists, a winter storm is exacerbating the disaster in the region where the earthquake occurred.

CNN meteorologist Karen Maginis said, “Millions of people are affected by this. It’s cold. It’s raining. Roads can be affected, which means your food, your livelihood, your children’s care, your family’s care.” “

According to Turkish officials, this climate makes relief, search and rescue operations difficult.

“The weather conditions and the scale of the disaster have made it difficult for our teams to reach the region,” Turkish Health Minister Fahrettin Koca said on Monday. for weather conditions”.

Along with the weather, there are other factors that contributed to the disaster, such as old buildings that do not have adequate construction against earthquakes.

The quake collapsed more than 5,600 buildings and damaged centuries-old archeological sites including Gaziantep Castle, a historic site and tourist attraction in southeastern Turkey.

The problem of old buildings is linked to the difficult situation in Syria. People affected by the earthquake were already vulnerable, as it is estimated that more than 4 million people in this country were dependent on humanitarian aid.

In addition, northwestern Syria, the region of the country most affected by the earthquake, has been in conflict over a civil war that began more than a decade ago, leading to talk of a “crisis within a crisis”. Currently, various parts of northwestern Syria, including Idlib, are still controlled by anti-government rebels.

How is humanitarian aid managed in Turkey and Syria? 3:33

With reporting by CNN’s Yong Xiong, Sahar Akbarzai, Atay Alam, Hira Humayun, Monica Garrett, Lilit Marcus, Youssef Gejer, Riya Mogul, Dalia Al Masri and Celine Alkhaldi.

Nation World News Desk
Nation World News Desk
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