Scientists call 2 major earthquakes in southern Türkiye ‘rare’

By Dildar Baykan Atalay

ANKARA (AA) – Scientists said that the two major earthquakes that, hours apart, jolted Türkiye’s south on Monday are seen as rare and came as a surprise to seismologists.

“There are many things that surprise the community about this earthquake sequence. And the fact that there were two very large earthquakes just a few hours apart, in fact, has on distinct faults that are nearby, but not the same. I believe that has never been seen before for an earthquake of this magnitude,” Sylvain Barbot, associate professor of earth sciences at the University of Southern California, told Anadolu.

He said that the fault that caused the second earthquake “was seismically inactive for all of historical times. So, based on current knowledge, we would not predict that. We would think that it would be an inactive fault that used to be active in the distant past and cannot create earthquakes, but we were wrong.”

Barbot said that there are large numbers of faults in the area and that the first earthquake was on the East Anatolian fault, “which is the kind of geographical boundary of Anatolia to the east.”

“And this fault connects two other major faults. The one to the north is the North Anatolian fault, which ruptured in 1999, with the Izmit and Duzce earthquakes,” and one line is going to south, said Barbot, adding: “Given the circumstance, we can certainly imagine that there will be other large earthquakes and nearby faults. So, these are two possibilities for earthquake triggering to the south and to the west of the ruptures.”

Barbot said that the quakes created a movement of a few meters due to the movement of tectonic plates.

“These faults do not actually move for quite some time. And eventually they release all of this displacement that was forced by the motion of tectonic plates into a single event within just a few seconds. And that's why for just a few seconds, you have displacements of several meters. This is the underlying driving force for earthquakes,” said Barbot.

“They release, they accommodate the motion of tectonic plates. So instead of having a very gradual motion, very steady, very small, for centuries, you have no motion at all, for quite some time and everything at once. It's very episodic. So that's what makes (these) earthquakes so devastating.”

- ‘There will be more quakes ahead than are typical for the area’

David Shelly, a seismologist with the United States Geological Survey (USGS), also told Anadolu that Türkiye is very prone to earthquakes, as it is located in an intersection of three major tectonic plates and has many active fault lines.

“So the earthquakes that happened yesterday were very large … earthquakes of that size are relatively rare,” said Shelly.

Although they can happen, like in the 1999 earthquakes in Türkiye that happened three months apart, that latest earthquakes were closer together in time, just hours apart.

“We know that earthquakes cluster together so the second earthquake can likely be considered an aftershock of the first earthquake,” said Shelly about the second quake of magnitude 7.6, about nine hours after the first, which was magnitude 7.7.

“Seismologically, we expect aftershocks to continue for some time. So there will be more earthquakes in the days and weeks and months to come than are typical for the area,” he added.

Over 18,340 people were killed and 74,240 injured in the twin quakes which hit southern parts of Türkiye, according to the latest official figures.

A total of 6,444 buildings collapsed due to the quakes, and Türkiye has declared a three-month state of emergency in provinces hit by the earthquakes.

The quakes, centered in the Kahramanmaras province, affected more than 13 million people across 10 provinces, also including Adana, Adiyaman, Diyarbakir, Gaziantep, Hatay, Kilis, Malatya, Osmaniye, and Sanliurfa.

Several countries in the region, including Syria and Lebanon, also felt the strong tremors that struck Türkiye.

More than 121,100 search and rescue personnel are currently working in the field, according to Türkiye’s Disaster and Emergency Management Presidency (AFAD).

A total of 75,780 people were evacuated from quake-hit regions, AFAD said.