The violent earthquake that struck southern Turkey and neighboring Syria early Monday was devastating due to a combination of its timing and location, a relatively quiet fault line for two centuries and poorly constructed buildings.

According to the final outcome, at least 3,500 people were killed, following a violent earthquake of 7.8 degrees, followed hours later by another earthquake of 7.5 degrees.

This high toll is due primarily to the unprecedented intensity of the earthquake in Turkey since the 1939 earthquake, which struck a densely populated area.

The quake struck at 01:17 GMT and the sleepers found themselves "trapped when their houses collapsed," said Roger Mawson, a researcher with the British Geological Survey.

And the structure of the dwellings "doesn't really correspond to an area at risk of violent earthquakes," explains the researcher, who wrote a book about earthquakes.

This can be explained by the fact that the seismic fault, where these dwellings are, was relatively calm in the past.

Turkey lies on a major seismic fault line in the world. An earthquake in Izmit, about 100 kilometers southeast of Istanbul, killed 17,000 people in 1999.

Monday's earthquake occurred on the other side of the country as well, near the Syrian border, along the eastern fault line of Anatolia.

This line has not witnessed an earthquake of more than 7 magnitude in more than two centuries, which prompted the population to "underestimate its danger," according to Mawson.

This duration also indicates that "a relatively large amount of energy has accumulated" along the fault.

What confirms this, according to the researcher, is the occurrence of a violent aftershock after the main earthquake.

A repeat of what happened in 1822

Monday's quake is "almost a repeat" of the earthquake that struck the area on August 13, 1822, with a magnitude of 7.4.

Mawson explained that at that time he caused "tremendous destruction, destroyed entire cities, and killed tens of thousands."

Monday's earthquake struck at a depth of about 17.9 kilometers near the city of Gaziantep, which has a population of more than two million.

It occurred as a result of the movement of the Arab tectonic plate, which is "advancing towards Turkey" towards the north, according to what the seismologist explained.

He added that when the movement activates, the painting suddenly advances and "this movement results in a big earthquake, like the earthquake we witnessed today."

The extent of the damage also relates to the length of the ground fault along the seismic fault line (100 kilometers for Monday's earthquake), according to the scientist, noting that "this means that any point close to this 100 kilometers is actually in the epicenter of the earthquake."

Unreliable build

Carmen Solana, a volcanologist at Britain's University of Portsmouth, says building construction is a major factor when an earthquake occurs.

She explained, "Infrastructure resistance, unfortunately, is uneven in southern Turkey, especially in Syria. Therefore, saving lives now depends on the speed of relief."

The 1999 earthquake in Turkey led to legislation in 2004 requiring all new buildings to comply with earthquake-resistant standards.

It is expected that the scale of the destruction recorded on Monday will prompt the Turkish authorities to verify the extent of respect for the law, according to Joanna For Walker, from the Institute for Risk and Disaster Reduction at University College London.

Volcanologist Bill McGuire, also from the British University, noted that many buildings "collapsed in layers", explaining that "this happens when the walls and floors are not sufficiently connected, and each floor collapses perpendicular to the basement", which leaves The population has little chance of survival.

"It is not uncommon for a building to be erected without major damage, as well as a completely collapsed building, due to unreliable construction or poor building materials," he added.