ISTANBUL - For kilometres around the small Turkish city of Erzin, the earth is shattered and buildings are razed, towns and cities turned into tombs of concrete by the Feb 6 earthquake of magnitude 7.8.

But Erzin still stands, an oasis of stability near the Mediterranean.

The question of why the city weathered the quake and a powerful aftershock, when so many others did not, is consuming the population.

In Erzin, the mayor said, no one died and not a single building fell.

The mayor almost immediately seized the moment to boast that he had long prevented slipshod construction, now the focus of authorities around Turkey.

But engineers and scientists credited other factors combining to save the city, like better construction that followed the latest seismic codes, and Erzin’s lucky location on very solid ground.

“Soil condition is the main reason why we don’t have heavy damage,” said Omer Emre, a geomorphologist who has spent 40 years studying the region’s fault lines and now works with a private research group, Fugro.

Erzin lies less than 80km from the earthquake’s epicentre, closer than cities to the south like Iskenderun and Antakya.

But Antakya was devastated, much of it reduced to rubble, and Iskenderun was badly hit, with a major fire at the port, seawater flooding the streets, and apartments and shops destroyed.

Many cities and villages of the region were built atop the layers of sand, silt and clay of an ancient riverbed.

That soil, like the soft coastal ground beneath Iskenderun, was more susceptible to shaking, Mr Emre said.

“These soft, water-laden sediments make cities and villages uniquely vulnerable to earthquakes,” he said. When one strikes, he added, “this land, it moves like a wave”.

In contrast, Erzin stands higher above sea level, and is built on hard ground comprising “bedrock and coarser grains than sand”, said Tamer Duman, a geographer.

The hard soil acts as a shock absorber between structures and a quake’s waves, reducing buildings’ sway, he said.

In one of the world’s most seismically active regions, Turkey has long had seismic codes for builders, upgraded over the past few decades.

Authorities have now turned their attention to finding contractors who could be held responsible for collapses, and have already detained dozens.

Builders have been accused of using cheap materials and skirting building codes to expedite projects and fatten profits – erecting structures that could not survive quakes.

Taking up that theme, Erzin Mayor Okkes Elmasoglu has framed himself as an unsung hero who stopped bad builders.

“With serious determination, the mayor hasn’t allowed for illegal construction in the past four years,” said an adviser to the mayor, Eray Guner, asserting that his office had reported nefarious contractors to prosecutors and ordered demolitions of shoddy projects.

Several engineers downplayed the mayor’s claims.

But they acknowledged the city had good engineers, and that lax law enforcement had played a role in the devastation outside Erzin.

“This is our problem in Turkey: Anyone in this country with land can decide to build – a butcher, a farmer, a chef,” said a civil engineer from Iskenderun, who declined to give his name for fear of retribution for criticising the government’s oversight.

He said that many developers were inexperienced and uneducated about regulations, like the seismic code for strong foundations.

“I’ve picked up concrete that fell through my fingers like sand,” said the engineer, who had travelled to Iskenderun to survey for evidence of malpractice.

He described beams that were too thin, made of cheap steel and connected by flimsy fixtures. “An earthquake was not the real killer here,” he said. “This was about the quality of our construction.”

Others echoed recent criticism of President Recep Tayyip Erdogan’s government over legislation, enacted a few years ago, that allowed property owners to pay a fee to have construction violations forgiven without bringing their buildings up to code.

“We told the government to impose engineering inspections before granting amnesty,” said Orhan Sarialtun, a board member of the Union of Chambers of Turkish Engineers and Architects, a group often at odds with Mr Erdogan’s party.

Mr Sarialtun also said that builders who wanted to bypass regulations would set up private inspection firms on behalf of relatives. “They began to inspect themselves,” he said.

Now, he said, inspection companies and city governments should be investigated alongside builders. “Coming down only on contractors is shoving the responsibility off the government’s shoulders,” he said.

He attributed Erzin’s good condition to the fact that it had largely developed over the past two decades, with better construction following the latest seismic codes. “The buildings were constructed abiding by the regulations,” he said. “Otherwise, it would have collapsed as well.”

Many residents applauded local engineers. During the earthquake, Hasan Aksoy said, he was jolted awake by the swaying of his sixth-floor apartment – in one of the district’s tallest buildings.

“The building was dancing,” said Aksoy, 39. He waited several minutes for the movement to slow, then spirited his wife and two children outside. The next day, he called the building’s engineer, a friend, to thank him.

“This quake is a testament to his good work,” he said.

Others were bluntly critical of city leaders. “This had nothing to do with our mayor,” said Seref Vural, a local official.

“Our mayor’s brags have only ensured that aid will not reach our people who are still sleeping in the streets,” he said, referring to thousands of residents who do not feel safe returning home yet.

The mayor’s office declined to comment on criticisms from residents.

But nearly 10 days after the earthquake, even as life regained a degree of normalcy, many still felt an intense fear about unstable buildings.

“We thought it was doomsday,” said Ayse Al, a 46-year-old landlord who, with about 30 tenants, was staying in one of the many relief tents dotting street corners and parks.

She said she and the others were still too afraid to return to home, though she added, “Of course we feel we are lucky – we have no casualties.” NYTIMES