It is not so much the city’s modern core, where two sleek Trump Towers and a huge airport terminal were built to withstand a major earthquake that is considered all but inevitable in the next few decades. Nor does Dr. Erdik agonize over Istanbul’s ancient monuments, whose yards-thick walls have largely withstood more than a dozen potent seismic blows over the past two millenniums.
His biggest worry is that tens of thousands of buildings throughout the city, erected in a haphazard, uninspected rush as the population soared past 10 million from the 1 million it was just 50 years ago, are what some seismologists call “rubble in waiting.”
Construction at the Atakoy Lisesi school. Istanbul has a program to secure its schools against earthquakes.
Istanbul is one of a host of quake-threatened cities in the developing world where populations have swelled far faster than the capacity to house them safely, setting them up for disaster of a scope that could, in some cases, surpass the devastation in Haiti from last month’s earthquake.
Roger Bilham, a seismologist at the University of Colorado who has spent decades studying major earthquakes around the world, including the recent quake in Haiti, said that the planet’s growing, urbanizing population, projected to swell by two billion more people by midcentury and to require one billion dwellings, faced “an unrecognized weapon of mass destruction: houses.”
Without vastly expanded efforts to change construction practices and educate people, from mayors to masons, on simple ways to bolster structures, he said, Haiti’s tragedy is almost certain to be surpassed sometime this century when a major quake hits Karachi, Pakistan; Katmandu, Nepal; Lima, Peru; or one of a long list of big poor cities facing inevitable majorearthquakes.
In Tehran, Iran’s capital, Dr. Bilham has calculated that one million people could die in a predicted quake similar in intensity to the one in Haiti, which the Haitian government estimates killed 230,000. (Some Iranian geologists have pressed their government for decades to move the capital because of the nest of surrounding geologic faults.)
As for Istanbul, a study led by Dr. Erdik mapped out a situation in which a quake could kill 30,000 to 40,000 people and seriously injure 120,000 at the very minimum.
The city is rife with buildings with glaring flaws, like ground floors with walls or columns removed to make way for store displays, or a succession of illegal new floors added in each election period on the presumption that local officials will look the other way. On many blocks, upper floors jut precariously over the sidewalk, taking advantage of an old permitting process that governed only a building’s footprint.
Worse, Dr. Erdik said, as with a doctor’s patients, not all of the potentially deadly problems are visible from the outside, and thousands more buildings are presumed to be at risk. “Little details are very important,” he said. “To say that a building is in bad condition is easy. To say that one is safe is hard.”
Some of Turkey’s biggest builders have readily admitted to using shoddy materials and bad practices in the urban construction boom. In an interview last year with the Turkish publication Referans, Ali Agaoglu, a Turkish developer ranked 468th last year on the Forbes list of billionaires, described how in the 1970s, salty sea sand and scrap iron were routinely used in buildings made of reinforced concrete.
“At that time, this was the best material,” he said, according to a translation of the interview. “Not just us, but all companies were doing the same thing. If an earthquake occurs in Istanbul, not even the army will be able to get in.”
Echoing other engineers and planners trying to reduce Istanbul’s vulnerability, Dr. Erdik said that the best hope, considering the scale of the problem, might well be that economic advancement would happen fast enough that property owners could replace the worst housing stock before the ground heaved.
“If the quake gives us some time, we can reduce the losses just through turnover,” Dr. Erdik said. “If it happens tomorrow, there’ll be a huge number of deaths.”
But when a potent quake hit 50 miles away in 1999, killing more than 18,000 people, including 1,000 on the outskirts of Istanbul, the city was reminded that time might not be on its side. That earthquake occurred on the North Anatolian fault, which runs beneath the Marmara Sea, just a few miles from the city’s crowded southern flanks.
The fault, which is very similar to the San Andreas fault in California, appears to have a pattern of successive failures, meaning the section near Istanbul is probably primed to fail, said Tom Parsons, who has studied the fault for the United States Geological Survey.
Istanbul stands out among threatened cities in developing countries because it is trying to get ahead of the risk.
