David O’Byrne, Istanbul -

The catastrophic flooding that killed 32 people in Istanbul in early September left few of the city's residents in any doubt that the city is ill prepared to cope with a major natural disaster. Uncontrolled building on unsuitable land, inadequate infrastructure, the complete absence of any disaster-warning provision and warnings of possible problems ignored for decades combined to turn what should have been a difficult situation into a calamity. But if this is what happens after only a couple of hours of heavy rain, what would happen in the event of a real disaster - an earthquake say?

By worrying coincidence, the previous month saw the 10th anniversary of the 1999 earthquake, which at 7.4 on the Richter scale devastated much of northwest Turkey, leaving 20,000 dead and close to half a million homeless. The anniversary was marked by a slate of media reports focusing on just how little has been done to prepare the city for the next big quake, which seismologists are united in warning will hit the next section of the fault line close to Europe's biggest city Istanbul.

A recent report by Istanbul municipality's Disaster Coordination Center (AKOM) predicts that an earthquake of between 7.5 and 7.7 would damage 750,000 of Istanbul's 1m odd buildings, killing between 70,000-90,000 people and leaving over half a million homeless.

While new building regulations introduced in 2000 mean that new buildings are thoroughly checked to ensure they can withstand quakes, official figures indicate less than 1% of the city's older buildings have been checked, and fewer still reinforced. And while some effort has been made with some state buildings, the private sector has largely been left to itself with no public information campaigns and no official efforts to encourage private owners to take responsibility for ensuring the safety of their own building.

Worse still, a pilot project launched in one district thought to be particularly at risk, backfired. Municipal surveyors identified 2,700 buildings as unsafe and issued warnings to owners to strengthen the structures to current building standards or face compulsory demolition. Few complied, most instead went to court, producing private surveyors who contradicted the official reports creating a legal deadlock that still hasn't been resolved, and has delayed extension of the pilot scheme.

Picking those most at risk

According to Semih Tezcan, professor of civil engineering at Istanbul's Bosphorus University, the problem is in the approach adopted. "There's over 1m buildings in the city, bringing them all up to current building standards would cost more than $25bn, and will take over 30 years," he says.

Instead, he points out that most of the deaths in the 1999 quake occurred in buildings that collapsed completely, and suggests that official efforts should concentrate on identifying those buildings at risk of total collapse. "We looked at the buildings which collapsed in Izmit in the 1999 quake and found that only 6% collapsed completely," he says.

Pointing out that many buildings in Izmit were constructed on soft coastal ground without proper foundations, he predicts that Istanbul, where most buildings stand on solid rock, would be less affected. "We estimate that around 4% are in danger of collapse - so around 40,000 buildings," he says, adding that these are the buildings that need to be identified and strengthened.

With this in mind, Tezcan recently launched his own surveying programme that uses 125 separate criteria to establish the level of risk faced by individual buildings, which he reckons could be implemented on a citywide basis for around $500 per building - considerably less than the $10,000 per building charged by engineering consultancies for a full building survey. To date, though, uptake has been slow with only 160 buildings surveyed, of which only a quarter were found to be sure to survive a quake.

With seismologists at Turkey's main Kandilli earthquake research centre suggest a 60% chance of the city being hit by a major quake within the next 30 years, you could be forgiven for thinking that the authorities might have been quick to appreciate Professor Tezcan's new system. Worryingly that isn't the case. "So far we've had no official response to our new system, at all," he shrugs.

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