And the death and misery for the earthquake-struck region is likely to continue for months, as heavy after-shocks cause buildings to collapse and hamper rescue work. Earthquakes have claimed hundreds of thousands of lives in the past 100 years but the improvements in the technology of predicting them has barely affected the devastation caused by tremors.
The experts have been predicting this tragedy for years. Only last year, when an earthquake killed 144 in the southern city of Adana, they issued their dire warnings. Istanbul, just 50 miles from the Anatolian fault line, has been struck by a severe earthquake almost every century since records began, and yesterday's came grimly on schedule. The fault has been ominously quiet for years: like storms, big earthquakes come after the calm.
The last time a major tremor hit Istanbul, it was a comparatively small city. Now it is a desperately overcrowded met-ropolis of some 14 million people, and nothing had been done to prepare the teeming city for disaster. There was no contingency plan. Instead, the city had been allowed to fill with shoddily constructed buildings to accommodate the never-ending stream of rural Turks coming to seek out a new life among the bright lights of the big city. Nothing was done to discourage the reckless building spree. When the earthquake struck, the inadequate buildings fell like houses of cards.
The damage from yesterday's shock was particularly severe because of the unusually shallow depth of the earthquake's focus, little more than six miles below the Earth's surface. This meant the shock waves were far stronger at the surface than for a deeper earthquake.
Geologists have been predicting a major earthquake in the region since the 1950s yet most of the buildings in the Izmit area to the south-west of Istanbul are poorly built with virtually no earthquake protection. Dr Russ Evans, a geophysicist at the British Geological Survey (BGS) in Edinburgh, said most of the victims would have died in their beds as the first early-morning tremors caused the heavy roofs of their badly built homes to cave in.
Dr Evans, who spent much of the 1970s and 1980s studying the geology of the Izmit fault lines, said the region has virtually no steel-framed buildings, which can withstand all but the strongest earthquakes. Most new buildings in the region are made of badly reinforced concrete, which crumbles during tremors. "Izmit is exactly the spot we thought an earthquake could nucleate from," Dr Evans said. "This is what we were fearing and was our worst guess of the kind of thing that could happen. The Turkish authorities had a building code but in practice there are not many buildings built to that standard. Often the materials are simply not available and the building regulations are not well policed."
The worst earthquake to hit this part of western Turkey in living memory measured 6.7 on the Richter scale but its devastating impact was the result of it occurring at the relatively shallow depth of 10km (6.2 miles), the BGS said.
Next to fire and flooding by tidal waves, the single biggest cause of death in earthquakes is collapsed buildings, and rescuers were digging with everything from bare hands to picks and shovels yesterday.
Turkey lies at the centre of an earthquake-prone region, resulting from the jostling of the tectonic plates of Africa, which are pushing northwards into Europe, and the Arabian plate squeezing eastern Turkey.
The North Anatolian fault line runs through the Izmit region, which is a "strike and slip" fault caused as two slabs of the Earth's crust slide past each other. Dr Evans says the fault is complicated by a second type of fault, caused when the two surfaces move apart.Reuse content