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TEHRAN, Dec 30: Poor design, primitive materials and widely ignored building codes were prime causes of the high death rate and vast human suffering in the Bam earthquake, Iranian officials and foreign experts said on Tuesday.
In stark contrast to a tremor of very similar strength last week in California that killed just two people, the toll in Friday’s Iranian quake is expected to reach about 50,000.
Iran’s building codes have been tightened after quakes in recent decades killed tens of thousands. But officials and independent scientists say enforcement is still inadequate.
Bahram Akasheh, geophysics professor at Tehran University, noted the California quake, on Dec 22, and that at Bam had almost the same magnitude and depth; the Iranian tremor measured 6.3 on the Richter scale, centred 16kms below ground.
“The question is why were only two killed in California but so many in Iran?” he said. “The answer is simple. The type of construction is totally different. There are building codes here but not followed. The laws are there, but only in theory. No one pays any attention. No authorities control construction.”
While the state apparatus keeps a close eye on many aspects of daily life, there is little policing of construction.
“I don’t think there are any shortcomings with our policies and construction codes,” said Mohsen Rezaei, secretary of Iran’s powerful Expediency Council.
“It is the construction managers who do not implement the codes. There is not enough supervision of construction and engineering. Individuals do not follow the rules.”
“Some builders disregard the codes to make bigger profits,” said Ali Bakhshi, a professor of civil engineering in Tehran.
MUD-BRICK BLAMED: Fingers are also being pointed at the mud bricks common in towns like Bam. They are cheap and also popular because they keep houses cool in summer and warm in winter. But they crumble easily, suffocating any who survive the quake’s initial impact.
“In Iran...the houses are essentially made of dust,” said Enzo Boschi, president of the National Institute of Geophysics in quake-prone Italy. “When buildings made of concrete collapse there are pockets of air where you can breathe and survive two, three, maybe even five days. But with mud houses, and the dust they produce when collapsing, you die much quicker.”
Experts, however, said that was only part of the problem and warn even that even Tehran, where modern steel-framed concrete buildings are common, is vulnerable to devastation from even moderate quakes around six on the Richter scale. A reading of at least seven is often seen as a threshold for major loss of life.
With suitable construction methods, cities can survive even much greater earthquakes, depending on where they strike. A tremor measuring a hefty 8.0 — releasing some many times more energy on the logarithmic Richter scale as Friday’s Bam tremor — caused just 500 injuries and no deaths in Japan in September.
“Earthquakes per se are not dangerous, it’s how buildings are constructed and the quake’s timing that cause deaths,” said Italy’s Boschi. “The Bam quake happened in the morning when people were all still in bed, unconscious and defenceless.”
Lars Ottemoller, a seismologist at the British Geological Survey in Edinburgh, noted: “This earthquake occurred very close to the city where there were many, many people living.”
Stavros Joannides, a Cypriot structural engineer who worked in Iran in the 1970s, said mud bricks were not flexible enough.
“Once that elasticity is lost and there is no steel, no reinforced concrete, the building will give,” he said. “Without warning. Mud brick doesn’t start dropping bits of plaster or brick like a concrete house will. It comes down at once.”—Reuters
