Many of those killed by the earthquake in Bam died only because of poor building methods and a lack of proper regulation, an expert on the devastated city said yesterday, write Tania Branigan and Brian Whitaker
In Iran, as in many developing countries, tremors that ought to be survivable often bring human tragedy on a vast scale because buildings collapse on top of people.
Two days before Christmas, California was struck by an earthquake similar in magnitude to the one that hit Iran yesterday, but only three people died, thanks largely to safer construction methods.
Bam, in contrast, was a disaster waiting to happen. Efforts to bring industrial development to what was a backward agricultural area caused a population boom and a shortage of housing which local builders tried to meet with cheap, jerry-built homes, or by adding extra floors to existing houses. "Many buildings collapse \ without earthquakes, because of the poor construction," said Prof Mohsen Aboutorabi of the architecture department at the University of Central England, Birmingham, who has worked in Bam.
"There are building regulations, but they haven't been enforced except for high-rises.
"People are desperately in need of housing so the authorities overlook the code of building for earthquakes." Much of the building work is done by property owners themselves, using untrained local labour. There has also been little research into low-cost techniques to protect buildings in the area against earthquakes, he added.
Building materials are often inadequate for normal purposes, let alone for use in an earthquake zone. Typical houses are constructed of burnt brick, with mud and lime for the bonding.
"On my last trip to Iran I banged two bricks together and they became like powder. Demand for materials is so high that manufacturers don't stick to any standards," Prof Aboutorabi said. "The cost of cement is very high, so they don't use much." Ideally, houses in earthquake-prone regions should have lightweight pitched roofs, closely bonded together, he said.
But builders in Bam had largely abandoned the use of corrugated metal - which would be suitable - because of short supplies and a belief that it does not last long.
Instead, they used industrial materials without understanding their properties, he said.
This results in lethally heavy roofs and ceilings. Many roofs are supported by metal beams between traditional brick arches.
On top of that they put a layer of concrete and waterproofing.
"The ends of the beams sit freely on the walls, so with any shake, if one goes, the whole roof collapses," Prof Aboutorabi said.
Although Bam had few tall buildings, in recent years the high cost of land had encouraged families to abandon the traditional style of single-storey homes, with rooms set around a courtyard, in favour of two or three floors, adding to the danger in the event of an earthquake. - (Guardian Service)