"The Gujarat quake distracts attention from the region where the greatest loss of life should be expected, a region which stretches from Kashmir in the West to Bhutan in the east. The danger zone compasses the capitals of Bangladesh, Bhutan, India, Nepal and Pakistan and several other cities with populations in excess of a million," according to a report appearing in Newsweek magazine.

Claiming that several dams, including the massive Tehri hydroelectric dam in Uttar Pradesh, have not been built to withstand earthquakes, it said "if the Tehri dam broke, it could kill 10 million people. In all 50 million people are at risk."

"If one of the large earthquakes occurred in Delhi with a population of 13 million, the fatality count may be unprecedented. It could be 10 per cent of the population," geologist Roger Bilham of University of Colorado said.

The report says the Himalayan arc is the site of the greatest continental collision on earth, where the Indian tectonic plate is ramming northward against Eurasia. Its progress is slow, about two cm per year but energy has been building up over the centuries.

"Eventually, the rock must fracture, allowing the Indian plate to lurch northward beneath the Himalayas," it says.

Stating that the rupture, or massive earthquake, is overdue, Bilham says the faultline running along the whole length of the Himalayas is set to crack.

"But it won't go all at once. Based on a re-examination of the region's seismic history for the past 300 years and on new GPS (Global Positioning System) satellite data, it is estimated that it would take at least seven massive earthquakes, each affecting a 200 km to 300 km strip of the faultline, to permit the entire plate boundary to slip."

"Not only would these quakes be more powerful than the Bhuj disaster, they would occur in more densely populated areas," he says.

The report says the programme for earthquake-resistant housing has lagged behind in Gujarat. "National building codes for the region were put in place a decade ago, but the government still has not made them mandatory even after Bhuj. Those few buildings in Bhuj that were designed and built in line with the new codes survived unscathed, even though the epicentre was just 60 km away.

But architects and builders tend to ignore the codes," Bilham says. "The codes have been in existence for many years. But private companies, as opposed to government organisations, do not follow them," says Vallaichamy Thiruvengadam, head of building engineering at School of Planning and Architecture.