Hong Kong considers making buildings quake-resistant

Proposal aired to make new buildings quake-resistant to tackle city's vulnerability

PUBLISHED : Sunday, 21 October, 2012, 12:00am
UPDATED : Sunday, 21 October, 2012, 3:45am

Shanghai has them. So does New York. And so, too, do France, Germany, Australia and South Korea. Hong Kong, where the risk of earthquakes is similar to all these places, doesn't.

But last week the government took the first step towards bringing in laws requiring new buildings to be built to withstand quakes.

And not before time, say academics and engineers, who point to recent significant seismic activity, which showed even areas at low risk from earthquakes can experience major tremors.

In April, two big earthquakes occurred beneath the Indian Ocean, far from the usual danger zones. The quakes triggered 11 aftershocks that measured 5.5 or greater in the six days that followed, including one as big as magnitude seven.

Remote shocks were felt 10,000 to 20,000 kilometres away, halfway round the globe.

"It was jaw-dropping," Dr Thorne Lay, a professor of earth and planetary sciences at the University of California Santa Cruz, said. "It was like nothing we'd ever seen."

Hong Kong has no laws requiring buildings to meet earthquake resistance standards in design and construction.

A public consultation, which began last week, proposes a tailor-made plan be formulated if statutory seismic-resistant building design standards are introduced. It should consider international standards and Hong Kong's geology, topography and construction practices.

The government has released the findings of a previous consultancy study on the safety of the city's structures in the event of a quake. Local structural engineering experts welcomed the move.

Greg Wong Chak-yan, former president of the Institution of Engineers, said he believed many buildings were in dire need of an upgrade.

"In the 1950s, buildings did not need a structural engineer to design and be responsible for the structure," Wong said. "Now we need to move with the times."

In Shenzhen and Macau, buildings had been designed and built to counteract the threat of a quake, he said.

"Requiring that buildings be specially designed here in case of earthquakes is a rational step. This region is of moderate seismicity and this [thinking] is in line with [building designs] in cities only kilometres from Hong Kong."

He did not think quake activities had worsened in this region, but warned that frequency was not the point.

"Earthquake risks are now higher because of the greater consequences, and the increased economic damages and injuries that just one would bring," he said.

Lau Chi-kin, chairman of the structural advisory panel for the Hong Kong Institution of Engineers, agreed with Wong's appraisal.

Lau noted that recent minor earthquakes in cities worldwide showed one could never fully eliminate the danger.

"A suitable seismic design provision would certainly enhance performance of our building structures for the coming years," he said.