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Thursday, March 10, 2011

Documentary warned of Christchurch earthquake danger

Documentary warned of Christchurch earthquake danger

Last updated 05:00 11/03/2011
The director of a 15-year-old documentary outlining the effects of a major earthquake on Christchurch's eastern suburbs and heritage buildings says lives could have been saved if officials had heeded the film's warnings.

An edited eight-minute clip of the 1996 documentary, Earthquake!, had received nearly 30,000 views on video website YouTube by last night. The documentary said Christchurch's "fatal flaw" was the land that it sat on – "a soft, shaky sponge of riverstones and silt half a kilometre deep".

"In any decent quake, the Garden City will shake like a leaf," it said.

The documentary said liquefaction would cause sewers and drains to come apart, roads to break up and buildings to sink or tip over.

Former Christchurch City Council sewers unit manager Alan Watson warned that Christchurch had a high risk of liquefaction, "especially in the eastern suburbs".

The documentary said "hundreds of old buildings" in the city had not been strengthened and were likely to collapse in an earthquake.

"Well, really, your heritage list, to be quite cruel, defines most of your earthquake-prone buildings," former council building control manager Brian Bluck said.

Documentary director Grant Dixon said the documentary was one of several that he made on the impact of a natural disaster in New Zealand.

The made-for-television film rated well but was greeted with "a deafening silence" from officials.

"I would have thought that the council and concerned citizens would take heed and make sure that something was actually done, but nobody took it for real," he said.

Dixon said the effect of the September 4 and February 22 quakes had not surprised him, but he regretted not making his point more forcibly.

"In hindsight, I should have gone and sat outside the mayor's office and demanded that something happened."

He had decided to upload an edited version of the film to YouTube after the latest quake to draw attention to the issue of soil resonance.

Soil resonance, as described in the documentary, occurs when a building and the soil beneath it vibrate at the same frequency, magnifying its "destroying effect".

Dixon said the collapses of the Canterbury Television and Pyne Gould Corporation buildings may have been due to soil resonance.

He said tests with seismic detectors could have identified buildings with problems at the time.

"Lives would have been saved if this simple procedure went ahead. People knew about it, but nobody did a thing."

He said the issue needed to be investigated during any inquiry into the collapses.

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