According to the NZ Herald, March 7, 2011,  a sizable portion of downtown Christchurch buildings that suffered major damage will not be rebuilt.

In a major departure from the usual recovery decisions after an earthquake, national officials in N.Z. have decided that “…parts of Christchurch will have to be abandoned and up to 10,000 homes could be demolished as a result of last month’s earthquake, Prime Minister John Key said today.” Earthquake Recovery Minister Gerry Brownlee previously told NZPA early estimates suggested 100,000 homes could need repairs while 10,000 could have to be rebuilt.

Prime Minister John Key confirmed those numbers this afternoon, and said the Government was working to identify which homes would have to be demolished.

There will be some homes that can not be rebuilt and, as a result of the second earthquake, potentially, some sections and some areas of Christchurch which will need to be abandoned,” Mr Key said.  We will have to present other alternatives for people to live in because the land has been so badly damaged we can’t fix it, certainly not in a reasonable timeframe.

This is not a common outcome after an earthquake in a major urban area, but one that bears watching on the part of public officials in other seismically active areas. If any readers can supply related examples, I would be interested in hearing about them. I did hear from Prof. Rob Olshansky who offered some additional insights into what the land issues might be:

As I read it, it’s not that the land is so unsafe as to be unbuildable. Rather, the ground deformation requires additional preparation (e.g., geotechnical investigation, regrading, possibly drainage measures, possibly import of fill material, and redesign of foundation concepts), that they cannot rebuild quickly and that extra expense would be involved.

Later in the day some additional information about the effect of liquifaction on the damaged buildings in question –today’s The London Daily Mail.

Additional resources include those of the USGS regarding landslides and land failures:  see: landslides.usgs.gov.

Related Articles

• 10,000 Christchurch homes to be demolished (cbc.ca)

A  high percentage of damaged buildings, many that are built in the Gothic Revival style and considered landmarks, in the central city cannot be repaired.  The sizable amount of rebuilding will require closing many businesses and the cathedral until they can have their structures rebuilt.

(1) Engineers reveal a THIRD of Christchurch’s buildings have to be demolished and city centre could be no go area for months
February 27,2011

Engineers have said that at least a third of Christchurch’s buildings must be demolished and rebuilt after the devastating earthquake on Tuesday.

The damage to the decimated centre of the city could mean it was completely unusable for months to come as the death toll reached 147 today.

People held open-air church services on church lawns today to pray for the dead and missing after the 6.3-magnitude quake.

(2) These facts don’t compute: On Feb. 27, ChannelNewsAsia, N.Z. reports that a former N.Z. Prime Minister compares earthquake outcome in N.Z. with that of Haiti. That seems odd to me since the no. of deaths in Haiti were about a thousand times greater than N.Z. and the ratio of impact — death and injury counts and building loss –are not as severe as Haiti.  Excerpts from article below:

The scale of devastation in quake-hit Christchurch is comparable with the destruction wreaked in the 2010 Haiti earthquake, New Zealand’s former premier Helen Clark said on Monday, as rescuers prepared for the final death toll to rise above 200.  The stark assessment came with much of the city lying in ruins after last Tuesday’s 6.3-magnitude quake caused widespread death and destruction, toppling buildings and tearing up roads.

“The building damage I’ve seen compared with Haiti,” Clark, who now heads the United Nations Development Programme, told Radio New Zealand on Monday, referring to the massive quake which killed at least 220,000 in the Caribbean island in January last year.

“Let there be no mistake, New Zealand has suffered a tragedy of monumental proportions and it’s going to require every ounce of recovery in this country to push through from this,” she added.

The death toll in Christchurch reached 147 late Sunday but police fear more than 50 still listed as “unaccounted for” lie dead in the rubble.

Regarding the ratio of deaths from the earthquake relative to the total population, for Haiti the no. is 8% and for Chile and NewZealand the no. is less than 1%.

(3) A source of good, basic information: see the MCEER site ( SUNY/Buffalo Earthquake Center) for an excellent, chronological listing of articles and documents.

(4) Reuters, on Feb. 28th, writes that combined cost of the two biggest quakes will be about $20B.

Image by Cafe Cecil via Flickr

In The Guardian, Feb. 25, some of the pros and cons about rebuilding are examined. Two significant comments:

Andrew King, an engineer at the Institute of Geological and Nuclear Sciences, said the city and its surroundings could be rebuilt in such a way that structures “can remain intact as the ground deforms around them”. The only question was whether the resources would be made available.

Gerry Brownlee, who has been appointed earthquake recovery minister, put on a brave face, rejecting suggestions that the cost of rebuilding could be economically crippling for the country. “New Zealand is one of the most insured countries in the world,” he said. “There is going to be a massive influx of capital into this country and this city.”

It is understandable that two major earthquakes, and perhaps thousands of smaller aftershocks, in the past 5 months have New Zealanders questioning a return to the city and wondering if they will be able to restore normalcy to their daily lives.

More on the economic costs and impacts, in the Christian Science Monitor.  This article estimates total damage at $12B.

Related Articles

• Christchurch exodus after quake (guardian.co.uk)

Image via Wikipedia

Newest info from the NZ Herald about the likelihood of more deaths, given the fact that many people are still trapped in collapsed buildings.

Earlier account from the L.A. Times of a powerful aftershock in Christchurch, N.Z. yesterday.The initial earthquake in Sept. 2010 was a 7.1 magnitude and this aftershock was a 6.3.  There have been many aftershocks, but none as damaging as this one.

After the powerful aftershock 65 people died, although the initial earthquake did not cause any deaths.  A sad reminder that after a major earthquake, there may be aftershocks for years.  They can cause deaths and injuries and always cause distress to residents.

Location and timing are identified as key variables for this major aftershock, according to Andrew Rivkin’s blog for the NY Times.

VIDEO:

See this video provided by the Weather Channel; Feb. 22. It comes close to feeling like the actual experience.

RELATED  ARTICLES:

• “NZ: 6.3 Magnitude Earthquake Hits Christchurch” and related posts (afludiary.blogspot.com)
• Second aftershock hits New Zealand (marketwatch.com)
• New Zealand: An earthquake hotspot (cnn.com)