Large aftershocks continued to rattle a nervous Christchurch today as the city and its residents looked to recover from two large tremors on Monday.
Scientists have said Monday’s 6.3 quake has increased the risk of another quake of up to 6.9 magnitude some time within the next 12 months to about 30 per cent and residents were given further reminders of this as they were woken by shakes of 5.0 and 4.2 in magnitude – both about 5km deep 20km southeast of the city – around 6.30am.
The aftershocks have to be upsetting to local residents and merchants, and they must be slowing down the work of public officials. Just a reminder that the recovery process from an earthquake has special characteristics. In the U.S. in the aftermath of some major earthquakes, there have been aftershocks for years.
New Zealand Prime Minister John Key said this week’s tremors have hit the same parts of the city that were devastated by the Feb. 22 earthquakes. He hinted that parts of the city may have to be permanently abandoned.
As might be expected, since the Canterbury earthquake, other cities in NZ that are vulnerable to earthquakes have reviewed their seismic safety efforts. For the capital city of Wellington, the concerns are considerable. Capital shaky over quake preparedness. TVNZ. Oct. 4th.
A report has found shortcomings in the preparedness of seven of the 10 emergency operations centres in New Zealand’s quake-prone capital. The Ministry of Civil Defence and Emergency Management assessed the effects of a big earthquake hitting Wellington and the audit questions whether some of the buildings could withstand a major shake. The report says the Wellington region is a geologically dynamic part of New Zealand and movement of the Wellington Fault could be expected to result in a quake of about magnitude 7.5. It says the risk to people is dependent on the timing, scale, location and nature of the event but an earthquake of similar magnitude to that in Christchurch would likely result in fatalities and significantly more injuries if it occurred in Wellington.
Note that in an earlier post about the recent NZ quote, I mentioned a 1995 indepth study of Wellington After the ‘Quake.
Former N.Z. Prime Minister, Helen Clark, praises the national preparedness efforts with minimizing the deaths and injuries in the recent Christchurch/Canterbury Earthquake, especially true when compared with the outcome of the Haiti earthquake of the same magnitude. Ms Clark also commented on the positive benefit of beginning recovery planning quickly. The ready availability of insurance money for reconstruction is an important feature of the N.Z. system.
If you put in place the systems which anticipate what disaster might strike, then you can act to thwart the worst effects. She was critical of how international aid funding was targeted after large natural disasters like the Haiti quake or the recent Pakistan floods. While the international community generally provided immediate humanitarian relief, early recovery schemes to help people rebuild were “the least funded part of any international appeal for help.
I think there is an immediate need for a comparative study of recovery in N.Z. and the U.S. , and I plan to engage in one. Please contact me if you are planning to research this topic.
New Zealand quake could cost up to $4.5 billion, Market Watch, Sept. 7. Some interesting differences between NZ and US – there most residential structures have earthquake insurance. And their new construction requires consideration of seismic risk, but relatively few older masonry buildings were retrofitted for seismic safety. Sadly, the central business district of ChristChurch lost many of its historic masonry buildings.
As noted two days ago in this blog, the contrast between the outcomes of the same-size earthquakes in NZ and Haiti is stark. Here is a discussion of one of the reasons for the difference. Building code saves NZ from serious destruction; Radio Australia, Sept. 6.
As we’ve heard in earlier reports, many New Zealanders are assessing the damage from the weekend’s earthquake. Jeff Crosier, is a structural and earthquake engineer from consulting firm Miyamoto International. While the New Zealand earthquake was larger than the one which devastated Haiti earlier this year, killing 200 thousand people, Mr Crosier says it is surprising how little damage has been caused in Christchurch.
On the downside, more than 100 aftershocks have occurred, some of which are sizable. It appears that the structure damage and the no. of badly damaged homes is growing. To call New Zealand seismically active is an understatement. According to a NY Times article on Sept. 6,
New Zealand sits above an area where two tectonic plates collide. The country records more than 14,000 earthquakes a year — but only about 150 are felt by residents. Fewer than 10 a year do any damage. New Zealand’s last major earthquake registered magnitude 7.8 and hit South Island’s Fiordland region on July 16, 2009, moving the southern tip of the country 12 inches (30 centimeters) closer to Australia.
Regarding the financial aspects of the recovery, the existence of insurance funds for residential reconstruction is an unusual feature. Nevertheless, the national government will have to assist public entities as is true in the U.S. system. See UPDATE: New Zealand Building Shares Rally After Quake; Bonds Weaken; Wall St. Journal, Sept. 7.
I recommend the interesting discussion , and useful comments, regarding resilience that is on the Homeland Security Watch blog for Sept. 5 and also Sept. 8th. Mark Chubb the author of the posting has extensive experience working in NZ.
By way of background, NZ has a very high risk of earthquake in most parts of the country. (For a listing of the major earthquakes in N.Z. in recent years, go to this site on GeoNet.) The leaders are aware of it and have taken many steps to deal with it, including the creation of special insurance, run by their Earthquake Commission. One surprise was that the fault that triggered the recent set of quakes was previously unknown.
One example of the foresight of the NZ government, which I am aware of — in 1995, the Commission was a sponsor of an international conference that dealt with recovery and rebuilding of a major city after an earthquake. I was privileged to participate in the conference, which was excellent, and a high quality report was issued. The report is titled “Wellington after the ‘Quake: The Challenge of Rebuilding Cities.” I hope the Commission makes the text available in digital form soon.
As noted earlier, the 7.0 earthquake in New Zealand miraculously did not result in any deaths. By contrast, the 7.0 earthquake that occurred in Haiti earlier this year resulted in about 225,000 deaths. The reasons for the differences would make an interesting research topic.
New Zealand prepared for further destruction on Sunday as aftershocks and an approaching storm threatened an area hit by the most devastating earthquake in decades. Prime Minister John Key said it was “a miracle” no one had died when the major 7.0 magnitude quake wreaked more than a billion dollars of damage on the nation’s second-biggest city of Christchurch. Civil defence officials warned that ongoing aftershocks with magnitudes of up to 5.4, coupled with a ferocious storm blowing in, could threaten already-weakened buildings.
New Zealand’s Christchurch and Canterbury remained on edge Sunday as the quake-hit region entered its second night following a powerful tremor that left buildings in ruins and people scrambling for shelter heavy rains and gale-force winds forecast to hit Monday threaten to knock down frail, quake-weakened buildings.
Comments from NZ geologists about some of the unique features of this quake:
The powerful earthquake that smashed buildings, cracked roads and twisted rail lines around the New Zealand city of Christchurch also ripped a new fault line in the Earth’s surface, a geologist said Sunday. (CNN, Sept. 5) and
“The quake was probably the worst to hit New Zealand for 80 years because it was a “bull’s-eye on a major city,” Warwick Smith, from the Institute of Geological Nuclear Sciences.”
One of the unique features of the ChristChurch event is that the country acknowledges its high earthquake risk and has mandated insurance for residential structures. More about this feature follows. Also, it will be interesting to see to what extent their construction and building inspection standards, zoning, and land use requirements may have contributed to the outcome of no deaths and relatively few injuries.
The cost of the damage is still being assessed, with teams working through the central city to check on building soundness. The Earthquake Commission, which covers residential damage on properties insured for natural disasters, said it had received about 2,800 claims for damage to property but was expecting a significant increase in claims over the next couple of days.
Earthquake Commission Chief Executive Ian Simpson said the quake was going to result in hundreds of millions of dollars worth of claims, “but it could be up to a NZ$1 billion” with around 100,000 claims expected to come in over the next three months.
The commission is a government-owned crown entity funded by insurance premiums and pays out the first NZ$100,000 of a claim. The fund currently has around NZ$5.6 billion and is backed by reinsurance from overseas groups and a government guarantee. Mr. Simpson said this will be the single biggest claim on the fund since it was established in the 1940s.