Learning from Earthquakes: First person reports


Post-quake Inspections Mislead Building Occupants in Christchurch, New Zealand

October 11, 2011 by

The Canterbury Television building was subjected the 7.0 magnitude earthquake near Christchurch, New Zealand in September 2010. The following magnitude 6.1 earthquake in February 2011 caused the building to collapse and resulted in the deaths of 115 people. An earthquake reconnaissance team inspected the building after the earthquake and marked it with a green sticker. They were using the rapid assessment system which originated in California and has been commonly used since the 1989 Loma Prieta earthquake in the San Francisco Bay Area. While the inspection system aims to determine if people are banned from the building (red), can gain limited access (yellow), or can continue to occupy the building (green), it is the owner’s responsibility to get a more in-depth and complete inspection. The father of the system, structural engineer Ron Gallagher, is writing a report on the lessons learned from Christchurch and hopes that, in the future, the system will educate building owners and occupants on the meaning of the colored tags and the necessary steps to be taken afterwards.

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Cars crushed, stranded, and recovered. Anne Wein, U.S. Geological Survey

March 21, 2011 by

Cascading facades crushed cars, some with occupants unfortunately. Three to four weeks after the February 22 earthquake car owners are gathering at the edge of the CBD, presenting keys, identification, and proof of ownership to police who will retrieve cars from parking structures. At the same time, thousands of cars are being towed out of the inner-cordon to Hagley Park to be claimed by owners.

Photo 1. Crushed car on the streets of Lyttleton March 18). Anne Wein. U.S. Geological Survey

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Calling on Social Scientists to Inform Recovery Decisions. Anne Wein, U.S. Geological Survey

March 21, 2011 by

Central government is calling on social scientists to inform recovery decisions. On March 15, David Johnston, director Sarah Beaven and Tom Wilson met with Lori Peek, Jeanette Sutton, Anne Wein, and a visiting geographer in the EOC. David shared the questions that are being asked of social scientists. Relevant observations and lessons learned are invited from the international research community regarding:

  1. Internal migration is the biggest ever in New Zealand since the first settlers arrived. Who and why did residents leave Christchurch after the February 22nd earthquake? How many migrants will return? What services need to be provided to reverse the migration?
  2. What range of social interventions should the Ministry of Social Development and Health be considering after back to back disasters?
  3. How do we communicate seismic risk and overcome fears of occupying multiple story buildings?
  4. How should the Ministry of Civil Defense and Science change hazard education while New Zealanders are receptive and demanding engagement throughout New Zealand?
  5. What public policy change will accommodate the redistribution of students in the tertiary education that was previously controlled by caps on student fees?
  6. What short and long term strategies can be used to manage tourism which contributes 9% of New Zealand’s gross domestic product and 19% of export earnings?
  7. How will 10,000 people be temporarily housed during repairs and reconstruction and what are the social implications of the different options?

Researcher Meeting

March 20, 2011 by

On Thursday, March 17, several members of the EERI team attended a second international researchers meeting. The event, which was attended by about 50 people, featured short presentations from a number of the international and local engineering teams. Mary Comerio represented EERI beautifully!


A Break in the Wake of the Quake: Family Fun Day

March 20, 2011 by

Heather Taylor, a Ph.D. Student at Massey University, has spent the past several years studying children’s experiences with flood risk in Indonesia. When Christchurch was rocked by a magnitude 6.3 earthquake aftershock in February, she, like many other New Zealanders, wanted to help. 

Heather, with the support of her home church in Spreydon, organized a series of “Family Fun Days” in three affected neighborhoods around Christchurch. These events offered families a “break from the quake.” Affected individuals were invited to eat, socialize, and share their earthquake experiences. A drawing table was set up for children (and young-at-heart adults) who wanted to use crayons and draw about the earthquake. There were also lots of other fun activities for children—including an art space, a play castle, and face painting.

The Family Fun Day events, which drew in hundreds of individuals at each site, also served an important educational purpose. Local academics gave a brief lecture at each of these events, where they explained the science behind earthquakes and liquefaction. Adults and children took time out from the social activities to listen to these lectures. One of the scientists who presented noted that he had “never had a more engaged audience,” as the people of Christchurch grapple to understand the causes of earthquakes.  


“Grief is the Price We Pay for Love”: The National Christchurch Memorial Service

March 20, 2011 by

On Friday, March 18, 2011, the Province of Canterbury observed a public mourning holiday. Most shops and restaurants closed down, and tens of thousands of people attended a National Memorial Service in North Hagley Park in the heart of Christchurch.

 People began flowing into the park early in the day. As families and friends spread out blankets and cushions to sit on, various local musicians and Maori artists performed musical tributes. Salvation Army and National Welfare volunteers roamed the crowd, handing out tissues in preparation for what everyone knew would be a solemn and tearful event.

At noon, the Woolston Bass Band marked the unofficial opening of the ceremony. At 12:15, Christchurch Mayor Bob Parker greeted the audience and introduced a 14-minute video of previously unavailable images of the destruction. There was no background music to the video; just a series of powerful photos of building collapse. The enormous crowd was starkly silent as the video played—only erupting into applause when urban search and rescue teams and firefighters and police officers made an appearance. Following the video, the official ceremony began at 12:30 sharp.

The service was one of the most exceptional events I have ever attended. Prince William delivered a particularly moving speech, where he quoted his grandmother who once said to him that “grief is the price we pay for love.” He also remarked on the resilience of Cantabarians and said they were an “inspiration” to people the world over.

 Mayor Bob Parker spoke on two separate occasions, and both times was met by raucous applause. Several other noted political figures, including New Zealand Prime Minister John Key and Opposition Leader Phil Goff both spoke during the ceremony as well. Common threads ran across the various addresses, including: an offering of condolences to the Japanese people; recognition of the trauma caused by the back to back earthquake events in September and February in Christchurch; and observations of the extraordinary bravery, courage, and resilience shown by the people of Canterbury.

 Additional highlights of the service included a beautiful acoustic rendition of the song “Loyal” by noted New Zealand Artist Dave Dobbyn and a performance of “Amazing Grace” by opera singer and native of Christchurch Hayley Westenra. If you have a few minutes, you can listen here to Loyal (http://www.3news.co.nz/Dave-Dobbyn-performs-an-emotional-Loyal-at-Memorial/tabid/309/articleID/202967/Default.aspx) and here to Amazing Grace (http://www.3news.co.nz/Hayley-Westenra-performs-Amazing-Grace/tabid/309/articleID/202980/Default.aspx). (You can really see the size of the crowd in these videos.)

 The ceremony ended with an inspirational and uplifting video of the emergency response and recovery efforts of officials and volunteers (the images of Bob Parker going into the port-a-loo got a big laugh). The video is just over 4 minutes and I think many of you will enjoy watching it (http://www.3news.co.nz/Uplifting-video-montage-ends-memorial-service/tabid/309/articleID/202992/Default.aspx).  

 The full program for the memorial service is available here (http://canterburyearthquake.files.wordpress.com/2011/03/christchurch-order-of-service-17-mar2-2.pdf).

 Kia Kaha Christchurch

 

 


Building Safety Evaluation

March 19, 2011 by

The New Zealand Society for Earthquake Engineering has developed procedures and guidelines for the rapid assessment of buildings following  earthquakes, Building Safety Evaluation in a State of Emergency: Guidelines for Territorial Authorities.  These guidelines, originally based on ATC-20 Procedures for Post-earthquake Safety Evaluation of Buildings (1989), have undergone a number of field tests.   After each field test the guidelines have been modified and updated.   The most recent modifications were implemented after the 2010 Darfield Earthquake, and the updated protocol was used for the 2011 Christchurch Earthquake.   Earlier modifications arose from experiences of earthquakes in Gisborne (New Zealand, 2007) , Padang (Indonesia, 2009), and L’Aquilla (Italy, 2009).   Training sessions based on the 2009 edition were run in Wellington, Christchurch, and Otago early in 2010.

The meaning of the red, green, and yellow placards required explanation for some building owners, tenants, and residents.   The Christchurch City Council provided extensive information on their earthquake recovery website regarding what the placards mean, and do not mean.

Perhaps a lesson from the 2010 Christchurch Earthquake relates to the usefulness of readily-available structural drawings of larger buildings in post-earthquake evaluations.

green placard

red placard

yellow placard


Indicator Buildings

March 19, 2011 by

Concerns of progressive collapse of marginally-stable structures has raised questions regarding the need to reinspect buildings following aftershocks.   The aftershock sequence has contained about 40 events greater than 4.0 and 12 events greater than 4.5 since 22 February.  Most of these aftershocks occured ate a depth of 2-5 km and within 10 km of the central business district.  In order to quickly assess the need for re-inspections, the EOC identified a sample of damaged structures, some of which have significant residual displacements.  These “indicator” buildings represent URM, RM, RC, and PC structures typical of Christchurch.    Increased damage in an indicator building following an aftershock triggers re-evaluation of all corresponding buildings.   The indicator building evaluations following the 4.9 M event on 6 March  did not reveal additional structural damage.   Some of the indicator buildings are shown below.

an indicator building

 

an indicator building

an indicator building

an indicator building


Heritage Buildings

March 19, 2011 by

The Europeans who settled Christchurch in the 1850’s formed an “Acclimatization Society” in an attempt to establish familiar environments in Christchurch.  This group advanced the introduction of European animals and plants, and the establishment of parks and architecture of their native England.  The grace of Christchurch springs from the stone and masonry architecture of heritage buildings.   The Christchurch Civic Trust has had influence in urban planning, and in demolition decisions following the 4 September 2010 earthquake.   The owner of the St. Elmo’s Court Building (Hereford St.) was advised to demolish the building, and sought council consent to do so.   The Heritage Trust prevailed in this case.  Their fight to preserve the Manchester Courts apartments was not successful and a methodological demolition of this site, preserving as much Kotare wood as possible, finished less than a month prior to 22 February 2011.   Earthquake damage to heritage buildings does not imply that they can not be saved.  The two heritage buildings shown below are one block from one another.  One had been seismically retrofitted.

Montreal and Kilmore

Montreal and Peterborough

Following the 4 September 2010 earthquake, this heritage building had been braced, but it collapsed on 22 February 2011.

Wocester and Montreal

Wocester and Montreal

 


Communicating (and exaggerating?) Risk

March 19, 2011 by

The stream of aftershocks since 4 September 2010 has rattled people’s nerves. The major aftershock of 22 February 2011, which heavily damaged heritage and unreinforced masonry structures, was the last straw for many residents.   By all accounts, tens of thousands of people have left Christchurch, and their return depends on events that are yet to unfold.  The overwhelming level of uncertainty regarding future aftershocks, the rebuilding process, and seismic safety in Christchurch is arguably one of the most difficult issues for residents.   The importance of uncertainty in aftershock predictions is accurately reflected in statements from geo-scientists and re-ebuilding plans will be slow to emerge.   In this environment people put stock in aftershock predictions and demolotion plans that are issued with conviction or authority.    Notable examples of this are aftershock predictions based on lunar proximity and home demolition plans based on incomplete information.

Cantabrians have been following the meteorological and seismological predictions of Auckland-based Ken Ring, also known as “the moon-man.”  Mr. Ring associates extreme meteorological and geophysical events with king tides and lunar proximity.  On this basis Mr. Ring has issued predictions of major aftershocks in Christchurch.     Earth-moon distance varies by about 14% on a lunar-cycle and an additional 5% on a longer-period cycle.  Minimal perigee’s occurred  in September 2010 and mid-March 2011.   The 4 September 2010 and 22 February 2011 earthquakes in Canterbury and the 11 March 2011 earthquake in Japan have likely reinforced his credibility with some who have been living through the aftershocks in Christchurch.  In an effort to inject accurate data into debates regarding Mr. Ring’s predictions,  Paul Nicholls of the University of Canterbury IT office has developed a live-animation and of the aftershock sequence and plot of seismic energy along with moon phase and moon proximity.

Relating to demolition and rebuilding plans, in the second week following the 22 February 2011 aftershock, Prime Minister John Key announced that 10,000 homes would be demolished on the basis of preliminary satellite imagery.  House demolotion decisions require detailed site assessments and structural evaluations. Civil Defense, under whose authority building inspections are carried out, estimates 2000-3000 homes would be demolished.

The Press , Tuesday March 8, 2011

In the days immediately following 22 February 2011, a walk-through assessment was made along streets with disproportionately large representation of unreinforced masonry.   Tabulation of red, yellow, and green-stickered buildings according to building type led to a prediction that 1 out of 3 buildings in the Central Business District had either collapsed or would be pulled down.

The sample did not include many modern buildings, many of which performed well and which contain many more square meters than the URM building stock.   At the time of this writing, fifteen or twenty buildings over six stories are considered demolition candidates.
The rebuilding process for the Central Business District will require many months.   Clearly, the long term economic impacts to Canterbury will be significant, and much depends on peoples’ decisions of where to live and work.   The re-built Christchurch will be more seismically resilient and poorly-founded predictions intended to fill an information void associated with uncertain geophysical and political processes can serve only to unnecessarily scare Cantabrians.


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