Buildings Collapse as New Zealand Hit by Magnitude 6.3 Earthquake

A magnitude 6.3 earthquake has hit the South Island of New Zealand near the town of Christchurch.  There are numerous reports of building damage and collapses and there have been multiple aftershocks. As can be seen from the USGS map graphic accompanying this post, this quake has the potential for moderate damage, including collapses depending on the type and quality of construction.. 

The quake occurred in the Canterbury region of New Zealand’s South Island at 12:51 pm local time on February 22.  It is not yet clear if this is a aftershock of the September 4, 2010 Cantebury earthquake or if it will be considered a new quake in its own right.  The shallower nature of this most recent quake is a factor in the building damaged experienced.

New Zealand media is also quoting the Civil Defense Minister as saying that a number of hotels have collapsed.  Details are sketchy at this point as to how many people may have been in those facilities or are trapped at this time.  Communication is difficult in some parts of the area as phone landlines have been damaged and a number of cell sites are operating off of backup power.

Areas of major damage have occurred including  the collapse of the PGG Building in central Christchurch.  The four story building completely collapsed trapping a number of individuals triggering an extensive rescue response to the site.  Damage and partial collapses of other buildings are being reported including the historic Christchurch Cathedral in the center of town, other churches and  the airport flight control tower.  Christchurch hospital was damaged but is reported to still be operational.  Many streets are littered with debris as facades have fallen, particularly on older masonry buildings.

Initial and unofficial USGS postings as seen in the shakemap graphic below confirm the location, magnitude and depth of the earthquake and are consistent with what is being reported by New Zealand officials including that the quake was centred southeast of Christchurch, at a depth of five kilometres.

Instrumental Intensity Image

More than 20 aftershocks, some significant have occurred to date.  Casualties have occurred in several locations and the number of people trapped in buildings may be in the hundreds.  Local reports and the latest updates on the quake can be obtained from stuff.co.nz.

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2 Responses to “Buildings Collapse as New Zealand Hit by Magnitude 6.3 Earthquake”

  1. Beth P
    February 22, 2011 at 12:08 pm #

    Seeing as NZ must be on a major faultline–do they use the same type of earthquake proofing that structures in the US adhere to? Obviously, historic buildings are always at risk–but this seems like an especially bad case of modern failures as well. Or would you say this is a common amount of failures for a quake of this size, regardless?

    • mkev
      February 26, 2011 at 11:28 pm #

      Christchurch is near a major known faultline but some scientists believe that previously undiscoverd or new faults developed with this quake and / or the one that occurred last year. Earthquake codes are considered relatively good in New Zealand and a number of improvements have been made in design and construction methods in the last five or six years. Most of the very new structures appear to have performed well although the reports are still coming in and a number of earthquake observation and assessment teams will be arriving as soon as rescue operations are completed. However, if early reports are verified, there was some damage to recently constructed buildings that was surprising and you can be sure the experts and code officials will be looking at those cases very closely to see what we can learn form this tragic event.

      There are a couple of things to remember when comparing this quake against the lager one from last year that produced less damage. The recent quake was centered directly under the downtown area of Christchurch and at half the distance below the surface compared to last year. This alone can explain why the recent event caused much more damage, particularly to older masonry structures and those which had not been upgraded to modern earthquake standards.

      Keep checking back for details on the specific lessons learned from this quake which will be provided in BFF as the assement teams provide preliminary reports.

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