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Another sizable earthquake in Christchurch, New Zealand

Yesterday, a 6.3 magnitude earthquake struck New Zealand's second largest city, a potential aftershock from an even bigger quake last September.

Last year, the city of Christchurch in New Zealand experienced a M7.2 earthquake. Luckily that earthquake was centered in a relatively unpopulated area outside the city in the middle of the night. On Monday, however, a potential aftershock of the September 2010 earthquake struck closer to the city during midday, a potentially much more dangerous mix. The new earthquake was a M6.3 (preliminary) at ~5 km depth and initial reports of the earthquake suggest a lot of damage in the city (top left and below). There is already some impressive video that seems to have captured one of the aftershocks of this new earthquake as it happened as well. You can see the webicorder of the region here as well. GNS New Zealand does have an excellent image showing the shockwave of the earthquake as it was received across the country (see below) – the stations are listed north (top) to south (bottom), with the signal from the main earthquake and aftershocks.

The shockwave of the 2/22 Christchurch Earthquake arriving across New Zealand. Click here to see a larger image.

More updates as I find them … and please post any you find as well. Until then, let’s hope that this earthquake isn’t as bad as it seems it could be.

UPDATES (note, you can see a running news feed from the NZ Herald)

  • Fatalities are confirmed to the latest earthquake. 
  • Extensive damage as well. Sad news indeed. 
  • The New Zealand cabinet is calling an emergency meeting to deal with the aftermath of the earthquake. 
  • For reference, the last earthquake in New Zealand with fatalities was in 1968
  • Lots of aftershocks as well, from M3 to M5.5.
  • See many images of the damage recorded so far.
  • And for those of you wanting to lend a hand, here is the NZ Red Cross.
  • Some background on the location of today’s earthquake.
  • More UPDATES:

    • The earthquake caused 30 million tonnes of glacial ice to break free from the Tasman Glacier, generating a mini-tsunami in the Terminal Lake.
    • As of Tuesday morning (Eastern Time), the death toll for the earthquake is at least 65.
    • This death toll is already the highest in New Zealand since over 230 people died in Hawke’s Bay earthquake in 1931, a magnitude 7.8.
    • There are still reports of many people caught in the rubble in Christchurch as well.
    • Highly Allochthonous has a great assessment of the new earthquake and its relationship to the September earthquake.
    • The BBC has a post on the importance of depth and location in regards to the destruction of the new earthquake, but they leave out the other vital aspect: time of day.
    • If you want to see an animation of all the aftershocks since the September 2010 earthquake, check this page out {Thanks to Eruptions reader Gabriele}.
    • Sadly, this new earthquake in Christchurch brings home some very important lessons when it comes to earthquakes: (1) magnitude doesn’t control the level of destruction; (2) location and depth of the focus are vital for understanding the level of destruction; (3) time of day can greatly effect the casualties in an earthquake. Had this earthquake struck during the night like last September’s earthquake, the death toll might have been smaller – individual homes tends to survive better than larger office or professional buildings. Truly a sad day for New Zealand.

      Damage to the Cathedral in Christchurch during the February 22, 2011 earthquake.


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