Large New Zealand Earthquake

Discussion in 'Earth Science' started by Yazata, Nov 13, 2016.

  1. Yazata Valued Senior Member

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    This is a 7.8, a major event. (In amount of energy released, this is close to the earthquake that destroyed San Francisco in 1906.) It was centered along the coast of South Island, about 100 miles north of Christchurch. (That relatively remote area might reduce the damage some.)

    People in Christchurch (pop around half a million I guess) the US Geological Survey predicts the shaking will be felt as 'strong'. To the north, in the small town of Kaikura, the USGS predicts it will be 'severe'. That level of shaking is associated with considerable damage.

    The Pacific Tsunami Warning Center is aware of this earthquake but doesn't have any tsunami warnings in effect for it.

    http://www.tsunami.gov/?p=PAAQ/2016/11/13/ogkuoy/4/WEAK53

    USGS models don't predict high loss of life, but do predict quite a bit of damage. They note that most structures in the area are built so as to be earthquake resistant. Given that Christchurch has been hit by a couple of previous earthquakes and sits atop soil prone to liquifaction, this might conceivably be a big economic hit to NZ. The USGS predicted shake maps have the effect mostly north of the epicenter though, up the coast towards Blenheim and Wellington. It will be felt over a wide area, but perhaps not very strongly everywhere.

    http://earthquake.usgs.gov/earthquakes/eventpage/us1000778i#executive

    They already record five moderate to large aftershocks, the largest 6.5, itself a significant earthquake.
     
    Last edited: Nov 13, 2016
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  3. Yazata Valued Senior Member

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    Local NZ news reports that a local tsunami warning remains in effect and police were warning people to stay away from beaches. Perhaps one unconfirmed fatality in Kaikura as a historic building collapsed. (One survivor already pulled out.) Urban search and rescue teams on the way. Photos of broken windows in Wellington. Light rail trains in Wellington not running until the rails are inspected. People are being advised to stay away fron the central business district in Wellington.

    Not clear to me whether all the news from Wellington is due to the earthquake being felt more strongly there or due to the news media being centered there. I would expect more damage in Christchurch frankly.

    http://www.radionz.co.nz/news/national/318002/live-7-point-5-quake-near-hanmer-rocks-whole-country

    http://www.radionz.co.nz/news/national/318000/earthquake-new-zealanders-in-shock

    Several Sciforums participants are in NZ, right? (Daecon calls himself 'kiwi fruit', and isn't Trippy a New Zealander?) You need to become news reporters if you can. Please report in.
     
    Last edited: Nov 13, 2016
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  5. arfa brane call me arf Valued Senior Member

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    Good grief.
    How much effect can Trump's win have on the goddam world?

    /sarcasm

    Seriously. I live in the North Island, currently staying in a town a bit north of Taupo (the big lake). Nothing happened here, but my partner has friends in Christchurch who reported via facebook that they're ok, no damage. So far no reports of more than a few deaths, but still no idea how much infrastructure has been damaged. I expect that will change as the day gets older (now just after 7am here).

    Not very often a major city like Wellington gets closed down though.
     
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  7. arfa brane call me arf Valued Senior Member

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    Schools are closed, rail services and ferries not running, some roads blocked, and thousands still evacuated. People advised to avoid the downtown areas of Wellington.
    Tsunami warnings still in effect as aftershocks are expected, no idea when this will be lifted.
    To add to all that, a major storm is heading towards the affected area. Not nice.
     
  8. Yazata Valued Senior Member

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    Hi, Arf, glad to hear that you are ok. Thanks for telling us what the news is saying where you are. You are going to have a lot more details than us.
     
    Last edited: Nov 13, 2016
  9. Yazata Valued Senior Member

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  10. arfa brane call me arf Valued Senior Member

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    No real updates, but repeated shots of a road tunnel blocked by a large slip, which is the main road into Kaikoura. Reports of a train trapped by slips somewhere.
    The storm hasn't arrived yet, but will most likely hamper efforts to bring aid (by air I suppose) into affected areas. Wellington city will remain closed until building inspectors can assess damage.

    We were lucky, this time. The quake's energy wasn't focussed but quite widely spread (lots of fault lines in the South Island, quite a complex picture for the geologists to unravel).
    If it had been focussed locally, perhaps Christchurch would have seen a lot more damage, Wellington too.

    For now the main problems are restoring power, communications (cellphone towers), and in some places the water supply. The road and rail blockages will take weeks if not months to clear.
     
  11. Yazata Valued Senior Member

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    Here's the image that the world is seeing: Three cows trapped on the tiny remaining fragment of their farm field, after everything around them disappeared in a landslide/slip.

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    I wonder if there were lots of cows in that field and the rest are... gone. These three, two adults and a juvenile, appear to have been in just the right spot at the right time. I wonder how/if they will be rescued.
     
  12. arfa brane call me arf Valued Senior Member

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    Because of major slips there are several new dams, and now the storm front has arrived with heavy rain predicted over the next 24 hours, these new dams could create a new civil emergency, if they break.

    One thing, the relatively low population densities in the affected South Island areas has meant only a handful of real emergencies and search and rescue operations. One truck driver was reported missing but eventually found trapped between two major road slips.

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    That's a railway line pushed across what's left of the main coastal access road into Kaikoura.
    The cleanup and repairs will cost at least 1bn, likely more. Engineers say work won't start for weeks, after they have assessed the damage.
    That means the Kaikoura township will remain cut off for quite a while; there is a NZ naval frigate en route to deliver aid to the area.
     

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  13. Yazata Valued Senior Member

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    The three stranded cows that became a world-wide sensation have been rescued!

    The farmer himself did it along with some helpers, using picks and shovels by hand to create kind of a ramp for the cows to descend. The farmer said that he lost lots of stock, to say nothing of his grazing pasture. The cows were basically ok, but they needed water and the adults had lost calves in the quake devastation and were kind of emotionally distraught. The farmer described them as 'very docile'.

    http://www.newshub.co.nz/nznews/stranded-quake-cows-rescued-2016111510

    That's what makes New Zealand great. It's the kind of place where you just knew the three cows would be rescued.

    Work is still proceeding on the more difficult job of aiding the stranded human beings in Kaikura and other small settlements that have lost lots of structures, electricity in many cases and their road and rail links with the outside world.

    News here says that the government has four Royal New Zealand Air Force helicopters flying in emergency supplies and flying out tourists and people who need medical aid, and they also have a C 130 cargo plane on stand-by to airdrop supplies if that becomes necessary. There also the Royal New Zealand Navy frigate that Arf spoke of that will try to land supplies in Kaikoura. Unfortunately, storm conditions threaten to complicate the relief efforts.

    Rebuilding road and rail links will take a long time, so the problem is going to persist.

    Apparently New Zealand geologists are hypothesizing that this might have been two earthquakes occurring almost simultaneously. That might explain why the strongest shaking extended so far north into the Wellington area. NZ is a high earthquake area crowded with seismographs, so the recorded data should presumably show if that's the case. The USGS has added some analysis to their website on this earthquake and they note that the complexity of the faulting in NZ can result in earthquakes triggering quakes on nearby faults. They also note that while epicenters are given as points, large earthquakes like this typically occur along entire stretches of fault. They estimate that this one might have been 200 km long.

    http://earthquake.usgs.gov/earthquakes/eventpage/us1000778i#executive

    http://earthquake.usgs.gov/earthquakes/eventpage/us1000778i#pager
     
    Last edited: Nov 15, 2016

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