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New Zealand earthquake: Tsunami follows powerful tremor

bbc.co.uk

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Re: New Zealand earthquake: Tsunami follows powerful tremor

#22

Post by dignick »

anondon wrote: post #20

Does anyone know if there is any special effort to construct buildings that can withstand reasonable earthquakes in New Zealand? Christchurch seems particularly prone to quakes in New Zealand. I hope the people of New Zealand are safe.

Christchurch is actually not on the fault line, and it was a surprise when such a severe earthquake hit in 2011, so they weren't well prepared. All the susceptible buildings collapsed then, and new buildings are earthquake-proof.

Re: New Zealand earthquake: Tsunami follows powerful tremor

#23

Post by adrianmacneil »

anondon wrote: post #20

Does anyone know if there is any special effort to construct buildings that can withstand reasonable earthquakes in New Zealand? Christchurch seems particularly prone to quakes in New Zealand. I hope the people of New Zealand are safe.

Yes, there are earthquake standards for new buildings, and mandatory retrofitting for older buildings (as they are updated).

From what I've seen, this is pretty similar to San Francisco. It would be interesting to see data comparing the standards across earthquake-prone countries/regions.

Re: New Zealand earthquake: Tsunami follows powerful tremor

#25

Post by idlewords »

anondon wrote: post #20

Does anyone know if there is any special effort to construct buildings that can withstand reasonable earthquakes in New Zealand? Christchurch seems particularly prone to quakes in New Zealand. I hope the people of New Zealand are safe.

A big problem in the Christchurch region is liquefaction. There's not much earthquake codes can do to keep the ground from turning to goop.

Re: New Zealand earthquake: Tsunami follows powerful tremor

#26

Post by toomanybeersies »

Currently in Wellington. Was fucking shaky, seriously thought the building was about to collapse. This was ~500 km from the epicenter.

We were evacuated and let back in. All the planning in the world doesn't prepare you for the real thing, the first thing you're meant to do is keep calm, and I sure as hell didn't. I sprinted right the fuck out of my apartment building, I have 4 levels above me, hiding under a table wasn't going to do shit to save me.

The building has some cracks in the plaster and food has fallen off all the shelves, but nothing serious. The water seems to be running a bit brown though, so maybe some damage to the water pipes.

Props to the crew at Bizdojo (http://www.bizdojo.com/) for opening an invitation for us to come and chill there if we couldn't get back into our homes. Doing the right thing there!

Re: New Zealand earthquake: Tsunami follows powerful tremor

#29

Post by zoltrain »

I'm from Christchurch, contacted family there. There's been mass evacuations from the coastline. Tsunami's have started but they can last for hours. Kaikoura has already had a a surge measured 2.5m, if this is the case the waves will get worse before they get better. But NZ is pretty prepared for these things, so hopefully everyone scampers to the safe distance from the coastline. I worry about the Chatham Islands, they're directly east of the epicentre, and Tsunami's travel very fast. I hope they've all gotten to high ground.

Re: New Zealand earthquake: Tsunami follows powerful tremor

#30

Post by doldge »

Cross-posting from my FB feed:

Here's some of the interesting stuff I've found on the internet about today's earthquake (that they're now calling a 7.8):

1) real-time Buoy data, for helping to determine the likelihood of a Tsunami: http://www.ndbc.noaa.gov/ Interestingly, the quake only caused a tiny change in the sea level (in the region of 5 cm's) but the expected swells on land are in the region of 3-5 meters. I believe this is because as the wave gets closer to land, it get's funneled into a smaller area, meaning the 5cm change in sea level gets amplified. Which is why it's hard for the civil service to accurately predict whether a tsunami is likely when these events occur (That, and the nearest working buoy is in Tonga), which would by why they almost always say yes, and then retract the warning later.

2) the USGS science-y explanation for what actually happened. The take-away seems to be that this may have increased the stress on the primary fault in NZ. Interestingly, their's a a suggestion that the rupture was across the hope fault, rather than along it, which helps to explain why the after shocks have been so varied (by location): http://earthquake.usgs.gov/earthquakes/eventpage/us1000778i#...

3) also from USGS, a map indicating affected regions, with town populations, and the likely economic impact of the quake: http://earthquake.usgs.gov/earthquakes/eventpage/us1000778i#...

4) The Canterbury Police shared a link earlier that indicated 3-5 meter swells is around the maximum we should expect from a locally generated earthquake (due to the nature of fault lines in NZ), that's not to say we can't experience a larger tsunami, but that said tsunami would have to be generated externally (like say, south america), which should in theory give us more time to prepare. But like all things, this isn't a hard and fast rule.

5) there's a pretty cool video of what purports to be lights in the sky over wellington during the earthquake (probably has something to do with magnetic interference from the energy released by the quake): https://www.facebook.com/plugins/video.php?href=https%3A%2F%...

6) stuff have had pretty good live coverage here: http://www.stuff.co.nz/national/86416304/live-north-canterbu...

7) The USGS website indicated that the quake lasted around 2 minutes, with the highest intensity coming around 50 seconds into the quake.

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