Sunday, September 05, 2010

Sitrep from Chch's Untouched North-east corner

Sitrep from the absolutely untouched north-east of Chch at Waimairi Beach: 100% habitable, no liquefaction, no problems, power, water on (we're 300m away from a coastal bore), Sewer/stormwater pipes have stayed in place, no chimneys to collapse, everyone going about their business. Also true of Forest Park and most of Parklands plus most of Tumara Park. That's over 4000 households total.

Key factors in success of this area:

* underlying strata not liquefaction risks
* recent (last 15 years) build to decent EQ codes
* easternmost part = furtherest away from the quake epicentre

So, chaps and chapesses, don't believe the MSM one-disaster-affects-everyone coverage.

The effects of the quake are in fact extremely variable. The known areas for liquefaction - around the rivers and Estuary, the peaty soils round St Albans and Papanui, and some sandy lenses over old swamp - are the ones affected. And the infrastructure damage to sewer and stormwater (pipes have literally been floated up through the road above) is a function of water table, soil types and amount of shaking. Interesting to drive through Tumara Park (between Burwood Hospital and Parklands) and see that a radius around the Travis Swamp has suffered pipe float and surface cracking, but the rest is quite simply intact.

The estimate of 20% is simply crap in terms of habitability. Chch has 160K households, so 20% is (counts on fingers) 32K dwellings. Yet only 200 people (at 2 per household, that's 100 households worth) overnighted at welfare centres. So there's an indication of the disconnect.

20% with Gib-board crack plastering needed, yeah, probably.

And the damage that Is there elsewhere is from the usual suspects: unreinforced masonry, lime-mortared bricks, untied veneer walls, and foundations that in the old days were just bricks tossed into a ring in a shallow trench and mortared over. No surprises.

The silver lining is that we won't have to worry aboot the predicted recession in the commercial construction industry, and the 20K job losses. There's a Lot of infrastructure to repair, and that will take months.

(Another decent jolt as I type, but blogging as I am in front of the log fire, with a cuppa joe at my side, and power, water on since 11 am yesterday and the camping loo deployed to ensure we don't add to the infrastructure loading, why worry?).

And a very high percentage of Chch households will be doing exactly the same thing.

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