We’ve had our second 4.something earthquake here in the Wellington region in a week. It shouldn’t really be anything to report given the devastation currently unfolding in Christchurch, but we’re all on edge at present and this little flurry of shakes is not helping!
There are just too many ways to get complacent about earthquakes. If nothing else, this earthquake of February 22nd in Christchurch has put to rest that silly notion of ‘The Big One’.In September, Christchurch was thanking its lucky stars that ‘the big one’ had come in the middle of the night, and that no one was killed as a result of this timing. Sure, a lot of things had been damaged and everyone learned a new word (liquefaction), but lots of people assumed that it was just because Christchurch was not the city that came to mind when you thought of earthquakes, and thus their buildings were founded on complacency. Not true – the now concertinaed Pyne Gould building was strengthened sometime in the last decade, according to the Listener, but it is pointed out in the same article that retro-strengthening older buildings is not done to the current earthquake-proof standard that new buildings must be built to, and the percentage of the strengthening done is set by local government bodies. So, assume nothing! Does anyone know what the standards all these older buildings are being strengthened to in Wellington? Can you look around and tell me which buildings have been done already? Probably not – there is often an older building being demolished somewhere, and one of the reasons usually cited is that the building required strengthening that was economically not viable. So there’s nothing to say that if you were in the CBD in Wellington, you could just hold on to a parking meter and enjoyed the view. You can try to protect a building from an earthquake, but there’s really no way of saying how it will behave until the earthquake happens.
Then, of course, we look at what happened to the suburbs of Redcliffs and Sumner in Christchurch, with rocks falling from cliffs and…. well, that sounds familiar, doesn’t it? Imagine a 7.something earthquake in Wellington after a week of rain! With houses atop those hillsides. Lots of fun, I’m sure. Look up some pictures of the Inangahua 1968 earthquake for an idea of how houses dissolve into the hillside.
Having an emergency kit is a good idea (mine has, so far, some candles, matches and 3 litres of water – I never thought I’d say this, but we need to drink more fizz) but not so great if your house is squished between two others at the bottom of the street. At our old house, the emergency kit was under the stairs, less than five metres from a bank, at the bottom of a valley. Yay.
In Paekakariki, built on a sand dune, our gardens will probably be subjected to liquefaction and damage to houses will likely be as a result of that. Our water supply will be obliterated, and lots of rocks will no doubt fall from the hills behind us onto State Highway One.
This little video is an excellent demonstration of just how liquefaction works, if, like me, you were a little mystified. I think it’s really clever.