Monday, September 06, 2010

Wake up call

Listening to: The Trip 3 - Various artists (1994). Starting in 1992 The Trips were a series of compilations put out by Warner Music in the 1990's to showcase the 'alternative' music scene as it was. I have 1 through 7. By the time 8 and 9 rolled around the series was starting to lose focus as the scene itself evolved. I think it got up to 10 or more before they pulled the plug.

Apologies for the cliches, but Christchurch city took one for the team on Saturday, while managing to dodge a bullet at the same time:

Big news linky

Slightly more scientific linky

Photo collection from various sources showing faulting, ground cracking, liquefaction, damage and the like linky

The taking for the team bit was reminding the country that powerful earthquakes can happen anywhere in New Zealand, even those bits thought not to be as prone to them as others, and that household disaster 'get through' kits are a good idea and a useful thing to have, and not just because some guy who used to be on Shortland Street says so on the TV. The bullet dodging was in the timing. 0435 was about the best possible time for a big earthquake to happen, with empty streets and people in their houses asleep. Not that many hours either way and it could have been a lot worse for the inhabitants.

Christchurch's experience has been interesting to watch unfold, thankfully from a distance. It is reassuring to see that building codes, plans and preparations seem to have worked, especially from a Wellington perspective, since this will happen here one day. Being on a different faultline, the Christchurch shake hasn't changed our odds any. The morgue is making a good point at the moment regarding preparation (link); it is something people need to think about, and judging by the reports about big buy ups of essentials over the weekend in Wellington a great many more are thinking about the inevitable than were last week. It is one of the reasons why I have my shoulder bag of useful stuff with me almost everywhere I go. I have certainly been pondering my scenarios a bit, and trying to plan ahead. We have the basis of a survival kit in our house, and will be completing it over the next little while (although part of me is aware it won't be much good if we aren't at home at the time, and wonders where you stop. Survival kits for the car maybe? Our cars already have first aid kits in them at least...).

Somewhat ironically, I slept through the earthquake even though it woke many others around Wellington. I didn't do my usual morning news check either, so remained unaware anything had happened until catching a bit of a news update around lunchtime. The ground under our place is a bit firmer than in other parts of the region, and seems to have a slight dampening effect on earthquakes, whereas other parts (like say where I work) could potentially amplify the shock. We have only noticed a few earthquakes since moving in four years ago. I felt this one no problem though (link).

Some on the ground in Christchurch say the earthquake was an audible thing, something I have no trouble believing. I have heard earthquakes coming before (albeit only a fraction of a second before they arrived, and have been known to tense up on sensing the bass rumble through the house generated by a passing truck. The first couple of seconds of any shake I always spend wondering if this is it, the fabled big one, and if I need to take cover. I have noticed though the biger the initial tremor, the more automatic my doorway finding is.

The worst shake I have experienced was this one (link) five years ago. It was only 5.5, but I was effectively at the epicentre. I had just sat down at my desk in my big industrial building, when there was a loud, very loud bang from the roofspace above. Knowing there was a lot of plant equipment up there, my first thought was that one of the air handling units had suffered a catastrophic failure and somehow exploded. I didn't quite finish the thought before finding myself in the doorway, not quite knowing how I got there as the shaking started. The bang was the first part of the shockwave hitting the metal roof structure of the building, having already passed through the concrete walls without causing attention. This all happened in less than a second, but it was an interesting thing to observe once the shaking had stopped and we had all calmed down.

While kind of inured to the notion of earthquakes over time, the actual sensation and accompanying adrenalin dose is something I have never quite gotten used to.


missrabbitty said...

nice to see you called it liquefaction...not liquification as purported in the media...and also...god didn't save the methodist van...interesting.

and on the plus side, i see christchurch now has a purpose...big ups for them :P!

i'm on the valley floor and i felt it. but as a wellingtonian who has lived through all our shaking i'm a bit blase. i hear it coming (being on the fault) and go 'cool, an earthquake', however will probably crap myself for the biggie.

and my favourite wellington earthquake memory is one from the early 90s. i was in the kirk building in a biochem lab in my second year at university. we felt the shake and turned around to see the first years on the other side of the lab had disappeared (they were under their benches). we second years just blithely carried on despite the threat of moving centrifuges that were all in use at the time. if it had been any bigger they'd have taken the corner off the building.

Off-Black said...

Thats because I know the difference between liquification and liquefaction, and did so before it became the media's new favourite word...:)

I saw a centrifuge walk across a bench once, grinding a test-tube to a very fine powder as it did so. I then spent a few years working amongst other things with a big industrial liquid centrifuge that could separate 1000+L an hour. Every so often it would need to clear itself of the built up debris, a valve would open and the whole thing wighing a couple of hundred kilos and hard-lined in several directions would twitch on its mounts at 1200 rpm. I never quite got used to it. I always had a slightly irrational fear that the twitch would turn in to a walk, which in this case would probably take it through a wall and anyone nearby...

missrabbitty said...

how flippant was i in this comment particularly seeing as three of the guys working in the methodist church for the 22/02 quake did not survive?