Friday, February 25, 2011

Earthquakes in Christchurch

While I was in Christchurch (a few days after the current timeline in the travel stories), there was one morning where there were about 6 earthquakes from 6 am to noon, varying in magnitude from ~3 to 5.  The first one woke me as I was sleeping on the floor at a friend's house.  Since the internet was still working, I surmised that it couldn't have been that strong and found a website that verified the earthquake and listed the magnitude.  Throughout the morning, every time I would feel a tremor, I would wonder how much longer it would last and if I should run to a doorway.  Having grown up in California, I was taught at an early age to find shelter under a desk or in a doorway, away from windows or things that could fall on top of you.  Unfortunately, my friend's house was of the older variety, and as I watched the cracks in the plaster grow, I began to wonder if maybe I should be running out of the house.  Luckily, that burst of activity subsided and really only provided fodder for the Busker's fair which started the next day.

These earthquakes in the Christchurch area started with the 7.1 quake in early September.  Located on a previously unknown fault line, the effects of the earthquake were obvious when I came through in November on my way south.  The town has a heavy use of brick construction, and most chimneys fell victim, as did several historic buildings.  The Boxing Day aftershock was even more damaging to some buildings due to the shallow depth of the quake (only 5 km below the surface) and the types of waves produced.  It was "only" a 4.9, less in magnitude than some of the ones I felt sitting on my friends couch on January 20th, but seriously added to the damage still lingering from the September quake.

Which brings us to this Tuesday, February 22nd.  If you've been avoiding the news, there was a magnitude 6.3, centered very close to the city center.  People are still trapped in fallen buildings and the death count keeps rising.  A friend from the ice left New Zealand only 24 hours beforehand.  The Windsor B&B just announced they are closing.  And my friend Biz is now homeless.  Not terribly surprising, most of her neighbors mentioned they thought the place would be condemned after the first two big earthquakes this year.  Most people were very lucky, but the town just can't seem to catch a break.  All the more disturbing because Christchurch had such a great atmosphere filled with wonderful people.  Having lived through the 1989 Loma Prieta earthquake (6.9, but at the time everyone said 7.0), I'm very familiar with the damage an earthquake can cause.  I'm still ridiculously nervous about driving across the Bay Bridge.  But the big ones in Christchurch just keep coming and the damage doesn't seem to end.

To recap the geology of it all, the first quake came from a unknown, dormant fault.  The damage caused by the quakes varied based on depth and distance of the epicenters.  The aftershocks are still occurring.

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