Wednesday, May 14, 2008

The China earthquake.

First Burma, now China. And with this latest disaster, the stories that break every parent's heart: schools buried under tons of rubble, entire families lost. I just read a CNN story about the tragedy at Juyuan Middle School, where hundreds of kids are still trapped. The sound of firecrackers fills the air each time a body is found; it's a Chinese tradition to ward off evil spirits.

A reporter says he hears firecrackers every five or ten minutes.

I think of China's one-child policy, and I almost can't read any more descriptions of grieving parents hurling themselves on their child's body.

The truth of the matter, which a lot of people don't talk about, is that when you have a child after miscarriage and infertility, one of the things that makes you want to have another child is the fear that something will happen to the first. Not that the second child could make up for the loss of the first. Nothing could. (Note: I didn't say that these feelings made sense. That's why another word for these feeling is "neuroses.") In fact, one of the feelings you have to manage, as the parent of a "singleton" (especially a singleton who almost didn't happen in the first place) is fear. Because if you don't find a way to manage the fear, you'll live your life like you're walking around with a gun to your head.

So in an effort to do something other than drive myself crazy and make donations to disaster relief (which I've done), I asked my brother the architect a few questions.

Cynthia: So why did all those schools and buildings collapse? Other than the magnitude of the quake. Don't they have building codes in China? Give me your architect's opinion and I'll put it on my blog. [Editor's note: If this sounds a bit like a sisterly demand, remember that this is the brother whom I once threatened, in my diary, to sue for ruining my childhood.]

Cynthia's Brother: The media is saying it's because of the vast right-wing conspiracy. Just kidding. Don't put that on your blog.

Seriously, I don't know enough about the facts to offer any type of opinion. [Editor's note: As you can see, my brother does not live in Silicon Valley.] It could be due to the amplitude of the quake, just as much as the magnitude. Amplitude is the measure of the quakes wavelength. Imagine ripples across a pond. Either they come in big rolling waves, or short frequent ripples. A building has amplitude also. If the amplitude of the building matches that of the quake, it's bad news. Thats what happened in Mexico City back in the 80s when that big quake hit, and why there were so many failures of a certain building type, such as newer 3-to-8-story apartment buildings, while a 150-year-old cathedral right next door was left undamaged. Sometimes it's just bad luck.

Cynthia: OK. But I don't understand how a building can have amplitude? (Sorry, English major here.)

Cynthia's Brother: A building is either built extremely rigid, or designed to flex. It depends on a lot on the structural system used. Imagine a Bundt cake taken out of the mold. One cake is Jello, the other is regular flour cake. Then you shake the plate it's sitting on. The Jello one wobbles (at a certain frequency/amplitude), the other one stays relatively rigid.

Cynthia: Which is better? The one designed to flex (Jello), right?

Cynthia's Brother: You want the building to flex to a certain point, but again, you don't want the amplitude of the building to match that of the quake. You have to shake pretty hard to get the flour cake to fall off the plate, but if you get the jello one going just right, it will wobble-roll right off.

There's one state-of-the-art high rise being built, I think in Taiwan, where they are placing a giant suspended counter weight at the top of the building to counter the oscillation of the quake.

A structural engineer would really be able to give you better information. If you'd like I can put you in touch with my structural engineer and she could fill in the blanks. [Editor's note: This is loving brotherly code for "I'm busy, sis, get back to work."]

Cynthia: Thanks, dear brother. (OK, I really didn't say that. But I should have.)

So now I understand the science of earthquakes and building a little bit better. I still don't understand the why. Not "why are there earthquakes?" I get the stuff about tectonic plates and all that. I don't understand the why of children buried under earthquakes. The why of firecrackers.

No comments: