Wednesday, December 29th, 2010
9

The Shake Of Things To Come

One of the things I remember most vividly about the 1994 6.7 magnitude Northridge earthquake is the Budweiser six packs of canned water they gave each of us at my elementary school a week later. I also remember waking up about thirty seconds before the quake, and sitting up in bed, and the wood shelf that fell where my head had just been. I sat on the edge of the bed and I looked out the window into the darkness and for some reason I felt like I was deep underwater as the world lurched into a kind of long, undulating wave. It lasted for 45 seconds, which of course felt like an hour. When it was over, more than 9,000 had been injured and 72 died. There was $20 billion in damage. It might've been worse, had it not happened at 4:31 a.m., with few cars on the road.

But still the canned water was somehow the most memorable. Anheuser Busch plants near disaster sites often divert their operations from beer to water and donate it—Louisiana and Texas were full of the stuff post-Katrina. When you see those cans of water, you know things are really bad. (Though when you see those cans of water at age ten, you also think they're awesome, but here I digress.) And given our track record, I'm half-expecting to see those cans again in 2011, or at least some time in the next decade. After all, we're due.


It is not a disaster coming toward us, but one that strikes under us, the earth itself erupting violently, and in this way a quake is far more insidious and terrifying than most "natural" disasters, a real-life armageddon scenario. We can predict and fight fires, floods, hurricanes and cyclones with decent accuracy—we can usually do it in time to run from them, too. But there is little one can do to hedge against earthquakes. Our most sophisticated prediction devices and dedicated seismologists are now capable of warning us of an earthquake seven minutes ahead at best. And even then, if you're on the train, or driving across the Bay Bridge, or in a tall soft-story wood frame building with a parking garage on the bottom, you're pretty much screwed anyway. You can't even insure for quakes anymore, thanks to how expensive Northridge ended up being.

And so if you live in one of these quake-prone places—there are millions of us—you are staring down a little End of Days every day.


The physics of a quake vary, depending upon the nature of the plates involved and how close the waves occur to the surface of the earth, though each causes foundations to crack and highways to crumble, tsunamis and landslides, death and destruction. Each follows a basic trajectory, though. Please allow a brief science lesson: The surface plates of the earth (the lithosphere) sit on top of a lubricated layer (the athenosphere); where these plates meet, we have fault lines. The plates are constantly moving apart, which allows lava to bubble up between them, and together, building energy and causing quakes, and sometimes surface ruptures.

The nature of each earthquake is distinct depending upon the exact movements of the plates. Some push into each other horizontally, some vertically, and others move against each other in opposite directions; some have huge magnitudes, or P waves, but weaker ground accelerations, while others, like the Northridge quake, are the opposite. The stronger the ground acceleration, or S waves, the worse the damage.




About 8,000 earthquakes are recorded every day, most of them under water or in the middle of nowhere or just too small to really be felt, or cause any damage. A 7.4 like the one that hit near the Japanese islands two weeks ago, or the 7.6 in Vanuatu just on Christmas Day, if they shook under Los Angeles, would likely cause far more destruction than 1994's $20 billion.

This year we saw some of those scenarios play out: a 7.0 in Haiti that killed 230,000 and displaced one million; an enormous 8.8 in Chile, which triggered a tsunami and killed 800; and a 7.1 in Christchurch New Zealand, which only injured two. The vast difference in resulting damage highlights the fact that we measly, delicate humans actually do have some defense against earthquakes, in designing our architecture and stocking up on canned food and bottled water. The Haiti quake was the most destructive this decade in large part due to Haiti's fragile infrastructure rather than the strength of the quake.


Californians have seemingly unhealthy relationships with earthquakes, a kind of necessary but deep denial—we dread them and yet we half-expect them constantly, half-want to just have it happen now, get it over with. And why wouldn't we? There is no real coming to terms with this. After all, there is a 99% chance—truly, 99%—that the state will be hit with a Haiti-level quake within the next 30 years. Broken down, that's a 67% chance that Los Angeles will face a 6.7 or greater quake in the next 20 years, and a 63% probability for the Bay Area. That is as specific as our seismologists can get. If we're lucky, we might find out with enough time to dig out the first aid kit or make a weepy phone call.

They've found that five quakes of about a 7.0 magnitude or greater have struck the East Bay's Hayward fault between 1315 and 1868; they don't know exactly when they hit, but that's an average of one every 140 years. Of course, 1868 + 140 = 2008. So we are not just due, really, but overdue.

If I were feeling more abstract and maybe religious about this I might say this is a morality lesson for how we might all face down our potential (and, let's face it, ever-closer) demise. That doesn't seem quite fair, though. Because I'm still fucking scared. I obsessed over the East Bay shake maps before I moved into my apartment in Oakland (in a two-story wood frame structure built after new earthquake preparedness codes went into effect). I live less than two miles from the Hayward fault, but there's no telling where an epicenter might be along that 37-mile strike-slip. Still, we're in the "very strong" and not "violent" zone, as we're on bedrock and not landfill. (Sorry, Alameda.)


So when people talk about our Mayan End Times come 2012, my only point of reference is 1994 and how all of the bricks from the sidewall next to our house were scattered into the street like Legos and I cut my feet on the glass in the kitchen in the dark. But this armageddon scenario is real, and for those of us in the San Francisco Bay Area, it's coming any second now. Any… second… Now! No? Well, anyway. All things considered, our chances of survival are still pretty decent!

Susie Cagle puts her journalism degree to good use by cartooning regularly about food, politics and her old government job.

9 Comments / Post A Comment

BoHan (#29)

I hear you. I looked out my broken window, saw fireworks shooting out of the top of every telephone pole, car alarms going off everywhere, and went "Fuck, the Big One." Boy was I wrong. On the plus side, the sexy drinky earthquake parties that next night were awesome.

Time gets very very weird and distorted during quakes.

This is why, even when I am not in earthquake country, I can't have heavy things that can potentially fall on me anywhere near the bed. See also, flashlights stashed in various places all over apartment.

On the other hand, I live over the methane gas pockets of Mid-Wilshire, so there's a good chance we'll explode in a huge ball of fire after the big one hits.

BadUncle (#153)

Or you'll sink into tar pits!

Eric Spiegelman (#3,968)

I was in 10th grade, lying on the floor of my bedroom, pulling an all-nighter to finish a U.S. government paper. At around 3am, our parakeet started making a very strange sound. A long, loud, single note. Not at all like the normal chirping. It was particularly weird because she was covered, like she was every night, and usually she was asleep. I went to check on her, she was wide awake. I decided then that I was tired, and that I'd done enough work on the paper and could probably finish it during first period. So I went to sleep.

Little over an hour later the earthquake hit, and my giant hundred plus pound bookshelf with dozens of books had ripped out of the wall (it was supposed to be earthquake-stabilized) and toppled over right where I was studying.

The other thing about that night was when I ran outside like you're supposed to, I forgot about the earthquake immediately and entirely for about five minutes, because for the first time anyone could remember, you could see the Milky Way from Los Angeles. A citywide blackout can be quite amazing.

omitofo (#4,921)

my family's house was on solid ground in the hollywood hills (granite absorbs the quake). Nothing even fell down off our shelves.

J.P. O'Malley (#7,367)

Not to be a shithead (I am a shithead!), but your fault diagrams are incorrect: normal faults are caused by extensive forces (i.e. walls moving away from each other; Foot walls move up relative to Hanging walls), and reverse faults are caused by compressive forces (walls move towards each other; Foot walls move down relative to Hanging walls). This is something I drill into my GEO 101 students relentlessly. Otherwise, your illustrations are very good!

Susie C. (#9,217)

You're not a shithead, J.P, you're totally correct! My late-night copy mistake there — normal and reverse should be switched.

BadUncle (#153)

The relationship of Californian to Earthquake almost seems like domestic abuse, with the victim alternately pretending the situation isn't that bad, and hoping that today won't be the day they piss off their tectonic assailant. Though a born-and-raised Californian, the only time I ever consciously noticed a quake was while I was in College in upstate NY.

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