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Nov 06 2011

The Night the Earth Moved

I used to believe I was a geologic disaster coward. I grew up in the shadow of the San Francisco Peaks, which is actually a single mountain that blew itself apart not all that long ago, on the edge of a volcanic field that was merrily tossing out lava flows and cinder cones a mere 900-odd years back. My elementary school was tucked in the flank of a rhyolite dome. Things had been quite exciting round there, and I used to watch the mountains with a wary eye, watching like a paranoid volcanologist for the slightest sign of steam or ash. We had city-threatening fires nearly every summer, winters sometimes dumped so much snow on us that roofs collapsed (and there was still talk of one winter in the 1970s when snow had reached the second floor and everybody was all snowed in, an event we had happily missed). We had all sorts of poisonous and/or violent wildlife running about. None of those more immediate threats terrified me half as much as the volcanoes.

But, said I, at least there were no earthquakes. Earthquakes were terrible, awful, no good, very bad things that I never ever in a million billion trillion years wanted to experience.

Then I moved to a subduction zone.

This may not have been the wisest choice for a geologic disaster coward. One might even say I hadn’t thought the matter through, and I really hadn’t. Oh, I knew there were volcanoes (St. Helens had blown her guts out right on my teevee when I was a wee little thing) and earthquakes (Nisqually, anyone?), but the volcanoes at least gave plenty of warning, so I could wave goodbye to the landlord on my way back home. And I just didn’t let myself dwell on the earthquakes.

When I did think about them, I figured the slightest tremor would send me into a blind panic. I’d scream like a little girl in a horror movie, I’d be as useless as the heroine tied to train tracks in a silent film, I’d lose my shit and freak the fuck out and, if I survived, probably flee Seattle never to return. But this place was too magnetically pretty for me to not give it a go, despite hazards. Forget San Francisco. I’d left my heart here and wanted to live with it again.

So this one night, not long after I’d moved up, I was lying in bed. Very late at night, everything’s still. We lived in an apartment complex not priced for college students, so the place was stone dead after midnight. Must have been around three or four in the morning. I had my physical geology textbook* open to the chapter on earthquakes, and I’d just got done with the earthquake strength section and was reading about earthquakes in the eastern United States when the bed did a little judder. I lowered the book and watched my feet. No, no cat down there – she was happily asleep somewhere else. No, no truck sounds. Nothing but deep silence and that tiny quiver. I waited for it to subside, and then flipped back a page to the Modified Mercalli Intensity Scale (Table 16.2) to look up the intensity (“II. Felt by only a few persons at rest, especially on the upper floors of buildings [hullo, that's me!]. Delicately suspended objects may swing”). I grinned, possibly giggled a bit, had that my-first-earthquake-how-adorable moment, and went on reading.

You never forget your first, even if it barely managed to wobble the bed. And the timing could not have been more exquisite.

The second earthquake was far more memorable.

So no shit, here I was beavering away at the blogging, and all of a sudden I notice the house is juddering and the cat’s sitting bolt-upright acting like the world’s coming apart. The shaking lasted nearly a minute. It wasn’t the kind of thing that would make a Californian blink, but to this Arizona girl, it was a little intense – and exciting.

Had to be an earthquake. The only other thing that could cause the house to start dancing would be an explosion, and while I had the headphones on, I didn’t have the music on that loud.

The cat is currently sitting by my chair pretending she never panicked, nuh-uh, not even a little bit.

The sensation of an earthquake’s hard to describe – it’s like being on a rollercoaster that’s rapidly weaving side-to-side. The power of it is astonishing. My gliding rocking chair didn’t know what to do – it was trying to go in all directions at once, which added something of a washing-machine-from-hell element to the whole experience. You can feel it in your whole body. Bizarre.

A moment before, all had been peace and stillness. I’d been enthroned in my gliding rocking chair, listening to music, tappity-tapping away on the laptop at five in the ay-em, and the cat had been sound asleep on the bed. I hadn’t noticed anything amiss. When you’re rocking and rocking out, banging away at a keyboard, a little thing like earth movement doesn’t get your attention right at first. But then she sat bolt-upright, straight and still with a panicked expression on her face, and stayed that way. I took my headphones off and looked round for the source of the disturbance. Nothing. I don’t even remember feeling the p-waves, which must have been what she was reacting to. But a few seconds later, the blinds started swaying. I watched them with total incomprehension. Why would they do a silly thing like that?

That’s when the s-waves hit in earnest, and the rollercoaster-washing-machine-from-hell-plus-maybe-a-bit-of-mechanical-bull-riding element impressed itself upon us, and that went on for what seemed like forever. Long enough, anyway, for me to go from confusion to the tiniest bit of fear and straight through to “holy fuck this is fun!” A glorious little 4.6 or thereabouts. A quite wonderful IV on the Mercalli scale. Lovely!

Mah First Biggish Earthquake

I went out into the living room to check things, and met my roommate coming out of her room. We did the “wow earthquake dude” babble, and then went back to our rooms, and I finished up my post on the excitement, and never did get my desired aftershock, alas.

I’ll never forget it. Never forget the sensation of those s-waves, or the thrill tinged with just the right amount of fear, or the sense that the earth round here is alive and kicking and stunningly fascinating.

There will be other earthquakes. They’re inevitable in a subduction zone. There will be felt ones, and ones that will knock things over, and ones that will do a hell of a lot of damage. But just so long as Cascadia doesn’t slip, and I don’t get whacked in the noggin by falling stuff, and I’m not out on a beach with a bluff just looking for an excuse to really let a landslide go, and I’m not on the Viaduct, I think you’ll be able to tell which one’s me in the crowd of hollering people. I’ll be the one screaming “Woo-hoo-hoo! Gimme a V, baby, yeah!”

And the last time I went to St. Helens, I looked deep into her non-steaming crater and pleaded, “C’mon, baby, just a little eruption. Something phreatic, sweetheart! Do some dome-building for Dana, now, there’s a good girl.” And I was disappointed when she didn’t go boom.

So much for my geologic disaster cowardice, then. I guess I’ll have to go find other things to be mortally terrified of.

 

(Inspired by Ron’s adventures with the Oklahoma quake, which in turn inspired the next Accretionary Wedge topic, but I just couldn’t wait.)

*No, I wasn’t studying for class. It’s a book I picked up used and was reading for fun. I do that. Leave me alone.

7 comments

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  1. 1
    terrypinder

    I’m still a little irate I’m the only one in my office who didn’t “feel” our big one (ha!) back in August. Everyone else did. I happened to be standing, stuffing a bunch of binders and was oblivious to our swaying building until everyone collectively gasped and I looked up to see blinds and lights swaying and the water in the water cooler sloshing.

    But I didn’t FEEL a thing. That is so weird!

    Everyone in my office is a native Pennsylvanian (Harrisburg) and most didn’t identify it right away. Some thought something exploded. I knew it had been an earthquake. I just didn’t know if it was close to us (there’s a low-level seismic zone to Harrisburg’s east, and there’s been a swarm of microquakes southwest of Harrisburg off and on for the last 2 years or so) or if it was far away. Once we saw people streaming out of the neighboring office buildings and I’d checked in on twitter to see people from DC freaking out, and New York freaking out, and Boston freaking out, and Toronto going what was that, I knew it had been a fairly large earthquake at some distance from us and we hopped on the USGS’s website and saw that big bright red box in Northern Virginia. It was huge! That’s when I got excited. It was cool!

    Needless to say, productivity was shot.

    This wasn’t my first earthquake. Growing up in the Philly burbs I felt 2 or 3 rather small ones that were so short in duration we weren’t certain they were quakes until the news told us so.

    My cousin got to be the lucky grandkid who got to go to San Diego with my grandmother. They promised him they wouldn’t have an earthquake. Guess what happened? Landers! Wish it’d been me!

  2. 2
    Marella

    I lived in Taiwan for five years, we had them all the time and typhoons too. Now I’m in Melbourne Australia, one of the least active places on the planet, very dull. There was actually an earthquake a while back but I missed it, I figured out I was probably driving at the time, so upsetting! Cars are terrible for noticing earthquakes, too well sprung and you’re already moving anyway. Then of course you can have too much excitement like in Christchurch!

  3. 3
    hotshoe, now with more boltcutters

    Great post, thanks !

    I’ll gladly take earthquakes any day over the inevitable disasters like tornadoes and floods which afflict most of the earth. Well, yeah, some places get more than one kind of typical disaster, but in the area I live, earthquakes are the only likely ones. Lucky me. And I love ‘em, just like Dana says – it’s a carnival ride. As soon as you’re confident you’re not going to be hit with a falling cornice, sit down and enjoy !

    A big enough quake or aftershock will be noticeable in a moving car. On the Mercalli Scale (wiki version) it’s VII, that is about Richter 6 and above. But my experience is that it’s noticeable at lower levels than that, at least in the aftershocks of a big quake when people are already sensitive. But it’s actually not too fun, because of the real fear that you or drivers around you will lose control of their cars and cause accidents.

    Hmm, that gets me wondering. I wonder if the amusement park rides near where I live have automatic earthquake-shutdown sensors. I’d hate to be going up the starting hill of a roller coaster when a big one hits.

  4. 4
    RowanVT

    I’m a bit opposite of you. My first earthquake was the Loma Prieta quake, and I was 7 years old. While I still live in the San Francisco bay area of California, I do worry a lot about another large quake. It took me until almost highschool to stop panicking at the feel of any shaking. I now have the proper Californian attitude of “Oh. Quake. Is it getting stronger? No? I’ll just stand here then and laugh at the non-natives.”

  5. 5
    geocatherder

    I had ceiling tiles shaking loose and falling in my vicinity during the Loma Prieta quake. The whole incident freaked me out — though I kept myself under control for several hours, until I was home safe and so was my husband — and for many years thereafter a truck going by could send my adrenaline pumping, much less a little quakelet.

    The important thing was that I knew what to do and I did it: go for cover, stay away from windows, wait until the shaking stops, and evacuate in an orderly manner. It was a shame I wasn’t outside; they say the waves in the ground were really impressive. Hunkered down on a concrete first floor, I could certainly feel them.

  6. 6
    Cujo359

    I have been through two significant quakes since I moved to the Seattle area. The first was in early 1995, a 5.0 quake that occurred when I was in a department store. Even though that sounds small, it was very close and it created some serious-feeling displacement. The second was the Nisqually quake, a 6.8 quake. I was working in a trailer that was about 6 miles from the epicenter.The floor moved enough to give me the impression of being on a boat for a few seconds. People who were outside said that they could see rippling in the parking lot’s asphalt as the quake passed.

    Neither was a pleasant experience. When the walls and the floor start to move it’s pretty unsettling. Smaller quakes are somewhere between annoying and amusing, but when they get big they are a disorienting and scary event.

  7. 7
    rutty

    I was “lucky” enough to be in 6.3 while serving with the Royal Air Force in Turkey. This was in 1997 I think. Our accommodation was “tent city” and I was sat in mine waiting for my shift to start. At first I thought the mother of all aircraft was taking off – such a HUGE noise – but the violent shaking soon made it obvious what was happening.

    Outside, everything was swaying about. It was very surreal. IIRC about 120 locals died in the nearby town (Adana), generally due to poorly-constructed buildings collapsing.

    A year later many thousands of Turks died in a much large 7+ earthquake in a different part of the country. Puts my little one into perspective.

    The potential power of our Earth’s geology is utterly terrifying.

    Thanks for the post :)

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