Earthquakes in the Sky

Back in March, Pruned posted a short video of a Japanese earthquake van – a video which I'll embed here for ease of reference:

If you don't know what a 9.0 earthquake really feels like – and, thus, how to stay safe when one hits – then you can just build a mechanical representation of a 9.0 earthquake, a kind of robotic stand-in for the earth's surface – call it RoboHeidegger® – and let the public step in for a ride.
You've got yourself an educational experience – and an interesting small business model, at the same time.
But maybe you don't need a van like this to simulate earthquakes; maybe there are other ways of experiencing seismicity that geologists have so far overlooked.
It occurred to me last week while flying over Canada that turbulence is a kind of unappreciated seismic resource. For instance, our plane hit a strange quilt of winds – an atmospheric event, like an earthquake in the sky – over the Canadian Arctic and so the plane began to lurch, rattle, drop, and slightly tilt, and this went on for several minutes.
To quote Wikipedia, we hit "invisible bodies of air which are moving vertically at many different speeds."
As far as I can tell, then, those "invisible bodies of air" are a permanent part of the sky geography of the Canadian Arctic; like a mountain range on land, these curling, rising, marbling, and sifting winds move invisibly through Arctic airspace like a permanent feature of aerial terrain, ready to rock passing airplanes.

In any case, it seemed like aerial turbulence might be a very good analogy for the structural motions of earthquakes.
In fact, you could install some sort of in-flight dashboard – with a BLDGBLOG Seismology Plug-In™ – that tells you, in real time, as you experience aerial turbulence, how that turbulence would register on the Richter Scale. I think people would be shocked to realize that they have very likely experienced a 6.0 earthquake in the sky – only it was called turbulence and they were sitting inside an airplane.
3.0s and 4.0s would be so common as to be coextensive with air travel.
So you take geology students up on an airplane in a thunderstorm – and they'd soon understand what an 8.5 feels like. Or a 7.2, and so on.
Of course, a few questions arise – such as how accurate this analogy really is, and whether I have any idea what I'm talking about. But I also wonder, if this does hold, whether airplane design has anything to teach engineers who work in seismic zones. Should the foundation of a Tokyo high-rise, or a single-family home in Los Angeles, be designed more like an airplane fuselage?
And could the exact same thing be said for ships at sea – that certain large waves, or certain stretches of choppy water, are like a 6.0 earthquake – and could this also extend, then, to particularly bumpy stretches of road – that, at 35mph this road is a 4.0 earthquake, but at 75mph it's a 9.3 – and could the same even be true for railroad travel and bumpy subways?
Could you deliberately build roads – with bumps and holes and bad paving – to simulate certain types of earthquakes? You then drive on these roads at certain, specific speeds, taking notes with Caltech geologists.
In which case, perhaps a car chassis would offer an intriguing structural analogue for future home designs in seismic areas...?
All these earthquake analogues – experiences awaiting their Richter Scale – constantly surrounding us.

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15 Comments:

Anonymous Irve said...

Could you deliberately build roads – with bumps and holes and bad paving – to simulate certain types of earthquakes?

Indeed you can, some of the roads in Tallinn, Estonia, register as magnitude 6 earthquakes on my internal Richter scale. This is by no means deliberate, however

July 11, 2008 1:06 PM  
Blogger Chris said...

I guess one of the primary differences between an earthquake and turbulence/bumpy roads is that the vibration due to an earthquake is largely horizontal, wheras turbulence and bumpy roads are largely vertical vibration.

July 11, 2008 1:44 PM  
Anonymous tomé said...

Oh, trains are so great.

July 11, 2008 3:25 PM  
Blogger Derrick said...

What would a fall down a flight of stairs be? At least a 6.0 my friend... :)

July 11, 2008 9:55 PM  
Blogger KimiK Gibson said...

I find it amusing that they built an earthquake simulator into a truck. Trucks have shocks, right? Full suspension wheels? Why don't they just build houses with full suspension, so in the event of an earthquake, people will have to worry less about climbing under tables to escape from falling ceiling tiles because the massive vibrations from the earthquake would be essentially nullified by the suspension system. This, of course, would only work if the entire ultrastructure of the house was built to withstand earthquake tremors.

July 12, 2008 10:29 PM  
Blogger J E Carter II said...

Airplane superstructures are made of Aluminum - a metal known to warp and bend easily. This gives airplanes flexibility to survive turbulence and rough landings and straining take-offs, but every flight ends (or begins) with structural inspections looking for damage. Is the aircraft safe to go up again?

Air frames are flexible, but built to need repair and replacement parts as a matter of normal operations.

Buildings, on the other hand, use steel, monolithic counterweights, fluid foundation interfaces and structures that do deflect a bit in earthquakes. They generally receive less scrutiny on a regular basis than buildings.

Advantage structural engineers - steel is too heavy to fly, even coach.

As for roads as simulators, Ohio's section of US 33 for a while simulated a pretty good 4.0, which I referred to as "the Michigan Simulator" because at the time, no road in MI was less than a 6.0.

July 14, 2008 6:55 AM  
Anonymous rfr said...

All late-model Apple notebook computers can already function as seismographs, so there are thousands of passengers who unwittingly have the capability to measure this. The Mac laptops have built-in accelerometers, originally intended to park the hard drive heads when they sense the computer is in free-fall, and maybe about to hit the floor. You need software to access the accelerometer data, but there is at least one shareware program that does this. It is called "Seismac," and is being used in California to attempt a kind of "crowd-sourced" earthquake-sensing network. (On terra firma, that is.)

July 15, 2008 11:34 AM  
Anonymous Anonymous said...

flexible airplane structures reminds me of the old russian airliners that used to flex so much that the overhead bins would all pop open on takeoff and landing. those were the days.

July 15, 2008 12:19 PM  
Anonymous Anonymous said...

I like your site and its very informative and interesting - but your sense of humour is a bit off-putting.

Eg - Dumb New Product Idea™ TWICE

July 18, 2008 11:07 PM  
Blogger Geoff Manaugh said...

Sorry®

July 19, 2008 1:37 PM  
Blogger the mad LOLscientist said...

My first flight ever - nonstop from Pittsburgh, PA to LAX when I was 17 - was at least a 7. We dodged thunderheads all the way.

July 19, 2008 2:32 PM  
Blogger Anthony said...

You've confused "magnitude" with "intensity". Magnitude (the numbers you were throwing around in your post) is a measure of the total energy of an earthquake. However, what's important to the people experiencing an earthquake, and people designing for one, is "intensity".

Intensity is a function of the magnitude of an earthquake, and the distance you are from the source of the earthquake. Any given earthquake has only one magnitude, but the intensity varies depending where you are.

There are a number of different ways of measuring intensity, but one way is to measure the peak acceleration caused by the earthquake at the location of interest. This is *directly* comparable to the accelerations experienced during airplain or automotive turbulence. The largest earthquakes cause accelerations on the order of 1g in the immediate vicinity of the epicenter. I haven't experienced airplane turbulence that bad, but I know people who have.

July 22, 2008 7:01 PM  
Anonymous Anonymous said...

Your analogy doesn't really work at all. Since we land creatures don't really belong in air-filled aluminum tube at 30,000' above the surface of the earth, what's a little turbulence, or a lot for that matter. Without that presurizd tube, you wouldn't be there anyway.

What's so disconcerting about a earthquake is that the actual ground beneath you become destabilized. If you can't trust the ground beneath you, what can you trust?

July 30, 2008 2:19 PM  
Blogger Geoff Manaugh said...

Your analogy doesn't really work at all. Since we land creatures don't really belong in air-filled aluminum tube at 30,000' above the surface of the earth, what's a little turbulence, or a lot for that matter. Without that presurizd tube, you wouldn't be there anyway.

Very well thought-out, anonymous: We shouldn't be there, so turbulence can't be compared to an earthquake.

That makes sense.

July 30, 2008 2:48 PM  
Blogger J E Carter II said...

Also known as a Non Sequitur bit of reasoning. Fits perfectly with we can't run faster than 30 mph or so, therefore we can't compare tread ware to breaking a sweat.

July 30, 2008 9:14 PM  

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