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How a 'Seismic Cloak' Could Slow Down an Earthquake
Daniel_Stuckey writes "The United States is currently gripped in a bout of earthquake mania, following a series of significant tremors in the West. And any time Yellowstone, LA, or San Francisco shakes, people start to wonder if it's a sign of The Big One to come. Yet even after decades of research, earthquake prediction remains notoriously hard, and not every building in quake-prone areas has an earthquake-resistant design. What if, instead of quaking in our boots, we could stop quakes in their tracks? Theoretically, it's not a crazy idea. Earthquakes propagate in waves, and if noise-canceling headphones have taught us anything, it's that waves can be absorbed, reflected, or canceled out. Today, a paper published in Physical Review Letters suggests how that might be done. It's the result of French research into the use of metamaterials—broadly, materials with properties not found in nature—to modify seismic waves, like a seismic cloaking device."
For some reason, this article made me think of that story about Tesla and his "oscillator" experiment:
http://www.angelfire.com/scifi...
I wonder if, rather than relying on these "metametals" in special soil, one could station units similar to these at strategic locations along fault lines, designed to pick up an earthquake's resonant frequency and generate a corresponding one tuned to cancel it out?
If you use waves to cancel out the quake I see two problems.
1. The amount of energy needed to cancel it out.
2. The risk that it may actually result in a worse situation somewhere else, possibly trigger an unexpected quake instead.
If builders built buildings the way programmers wrote programs, then the first woodpecker would destroy civilization.
Is the seismic cloak made of sheep's bladders?
I wonder if one could station units similar to these at strategic locations along fault lines, designed to pick up an earthquake's resonant frequency and generate a corresponding one tuned to cancel it out?
What are the power requirements? How many stations do you need to do the job?
I remember reading about this!
http://www.gutenberg.org/ebook...
"I'm too busy to research this and form an educated opinion, but I do have time to tell everyone my uninformed opinion."
Let's see, first let's try and stop Plate Tectonics. First let's shut down that big old nuclear furnace at the center of the Earth... Nothing to big to do there...
After which the electromagnetic field shielding the earth stops
and we all get hella bombarded by solar winds..
This is a bad sci fi movie plot, April Fools
Harrison's Postulate - "For every action there is an equal and opposite criticism"
I'd like to order ten thousand amplifiers and about 20,000 kick-ass bass cabinets... oh, and one microphone and phase inverter...
if this is supposed to be a new economy, how come they still want my old fashioned money?
But where would we get a set of headphones that big??
Coder's Stone: The programming language quick ref for iPad
Everyone knows earthquakes are particles not waves!
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What they do, as I gather from the article, is that they drill holes in specific patterns around installations. The pattern then absorbs seismic waves and turns them into sound and heat at the focal points of the waves. No idea how much heat or sound, but in general it's an improvement over having the building destroyed.
Therefore, by the (faulty) logic you're using, you're just a cow with a keyboard - osu-neko (2604)
It doesn't mean what you think- oo practical building can resist all earthquakes. The building standards are more about if a large earthquake occurs the building damage should be it limited to a small area. And it isn't about having a usable building after a quake - it is about not killing the people inside or around it.
Speaking from experience, just because a building stands up during a quake it doesn't mean that the building won't be structurally broken and require significant repairs or replacement before it can be used. The energy has to go somewhere!
There's also a small chance of creating an unexpected doom.
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"Significant tremors in the west"? The recent earthquakes used to be business as usual back in the 80's-90's. We'd have them at least once or twice a year, if not more, and it never really raised an alarm. We've just had such a dry spell since 1999 (or '94, if you want to keep it in the LA basin), that these light/moderate earthquakes seem like big news. The bigger story should have been "Where the hell are all the earthquakes??" for the past 20 years.
What if you could attach a line of giant shock absorbers across fault lines? The plates wouldn't be able to move fast enough to cause an earthquake right?
Totally impractical, especially considering the amount of anchoring that would be needed to get a meaningful structural attachment to a tectonic plate, but I wonder if it would work in theory.
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The primary problem with this concept is that you have to know very precisely the composition of the ground where you install this barrier. Another problem is that environmental changes - soil moisture, temperature, are going to affect the material properties somewhat (but maybe not enough to matter).
Essentially, extremely low frequency waves that trash buildings don't perceive the ground as atomic, the waves act over their wavelength, which is very long, and so if you put things into the ground, it changes the material properties. Carefully drilled holes apparently can change the properties in dramatic ways. The word "cloak" is sexy, but the more interesting bit mentioned at the end of the paper was the prospect of building a bandstop damper with the low corner at 0 Hz.
It doesn't do you much good if your earthquake prevention device reflects the energy somewhere else dependent on the epicenter, and it also doesn't do you much good if it doesn't block enough frequencies to stop it from trashing your buildings. A bandstop filter would operate over a broad enough band to attenuate all the frequencies, and it wouldn't reflect energy to other buildings (which could have obvious liability concerns.) Imagine a plaintiff's attorney showing a standing wave pattern of destruction emanating from a field of holes drilled by the defendant's firm.
The other satisfying nature of this tech is that it's proactive. Instead of building structures that will probably collapse if a magnitude 8 happens anyway, you go out there and build armor that will stop the earthquake entirely. Also, a field of holes and concrete and various pertubations, all buried, is a lot less ugly than the structural changes needed to reinforce a building against a major earthquake.
It would be expensive to do the detailed surveys and compute the solution, but it would create more high education jobs, and it's probably worth doing.
Seems a lot easier to just build the building properly to begin with.
I think the idea with the metamaterials is that it would cancel out the waves passively.
I think we're ok with triggering a worse situation somewhere else. That's what we do best.
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Very true. Waves have both constructive and destructive interference, and the sources would have to be perfectly aligned to really negate the energy. That of course means your cloak would need to be deep inside the earth exactly where the seismic energy is coming from. And good luck at injecting enough energy to affect trillions of tons of rock exactly in phase with a seismic wave that you didn't know was coming exactly at that instant. This kind of nonsense could only happen on April 1st.
But not for technical reasons. While the engineering would be difficult to do, it's possible.
The problem is legal. It stems back to a question a friend of mine asked when noise-cancelling headphones first appeared. "If a sound wave has energy, and an equivalent wave 180 degrees out of phase also has energy, and when you combine the two you get no sound, where does the energy go?" Obviously the energy for both waves goes to regions where the two waves don't cancel.
So if you protected an area with this device, after an earthquake you'd be sued into oblivion by neighbors claiming your device increased damage to their property.
what are the consequences of sending those "anti-waves" on other parts of the world, there is a reason those 'waves' are going on.. those 'waves' are also a way of releasing kinetic energy that has been building up, but what will happen if you just send the released energy back, it might just pop out at the other side..
If you start putting stupid autoplay on stories, they cannot be read at work. And Slashdot will die.
What the heck is wrong with you guys?
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True. But what if the building is built already? Say, a building from 20 years ago.
If it can produce waves powerful enough to dampen an earthquake, then it can produce an earthquake.
I am very small, utmostly microscopic.
Seriously, somebody needs to find a way to eliminate the wave propagation of heavy traffic. IMHO, those entrance ramp meters are a dumb idea. It just backs up traffic onto the local roads. Foot on the gas, people!
I call BS on this. There is a basic "fault" to this argument.
Ground can be solid rock or sedimentary deposits and the two react to quakes differently.
The 1926 Yokohama earthquake had vertical displacement of up around 9 feet as I recall from the books I have on it. A cloak would be worthless.
A slip fault at the San Andreas in Parkfield, CA might have part of your property moving North by some feet compared to the other side. You are not going to be able to stop those amounts of movement.
I understand we can build cancellation structures for waves that do horizontal propagation, but what about vertical propagation?
I'm pretty sure this is an April Fools joke. While it would be *theoretically* possible to cancel out an earthquake by producing waves of the exact same amplitude but opposite phase, people are forgetting the "same amplitude" part. Earthquakes generate a HUGE (absolutely HUGE) amount of energy, and you have to throw the exact same amount of energy (with inverted phase) back at it. How are they going to generate this huge amount of energy? Certainly not with a few speakers. Even small earthquakes generate as much or more energy than a nuclear weapon.
Good points. The amount of energy a Mag 8 earthquake (like the one that just hit Peru) is roughly equivalent to 2,500 nuclear bombs. So presumably the power to generate "noise cancelling waves" would be of a similar order of magnitude. Presumably this amount of power would have to be deployed at an exact time and location in order to be effective. I think I'm starting to see a problem with this plan.
As for Korea, just detonation 2,500 A-bombs should do it, we don't need no stinkin earthquake generator.
People seem to completely miss the key part of this experiment... The energy has to go somewhere:
Just think of it... Those with the most money to spend, get to be earthquake-free, but everyone else gets their earthquake intensity INCREASED, perhaps DOUBLED.
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Can we somehow make something that turns earthquakes into usable energy like electricity?
Kinda being serious. Feel free to laugh me out of /. for a month.
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Exactly. Or even older structures in "historical" areas. You can't always build fron scratch. This is a promising way to deal with area protection.
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