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Earth Science

How a 'Seismic Cloak' Could Slow Down an Earthquake 101

Posted by Soulskill
from the shake-rattle-and-roll dept.
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."
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How a 'Seismic Cloak' Could Slow Down an Earthquake

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  • Interesting .... (Score:5, Interesting)

    by King_TJ (85913) on Tuesday April 01, 2014 @03:41PM (#46632981) Journal

    For some reason, this article made me think of that story about Tesla and his "oscillator" experiment:

    http://www.angelfire.com/scifi... [angelfire.com]

    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?

    • 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?

      • by BreakBad (2955249)

        How many stations do you need to do the job?

        And where?

        Sometimes I feel like the people who make all the squiggly looking equations are just making shit up to spend tax dollars.

        • Re: (Score:2, Offtopic)

          by geekoid (135745)

          your statement sums up the tea party.
          The government is spending money on stuff I don't understand, therefore waste.

          • your statement sums up the tea party.
            The government is spending money on stuff I don't understand, therefore waste.

            Then explain it.

            If, after you've explained the topic in an understandable and non-biased manner, the person in question maintains their previous mentality, then it's appropriate to be a dick about it.

            But not before. "Catch more flies with honey," and whatnot.

      • A couple of free energy generator will suffice.

      • Enough to move a Continental plate.

      • by King_TJ (85913)

        Well, obviously, I'm not Mr. Tesla and I'm just throwing the general idea out there, for people more knowledgeable than myself to argue the details / merits of it.

        But his original oscillator was steam powered and quite small in size. The whole point was that it would continually amplify the initial frequency with each repetitive slamming of the piston into the ground, making an initially small wave very large. It doesn't sound like it would require all that much energy, even if you built it much larger in

    • Re: (Score:2, Interesting)

      by Anonymous Coward

      The difficulty in wave cancellation is that you have to work with the interference patterns. Unless the source and countersignal are in exactly the same location, the interference will lead to both flat regions and double-amplitude regions. Noise-cancelling headphones work by exploiting a chokepoint where the signal strength involved is low enough that the constructive interference will be miniscule and in (for the numbers involved) harmless locations.

      If you can't artificially dampen the quake, the next m

      • by CanHasDIY (1672858) on Tuesday April 01, 2014 @05:08PM (#46634051) Homepage Journal

        If you can't artificially dampen the quake, the next most viable method would be to surround vulnerable locations with possible countersignal generators and turn on those that would interfere favorably for the protected area. This may have dramatic and destructive side-effects elsewhere...

        Like how 2 raindrops in a puddle can cancel the waves of a third in the middle, but send waves of their own radiating outward from their own epicenters.

      • by AK Marc (707885)
        I think digging a city out, and filling the gap with a new material that moves in an earthquake, absorbing the waves, or reflecting them, protecting the city. No need for anything active to make a seismic cloak.
    • by mikael (484)

      Given the magnitude of energy involved (every level on the Richter scale is 10x the one below itI think it would be easier to build floating cities like Buckminster suggested. Build a skyscraper frame using a hollow superstructure, get enough sealed air in the superstructure and you actually end up with a structure that will actually float in the air due to differences in air density.

    • Which fault lines are you talking about?
      The few people have found or the unknown ones that aren't discovered until they rupture?
      Last year New Zealand had a series of 5+ quakes on a previously unknown fault line, despite thousands of faults already mapped.

      California's 'Next Big One' may have nothing to do with the San Andreas fault.

      Protecting a small area from surrounding fault lines is much more realistic than protecting an area surrounding a single fault line.

      • by Dahamma (304068)

        California's 'Next Big One' may have nothing to do with the San Andreas fault.

        Any "big one" in California will have something to do with the San Andreas fault. We pretty much shrug off at 5+ quakes, those are just minor annoyances caused by offshoots of the San Andreas ;) When we talk "big one" we're talking 7+, and whether it's directly caused by the San Andreas or another related fault, the energy for that is almost definitely coming from the movements of the Pacific and North American plates...

  • by egcagrac0 (1410377) on Tuesday April 01, 2014 @03:46PM (#46633043)

    Is the seismic cloak made of sheep's bladders?

  • I remember reading about this!

    http://www.gutenberg.org/ebook... [gutenberg.org]

  • 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

  • by swschrad (312009) on Tuesday April 01, 2014 @03:54PM (#46633157) Homepage Journal

    I'd like to order ten thousand amplifiers and about 20,000 kick-ass bass cabinets... oh, and one microphone and phase inverter...

    • by Hobadee (787558)

      phase inverter

      You can't invert phase. You *can* invert polarity. (Unless you figure out some way of inverting time - then you could invert phase.) ...also, this story is an April Fools.

      • by mikael (484)

        You can shift it by +/- 180 degrees. That's good enough for a sinusoidal wave.

  • But where would we get a set of headphones that big??

  • by funwithBSD (245349) on Tuesday April 01, 2014 @03:56PM (#46633175)

    Everyone knows earthquakes are particles not waves!

  • 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 befor

    • Yes, but if you use the meta-materials correctly you can fully demolish the building and burn any survivors before any insurance payments have to be made out. Saves on costly search and rescue efforts as well as demolition fees and permits. Extra profits can be made by using anonymous corporations to sell/promote the building "cloak" while being the owner of the upstanding and completely ignorant meta-materials manufacturer.

  • "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.
    • by geekoid (135745)

      Right here:
      http://en.wikipedia.org/wiki/L... [wikipedia.org]

      There have been more in the last 10 years then there were in the 90s

      • None of them of any appreciable size in the greater Los Angeles area since Northridge. None of the larger ones since Hector Mine were widely felt in LA, and the majority of them were off shore or way out in the sticks. Look at the fault map for LA.. there's tons of them, yet none of them produced anything newsworthy in 20 years. The period between Whittier Narrows and Hector Mine was the most active, with many quakes that didn't make it on that list but I still remember to this day. 1992 was a a crazy year
      • by hondo77 (324058)
        You didn't really just use a Wikipedia page as a definitive list of earthquakes in California, did you? For starters, people are really inconsistent about what quakes they're adding. I mean, really, people are adding 4.1 quakes to that list. I did a quick check and found a 6.0 from 1993 that was missing from the list (it is missing no longer).
  • 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.

    • by u38cg (607297)
      The engineering would be impossibly gargantuan. A variant which is commonly suggested is the opposite, lubricating the plates to try and get a series of small earthquakes rather than one large one. This would be ideal *if* you could guarantee that you wouldn't simply trigger the big one.
    • by coofercat (719737)

      Or how about digging out deep trenches alongside the fault line and filling them up with foam to absorb some of the shock wave?

  • by ShooterNeo (555040) on Tuesday April 01, 2014 @04:20PM (#46633535)

    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.

    • 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.

  • by l0ungeb0y (442022) on Tuesday April 01, 2014 @05:16PM (#46634137) Homepage Journal

    Protect your home and family from deadly earthquakes with Bose's Patented QuakeGaurd® Home Audio system that instantly detects earthquakes and sends seismic-neutralizing audio waves through our fashionable and amazing hi-def speaker that fits conveniantly on any book case, desk or night stand. When not fending off quakes, it plays CDs and even works with your grandchildren's iPhone to play those new fangled MP3s kids love so much these days. Order now and get a complementary pair of stylish Bose AudioWave Earbuds that work with any Walkman or portable CD player.

    • by slapout (93640)

      I think you just wrote the plot to the next syfy movie of the week (after Snarknado 2): a small group of geologists notice a series of small quakes. They believe a much larger one is coming. They try to warn people but no one listens. As the story unfolds one of the geologist is reunited with her former boyfriend -- a computer hacker. As time is about to run out, they hack into all the computers on the west coast and set them to play a certain sound. This ends up stopping the earthquake.

      Crazy? Yes. Too craz

  • 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 t
    • "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.

      No, no you're thinking about this wrong. It the same basic principle as what happens when two people push against each other with equal force - they both go nowhere. The energy involved in sound wave is very very low and essentially you're pushing down on the carrier medium (air molecules) at the same but directionally opposite pressure as the original sound wave. Now for high energy applications this can lead to highly interesting and destructive results (think head on car crashes, football linebackers

  • 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..

  • by SimonInOz (579741) on Tuesday April 01, 2014 @06:32PM (#46634733)

    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?

    • by matria (157464)
      AdBlock rule |http://slashdot.org/*.mp3?*
      • by SimonInOz (579741)

        Yup, that works nicely, thanks.

        But - more to the point - Slashdot should not be doing this in the first place!

        Bring back CmdrTaco!

      • by coofercat (719737)

        Great idea - thanks. Up until now I just had my speakers on mute. This is better :-)

  • If it can produce waves powerful enough to dampen an earthquake, then it can produce an earthquake.

  • 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 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 genera
  • People seem to completely miss the key part of this experiment... The energy has to go somewhere:

    As you can see, in the region where bores were drilled, wave strength dropped immensely. Near the source, the strength increased, as waves were reflected backwards.

    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.

  • 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.

  • Yet even after decades of research, earthquake prediction remains notoriously hard ...

    We've been working on the existing of God for between 3,000 and 10,000 years now. The divine entity remains notoriously hard to confirm. News at 11.

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