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Earth Science

Air Guns Shake Up Earthquake Monitoring 38

Posted by samzenpus
from the shake-it-up dept.
sciencehabit writes "Petroleum geologists have long used air guns in their search for oil and gas deposits. Sudden blasts from the devices generate seismic waves that they use to map underground rock formations. Could the same technique be used to study earthquakes? A team of Chinese scientists thinks so. The researchers have designed an air gun that could be useful in monitoring changes in stress buildup along fault zones."
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Air Guns Shake Up Earthquake Monitoring

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  • by dietdew7 (1171613) on Sunday February 05, 2012 @12:00PM (#38935403)
    You'll put your eye out.
    • by ColdWetDog (752185) on Sunday February 05, 2012 @12:19PM (#38935507) Homepage

      OTOH, Just imagine this conversation:

      Engineer 1: Man, this is boring.
      Engineer 2: Yep, nothing happening.
      Engineer 1: How many of those guns do we have around here anyway?
      Engineer 2: Dunno, couple dozen. Home office just dropped off a bunch last week.
      Engineer 1: How many of these things can we tie together anyway?
      Engineer 2: Dunno, probably all of them, they just hook up with that cable.
      Engineer 1: Think those guys at the Earthquake Monitoring Program [usgs.gov] are awake yet?
      Engineer 2: Dunno, we could find out, I suppose.

  • Well, if they blow hard enough, they might be able to rock somebody.

  • Or create some instead... following the same pattern as "shale gas"
  • by G3ckoG33k (647276) on Sunday February 05, 2012 @12:18PM (#38935501)

    "None of the lake's fish were killed or stunned by the shots, and instruments installed at a dam 1.4 kilometers away from the test site showed that peak ground accelerations were far below those detectable by humans"

    Impressive, and probably cheaper and less risky than dynamite. No animals were harmed.

    Good work!

    • by tqk (413719) <s.keeling@mail.com> on Sunday February 05, 2012 @04:10PM (#38937129)

      ... probably cheaper and less risky than dynamite.

      Dynamite's pretty safe. Blasting caps can be dangerous. However, most of the blowback wrt using dynamite in this application is it annoys the neighbours, is environmentally unfriendly, and bad guys love to steal the stuff.

      As for TFA, it depends. Shear waves (the twisty kind) travel quite a ways, but don't tell you much. Pressure waves don't travel very far but do tell you a lot, dependent upon the range of frequencies transmitted by the wave, and the medium through which they're transmitted. An 8 Hz p-wave will travel farther than a 500 Hz p-wave, but you won't learn much of any interest at 8 Hz.

      Unfortunately, TFA says nothing about the frequency range produced by these air guns. I doubt it's anywhere near the range produced by dynamite.

      BTW, it's geophysicists who do this stuff, not geologists. The latter are the guys with rock hammers and sample bags.

  • What is that really

  • by Doc Ruby (173196) on Sunday February 05, 2012 @12:41PM (#38935651) Homepage Journal

    Is there any scientific study showing how much these seismic impulses, from air guns or from other giant synthetic "pings", increase the rate and/or intensity of earthquakes? There's some data from fracking and other injection wells, but those also introduce (possibly lubricating) newly active materials. How about just an energetic impulse? Or are we just blindly pulling the dragon's tail?

    • by tomhath (637240)

      Is there any scientific study showing how much these seismic impulses, from air guns or from other giant synthetic "pings", increase the rate and/or intensity of earthquakes?

      According to the article, that's part of the field tests they're doing now.

    • by jackbird (721605)

      It's sort of on the scale of "Is there any scientific study showing how much knocking on front doors, with fists or with synthetic "knocking devices", increase the rate and/or intensity of houses collapsing? Or are we just blindly pulling the dragon's tail?"

      • by Doc Ruby (173196)

        Where's your scientific evidence to show that's the "scale"? Or aren't you just making it up?

        • by DRJlaw (946416)

          Why does he bear the burden of proving your original question is relevant?

          Hint: he doesn't.

    • by ljw1004 (764174)

      I think the default assumption would be that anything we do would DECREASE the intensity of earthquakes.

      (explanation: earthquakes are the huge release of energy when pent-up forces are released; anything that lets it be released earlier in smaller amounts would decrease that).

      • by Doc Ruby (173196)

        I dunno - the natural system might be prone to releasing the energy more gradually, over a longer time series of quakes. "Popping" a quake outside its own rhythm might bypass natural mitigating mechanisms.

        But I don't know. That's why I'm looking for scientific evidence.

        I would like to believe there's at least a scientific model, based on measured data, that indicates it's safe. Not just oil/gas corps assuring us it's OK.

    • by kubernet3s (1954672) on Sunday February 05, 2012 @10:21PM (#38938761)
      The actual acoustic energy used in this technique is pretty low. 15 MPa is about the pressure you'd expect a very full lecture bottle to be at, and probably something you wouldn't think twice about were you to feel a jet of it against your skin. I've had 2000 psi lines fail near me, and while it hurts your ears like a bitch, it isn't even enough to puncture them. The article says it gives seismometer readings equivalent to a .5 intensity earthquake. A quick look at a seismic activity map will reveal that these happen *literally* all the time. If these airguns were enough to cause, or even influence seismic activitoty, we'd be in danger every time someone dropped a full gas cylinder (not to mention rocket launches should cause massive quakes across the globe).

      While measuring something indeed influences it, there are fundamental energetic limits below which this influence is negligible (i.e., shining light on a truck to measure it's position. I believe these air guns fall into this category
  • Thumper trucks (Score:5, Interesting)

    by p51d007 (656414) on Sunday February 05, 2012 @01:42PM (#38936063)
    When I worked as a bench tech for TI in Houston, in the 80's, they brought a "thumper truck" to the office for us to look at. The doodlebuggers used it when they were searching for oil, in areas they couldn't use explosives for the shock waves. They had a similar thingy for oceans that would blast high pressure air into the sea floor.
    • They had a similar thingy for oceans that would blast high pressure air into the sea floor.

      Wouldn't that attract Kraken?

  • by Panaflex (13191) <convivialdingo AT yahoo DOT com> on Sunday February 05, 2012 @04:32PM (#38937241)

    I worked in seismic data processing for a couple of years - there's a MOUNTAIN of data out there. The big problem for researchers is that it's mostly locked away as trade secrets. There are a few firms that can license you a few shot lines - but they are pretty limited compared to the big companies.

    This sort of geological study is already used for 4D studies, where shots are compared over a period of time. The hydrophone shot technology has been pretty stable for 20 years now - but older data may have limited depth and frequency.

  • They're indispensible for Antlion outbreaks.

  • This is really going to piss off the Silurians.

"There is nothing new under the sun, but there are lots of old things we don't know yet." -Ambrose Bierce

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