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Air Guns Shake Up Earthquake Monitoring

samzenpus posted more than 2 years ago | from the shake-it-up dept.

Earth 38

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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38 comments

First (-1, Offtopic)

Ethanol-fueled (1125189) | more than 2 years ago | (#38935373)

Fucka fuck afucka

Let me be the first to say... (5, Funny)

dietdew7 (1171613) | more than 2 years ago | (#38935403)

You'll put your eye out.

Re:Let me be the first to say... (4, Funny)

ColdWetDog (752185) | more than 2 years ago | (#38935507)

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.

Re:Let me be the first to say... (-1)

Anonymous Coward | more than 2 years ago | (#38935619)

...and if that doesn't wake them up, this will. [youtube.com]

Re:Let me be the first to say... (0)

Anonymous Coward | more than 2 years ago | (#38941111)

Ugh, so close. It's "you'll shoot your eye out." If your going to quote it, actually quote it. Still, close enough I suppose. If I had a leg-lamp image handy, I'd give it to you as a prize.

Also, what's with this thread attracting racists? Not one but two links that are inexplicably anti-black? And thanks a lot for it jerks, I hope I don't get fired for that being in my web history. Of course, that's what I get for assuming that maybe the one link was to some Irish guy who made himself go deaf from an air-gun. Seriously, at least give a NSFW warning.

Impressive, and probably cheaper and less risky (4, Insightful)

G3ckoG33k (647276) | more than 2 years ago | (#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!

Re:Impressive, and probably cheaper and less risky (0)

Anonymous Coward | more than 2 years ago | (#38935977)

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

Quick, switch to nuclear tests before the hippies continue!

Re:Impressive, and probably cheaper and less risky (0)

Anonymous Coward | more than 2 years ago | (#38936885)

"Quick, switch to nuclear tests before the hippies continue!"

Yeah, this must attract a lot of Hollywood actors.

Re:Impressive, and probably cheaper and less risky (4, Informative)

tqk (413719) | more than 2 years ago | (#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.

Measuring Something Changes It (4, Interesting)

Doc Ruby (173196) | more than 2 years ago | (#38935651)

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?

Re:Measuring Something Changes It (1)

tomhath (637240) | more than 2 years ago | (#38935951)

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.

Re:Measuring Something Changes It (2)

jackbird (721605) | more than 2 years ago | (#38935965)

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?"

Re:Measuring Something Changes It (1)

Doc Ruby (173196) | more than 2 years ago | (#38937015)

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

Re:Measuring Something Changes It (1)

DRJlaw (946416) | more than 2 years ago | (#38938351)

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

Hint: he doesn't.

Re:Measuring Something Changes It (0)

Anonymous Coward | more than 2 years ago | (#38938395)

There are thousands of seismic surveys run around the world every year. Have you noticed the shaking on land?

There's nothing to cite because there is no effect to study. Hell, anecdotally, pilot whales often follow the seismic boats because they like to get the few fish that are stunned in the immediate vicinity of the airguns (within a few metres). The whales don't mind the airguns much, as long as they keep their distance. Airguns aren't powerful compared to the scale of moving large parts of the Earth. They're like a tap on a table surface that makes a detectable sound. They aren't going to smash it like a sledgehammer. It's sound, not a blast wave.

Re:Measuring Something Changes It (2)

ljw1004 (764174) | more than 2 years ago | (#38936377)

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).

Re:Measuring Something Changes It (1)

Doc Ruby (173196) | more than 2 years ago | (#38937045)

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.

Re:Measuring Something Changes It (0)

Anonymous Coward | more than 2 years ago | (#38936633)

If the air gun pulses can measure tension, perhaps some other method could be used to cause the plates to slip while there is little tension. Would that not be similar to avalanche control on mountains? Avalanche control entails causing smaller slides in areas that are troublesome. Perhaps in the same way the air gun measurements and intentional blasts could be used to help manage plate tension below a certain level of tension. Many smaller tremors, instead of "the big one" all at once.

This type of management would require measuring other faults and surrounding plates, as a small slip here may have a larger effect elsewhere. I'll admit that this is getting into an area where we really don't know what the long or even short term affects of this type of management would cause, if it would work at all.

Re:Measuring Something Changes It (2)

ColdWetDog (752185) | more than 2 years ago | (#38936977)

If the air gun pulses can measure tension, perhaps some other method could be used to cause the plates to slip while there is little tension. Would that not be similar to avalanche control on mountains? Avalanche control entails causing smaller slides in areas that are troublesome. Perhaps in the same way the air gun measurements and intentional blasts could be used to help manage plate tension below a certain level of tension. Many smaller tremors, instead of "the big one" all at once.

This type of management would require measuring other faults and surrounding plates, as a small slip here may have a larger effect elsewhere. I'll admit that this is getting into an area where we really don't know what the long or even short term affects of this type of management would cause, if it would work at all.

Given the relative energies, it would be more like attempting to control avalanches by shooting spitwads at the slopes.

Re:Measuring Something Changes It (2)

Doc Ruby (173196) | more than 2 years ago | (#38937047)

Except the triggering event need not be at the scale of the energy increased. It's not the additional energy from the trigger, it's what mechanical configuration that energy acts upon. You're saying that no straw can break a camel's back, because the camel is so much bigger than the straw. I'm not so sure.

Re:Measuring Something Changes It (3, Informative)

kubernet3s (1954672) | more than 2 years ago | (#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 (5, Interesting)

p51d007 (656414) | more than 2 years ago | (#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.

Re:Thumper trucks (1)

ArsenneLupin (766289) | more than 2 years ago | (#38940765)

They had a similar thingy for oceans that would blast high pressure air into the sea floor.

Wouldn't that attract Kraken?

What's the frequency? (4, Interesting)

Panaflex (13191) | more than 2 years ago | (#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.

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