Slashdot Mirror
Earthquakes Detectable From Space by GPS
Iphtashu Fitz writes "Research sponsored mainly by the European Space Agency has demonstrated that earthquakes generate acoustic signals, almost like a huge loudspeaker, that can be detected from space. According to an ABC News Science/Technology article, geophysicist Juliette Artru came up with the concept while working on her doctorate degree. By monitoring an array of GPS receivers located throughout California she was able to determine that a massive 7.9 earthquake in Alaska last year resulted in the constillation of GPS satellites generating a mesaurable amount of interference. According to Artru, "A displacement of one millimeter on the ground can cause a displacement of 100 meters in the ionosphere," so a tiny pressure wave created by an earthquake can undergo huge amplification by the time it reaches the ionosphere. The resulting shockwave causes a tiny but very distinct pattern of interference in the GPS signals broadcast by the satellites."
I for one have had a hard time in the past detecting the ground shaking under me here on the surface of the earth, what with the dishes rattling off the shelves and pictures falling off the walls and all. Now there is a way to know for certain!
Karma: Marginal (mostly due to the border around the website)
"A displacement of one millimeter on the ground can cause a displacement of 100 meters in the ionosphere,"
So presumably the same technique can be used to detect stealthed underground nuclear bomb tests as well.
Next question: do arrays of GPS devices exist in India, Pkistan, and China? If not, could they be put in place easily and stealthily, as by airdrops of a number of small GPS receivers designed to transmit results to another sattelite?
Opinions on the Twiddler2 hand-held keyboard?
Anyway, while your comment is lame and you clearly didn't read the article, it's not bad for a first post. BTW, buy a subscription to slashdot, you can read the article and still get first post. I've taken five minutes to write a good post and still made first post.
we don't care about an earthquake unless it's big enough to disrupt my car's Nav system while stuck in traffic on the 405.
0- Eamonman Proud member of DNRC
The write-up here on Slashdot is kind of stupid
/. ??? I certianly wouldn't waste my money on a website where people like you first lambaste others who actually post interesting articles and then in the same breath try to convince people to subscribe. If I was a betting man I'd lay odds that you're involved with /. and actually make money from their subscriptions.
What's stupid about it? It looks like a pretty accurate summary to me.
They aren't "detectable from space" at all. They are detected in the travel of radio waves from space to earth. The detection happens on earth.
A matter of semantics. What is being detected is interference up in the ionosphere. It's only being detected by analyzing radio signals on earth. You might as well be claiming that all the data collected by the various rovers to Mars was actually collected here on Earth since this is where the radio equipment that ultimately received the data is located.
It wouldn't surprise me if the GPS satellite constillation could be modified to detect these sorts of things entirely from space. They simply monitor each others signals themselves and report back any anomolies that fit into the interference pattern that this geologist discovered.
BTW, buy a subscription to slashdot, you can read the article and still get first post. I've taken five minutes to write a good post and still made first post.
What are you, a shill for
Thanks a lot for being such a childish jerk. What's wrong, Mr. Anonymous Coward, afraid to call me lame and stupid and actually admit to who you are? And then you have the gall to suggest that I actually subscribe to slashdot? Why should I if idiots like you are going to bash me for submitting interesting articles? The only reason I can guess is that you'd be getting that money (at least some of it), which really makes you all the more pathetic. First you have to bash people then you beg them for their money. Next time try being a man and don't post anonymously.
A paper of hers from 2001 presents information on the Mount Pinatubo eruption. An abstract of the paper discussed in the ABC story is also available.
Carousel is a lie!
Wow, you call me childish? That's quite a temper-tantrum you threw there, sporto. GO apologize to your mother right now.
If small ground motions propagate to large amplitude acoustic effects in the ionosphere, then the effects should be detectable with shortwave radio. A bistatic transmitter-receiver pair would be configured to bounce its signal off some part of the ionosphere. Acoustic vibrations in that layer should create detectable distortion in the shortwave signals. It may not be as exciting as GPS, but it may enable detection of ionospheric disturbances over inaccessible parts of the planet by locating the bistatic pair on either side of the region.
Two wrongs don't make a right, but three lefts do.
Cool, a flame war! Can I join in?
Thanks a lot for being such a childish jerk. What's wrong, Mr. Anonymous Coward, afraid to call me lame and stupid and actually admit to who you are?
AC attacks are pretty lame, aren't they. But here's the strange part:
And then you have the gall to suggest that I actually subscribe to slashdot?
An AC says you should subscribe? That's a laugh.
Why should I if idiots like you are going to bash me for submitting interesting articles?
Dude, if your article was boring, the AC wouldn't have bothered to bait you.
1) Troll
2) Bite
3) ???
4) Profit!
The only reason I can guess is that you'd be getting that money (at least some of it), which really makes you all the more pathetic. First you have to bash people then you beg them for their money.
Are you suggesting that CmdrTaco's krew is posting AC just to harass you into subscribing? I think you've gone over the edge on this one. If they had time to putz around like that, Slashdot would be little more than "CmdrTaco's Blog."
Next time try being a man and don't post anonymously.
Don't be a fool! There's enough men (and overgrown boys) on Slashdot already. Next time, I want the AC to try being a chick!
Stressed? Me? Of course not. Stress is what a rubber band feels before it breaks, silly.
from the article: ...the displacement sends out an acoustic signal, or radio wave, that moves up through the atmosphere.
Uh, is it an acoustic wave, or a radio wave? There is a difference.
From the post: resulted in the constillation of GPS satellites generating a mesaurable amount of interference.
The constellation of GPS satellites did not generate any interference. Rather the effect of the wave on the ionosphere caused interference in the RF signals from the GPS sats.
Unless this is a new technique, GPS has been used for years by geologists looking for earthquakes and crust movement(and I don't mean the lojack in grandma's blueberry pie).
Please help metamoderate.
This discovery (the only really interesting bit is a way to detect the perturbations using existing equipment) is well and good for post-event quake analysis, but is of limited use for prediction and harm minimisation.
It is well known that ELF waves are detected in a crescendo that peaks (and dissapears) 48 to 72 hours before a geological event of sufficient magnitude.
The University of Queensland in Brisbane Australia had just developed the most accurate system of earthquake modelling and prediction in the world (using data from 50+ sensor stations) at the point they had their budget cut and all but 2 (IIRC) stations junked.
So once again the penny pinchers get to dictate the worlds scientific and cultural achievments - secure in their complete and comfortable ignorance.
Q.
Insert Signature Here
Does this mean one might construct an algorithm to determine which of these 'female' specimines is more likely to be infact genuinely screaming out their makers name as they procreate.