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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)
Underground nuke test can already be detected. They use a new device called a seismograph.
That is one of the ways the US/USSR/China monitored each others tests
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
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!
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.
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.