Detecting Tectonic plate shifts

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by KoenigMKII</i>
<br />This is too simple right? <hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">Right. The change would be so tiny that it would take hours to detect (the time for a complete orbit). But the difference in onset times would be no more than milliseconds. -|Tom|-

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by tvanflandern</i>
<br /><blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by KoenigMKII</i>
<br />This is too simple right? <hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">Right. The change would be so tiny that it would take hours to detect (the time for a complete orbit). But the difference in onset times would be no more than milliseconds. -|Tom|-
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O.K. I see the problem, how about a Geosynchronous satellite chain arround the Earth's equator and the largest possible Earth quake (8.5+)?

[After the terrible disater in Bam in Iran I am making myself sick by suggesting taking scientific advantage of Human misery, I hope the board will forgive me for talking about a senstive subject in such a glib way]

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by KoenigMKII</i>
<br />O.K. I see the problem, how about a Geosynchronous satellite chain arround the Earth's equator and the largest possible Earth quake (8.5+)?<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">No, same problem. The delay in affect on one satellite vs. another is a matter of milliseconds. Yet one cannot see that any effect has occurred until the satellite completes most of a revolution, in this case about 24 hours later.

A very small effect that began 24 hours ago, and an almost identical effect that began 24 hours plus 10 millisecongs ago, are so nearly identical that their difference is many, many orders of magnitude below the threshold of detection. -|Tom|-

Dr. Van Flandern,

I understand about the size of the effect.

* Even an entire plate is a tiny tiny fraction of Earth's mass.
* A very fast one meter shift in something that large is equally miniscule.

Comparing this to your experience with the gravimeter detecting you moving around in a lab, the satellite gravimeters would have to be out at several Moon orbit radii and the entire Earth would need to be moved by dozens of Earth diameters to achieve the same relative detector output.

===

But I don't get the part about timing. If each satellite is monitoring the instaneous local acceleration field at, say, one second intervals it seems that a detectable event would show up on the next sample.

Still too slow see any SOG effects, of course.

???,
LB

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Larry Burford</i>
<br />If each satellite is monitoring the instaneous local acceleration field at, say, one second intervals it seems that a detectable event would show up on the next sample.<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">You are right that there is no special significance to waiting one period, as opposed to some other interval. It is just a question of magnifying a small effect as much as possible.

The most readily detectable effect of a change in the strength of an attractive central force is a change in orbital period. Although the sample-by-sample changes exist, they are truly miniscule. But even a miniscule change in semi-major axis can built to a significant delay after one or more revolutions. If the effect is small enough, it might not show up at a detectable level for dozens or even thousands of revolutions. -|Tom|-

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by tvanflandern</i>
<br /><blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by KoenigMKII</i>
<br />O.K. I see the problem, how about a Geosynchronous satellite chain arround the Earth's equator and the largest possible Earth quake (8.5+)?<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">No, same problem. The delay in affect on one satellite vs. another is a matter of milliseconds. Yet one cannot see that any effect has occurred until the satellite completes most of a revolution, in this case about 24 hours later.

A very small effect that began 24 hours ago, and an almost identical effect that began 24 hours plus 10 millisecongs ago, are so nearly identical that their difference is many, many orders of magnitude below the threshold of detection. -|Tom|-
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Well if we use laser gyro's as gravimeters, the speed of light being reflected continuously between mirrors can be used to amplify any tiny accelerations the geosynchronous satellite due to a "gravity signal" from a tectonic plate.

Because the detecting satellite (in MM at least) experiences the gravity flutuation instantaneously and the 25,000 mile height of the satellite should give a 0.13 millisecond "light time" delay for the SR model, don't we get a chance to see the difference?

I meen in 0.13 milliseconds light moves 39,000,000 meters. if the light path in the laser gyro is 1 meter, the gyro can "cycle" 39 million times before SR says it should see any signal.

Please excuse me If I got my numbers wrong, maths is not my strong point (to put it kindly!)

light speed= 300000000000 ms -1