[time-nuts] Q/noise of Earth as an oscillator

[Dave Brown]

The main issue has been deemed to be safety- or lack of it, due to the ring 
lasers location in an underground cavern that cannot continue to be used 
because of a high risk of additional ground/rock failure. For the present 
there has been no further ring laser work at canterbury university since the 
2010/2011 quakes and cave access is not permitted.
 DaveB,
Christchurch, NZ


----- Original Message ----- 
From: ""Björn Gabrielsson"" <bg at lysator.liu.se>
To: "Discussion of precise time and frequency measurement" 
<time-nuts at febo.com>
Sent: Saturday, July 30, 2016 8:48 AM
Subject: Re: [time-nuts] Q/noise of Earth as an oscillator


> I'am  not sure how the big ring lasers have progressed over the past
> years. It seems the big New Zeeland earthquake messed up the nice ring
> lasers over there.
>
> http://www.fs.wettzell.de/LKREISEL/G/LaserGyros.html
> http://www.phys.canterbury.ac.nz/ringlaser/about_us.shtml
>
> --
>
>    Björn
>
>> I believe a phase noise plot deep into the uHz or lower would apply to 
>> the
>> rotation rate of the earth.
>>
>> On Saturday, 23 July 2016, Hal Murray <hmurray at megapathdsl.net> wrote:
>>
>>>
>>> tvb at LeapSecond.com said:
>>> > Earth is a very noisy, wandering, drifting,
>>> incredibly-expensive-to-measure,
>>> > low-precision (though high-Q) clock.
>>>
>>> What is the Q of the Earth?  It might be on one of your web pages, but I
>>> don't remember seeing it.  Google found a few mentions, but I didn't
>>> find a
>>> number.
>>>
>>> I did find an interesting list of damping mechanisms in a geology book.
>>> Geology-nuts are as nutty as time-nuts.  Many were discussing damping of
>>> seismic waves rather than rotation.
>>>
>>> I've seen mention that the rotation rate of the Earth changed by a few
>>> microseconds per day as a result of the 2011 earthquake in Japan.  Does
>>> that
>>> show up in any data?  Your recent graph doesn't go back that far and
>>> it's
>>> got
>>> a full scale of 2000 microseconds so a few is going to be hard to see.
>>>
>>>
>>>
>>> --
>>> These are my opinions.  I hate spam.
>>>
>>>
>>>
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