[time-nuts] Change to Earths rotation rate due to Chinese earthquake

phil fortime at bellsouth.net
Fri May 16 02:12:21 EDT 2008


----- Original Message ----- 
From: "John E Burgar" <johneburgar at cox.net>
To: <time-nuts at febo.com>
Sent: Friday, May 16, 2008 12:26 AM
Subject: [time-nuts] Change to Earths rotation rate due to Chinese 
earthquake


> Have any of your members seen any data regarding a change to the earths
> rotation rate due to the recent Chinese earthquake? I seem to recall that
> the Banda Aceh earthquake in December a few years ago had a measurable
> impact on the rotation rate.  Many regards to the many extremely
> knowledgeable members of this group, John B.

I believe the December quake you reference is the 8.4-magnitude 2004 
Indonesian earthquake
It supposedly changed the earths length of day: -2.676 microseconds or the 
day became shorter by 0.0000027 seconds. As I understand it, the length of 
the day can be measured with an accuracy of about 20 microseconds.

What was affected was the so-called Chandler Wobble. Some believe it is the 
cause of the earthquakes rather than the effect. This is an extremely 
interesting subject.  I haven't seen anything on the present quake but it 
usually takes a while for anything to be published.

You might find more searching Chandler Wobble

Phil




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