[time-nuts] UTC and leap seconds

jimlux jimlux at earthlink.net
Sat Jun 12 01:50:22 UTC 2010

Hal Murray wrote:
> jimlux at earthlink.net said:
>> The Chilean earthquake changed the angular rotation rate (or, probably  more
>> accurately, changed the direction of the axis of rotation as well) 
>> of the earth a small amount, as do most large earthquakes. 
> Has anybody measured that?

I don't think you can measure it directly.. it's way smaller than lots 
of other effects
> Is there a good URL on this?  (predictions if not data)  All I've found so 
> far is a small NASA press release predicting 1.26 microseconds per day:
>   http://www.nasa.gov/topics/earth/features/earth-20100301.html
> (and a zillion news sources repeating it)


I remember reading something fairly detailed..it might have been on a 
newsgroup at work.I work at JPL, and Richard Gross is in a section with 
a lot of people I work with at JPL, so it might have been discussed at 
lunch.   I'll see if I can find out

You could probably send him an email and ask..
richard.gross at jpl.nasa.gov

heck, he might be lurking on this very list..

Day length is one of his things
> 1 microsecond/day is 1 part in 1E11.
> ---------
>>From a friend in radio astronomy (VLBI):
> They had a lot of the right instruments in the right place.
>   Graph of position (3 meters!):
>     http://ivsopar.obspm.fr/earth/tigo
>   Description of the  TIGO package:
>     http://cddis.gsfc.nasa.gov/lw12/docs/Riepl_Tigo.pdf
>   Letter from the director:
>     http://www.expres-eu.org/Chile_06032010.html

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