Le 05/11/2012 09:19, Poul-Henning Kamp a écrit :
Tamino has an interesting analysis here:
http://tamino.wordpress.com/2012/11/03/unnatural-catastrophes/
His quadratic fit of "geophysical catastrophes" peaks duing the
abnormally long dec98-dec05 leap second interval.
Gentlemen, please start your speculations...
Well, why not? The original data points show peaks from 98 to 01 with
the rest of the period being pretty level. During that time there was at
least one significant geophysical event which in theory could have
affected earth rotation, the 2004 Chile quake. However, rotational
changes due to geophysical events ( usec level ) are lost in the noise
from other factors and don't take any significant part in the slowdown
requiring leap seconds which accumulates mainly from tidal friction ( ms
level). Bottom line, no relevance.
It might be that as the earth is not solid, the slower rate of change in
UT1 from say 2001 could be due to a less active core/mantle which might
have limited crustal stresses and so reduced frequency of quakes.
--
Les chiens aboient, et la caravane passe.
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