[IGSMAIL-5069]: Traces of Earthquake in Earth Rotation

[Urs Hugentobler <urs.hugentobler @ aiub.unibe.ch>]

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IGS Electronic Mail      29 Dec 07:53:53 PST 2004      Message Number 5069
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Author: CODE AC Team


Dear colleagues,

the devastating earthquake in the Indian Ocean on December 26 shows its 
traces even in the Earth's rotation. Preliminary results from the CODE 
rapid analysis for the IGS indicate a displacement of the rotation axis 
by about 3mas (or 8cm on the Earth's surface) with respect to the 
prediction from Bulletin A. The length of day changed by nearly 0.1 
msec/day.

You may find plots of the CODE rapid pole parameters together with 
Bulletin A predicted values under

  http://www.aiub.unibe.ch/code/dec26_pole_xy.gif
  http://www.aiub.unibe.ch/code/dec26_pole_x.gif
  http://www.aiub.unibe.ch/code/dec26_pole_y.gif
  http://www.aiub.unibe.ch/code/dec26_pole_ut.gif
  http://www.aiub.unibe.ch/code/dec26_pole_lod.gif

The rapid analysis did not show significant displacement of the tracking 
stations around the Indian Ocean processed by CODE except for NTUS 
(Singapore) for which the measurements indicate a displacement of 2cm in 
westward direction.

That an earthquake influences the Earth's rotation underlines the
inconceivable extent of this catastrophical natural disaster.


Best regards
Urs Hugentobler
The CODE AC Team