Indonesian Earthquake affects Earth's rotation

I had this in my inbox when I came back to work today:

******************************************************************************
IGS Electronic Mail 29 Dec 07:53:53 PST 2004 Message Number 5069
******************************************************************************

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