In article ,
Oscar Lanzi III wrote:
The South Asian tsunami did it. IIRC it caused a speeding up of the
rotation by 3 bilionths of a second.

Three billionths of a second is too small to detect. At a department
meeting at work yesterday the guy who reduces the VLBI data for earth
orientation showed his latest plots, and there is currently no strong
evidence that any effect is seen in the data.