NASA: Japan quake appears to have shortened Earth days, shifted axis

NASA reports that the March 11, magnitude 9.0 earthquake in Japan may have shortened the length of each Earth day by about 1.8 microseconds and shifted its figure axis by about 17 centimeters . "But don't worry--you won't notice the difference," and "calculations will likely change as data on the quake are further refined. "

Boing Boing editor/partner and tech culture journalist Xeni Jardin hosts and produces Boing Boing's in-flight TV channel on Virgin America airlines (#10 on the dial), and writes about living with breast cancer. Diagnosed in 2011. @xeni on Twitter. email: xeni@boingboing.net.

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AndyBooth

Not to be a douche, but I submitted this yesterday.

Oh god. I’m a douche, aren’t I?
- Jack
  
  Yesterday minus 1.8 microseconds.
cory

Well, if you’re required to work a certain amount of hours per week for a paycheck, it’s also effectively a raise.
Anonymous

Lots of things change the length of the day: e.g. hurricanes, El Nino, glaciers melting and earthquakes. It’s due to conservation of angular momentum and changes in the Earth’s moment of inertia (redistribution of mass).

Also, magnitude 10 earthquakes are about 32 times more powerful than magnitude nine earthquakes. The same is true for any two earthquakes whose magnitude differs by one point on the scale.
- Donald Petersen
  
  magnitude 10 earthquakes are about 32 times more powerful than magnitude nine earthquakes.
  
  I was gonna “Huh?” so I done wikipediaed you. To clarify, for those lunkheads like me that thought it was “just” a base-10 logarithmic scale, a 10.0 quake has 10 times the shaking amplitude of a 9.0, just as a 9.0 has ten times the shaking amplitude of an 8.0, and so on. But that 10x factor equates to a 31.6x factor when it comes to energy release. So in terms of destructive energy, a 10.0 is around 32 times as powerful as a 9.0.
  
  Did I get that right? If I did, how ’bout that!
penguinchris

It’s commonly related that a magnitude 10 earthquake would essentially mean the earth tearing itself in half (the crust, anyway). Not hard to imagine that when you hear about this kind of thing coming from a magnitude 9, which is far, far less powerful than a magnitude 10.
EdCS

I wonder if that’ll change the position of the next leap second (or, more likely, a leap second a few hundred years in the future).
Anonymous

Is this something that will affect GPS measurements, or is that separate from Earth-time?
Anonymous

Dang, I thought it was just this stupid daylight savings time thing…
sla29970

Look at the amount that the pole moves and the length of day changes annually
http://hpiers.obspm.fr/
The normal variations are 1000 times greater than anything the earthquake has caused. See the IERS saying “hardly discernible”
http://hpiers.obspm.fr/eop-pc/index.php?index=news
because a large snowstorm can cause a greater change.
Anonymous

Maybe YOU won’t notice, but I need those 1.8 extra microseconds. I just bet it’s coming out of my sleep time.

Plus, it’s effectively a rent increase. I mean, those microseconds really add up.
- monopole
  
  This will not effect GPS time in that it explicitly differs from UTC in that it leaves out leap seconds. As for distortions in the GPS navigation signals the Ground Control Segment Stations should have smoothed that out in less than 24 hours. In most likelihood these measurements of rotation shift the movement of Japan and the like was detected by precise Carrier Differential GPS and laser bounces off the GPS satellites and geodedic satellites. For the most part, the satellites stay in their existing orbits while the earth shifts (eventually higher order orbital perturbations come into play.
- oasisob1
  
  The rent is too damn high (At NASA, everything is too damn high)!
oxrs

I was doing something with that fraction of a second every year… :( Also, my head hurts when I try to fathom the calculation of microseconds.
eaglescout1984

Good, the end of the world in 2012 has been delayed by at least half a second.
SamSam

Even more amazing, the quake pushed Eastern Japan 13 feet closer to the US. That is a very measurable distance, and was confirmed by their GPS stations on the coast. Time link.

The Times has been really good with their science recently. This article explained that much of Japan is actually on the North American shelf, something I had no idea about, and that the Western edge of that shelf has been buckling up as the plates crush together. This in turn creates tension which is released when the quake happens. The East side snaps back to the East, and the ground drops. Indeed, the ground dropped two feet over most of the coast, causing the tidal waves to be even bigger than they would have been.

Another great recent article on the quake was http://www.nytimes.com/2011/03/13/science/13radiation.html. Every-freekin’-other sentence was a well-explained scientific description of the terms they were talking about: what nitrogen-16 is and how it is formed; what tritium is; why Iodine-131 affects your health; what the half-lives are for all these things. I sent it to my friend who is a chemistry high school teacher and she loved it and went through it with her kids.