Japan Earthquake March 2011

OK we all have been watching the TV and internet all day and we know that Japan had a big quake, but the 8.9 monster quake is not the beginning of this quake and not the last.
The 8.9 quake was not the primary quake but an aftershock of a quake that happened just 2 days before. On usgs.gov 2011/03/09 02:45:20 there was a 7.2 quake and then a number of after shocks, 20 aftershocks of 5.0 or higher and at 2011/03/11 05:46:24 we had the 8.9 (or now it is considered a 9.1 according to CNN)
There is a grow body of evidence that quakes are not as unpredictable as they are commonly assumed. Coulomb stress transfer or Earthquake storms are caused because there are plate boundaries where two plates come together and as you have an earthquake in one portion of the fault that relieves stress at that part of the boundary. But the rest of the boundary is still locked and the pressure that is causing the plates to press against each other is still there, the plates are moving still. And so that stress is transferred to other portions of the boundary fault and raises the risk of those other portions and most likely to the parts of the not ruptured adjacent to the part that did rupture. It is these forces trying to balance out that cause after-shocks and in this case the aftershock was larger than the initial quake.
Now with this huge amount of energy released in this one region, dozens of 5+ shocks, lots of 6’s, and 7’s and thousands of smaller quakes. But now that that energy is released there and that part of the fault is now fairly free of tension the rest of the fault is now holding back the whole of the tectonic pressure and so other parts of the fault system will now be set for new quakes that could happen at any time now or in the future.
The news out of Japan will continue to flow over the next days and weeks. Some good, people who escaped, and some bad.

About echlinm

Computer Programmer/Systems Analyst/Hacker S31
This entry was posted in Earth Science. Bookmark the permalink.

One Response to Japan Earthquake March 2011

  1. Pingback: Can earthquakes be predicted | Borg or No (S31)

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