Also this:
Update:
Here is a comparison between what's happening in Japan now (last seven days) vs the week leading up to the M9.1 Great Tohoku Earthquake 03/11/2011. Except for the 7.3 foreshock that occurred in 2011, the pattern is nearly identical, and what's happening now has seen more seismic energy released in the M6.0-6.9 range than for 2011.
The geologic setting is basically identical for both locations in the Japan Subduction Trench because the two zones of swarming (present and past) are only 100-200 km apart. It would be most likely that high-magnitude events would behave similarly across geologic time.
If the seismic energy release during the foreshock sequence scales to the magnitude of the main shock, then a magnitude 8.7 megaquake is in the cards for Japan in the immediate future because that is 25% the seismic energy release of a M9.1, and the energy release of this swarming thus far is ~25% of what occurred March 2011. The most likely time window for this to occur would be this month based on how the foreshock sequence played out in 2011, with the window of highest risk being the next seven days. I would place this probability as more likely than this swarm dying out and that being that, but not by that much, maybe 60/40. There is also a chance we see a magnitude 7.0-7.9 in the immediate future for this
http://youtube.com/post/UgkxqPbSxEB5FbJP_qldpILdHEvnBNWyrplr