If I'm going to post on this page I may have a small responsibility to qualify predictions like this, since some know that I work with active faults, although I am not a seismologist. I am posting this in case Shan is taken seriously in the predicted areas. At the same time, I don't want to discourage Shan from posting here. I have read Shan's predictions over the years and nothing has jumped out at me as his method being very accurate...although Roger may have once posted a more favorable evaluation.

The same area that already broke, between 3 and 14 deg N, almost certainly is not capabable of another M9 until a century or much more has passed. However, areas to the north and south are capable of Great quakes....we don't know if they would break in several M8 quakes or 1 giant M9. So, education and preparedness are good ideas. If you live at low elevation near the coast, and you feel shaking that lasts more than a minute, you get to higher elevation. If you are in an area more distant from a subduction zone, and do not feel the shaking, but see the ocean behave strangely, for example, retreat, then get to higher ground (immediately). In advance of this, you might look into whether your local government has set up a warning system for tsunamis, and what the warning would be.
Again, my personal opinion is to have little or no confidence in Shan's prediction, but to use it as an opportunity for being prepared.
Chris