I have to admit that Shan was close on this one. The Pacific tsunami warning center does say that a widely destructive tsunami is possible. Since this quake just happened, the magnitude may actually be different....

Let's look to see if a tsunami has already occurred opposite the rupture...if it has and it was large, then people at greater distances should look for warnings, or to be on the safe side, get to some elevation. It is possible that in this area of northern Sumatra information on tsunamis will not get out fast enough
Chris