Why 2004 Sumatra 9.0 produced huge Tsunamis, but 2012 Sumatra 8.6 & 8.2 produced none at all

i would just thought its random chance cuz it looks so complicated to guess,

but scientists already know/theorize from evidence on hand, why there were no tsunami this time, not just the magnitude but other thingys; there is the technical size/analysis to all the peculiarities of mass & momentum:

for animation and learn more go to

www.iris.edu...
and
earthquake.usgs.gov...

Good straight to the point explanation. I like it. It's a good thing they were not thrust quakes or that part of the world would be in serious trouble again.

I'm sure someone can correct me if I'm way off...but I thought the difference between a Tsunami and not having one is whether there is a major up/down shift in the Ocean floor that displaces the column of water?

reply to post by Wrabbit2000


Your correct. These quakes were strike slip quakes which means they were moving side to side from stress on the plate. Now the quakes in the subduction zones where the plate is moving under cause more thrust quakes that force the plate to snap back up during a large quake causing an updraft in the water and producing a tsunami.