Geodyne wrote:

The Macquarie Island quake wasn't much smaller than the Aceh one though
Pete - 8.5, as compared to 8.9. The type of motion at Macquarie is very
different to that of the plate boundary in Indonesia, fortunately.

To expand on that for everyone's understanding, the Aceh earthquake was
a result of a release where two plates are colliding, with one going
below the other. Incredible forces until something gives. When it gave
way, a large section of ocean floor lifted, causing the tsunami. We know
the result. The Macquarie Island quake was a result of two plates moving
apart, and in that case there was no uplift to cause a tsunami. Not that
that earthquake wouldn't have caused massive damage if it was close to
population centres.

If the one in the Balleny Islands in Antarctica ever went off though -
those of us in SE Oz should all brace.

Brace or head for the hills???

Can you fill us in on the situation at Balleny Islands?

Another point (not to scare but just for a heads up), is that the Indian
Ocean tsunami was by no means a big one, as far as tsunamis go. Japan
has copped some nasty ones over time, the Krakatoa one was bigger and
the one in Alaska (northern pacific) in early 60's was quite a bit
bigger. The bummer about larger tsunamis is that twice the size is more
like an order of magnitude more powerful / destructive.

Bryan