Thanks for the clarification..my mistake..among many..hehehe..was in conceptualizing the epicenter as the source of the tsunami..when in fact it is the entire length of the fault...But since you're obviosuly knowledgeable, I'm going to impose and ask another question..
I heard a scientist say today that when they measured a 9.0 quake..he knew it was a 1000 km fault slippage...HOw/why is the severity of the quake related so rprecisely to the length of the fault..
It's based on what we already know about previous quakes. The energy released is proportional to the surface of the fault plane that moves. All previous quakes in the M 9 range have had really long fault lengths, and have been suduction quakes. There are (fortunately) only a fairly small number of locations on the planet that can generate an M9. South of Java and Sumatra, Kamchatka, Alaska, off Washington and Oregon, and off South America. Things get complicated near Japan, I don't think you can quite reach M9 right near Japan because things are broken up into shorter faults. The 1755 Lisbon earthquake off Portugal is guestimated at M 8.7. There doesn't seem to be enough fault there to generate a 9. But they're actually not exactly sure where that quake was.