Hercules,
I'm not sayin its possible, but no one expected a 9/11 in US until it happened.
It's an apples and oranges comparison between a Mag 12 earthquake and 9/11.
9/11 was always possible. The Towers had already been bombed once, Tom Clancey had already written a novel about terrorists who crashed an airliner into Washington, DC and Japan used manned missles (Kamikazi) as weapons.
The Mag 12 earthquake is another matter. In that case it comes down not only to a proper scenario for it to happen - the scenario has to contain sufficient energy. The reason that it is so highly unlikely is that the plates can't store that much energy. That's why Mag 10 is just about the maximum. The stress on the plates is so high that they can't store any more potential energy.
The energy release of a Mag 12 would represent about .1% of the gravitational energy of the entire planet.
Same is the case with Tsunami Tragedy. You can say a super volcano cannot erupt?
Sure, a super volcano can erupt. But the scenario that you've refered to isn't going to result in a civil war between the country folks in the Breadbasket versus the City Dwellers.
In the scenario that you've refered to the middle of America is covered in volcanic ash, firey rock and sulphorous gas. Most of the people in middle America would be dead. The rest, including the City Dwellers, would starve to death within four to six weeks because the food supply would be gone.
I applaud your enthusiasm and thoughtfulness with analyzing Titor's missives. But you've focused on two scenarios that, if true, would be so disasterous that Titor's Saga would never come to pass...not even his time machine...because there would be no one left to play the parts in his story, not even Titor himself.
