Hi Chris. Math was never my strong point, but here are some figures you can look at. Rather then trying to work with segments I chose to look at it in its entirety. It appears that the loading would be around 40 to 50mm per year and would more or less be towards the northeast.

The 1833 quake appears to have ruptured an area of 650 to 700 miles long with a movement of about 60 feet. The 1861 quake appears to have ruptured an area of about 250 to 300 miles long with a movement of about 20 feet. These figures are only estamates based on the movement seen with the Dec.26 quake, which if memory serves was more then 120 feet and the rupture was more then 700 miles. Keep in mind that the movement would be horizontal as well as vertical.

Lets assume (I hate that word) that the 1833 quake loaded the area of the 1861 quake, which in turn loaded the area of Dec.26 quake. There was a time span of 28 years between the 1833 and 1861 quake, but more then 140 years between the 1861 quake and the 2004 quake. Was this because there was less stress transferred, or because the resistance to movement was greater?

What happened to the stress from the Dec.26 quake? Did it continue north, did it go south, or did it go both north and south? If all of it went south, how far south did it go? Did it go the area of the 1833 quake, or did it go to an area northwest of Australia? What affect did this quake have on the Great Sumatra Fault?

Based on the history of two quakes, which is really no history at all, we may have 28 to 140 years before the next quake. Then again maybe not. Take Care…Don in creepy town