There's a lot of subduction zone off Sumatra, which is a big island, that didn't break....actually (due to logistical reasons, ease of getting to the site, Indian Government travel restrictions) that section was much more heavily studied by geologists..most prominently Kerry Sieh...than the section that did break.
It basically starts immediately south of the area of the December quake. It ruptured in a massive quake in 1833 and in a smaller quake that preceeded it in 1897. Based on the length of the area it would produce a quake in the 8.5-9 range, not bigger than the December quake. Even before the December quake it had been considered extremely dangerous.
It could pop tomorrow or in 20 years. That the December quake increased stress on it is a pretty valid theory (recently published in Nature.) The orientation of that segment would mean very small or no tsunami in India, Sri Lanka, and Thailand but would hit Indonesia very hard again (in a densely populated area) and also give NW Australia more of a hit. Potentially Madagascar too.
The odds of Yellowstone erupting in our lifetimes is vanishingly small. Despite what a lot of kook sites claim, there's no particular evidence the entire Caldera is getting ready to erupt.
That should be 1797, not 1897, in the above, sorry.
I'm aware that the data on Yellowstone is perhaps best described as neutral to confusing in terms of any predictive usefulness about a quake in the near future.
I couldn't find that Times of India article again. But I didn't type the India Daily in my original search way back with the posting of the Daily article. For some reason, I thought it was the Times of India a that had the article. And, I did find it on their site. Don't know why I can't find it now.
I'm glad you brought that up, there was a tv program on, I think Discovery Channel, recently about the "imminent threat to North America of the Yellowstone Supervolcano."