Isaac is doing an AMA on reddit, and I got confirmation that this overlay of the Elendel Basin over the Final Empire map was pretty close, size and location-wise. It's crazy thinking of how many people must have died and how little ground has been resettled since then! If I remember correctly, the population of Elendel is in the low millions somewhere, and the population of TFE was in the 100 million range. So we're talking a 90% loss of life. And pretty close to that for land, it seems.