Surely, there must have been some parts of the world's land that, in the film, were not covered by either tsunamis or lava from volcanoes. Is it conceivable that parts of the Americas, Europe, Africa, Asia and Australia were not wiped out?
They say the whole African-continent rose 7000 ft, as it shifted from where we know it to somewhere around Everest, and likely some survived
Others may have survived the shift and the waves and the earthquakes
3 Arks survived, Once the atmosphere cleared, and the water run off, and some rains to cleanse the soil,and start something of growth, I would imagine they'd split to differing land masses and start again, a little easier with nuclear powered craft
Would be interesting to see what form of governments would survive and take root
You don't have to stand tall, but you do have to stand up!
It is likely that there are survivors in Africa. I believe the director even hinted it during talks of a possible sequel. The sequel would basically be a conflict between the native African survivors and those from the arcs, and the powerplay between the two groups.
It is also likely that there are survivors from all over the world as well, even the ones whose cities have been destroyed. It is also possible that some lands, even countries, were spared from the apocalypse.