Eh, I personally enjoyed the series, but I wouldn't recommend anything beyond book 1. Book 2 is ok. Book 3 really spoiled the series for me because of the inconsistent behavior if the main character. (Keeping it vague to avoid spoilers)
The Deccan plateau is one of the world's most geologically inactive areas. The ring of fire goes through the circle but isn't a major component of the circle. There aren't even a remarkably high destiny of volcanoes.
I would imagine the definition of surround would have to be modified accordingly.