Well, I've read all you've got, and I think it's great. I think when I review something I'm supposed to offer tips or something, but there is nothing I can say to improve what I think is a seriously gripping story, what is well written.
What I suspect though, is that you've set the scene for what could be several books. There are so many questions that need to be answered, although the ultimate is - can humanity find a solution, and move to the surface again.