2 Peter 3:6 says that the earth was overflowed with water, verse 7 says that this earth has fire reserved for it. Dont see a big difference.
looking at 2 Peter 3:9-11 sounds a little more specific to the heavens, the earth, and then also the works(mankinds) on earth shall melt. it lists also the elements, that could be taken a few ways, but its kind of funny that we have a chart of the elements, that pretty much makes up everything that we as man know, not to get too scientific on ya.
verse 11 says that
all these things listed shall be dissolved.
.
to me these verses are saying the same thing, the ungodly will be removed from the earth forever by death.
I do believe the wicked shall receive a reward of actual fire, but i also believe that the earth shall get a little crispy. Just as Sodom and Gomorrha got burned.
FOA