Wouldn't it be funny if PH is the island that Aokiji and Akainu fought on? Would explain the whole lava/ice thing :P Hahaha
That is becoming less likely to me with every chapter. Even though it could be possible, the island has a lot more activity than Smoker and Tashigi know. Unless who ever is behind this set up shop after Aokiji and Akainu totaled the place this could just be a strange island.
We have lightning raining on Raijin island so any wacky climate is on the table.