Board Game Arena

In the Amazonis Planitia expansion, there are volcano symbols on the board. What benefit do these hexes provide? What should you put there and what can you get?

Like on Tharsis map, Lava Tube and Lava City must go on those spots if you play them. Any regular tile can go there as well. If you think about symbols indicated on the map, those are delegates in Turmoil expansion.