How do you end your turn on an empty space? When you end your turn, the space isn't empty anymore.
ERUPTION
Magma starts each game with 4 molten lava tiles on her Army Card. If Magma ends her turn on an empty land space, you may place a molten lava tile from her Army Card onto the space she occupies if the molten lava tile fits normally onto that space.
So are "land spaces" any one-hex high tiles that are not road or wall walk?