Eruption is an offensive Fire-type move.
Eruption's power changes proportionately with the user's remaining HP, and is calculated as follows:
Power = 150 * (User's current HP / User's maximum HP)
Ergo, Eruption has 150 power if the user is at full health and grows steadily weaker as the user loses health.
Pokémon that learn Eruption
By leveling up