Foreigners like you often face difficulties in understanding the logic behind this process. You must comply with it anyway, because it is under jurisdiction of King #9. Don't be mistaken: they are many.

     When the first of them erupts, the last one erupts too, but there is only one eruption.

     Since all intermediate eruptors are usually checked out by the mayor, you have no choice but to revert the first crater to its previous revision.

     And then blow in it so it erupts! And again the story repeats.