At the moment, the only known exploding lakes are in Africa. It would appear they only develop under very special circumstances. However, I would bet my bottom dollar more exist in the world. I also saw examples of possible limnic eruptions on other deep likes such as Crater Lake in Oregon. Truth be told, our knowledge of this planet is fairly limited. That's not to say we don't know anything, but it would appear the geological processes occurring here have more in store for us in the future.