While evidence of pyroclastic dams occur within the geologic record,[6] they are best known and studied in relation to recent and current volcanic eruptions. Examples worldwide include associations with El Chichon in Mexico,[7] and the Karymsky Volcano in Russia.[8] The caldera lake associated with Taal Volcano, which was previously open to the East China Sea, was permanently closed by a pyroclastic dam during the 1749 eruption, and remains in equilibrium at a higher level to this day,[9] while the pyroclastic dam comprising the low rim of crater Lake Nyos in Cameroon is considered less stable.[10]