cataclysm

nouns

a sudden violent change in the earth's surface
cataclysm, catastrophe
an event resulting in great loss and misfortune
"the whole city was affected by the irremediable calamity"; "the earthquake was a disaster"
calamity, cataclysm, catastrophe, disaster, tragedy
is derived from
cataclysmic
is derived from
cataclysmal