1. 大灾难；剧变
A cataclysm is an event that causes great change or harm.

1. an event resulting in great loss and misfortune

e.g. the whole city was affected by the irremediable calamity
the earthquake was a disaster

Synonym: calamitycatastrophedisastertragedy

2. a sudden violent change in the earth's surface

Synonym: catastrophe