occurrence vs natural event

occurrence and natural event both are nouns.

Word	Noun	Adjective	Verb	Adverb
occurrence	Yes	No	No	No
natural event	Yes	No	No	No

As nouns, occurrence and natural event are synonyms defined as:

Other synonyms of occurrence include happening, occurrent.

occurrence (noun)	natural event (noun)
an event that happens	an event that happens
an instance of something occurring