erupt vs flare up

erupt and flare up both are verbs.

Word	Noun	Adjective	Verb	Adverb
erupt	No	No	Yes	No
flare up	No	No	Yes	No

As verbs, erupt and flare up are synonyms defined as:

Other synonyms of erupt include break open, burst out, flare, irrupt.

erupt (verb)	flare up (verb)
become active and spew forth lava and rocks	erupt or intensify suddenly
start abruptly	ignite quickly and suddenly, especially after having died down
erupt or intensify suddenly
become raw or open
break out
appear on the skin
force out or release suddenly and often violently something pent up
start to burn or burst into flames