Verbs

(v)erupt, break outstart abruptly“After 1989, peace broke out in the former East Bloc”
(v)erupt, irrupt, flare up, flare, break open, burst outerupt or intensify suddenly“Unrest erupted in the country”, “Tempers flared at the meeting”, “The crowd irrupted into a burst of patriotism”
(v)erupt, ignite, catch fire, take fire, combust, conflagratestart to burn or burst into flames“Marsh gases ignited suddenly”, “The oily rags combusted spontaneously”
(v)erupt, come out, break through, push throughbreak out“The tooth erupted and had to be extracted”
(v)erupt, belch, extravasatebecome active and spew forth lava and rocks“Vesuvius erupts once in a while”
(v)break, burst, eruptforce out or release suddenly and often violently something pent up“break into tears”, “erupt in anger”
(v)eruptappear on the skin“A rash erupted on her arms after she had touched the exotic plant”
(v)erupt, recrudesce, break outbecome raw or open“He broke out in hives”, “My skin breaks out when I eat strawberries”, “Such boils tend to recrudesce”