erupt

To eject something violently (such as lava or water, as from a volcano or geyser).

The volcano erupted, spewing lava across a wide area.

To burst forth; to break out.

The third molar tooth erupts late in most people, and sometimes does not appear at all.

To spontaneously release pressure or tension.

The crowd erupted in anger.

And Stamford Bridge erupted with joy as Florent Malouda slotted in a cross from Drogba, who had stayed just onside.

(Of birds, insects, etc.) To suddenly appear in a certain region in large numbers.

After particularly good seasons, flocks "erupt" from their breeding grounds and appear in reed beds where they have not been seen for years, if ever.