Related Clues:

• Etna does it
• What a volcano can do
• Go off like Mount St. Helens
• Eject violently
• Emulate 18 Down
• Emulate a geyser
• Gush, as a volcano
• Eject, as 16-Across
• Eject, geyser-style
• Break out, as fighting
• Expel, as lava
• Belch
• Go off like Vesuvius
• Totally blow?
• Really lose one's temper