1. Loud enough to shake the very earth 
2. Sufficiently significant to affect the whole world
   "earthshaking proposals"
   - world-shaking, world-shattering, earth-shattering

See also: important, loud, significant

• air-to-surface missile
• airborne
• airborne patrol
• airborne transmission
• airbrake
• airbrush
• airburst
• airbus
• aircraft
• aircraft carrier
• aircraft engine
• aircraft landing
• aircraftman
• aircraftsman
• aircrew
• aircrewman
• airdock
• airdrome
• airdrop
• Aire
• Aire River
• aired
• Airedale
• Airedale terrier
• airer