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

• court favor
• court favour
• court game
• court of appeals
• court of assize
• court of assize and nisi prius
• court of chancery
• court of domestic relations
• court of justice
• court of law
• Court of Saint James's
• court order
• court plaster
• court tennis
• court-martial
• court-ordered
• Courtelle
• courteous
• courteously
• courteousness
• courtesan
• courtesy
• courthouse
• courtier
• courting