Synonyms for earthshaking

Adjective

1. earthshaking, loud (vs. soft)

usage: loud enough to shake the very earth

2. earthshaking, world-shaking, world-shattering, significant (vs. insignificant), important

usage: sufficiently significant to affect the whole world; "earthshaking proposals"; "the contest was no world-shaking affair"; "the conversation...could hardly be called world-shattering"