seismic shift

Etymology
An allusion to the drastic change to the landscape caused by a massive earthquake.

Noun

 * 1)  A fundamental reorientation of a state of affairs.
 * 2) * 1958, Waldo Frank, "Mexico" in The Romance of North America (Hardwick Moseley, ed.), Houghton Mifflin, p. 127 (Google snippet view):
 * The seismic shift in Mexico began in 1810 with the movement toward independence from Spain.

Usage notes

 * Often used in social, political, or economic contexts.