seismic shift

plural seismic shifts

1. idiomaticA fundamental reorientation of a state of affairs.

   The seismic shift in Mexico began in 1810 with the movement toward independence from Spain.

   1958, Waldo Frank, "Mexico" in The Romance of North America (Hardwick Moseley, ed.), Houghton Mifflin, p. 127 (Google snippet view)

   3 more examples

   For the republican movement, the acceptance of seats in a "partitionist" Assembly signaled a seismic shift in historical attitudes since the division of Ireland in 1921.

   1999 December 6, Eamon Phoenix, “Peace Is Breaking Out”, in Time, retrieved 19 May 2015

   [T]he U.S. could be on the verge of a seismic shift, where it is possible to envision a time when it will no longer be the dominant economic superpower.

   2007 December 10, “Most Important of 2007”, in Businessweek, retrieved 19 May 2015

   Baby boomers began turning 65 in January, heralding a seismic shift in demographics worldwide.

   2011 February 5, “The Aging of America”, in New York Times, retrieved 19 May 2015

   Synonyms: upheaval