A sudden or rapid change in physical properties of rocks within the Earth Discontinuities are recognized by seismic data See also: Mohorovicic discontinuity
Comparatively large contrast in meteorological elements over a relatively small distance or period of time In oceanography, it is the abrupt change or jump of a variable at a line or surface
A major shift in a trend, that is so drastic that it cannot be accounted for by normal variation An example might be the population shifts due to the baby boom A larger scale example would be change from the industrial revolution to the information revolution