subsidence

Etymology

Latin subsidens, subsidentis, present participle of subsidere.

noun

1. The process of becoming less active or severe.
   The subdual or subsidence of the more violent passions. 1754, William Warburton, Sermon preached before the King, at Kensington, October 27, 1754
2. (geology) A sinking of something to a lower level, especially of part of the surface of the Earth due to underground excavation, seismic activity or underground or ground water depletion.
   Everyone knows that a main line running through a coalfield is prone to speed restrictions because of land subsidence. […] The rate of subsidence may vary from less than an inch a month in the case of a deep seam of coal, to as rapid a decline as 16in a month above a shallow seam. The effect of subsidence on permanent way and civil engineering structures needs no emphasis. 1961 November, “Talking of Trains: The subsidence problem”, in Trains Illustrated, page 651
   Subsidence was first noted in the late nineteenth century. An increasing thirst for groundwater, which creates subterranean pockets that are then compressed by the land above, and upriver damming of the Mississippi, which prevents the replenishment of sediments, have undermined the city to the point that it is now thought to be subsiding by up to 12 millimetres per year. 2020, David Farrier, “Thin Cities”, in Footprints, 4th Estate