Blowout: a depression created by
wind erosion typically in either a partially vegetated
sand dune ecosystem or dry soils (such as a post-glacial
loess environment).[1]
Oceanic trench: a deep linear depression on the ocean floor. Oceanic trenches are caused by
subduction (when one tectonic plate is pushed underneath another) of
oceanic crust beneath either the oceanic crust or
continental crust.
A basin formed by an
ice sheet: an area depressed by the weight of the ice sheet resulting in
post-glacial rebound after the ice melts (the area adjacent to the ice sheet may be pulled down to create a peripheral depression.)[4]