Sea Level and Dry Land
Several terms are used to describe the changing relationships between sea level and dry land. When the term "relative" is used, it means change relative to a fixed point in the sediment pile. The term "eustatic" refers to global changes in sea level relative to a fixed point, such as the centre of the earth, for example as a result of melting ice-caps. The term "steric" refers to global changes in sea level due to thermal expansion and salinity variations. The term "isostatic" refers to changes in the level of the land relative to a fixed point in the earth, possibly due to thermal buoyancy or tectonic effects; it implies no change in the volume of water in the oceans. The melting of glaciers at the end of ice ages is one example of eustatic sea level rise. The subsidence of land due to the withdrawal of groundwater is an isostatic cause of relative sea level rise. Paleoclimatologists can track sea level by examining the rocks deposited along coasts that are very tectonically stable, like the east coast of North America. Areas like volcanic islands are experiencing relative sea level rise as a result of isostatic cooling of the rock which causes the land to sink.
On other planets that lack a liquid ocean, planetologists can calculate a "mean altitude" by averaging the heights of all points on the surface. This altitude, sometimes referred to as a "sea level", serves equivalently as a reference for the height of planetary features.
Read more about this topic: Sea Level
Famous quotes containing the words dry land, sea, level, dry and/or land:
“I know only one person who ever crossed the ocean without feeling it, either spiritually or physically.... he went from Oklahoma to France and back again ... without ever getting off dry land. He remembers several places I remember too, and several French words, but he says firmly, “We must of went different ways. I don’t rightly recollect no water, ever.””
—M.F.K. Fisher (1908–1992)
“Then Moses stretched out his hand over the sea. The LORD drove the sea back by a strong east wind all night, and turned the sea into dry land; and the waters were divided. The Israelites went into the sea on dry ground, the waters forming a wall for them on their right and on their left.”
—Bible: Hebrew, Exodus 14:21,22.
“Nihilism as a symptom that the losers have no more consolation: that they destroy in order to be destroyed, that without morality they no longer have any reason to “resign themselves”Mthat they put themselves on the level of the opposite principle and for their part also want power in that they compel the mighty to be their hangmen. This is the European form of Buddhism, renunciation, once all existence has lost its “meaning.””
—Friedrich Nietzsche (1844–1900)
“The sea was wet as wet could be,
The sands were dry as dry.
You could not see a cloud, because
No cloud was in the sky:
No birds were flying overhead—
There were no birds to fly.”
—Lewis Carroll [Charles Lutwidge Dodgson] (1832–1898)
“In 1862 the congregation of the church forwarded the church bell to General Beauregard to be melted into cannon, “hoping that its gentle tones, that have so often called us to the House of God, may be transmuted into war’s resounding rhyme to repel the ruthless invader from the beautiful land God, in his goodness, has given us.””
—Federal Writers’ Project Of The Wor, U.S. public relief program (1935-1943)