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.
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Famous quotes containing the words sea, level, dry and/or land:
“repression, however, is not the most obvious characteristic of the
sea;
the sea is a collector, quick to return a rapacious look.”
—Marianne Moore (1887–1972)
“Even a nine story pagoda must be built up level by level.”
—Chinese proverb.
“Scarlett O’Hara: Oh, oh, Rhett. For the first time I’m finding out what it is to be sorry for something I’ve done.
Rhett Butler: Dry your eyes. If you had it all to do over again, you’d do no differently. You’re like the thief who isn’t the least bit sorry he stole, but he’s terribly, terribly sorry he’s going to jail.”
—Sidney Howard (1891–1939)
“I have observed the misery of my people who are in Egypt; I have heard their cry on account of their taskmasters. Indeed, I know their sufferings, and I have come down to deliver them from the Egyptians, and to bring them up out of that land to a good and broad land, a land flowing with milk and honey, to the country of the Canaanites, the Hittites, the Amorites, the Perizzites, the Hivites, and the Jebusites.”
—Bible: Hebrew, Exodus 3:7,8.