Quicksand
From Freepedia
- This article is about the geological feature. For other meanings, see Quicksand (disambiguation)
Quicksand is loose, water-logged soil that yields easily to weight or pressure. It can be formed when sand, silt, clay, or other grainy soil is saturated or supersaturated by water flowing from below ground (such as from an underground spring) with enough pressure to separate and suspend the grains. The undisturbed sand often is or appears solid until some shock or sudden increase in pressure, such as a person stepping on it, causes it to liquify and lose its friction.
Quicksand is not as dangerous as depicted in many movies. Because quicksand is denser than the human body, a person will float in it. As quicksand is rarely more than a few feet deep, there is usually little danger of sinking below the surface. Furthermore, even when the quicksand is deep enough, deliberate effort is required to sink below the surface, as the human body is much more buoyant in quicksand than water. The sand's higher density will gradually push a human body upward, eventually allowing one to paddle toward more solid footing. Typically, the greatest danger of getting stuck in quicksand comes from exposure, starvation, flash flooding, or tidal flooding.
Quicksand can be found inland (on riverbanks or in marshes) or near the coast. It can also form when an earthquake increases groundwater pressure, forcing the water to the surface and allowing buildings to sink into the ground.
One region notorious for its quicksands is Morecambe Bay, England. As the bay is very broad and shallow, a person trapped by the quicksand would be exposed to the danger of the returning tide, which can come in very rapidly.
