Quicksand is not quite the fearsome force of nature that we think it is. In fact, quicksand is rarely deeper than a few feet. It can occur almost anywhere if the right conditions are present. Quicksand is basically just ordinary sand that has been so saturated with water that the friction between sand particles is reduced. The resulting sand is a mushy mixture of sand and water that can no longer support any weight.
If you step into quicksand, it won`t suck you down. However, your movements will cause you to dig yourself deeper into it.
Flowing underground water - The force of the upward water flow opposes the force of gravity, causing the granules of sand to be more buoyant.
Quicksand is in fact an interesting natural phenomenon -- it is actually solid ground that has been liquefied by an over saturation of water. The "quick" refers to how easily the sand shifts when in this semi-liquid state.
Quicksand is not a unique type of soil; it is usually just sand or another type of grainy soil. Quicksand is nothing more than a soupy mixture of sand and water -- in essence, the sand is floating on water. It can occur anywhere under the right conditions, according to Denise Dumouchelle, geologist with the United States Geological Survey (USGS).
Quicksand consists of a buoyant blend of round granules of light sand, blended with water, or of light soil and gritty mud, or of mud peppered with pebbles. Water injects itself into the grains of any one of these mixtures, which separates and lifts them, causing them to tumble over one another, and rendering them helpless to support weighty objects.
Quicksand typically surfaces near the deltas of mighty rivers, or near shores, where a layer of stiff clay below collects and retains the water. Quicksand does not suck unsuspecting victims to their untimely deaths, a theory espoused my most until recently. This nightmarish theory did, however, provide good fodder for a host of low-budget horror films!
The discovery of quicksand`s buoyant properties, akin to those of the salty Dead Sea, quashed this prevalent theory. Since quicksand is saturated with liquid, and far outweighs water, it allows anything or anyone who steps into it, to float higher than possible in water alone. The key to swimming in this non-chlorinated swimming hole, is slow motion. By moving slowly, when initially landing in quicksand, one provides the quicksand with the lead-time necessary to flow around one`s body, thereby making swimming or floating possible.
Quicksand forms when uprising water reduces the friction between sand particles, causing the sand to become "quick."
Quicksand is created when water saturates an area of loose sand and the ordinary sand is agitated. When the water trapped in the batch of sand can`t escape, it creates liquefied soil that can no longer support weight.
There are two ways in which sand can become agitated enough to create quicksand:
Earthquakes - The force of the shaking ground can increase the pressure of shallow groundwater, which liquefies sand and silt deposits. The liquefied surface loses strength, causing buildings or other objects on that surface to sink or fall over.
Vibration tends to enhance the quickness, so what is reasonably solid initially may become soft and then quick, according to Dr. Larry Barron of the New South Wales Geological Survey.
The vibration plus the water barrier reduces the friction between the sand particles and causes the sand to behave like a liquid. To understand quicksand, you have to understand the process of liquefaction. When soil liquefies, as with quicksand, it loses strength and behaves like a viscous liquid rather than a solid, according to the Utah Geological Survey. Liquefaction can cause buildings to sink significantly during earthquakes.
While quicksand can occur in almost any location where water is present, there are certain locations where it`s more prevalent. Places where quicksand is most likely to occur include:
Near underground springs
The next time you`re at the beach, notice the difference in the sand as you stand on different parts of the beach that have varying levels of moisture. If you stand on the driest part of the beach, the sand holds you up just fine. The friction between the sand particles creates a stable surface to stand on.
If you move closer to the water, you`ll notice that the sand that is moderately wet is even more tightly packed than the dry sand. A moderate amount of water works to increase the friction between sand particles. This is what allows you to build sand castles.
But beach sand could easily become quicksand if enough water were thrust up through it. If an excessive amount of water flows through the sand, it forces the sand particles apart. This separation of particles causes the ground to loosen, and any mass on the sand will begin to sink through it. In the next section, you will find out how to save yourself if you happen to fall into a pit of quicksand.