Quicksand

Quicksand - a dangerous phenomenon and still unexplored. Scientists are still unable to thoroughly describe the nature of their formation. American scientist George Clarke sees the cause of this phenomenon in the water. According to experts, the properties quicksands are similar to the properties of the liquid medium, and "fluidity" is characteristic of the state of the sand. As an argument, he recalled that this phenomenon is usually found in areas where groundwater flows very often change their direction, rise and fall. Sands danger fraught it from sinking streams. Then sand and acquire property tightening that from unnecessary movements only increased. So the only hope for salvation - calm and quickly assisted by. So, it is the presence of a huge underground river under the Sahara today are inclined to explain the nature of the quicksand of this desert. This hidden river able to "calculate" with the help of images taken by satellite.

Source: scienceblog.ru/2009/10/01/uchenye-obyasnili-prirodu-zybuchikh-peskov/