LIQUEFACTION
Liquefaction
is the process of loose soil acting like a liquid during an earthquake.
Most
of the time, buildings and homes are built upon solid bedrock. However,
building also happens on what seems like solid ground. But underneath a
solid layer of compact sediment, there is lurking a loose layer of sandy soil
or soil that has been saturated with water. During the shaking of a
powerful earthquake, this loose soil will act like
quicksand. When liquefaction occurs, the homes and buildings atop
this soil can sink or fall over when their foundations loosen or break
apart. The surface of the ground will become very uneven and unstable.
Crevices and gaps open up. Roads and sidewalks break into pieces and
become hazardous.
These
are not the only effects of liquefaction. Loose, sandy soil, or the water
saturated soil underneath the compact layer of sediment can make its way up
to the surface. The columns of rising sandy soil are called sand
dikes. When the sand emerges on the surface it is called a sand
boil. The results of this liquefaction phenomenon are often seen after
high magnitude earthquakes. Street pavement will break apart, and
sand boils can be seen on roadways and other areas. Sewer channels
underneath streets can rise up during liquefaction. As a result, the
manhole cover you see everyday on your way to school could be several inches to
a couple of feet higher than the surface of the road. This is a common
side effect of liquefaction. Other underground structures can break also;
important things like gas and water lines.
SOIL LIQUEFACTION EFFECTS
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