Answer 1:
The processes that are responsible for the
destruction of rocks at the
Earth's surface are conventionally divided into
weathering (in which
chemical and physical processes break big rocks
into tiny pieces) and
erosion (in which those tiny pieces are carried
from their original
place down slope or downstream). Naturally you
will be worried about
erosion if your house is built on a steep slope
and the ground is
eroding out from beneath you or if you might be
buried in a landslide.
If you travel on a winding road cut into a steep
mountainside, you
might notice that over the years the down-slope
side is slowly
retreating back as the edge of the road erodes a
way, while the road
might occasionally get buried by debris that
washes in from above.
Another way that erosion can affect us is in the
erosion of
topsoil--modern farming methods (like plowing
the ground with
tractors) can lead to soil being blown away by
the wind or being
carried into rivers when it rains, and this is a
problem because soils
form very slowly and in many places soil
formation can't keep up with
the high rates of soil loss due to erosion.
During the Dust Bowl of
the 1930s, when a severe drought hit parts of
the central U.S. that
were being farmed unsustainably, up to 75% of
the topsoil in some
areas was blown away. But processes of
weathering and erosion affect
us in grander ways too because they are some of
the basic forces that
shape the face of our planet. They wear down
mountains and fill in
valleys; they are why the seas are salty and the
land is clothed with
life-giving soil.
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