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 The Mohole
Project drilled a hole down to the
boundary between the earth's crust and mantle.
Doing so would, it was believed,
provide a concrete check on theories about the
age, origin, and composition of the earth. |
 Parícutin,
"The Corn Field Volcano" On February 20, 1943, Dionisio Polido
noticed a column of smoke coming out a 3-inch
hole in the corn field he was plowing. Today
Parícutin stands at exactly 1,345 feet above the
ground, and 9,210 feet above sea level. |
 The San Andreas Fault
is a fracture in the earth's crust
marked by a zone of disrupted land in California.
The fault extends more than 750 miles from off
the coast of northwestern California to the
southeastern part of the state near the Mexican
border. |
 Four Ways to
"Make" a Mountain Mountainous regions are created by
movements of the earth's crust. These movements
occur very slowly, but on a large scale.
Different parts of the earth's crust react in
different ways to these movements, and form four
basic types of mountains. |
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