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Constructive Earthquakes
Why Is an Earthquake Constructive?
By Kevin Lee
Newspaper headlines seldom read, "Catastrophic earthquake brings happiness and well-being to
all."
Instead,
you often hear about toppling buildings, raging fires and devastating tsunamis.
Yet,
even in the midst of smoldering ruins, nature repeatedly transforms bits of
calamity into pieces of triumph by using earthquakes for constructive purposes.
Faults, Plates and Quakes: The Earth in
Motion
Earthquakes
pose a threat to more than 70 million Americans in 39 states.
When
a major earthquake begins, shaking and ground displacement may follow when
high-energy seismic waves move through the ground.
Although
volcanoes and other events trigger quakes, most occur along tectonic plate
boundaries where faults form.
A
fault, such as San Andreas Fault in California, is a crack or series of cracks
between massive blocks of rock.
This
same tectonic plate motion also causes volcano eruptions and continental drift,
the process that causes land masses to move slowly.
Instant Tourist Attractions
The
Earth has several layers, but the only one fragile enough to fracture during an
earthquake is the lithosphere. That's the layer that contains tectonic plates.
Earthquakes
can be so powerful that they reshape the landscape in surprisingly novel ways.
For
example, a lake just south of New Madrid, Missouri, was formed in 1912 thanks
to an earthquake.
The
hole it created filled with water, creating an exquisite lake that attracts
tourists today.
Hot
springs can also form as a result of earthquakes.
Land Where There Was None
Faults
have the ability to create important geological entities called rift valleys.
Rift
valleys are block-fault graben surrounded by horst mountains.
A
horst is a section of ground that's moved up to an altitude higher than the
graben.
Grabens
are collapsed or down-dropped rock surrounded on their longest sides by faults.
If
you love scenic cliffs, it's possible that an earthquake created one of your
favorites.
A
cliff can form in a location where quakes happen frequently.
Earthquake
activity may also lead to the formation of land masses at sea. For instance,
NASA satellite photos taken in 2013 reveal a new island created after a
7.7-magnitude earthquake ravaged Pakistan.
The
island formed offshore even though the actual quake occurred around 380
kilometers (230 miles) away from the shore inland.
Scientists
believe that the island rises up to 20 meters (70 feet) from the water line and
has a width of up to 90 meters (300 feet). Its surface consists of rock, sand
and mud.
Indirect Earthquake Benefits
Earthquakes
can be constructive in other ways besides creating new land masses. Scientists,
for example, cannot study Earth's interior directly, but geologists can by
analyzing the way seismic waves move below ground.
That's
possible because these waves behave differently as they travel through
materials of different densities and rigidities, and this gives scientists
clues about the makeup of different layers of the planet.
Special
scientific stations around the world record seismic data to help geologists
learn about the planet's interior.
About the Author
After
majoring in physics, Kevin Lee began writing professionally in 1989 when, as a
software developer, he also created technical articles for the Johnson Space
Center. Today this urban Texas cowboy continues to crank out high-quality
software as well as non-technical articles covering a multitude of diverse
topics ranging from gaming to current affairs.
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