EARTHQUAKES!
Jody Pearl, Kasie Drobnick, Ellen Cochran
An earthquake is…
A
phenomenon that results from
and is powered by the sudden
release of stored energy in the
crust that propagates seismic
waves.
Why do earthquakes happen?
•The earth's crust (the outer layer of the planet) is
made up of several pieces, called plates. The plates
under the oceans are called oceanic plates and the rest
are continental plates.
•The plates are moved around by the motion of a
deeper part of the earth (the mantle) that lies
underneath the crust.
•These plates are always bumping into each other,
pulling away from each other, or past each other. The
plates usually move at about the same speed that your
fingernails grow. Earthquakes usually occur where two
plates are running into each other or sliding past each
other.
Map of the Tectonic Plates
Where do most earthquakes happen?
•Earthquakes occur all the time all over
the world, both along plate edges and
along faults.
•Most earthquakes occur along the edge
of the oceanic and continental plates.
•http://www.classzone.com/books/earth
_science/terc/content/investigations/es1
001/es1001page07.cfm
How are earthquakes measured?
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Seismology is the study of earthquakes and
seismic waves that move through and around the
earth.
A seismologist is a scientist who studies
earthquakes and seismic waves.
Seismic waves are the waves of energy caused by
the sudden breaking of rock within the earth or an
explosion. They are the energy that travels through
the earth and is recorded on seismographs.
Earthquake Detectors!
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Work in teams of 3 to build a replica of an earthquake
detector. Use a ruler and scissors to cut 4-inch (10 cm)
slits in the bottom edges of the two long sides of the box.
Cut paper into strips slightly smaller than 4 inches (10
cm) wide. Attach pieces together with clear adhesive tape
to form a long strip. Insert the strip of paper into the slits
so the ends of the strip extend out of the slits.
Attach two rubber bands around the box so the bands
are stretched wide to the sides of the other two slits.
Place a fine tip marker between the two rubber bands.
Cut two pieces of yarn with scissors and tie the marker
into place between the rubber bands so the tip lightly
rests on the strip of paper in the box.
Work together with one partner jiggling the box and the
other pulling the paper through to get a continuous
reading of the magnitude of the simulated earthquake.