Transcript Earthquakes - Boone County Schools

Earthquakes
A Whole Lot of shakin’ going
on!
What are Earthquakes and where
do they occur?
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Seismology is the study of earthquakes.
Most earthquakes occur near the edges of
tectonic plates due to their movement.
Faults are breaks in the crust along which
blocks of the crust slide relative to one
another. They occur in many places, but
are most common near the edges of
tectonic plates.
Earthquakes
Location of worldwide earthquakes
What Causes Earthquakes?
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As the tectonic plates scrape against
each other, stress builds up along
faults near the plates’ edges.
As a response to the stress, the rock
in the plates bend or fold.
Bending or folding, also called
deformation is the change in the
shape of rock in response to stress.
What Causes Earthquakes?
How Do Earthquakes Travel?
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The energy released travels in the form of
seismic waves.
Seismic waves are waves of energy that
travel through the Earth.
Waves that travel through the Earth’s
interior are called primary waves (P
waves).
Waves that travel along the Earth’s
surface are called surface waves (S
waves).
Surface Waves
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Surface waves
move the ground
up and down in
circles as the wave
travel along the
surface.
Surface Waves
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Move along the Earth’s surface
Produces motion in the upper crust
More destructive
How are Earthquakes Measured?
Richter Scale
Typical
Seismogram
http://isu.indstate.edu/jspeer/Earth&Sky/EarthCh11.ppt
How do scientists calculate how far a location is
from the epicenter of an earthquake?
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Scientists calculate the difference
between arrival times of the P waves
and S waves
The further away an earthquake is, the
greater the time between the arrival of
the P waves and the S waves
Seismologist
Focus – point inside the Earth where an
earthquake begins
Epicenter – point on Earth’s surface above
focus
Haiti
January 2010 killed more than 200,000
people and left 1.5 million homeless.
Haiti
San Andreas Fault
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The San Andreas Fault is the sliding
boundary between the Pacific Plate
and the North American Plate. It
slices California in two
San Andreas Fault
San Andreas Fault
San Andreas
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01/09/1857 -Fort Tejon, 7.9 magnitude
04/18/1906 - San Francisco, California, with a magnitude 7.8,
was one of the worst earthquake in California history. The
earthquake killed over 3,000 people and caused $524 million in
property loss. The damage in San Francisco alone was over $20
million. Due to broken pipelines, water was shut off to the entire
city. Many fires soon broke out throughout the city and caused
major devastation as there was no water to put them out. This
earthquake caused the lengthiest rupture of a fault in U.S. history.
People as far as western Nevada and southern Oregon could feel
the tremor.
On 02/24/1892- Imperial Valley, California with a magnitude of
7.8, the third largest earthquake in California history occurred.
This earthquake did quite a bit of damage, but caused no
casualties. It destroyed many homes and cause rockslides. About
155 aftershocks were felt in the 12 hours following this quake.
San Andreas
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Last big earthquake in California was
in 1999.
7.1 magnitude
In a remote location, so next to no
damage.
California is over due for the next big
earthquake.
New Madrid Fault
New Madrid
New Madrid Fault
http://www.youtube.com/watch?
v=SjqVidNX23o
New Madrid
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http://en.wikipedia.org/wiki/New_Ma
drid_Seismic_Zone
Tsunamis
http://www.uwgb.edu/dutchs/EarthSC-102VisualsIndex.HTM
Formation of a tsunami
http://isu.indstate.edu/jspeer/Earth&Sky/EarthCh11.ppt
Earthquakes
Tidal waves or Tsunamis result when the low amplitude long wavelength w
reach the shallow shoreline and begin to feel the bottom of the sea floor.
Shortens the wavelength and increase the amplitude (height).
Japan
8.9-magnitude
March 11, 2011
20,000 lives lost
Japan
Japan
Ring of Fire
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90% of all earthquakes occur along
the ring of fire.
Other quakes
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http://www.youtube.com/watch?v=8
6OXNrqV4-M