Download File

Earth Shakes, Rattles, and
Rolls
Plate Tectonics
Earthquakes
What is the relationship
between the earth’s
plates, volcanoes, and
earthquakes?
Plates
http://www.extremescience.com/PlateTectonicsmap.htm
Earthquakes
Volcanoes
http://hsv.com/scitech/earthsci/quake.htm
Let’s look at those
maps again.
http://www.teachersdomain.org/ass
et/ess05_int_tectonic/
Plates
Volcanoes
Earthquakes
Earthquakes and Volcanoes are found
where plates meet.
Evidence Wegener used to
support theory of continental
drift:
• Continents fit like a puzzle
• Fossil evidence
• Rocks were similar in Africa and
South America
• Evidence Antarctica once had a
tropical climate
SUPERCONTINENT PANGAEA
How did geologists explain
how the earth’s plates
moved?
To see how geologists believe
the plates moved go to the
sites below.
Notice the Atlantic Ocean seafloor
spreading (Handout).
Seafloor spreading
• More!
Label the following:
•Trench
•Ridge
•Crust
•Mantle
•Outer core
•Inner core
Use p. 92 (Fig. 10.5) to
help!
Convection currents
in the magma move
the earth’s crust.
Convection currents in the
Earth's mantle are what drive
plate motions. Convection
currents are driven by the
simple fact that hot things
(such as gases and liquids)
rise while cool things fall.
VIDEO
• http://www.youtube.com/watch?v=QDqskltCixA
Convection currents in action! At left, two animal
cookies represent two of the Earth's tectonic plates.
At right, the two plates have moved apart, much like
what happens at a divergent margin. The chocolate
pudding represents the Earth's mantle. The heat
source beneath the pot created convection cells in the
chocolate pudding. Think of the cookie on the left as
South America, and the cookie on the right as Africa.
Over time they have moved apart. You'll see this
again.
http://images.google.com/imgres?imgurl=http://visearth.ucsd.edu:16080/VisE
_teach/Kimball/untitled18.jpg&imgrefurl=http://visearth.ucsd.edu:16080/VisE
_teach/Kimball/Kimball2.html&h=200&w=308&sz=35&tbnid=sEa1xg46QV
MJ:&tbnh=72&tbnw=110&start=9&prev=/images%3Fq%3DCONVECTION
%2BCURRENTS%26hl%3Den%26lr%3D%26sa%3DN
Earthquakes
How do we measure the
intensity of an earthquake?
epicenter
The point on the surface of Earth that is right
above the focus of an earthquake
http://www.harcourtschool.com/glossary/science/define/gr4/epicent
er4c.html
Seismograph
measures
or the strength of an
earthquake
Seismograph records energy waves of the earth
Richter Scale
Earthquake Magnitudes
Less than 3.5
Effects
Generally not felt
3.5-5.4
Rarely causes damage.
Under 6.0
Slight damage to well-designed buildings.
6.1-6.9
Destructive to about 100 kilometers across
7.0-7.9
Major earthquake. Serious damage over larger areas.
8 or greater
Great earthquake.
Each number is 10X stronger than the
previous number.
How much stronger is the 3
than the 1? 100
Times
How much stronger
is the 8 than the 1? 10,000,000
Write the number in
scientific notation.
106
Richter Magnitude
1.0 to 3.9
Number of Earthquakes
per year
900,000 +
4.0-4.9
6200
5.0-5.9
800
6.0-6.9
226
7.0-7.9
18
8.0-8.9
Less than 2
Can you think of a recent earthquake?
Haiti
http://www.youtube.com/watch?v=
79S-6UqGCbU
Earthquakes in the ocean cause
30’ Wall of Water
Destruction