1. By: Lauren Showers
EDU 290 Tu/Th 11:00am
EARTHQUAKES

2. WHAT IS AN EARTHQUAKE?
 Merriam-Webster Dictionary defines an
earthquake as a shaking or trembling of the
earth that is volcanic or tectonic in origin.
http://questgarden.com/71/26/9/081013095448/

3. HOW DO EARTHQUAKES OCCUR?
 Earthquakes occur when two blocks of land
suddenly slip past each other along a fault
line(USGS).
 The location in which the earthquake starts is
called the Hypocenter. The location directly
above the hypocenter on the earth’s surface
is called the Epicenter (USGS).

4. HOW DO EARTHQUAKES OCCUR CONT.
jclahr.com

5. WHERE DO EARTHQUAKES OCCUR
Earthquakes occur along fault lines. There are
three major types of fault lines.
 Strike-slip Faults
 Normal Faults
 Reverse Faults

6. STRIKE-SLIP FAULTS
 Occur along transform boundaries
 The two blocks of land move sideways past
each other on a horizontal plane (Plate-
tectonics.org).
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7. STRIKE-SLIP FAULTS CONT.
 Famous strike slip faults include the San
Andreas fault in California and the Alpine
Fault in New Zealand.
Geology.com

8. NORMAL FAULTS
 Occur at divergent plate boundaries.
 The rocks on one side of the normal fault
moves downward against the rocks on the
other side (plate-tectonics.org).

9. REVERSE FAULTS
 Reverse faults occur at convergent boundaries.
 The rocks on one side of a reverse fault moves
upward. This movement of rocks at reverse faults
often causes earthquakes (plate-tectonics.org).
claremontgeography12.blogspot.co
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10. HOW ARE EARTHQUAKES MEASURED?
 The Richter Scale is used to measure
earthquake magnitude.
 On a 1-10 scale. 1 being the smallest, 10
being the largest.
 Measured with a device called a
Seismograph.
aggas2nd.blogspot.com

11. TYPES OF WAVES
 There are two types of waves associated
with earthquakes.
 P-Waves
 S-waves

12. TYPES OF WAVES CONT.
 P-waves- Travel through solid rock and
liquids.
 As it spreads out, it alternately pushes
(compresses) and pulls (dilates) the rock
(allshookup.org).
web.ics.purdue.edu

13. TYPES OF WAVES CONT.
 Slower than P-waves
 Can only move through solid rock.
 As an S wave propagates, it shears the rock
sideways at right angles to the direction of travel
(allshookup.org).
web.ics.purdue.edu

14. AFTERSHOCKS
 Smaller earthquakes that occur after the
main earthquake.
 Aftershocks can last for weeks or months
after an earthquake.
 The larger the main earthquake, the longer
aftershocks will continue to occur(usgs.gov).

15. PROTECTING YOURSELF IN AN EARTHQUAKE
 “Drop, cover, and hold on!”
 Drop down to your knees
 Cover your head and neck
 Hold on to a sturdy structure (if available).

16. REFERENCES
 http://www.merriam-webster.com/dictionary/earthquake
 http://earthquake.usgs.gov/learn/kids/eqscience.php
 http://www.plate-tectonics.org/earthquakes/types-of-
faults.html
 http://allshookup.org/quakes/wavetype.htm
 http://earthquakecountry.info/dropcoverholdon/