What Does It Take To Create A Big Quake

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What Does It Take To Create A Big Quake?
v1.2 Created by the IRIS Education Outreach
Program
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Did Anyone Watch This Over the Weekend?
THREE-MINUTE BRAINSTORMING! Everything you
think of w/ reference to the title 10.5!
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Goals

• Students will be able to describe earthquake
  magnitudes
• Students will be able to explain major factors
  that contribute to the amount of energy released
  from an earthquake.
• Students will be able to explain the likelihood
  of a mega-quake like a 10.5

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Magnitude is a number that characterizes the
relative size of earthquakes is proportional to
energy released
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An Earthquake
After
Before
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Measure It!
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Using Models
What is a model? How could it be useful?
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Factors Contributing To Energy Release

• An estimate of the energy of an earthquake is
  called the Seismic Moment (Mo). Typically given
  in units of Newton-meters (Nm)
• What factors contribute to the amount of energy
  released by an earthquake?
• S Surface Area of Fault (m2) (Fault length x
  Fault width)
• D Displacement or slip (m)
• µ Rigidity of rock along the fault (N/m2)

Mo SD µ
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Rigidity - the physical property of being stiff
and resisting bending
Standard Rigidity of the Earths crust
3x1010n/m2
Below 40km the earth acts like Silly Putty
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Moment Magnitude
The moment magnitude scale is a way of
representing the seismic moment of an earthquake
with a simple, logarithmic numerical scale. The
scale is designed to dovetail with the original
Richter magnitude scale that was designed for
smaller earthquakes .
Mw 2/3 log10 Mo - 10.7